ATV RULES AND STANDARDS
W A S T E W A T E R - W A S T E
ATV STANDARD
ATV A 125E
Pipe Driving
September 1996 ISBN 3-934984-14-2 Marketing:Gesellschaft zur Förderung der Abwassertechnik e.V. (GFA) Theodor-Heuß-Allee 17 D-53773 Hennef
The ATV Working Group 1.5.3 (formerly 1.6.4) "Trenchless Construction Methods" within the ATV Specialist Committee 1.5,(formerly 1.6) " Implementation of Drainage Systems", which has prepared this Standard, has the following members:
Dipl.-Ing. Möhring, Berlin (Chairman) Dipl.-Ing. Becker, Berlin
Dipl.-Ing. Deisenroth, Köln Dipl.-Ing. Dirkes, Essen Dipl.-Ing. Donath, Nürnberg Dipl.-Ing. Ensinger, München Dipl.-Ing. Ernst, Dresden Dipl.-Ing. Hähnig, Tübigen
Dr.-Ing. Hein, Saarbrücken (Retired) BDir. Heinzmann, München
Dr.-Ing. Hornung, Stuttgart Dr.-Ing. Howe, Köln
Dipl.-Ing Jochenhöfer, Bonn Dipl.-Ing. Kühl, Hamburg Dr.-Ing. Leonhardt, Düsseldorf Uni.-Prof. Dr.-Ing. Maidl, Bochum Dipl.-Ing. May, Duisburg
Dipl.-Ing. Pinkernell, Moers Dipl.-Ing. Rapp, Regensburg Dipl.-Ing. Sievers, Berlin
Dipl.-Ing. Spiess, München (Retired) Uni.-Prof. Dr.-Ing. Stein, Bochum
Dipl.-Ing. Ueker, Bad Soden-Salmünster Dipl.-Ing. Walter, Saarbrücken
The Standard presented here has been prepared within the framework of the ATV committee work, taking into account the ATV Standard A 400 "Principles for the Preparation of Rules and Standards" in the Rules and Standards Wastewater/Wastes, in the January. 1994 .version. With regard to the application of the Rules and Standards, Para. 1 of Point 5 of A 400 includes the following statement "The Rules and Standards are freely available to everyone. An obligation to apply them can result for reasons of legal regulations, contracts or other legal grounds. Whosoever applies them is responsible for the correct application in specific cases. Through the application of the Rules and Standards no one avoids responsibility for his own actions. However, for the user, prima facie evidence shows that he has taken the necessary care.
All rights, in particular those of translation into other languages, are reserved. No part of this Standard may be reproduced in any form by photocopy, microfilm or any other process or transferred or translated into a language usable in machines, in particular data processing machines, without the written approval of the publisher.
Produced by: JF. CARTHAUS GmbH & Co, Bonn
Translator's note:
The installation techniques described in this Standard are procedures which can be grouped under the general term "Trenchless Technology". This technology is a relatively new aspect of civil engineering and as such there is a lack of standard terminology. The title of this Standard in its original German: "Rohrvortrieb" has no direct translation into English. However, as a collective term for a number of trenchless techniques, the term "Pipe Driving" has been selected as the most appropriate translation, as "Vortrieb" is translated, in mining terms, as "driving" or "heading". In its turn "driving" is described as "Digging a shaft, mine or tunnel in a more or less horizontal direction" and implies an "impelling force in a particular direction". Therefore, following discussion with members of the drafting committee, it was agreed that "Driving" was the most appropriate translation for "Vortrieb". Hence "Rohrvortrieb" becomes "Pipe Driving" and "Vortreiben" is "Driving". These translations are used not only within ATV Standard A 125 but also in all other ATV Standards which cover or refer to the subject of "Rohrvortrieb".
Contents
Preface 6
General 6
1 Area of application 6
2 Methods for unmanned active pipe driving 7
2.1 General 7
2.2 Non-manoeuvrable methods 7
2.2.1 Soil displacement methods 8
2.2.2 Soil removal methods 8
2.3 Manoeuvrable methods 9
2.3.1 Pilot pipe driving 9
2.3.2 Press boring pipe driving 9
2.3.3 Shield pipe driving 10
2.3.4 Horizontal water jetting 10
2.3.5 Horizontal-Directional-Drilling (HDD method) 10
3 Methods for manned active pipe driving 11
4 Construction and mechanical facilities, driven pipes and pipe
connections, shafts 11
4.1 Construction facilities 11
4.2 Mechanical and electrical facilities 12
4.2.1 General 12
4.2.2 Driving shield 12
4.2.3 Other installations 13
4.3 Driven pipes and pipe connections, shafts 13
4.3.1 Pipes 13 4.3.2 Pipe connections 17 4.3.3 Packaging 22 4.3.4 Marking 22 4.3.5 Connections 23 4.3.6 Quality surveillance 23 4.3.7 Shafts (manholes) 23 5 Preparatory planning 23
5.1 Inventory of available structures and facilities 24
5.2 Subsoil and groundwater conditions 24
5.2.1 Details for structural analysis 25
5.2.2 Details for methods and execution of pipe driving 25
5.3 Details on settlement 26
5.4 Cover 26
5.5 Structural calculation, driving forces 26
5.6 Preferred nominal sizes for product and jacket pipes 26
5.7 Start and finish shafts 27
6 Implementation 27
6.2 Requirements on implementation 28
6.2.1 General 28
6.2.2 Driving protocols 28
6.3 Measurement and steering installations 29
6.4 Removal and conveyance 29
6.4.1 Types of removal 29
6.4.2 Removal conditions 30
6.4.3 Conveyance 30
6.4.4 Filling of cavities 30
6.5 Entry and exit openings 30
6.6 Drainage 30
6.6.1 Open drainage 31
6.6.2 Closed drainage 31
6.6.3 Combined drainage 31
6.6.4 Drainage using compressed air 31
6.6.5 Liquid stabilisation 32
6.6.6 Special procedures 32
6.7 Stabilising and lubricating means 32
7 Pipe driving under railway property of the
German Railways (Deutschen Bahn AG) 33
7.1 General 33
7.2 Protective measures 34
7.2.1 Operational protective measures 34
7.2.2 Constructional protective measures 34
7.3 Changes to track position 35
7.4 Employment conditions for driving procedures 35
7.4.1 Unmanned active methods 35
7.4.2 Manned active pipe driving 36
7.4.3 New installation methods 37
8 Pipe driving under Federal trunk routes 37
8.1 General 37
8.2 Operational and constructional protective measures 37
9 Pipe driving under Federal waterways 38
9.1 General 38
9.2 Operational and constructional protective measures 38
10 Normative references 39
10.1 Laws/decrees 39
10.2 Regulations for the prevention of accidents 39
10.3 Safety regulations 40
10.4 ATV/DVGW Rules and Standards 41
10.5 Additional standards 41
10.6 Standard specifications 42
Preface
Since the appearance of ATV Standard A 125 and the DVGW Advisory Leaflet GW 304 in December 1975 measures for pipe driving have gained in significance and today stand equal with open construction methods for the construction of wastewater sewers and drains. To this the further development of driving procedures including manoeuvrable driving machinery for unmanned driving, the production of high-grade driven pipes for all nominal diameters as well as the development of special construction methods have particularly contributed.
The Standard or Advisory Leaflet is to be a guide for specialists involved in planning and implementation. Through the application of this Standard no one is exempted from responsibility for their own actions. The following documents are additionally available on the subject "Pipe Driving":
- ATV Standard A 161 identical with DVGW Advisory Leaflet GW 312 "Structural Calculation of Driven Pipes"
- ATV Standard A 132 and DVGW Guide W 309 Standard Performance Book for Construction, Performance Range 911 "Pipe Driving - Throughpressing".
- General Technical Contract Conditions for Construction Services (ATV), DIN 18319" Pipe Driving Tasks".
- ATV Standard A 142 "Sewers and Drains in Water Catchment Areas"
DVGW Advisory Leaflet GW 304 and ATV Standard A 125 E are identical. Currently DVGW are preparing Technical Rules for trenchless pipe laying procedures which, following publication, supplement the definitions of GW 302 for the supply of gas and water.
General
Underground construction methods are always applied in sewer and pipeline construction if this type of implementation is necessary or offers particular advantages for reasons of traffic, construction, economy or due to their smaller influence on the environment.
Along with pipe driving, shield driving, knife driving and other mining methods also belong to underground constructional methods.
1 Area
of
Application
This Standard deals with the underground installation of prefabricated pipes of any desired cross-section whereby a cavity is created in the soil, by displacement, ramming, boring, pressing or through removal, into which the pipe is pulled, pushed or pressed. With this, the pipes are driven in a straight or curved location line in a straight, inclined or curved gradient. The soil at the working face is either displaced or conveyed away. Crossing and displacement of existing sewers or drains constitute a special form of pipe driving. For these the contents of the Standard can be applied analogously.
The pipes are connected to each other rigidly or flexibly in accordance with the material used and the respective connection method.
The finished pipe stretch serves either as product pipe for wastewater, gas, water, etc. or as jacket pipe1) for the installation of product pipes, cables, etc.
The Standard can be applied analogously for shield and knife driving. It does not apply for mining construction methods.
2
Methods for Unmanned Active Pipe Driving
2.1 General
Jacket or product pipes are driven with the aid of dynamic energy (ramming) or static energy (pressing) through the subsoil from a start shaft or start construction trench into a finish shaft or a finish trench. The soil is either displaced, removed at the driving face and subsequently conveyed through the driven pipe length using worm screws, hydraulically or pneumatically to the start shaft or start trench or, following completion of driving, removed from the pipe as soil core.
Non-manoeuvrable or manoeuvrable driving methods are selected dependent on the objective or positional accuracy of the driving.
2.2 Non-Manoeuvrable Methods
The final accuracy of this type of driving is, inter alia, very heavily influenced by the subsoil (e.g. type of soil), inclusions and stratification and it decreases with the driven length. From this there results employment limitations for pipelines which, for operational reasons, require a precise positioning. It must be ensured that damage to neighbouring installations is excluded through the determination of sufficient separation.
For employment in water bearing layers supplementary measures, e.g. groundwater drainage, are necessary.
Table 1: Summary of presented non-manoeuvrable methods
Experience values for the area of application
Serial Method External
pipe diameter De (mm) Driven length (m) Minimum covering (mm) 2.2.1.
1 Soil displacement hammer 2.2.1.
2 Horizontal rammer/press with closed pipe 2.2.1.
3 Horizontal press system 2.2.2.
1 Horizontal rammer with open pipe 2.2.2.
2 Horizontal press boring equipment
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2.2.1 Soil Displacement Methods 2.2.1.1 Soil Displacement Hammer
Displacement of the soil with the aid of rammer energy with automatic driving of the soil displacement hammer using compressed air or hydraulically. Pipe laying takes place either simultaneously or, with sufficiently stable soils, through subsequent pull or push insertion. A shrinking of the hollow space made by the displacement body (soil displacement hammer) of 5 to 15 % is to be taken into account here. The procedure is employed in dry or moist, mixed grain displaceable loose soil, in general up to ca. 200 mm external diameter. Depending on the soil present the applicable driven lengths go up to 25 m. The necessary minimum covering is 10 x De; below solid road surfaces the minimum covering is to be increased.
2.2.1.2 Horizontal Rammer/Press with Closed Pipe
Displacement of the soil through the driving of a closed steel pipe length (jacket or product pipe) with the aid of rammer or press energy. Employment in general up to 150 mm external pipe diameter in displaceable loose soil. Supplementary measures in water carrying soils are not necessary. Driven lengths as a rule up to 20 m, minimum covering 12 x De.
2.2.1.3 Horizontal Press System
Displacement of the soil by injection of a pilot rod. Having reached the finish trench the rod is connected to a conical puller head, in turn connected with jacket or product pipes, and the complete train is withdrawn. Employment in all displaceable loose soils with pipes up to 100 mm external pipe diameter. Supplementary measures in water bearing soils are not necessary. Driven length in general up to 15 m, minimum covering 10 x De. 2.2.2 Soil Removal Methods
2.2.2.1 Horizontal Rammer with Open Pipe
Driving of a jacket or product pipe length with open front end, with the aid of rammer energy. The soil core which ensues in the pipe is, in general, pushed out, washed out or bored out after completed driving. As a rule the area of application ranges up to external pipe diameters of 1600 mm. In solid rock and in severely swelling plastic soils application is possible only to a limited degree. The driven lengths are, dependent on the existing soils and on the external pipe diameter, as a rule up to 70 m. The minimum covering is 2 x De, however, not less than 1.00 m.
Supplementary measures, e.g. lowering of the groundwater, are necessary in water bearing soils, dependent on the groundwater level and the type of soil.
2.2.2.2 Horizontal Press Boring Equipment
Driving of a jacket or product pipe length made of steel with the aid of a press station with simultaneous mechanical removal of the soil at the cutting face using a boring head and mechanical conveyance of the cuttings using a spiral conveyor. The drive of the boring head with spiral conveyor is located in the start shaft or in the start trench. Depending on the choice of boring head and the spiral conveyor the area of application ranges, as a rule, up to 1600 mm external pipe diameter in loose and firm soil. In water bearing soils supplementary measures are necessary, e.g. lowering of groundwater. Driven lengths dependent on diameter, as a rule up to 80 m. The minimum covering is 2 x De, however, at least 0.80 m.
2.3 Manoeuvrable Methods
Table 2: Summary of listed manoeuvrable methods
Experience values for the area of application
Serial Method External pipe
diameter De
(mm)
Driven length (m) 2.3.1 Pilot pipe driving ≤ 200 ≤ 100 2.3.2 Press pipe driving ≤ 1300 ≤ 100 2.3.3 Shield pipe driving ≤ 1850 ≤ 250 2.3.4 Horizontal water jetting ≤ 400 ≤ 250 2.3.5 Horizontal directional drilling (HDD method) ≤ 1500 ≤ 1500
2.3.1 Pilot Pipe Driving
Driving of a pilot tube by soil displacement or removal. Survey takes place in the system axis using theodolite, laser or transmitter-receiver principle, whereby the transmitter is arranged in the system axis. Directional changes are carried out from the start shaft or start trench by turning the pilot tube. Subsequent driving of jacket or product pipes using widening by soil displacement or removal with simultaneous extrusion or extraction of the pilot tube into the end shaft or into the end trench.
The application takes place for the production of connecting sewers and for the installation of pipelines and cables up to 200 mm diameter. The achievable driven lengths with the production of connector sewers is ca. 30 m, with the installation of pressure pipelines and cables is ca. 100 m. Implementation requires displaceable and mixed grain loose soil. In water bearing soils supplementary measures, e.g. lowering of the groundwater, are necessary.
2.3.2 Press Boring Pipe Driving
Driving of jacket or product pipes with simultaneous soil removal at the working face using a boring head. Survey is by laser beam. Changes of direction are carried out using a hydraulically slewable control head.
Movement of soil takes place continuously using a spiral conveyor. Boring head and spiral conveyor are, as a rule, driven from the start shaft or start trench. The area of application ranges over external pipe diameters up to 1300 mm and over driven lengths up to 100 m in loose soil. With cohesive soils with a firmer constituency the removal and the conveyance of the soil can be simplified by addition of water at the working face. In water bearing soils supplementary measures, e.g. application of compressed air, are necessary.
2.3.3 Shield Pipe Driving
Driving of jacket or product pipes with simultaneous total area soil removal at the mechanically and fluid supported working face using a boring head. Survey is by laser beam. Changes of direction are carried out using a hydraulically slewable control head. Soil conveyance takes place continuously, as a rule, hydraulically. Boring head drive is located in the driving shield. Normally the area of application ranges over external pipe diameters up to 1850 mm and, according to nominal diameter, over driven lengths up to 250 m in loose and firm soils with and without groundwater.
2.3.4 Horizontal Water Jetting2)
Driving of a pilot pipe length using the water-jetting method. The existing soil is loosened by the bentonite suspension exiting at high pressure at the tip of the boring head and it is then removed along the boring pipe length to the start shaft or to the start trench. The bentonite suspension supports the borehole walls and reduces frictional resistance. Survey is by transmitter-receiver principle. Steering takes place via the bore head with oblique steering plate in connection with the jets at the tip of the bore head.
The product pipe made of steel, ductile cast iron or PE-HD is retracted by withdrawal of the pilot pipe length from the finish shaft or finish trench into the start shaft or the start trench with simultaneous widening by means of the scraper or widening head. During the widening or withdrawal process bentonite suspension is applied for the support of the borehole walls and for the reduction of frictional resistance via radially mounted jets. The area of application, depending on the type of soil, to product pipe external diameters up to 400 mm and driven lengths up to 250 m, whereby implementation is also possible in curved location lines, if required without start or finish trenches. Application in displaceable loose rock. Supplementary measures in water bearing soils are not necessary.
2.3.5 Horizontal Directional Drilling (HDD Method)
Driving of a pilot boring with the carrying of a jacket pipe using the water jetting method in a large bore system. The employment of the pilot boring takes place from the terrain surface at an angle of 10° to 15°. The borehole motor located in the bore head is driven with bentonite suspension, whereby the borehole walls are supported by the bentonite suspension. For passage through rock a borehole motor with pilot drilling bit can be mounted ahead.
Survey is by transmitter-receiver principle.
The steering of the pilot boring takes place by turning the angled header pipe mounted in front of the drill pipe.
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2) This section is supplemented for the supply of gas and water by the publication of special DVGW Technical Rules which are
Widening of the pilot boring is achieved by withdrawal (also repeated) of the drill pipe with the widening head placed behind it. Following this the product or jacket pipe is inserted. During the widening and insertion process bentonite suspension for the support of the borehole walls is continuously applied.
The area of application ranges, according to soil type, for product and jacket pipe nominal widths up to 1500 mm and driven lengths of up to 1500 m, whereby the implementation is possible in curved gradients (e.g. inverted siphons) only.
Employment in all soils, with the exception of non-cohesive gravel without cohesive component. Supplementary measures in water bearing soils not necessary.
3.
Methods for Man-Entry Pipe Driving
Pipes are driven from a start shaft or start trench through the subsoil to a finish shaft or trench with the aid of a press system, if required, also with the engagement of underground intermediate press stations.
The driving in straight or curved lines is made possible by a manoeuvrable shield which is placed ahead of the first pipe.
Here, the soil at the working face is removed by hand, by mechanical means or through liquid pressure jets and conveyed through the driven pipe length to the start shaft mechanically, hydraulically or pneumatically.
Pipe driving in both loose soil and rock is possible. Rock can be removed by special machines; blasting is also possible. A rock face examination is to be carried out before and after blasting. It is to be determined whether safety measures for the support of the working face are to be carried out; if required, care is to be taken that crushed rock does not lead to wedging with the rock face and to a stopping of the pipe driving.
As a rule an internal diameter of at least 1200 mm is necessary; under compressed air at least 1600 mm. The internal diameter of driven pipes may, in exceptional cases, be reduced to 1000 mm, if
- a driven length of 80 m is not exceeded, and
- an advanced working pipe with an internal diameter of 1200 mm with at least 2000 mm length is available.
For the removal of water from water bearing soils the following possibilities exist (see also Sect. 6.6):
- drainage of water through the driven pipe (open water drainage), - lowering of the groundwater,
- support of the working face by compressed air and/or liquid.
4
Construction and Mechanical Facilities, Driven Pipes and
Connections, Shafts
4.1 Constructional Facilities
For the design and construction of start, end and rescue shafts or trenches as well as other excavations, DIN 4124 applies. DIN 4123 is to be observed in the area of
neighbouring structures. The relevant Rules and Standards and regulations of the service operations involved and the accident prevention regulations are to be observed. Verification against hydraulic subsidence during production of the trenches before introduction of a groundwater resistant trench footing as well as the lift safety after installation of the groundwater resistant footing is necessary. If prefabricated shafts made from reinforced concrete, steel, fibre cement or other materials are used as start or finish shafts a proof of stability is to be carried out.
Abutments for the reception and transfer of driving forces are to be dimensioned according to the actual conditions. With this, along with permitted stresses in all loaded components, account is also be taken of the permitted deformations which can be accepted without danger by the neighbouring soil and the press installation. Movements of the press abutment may not have any damaging effect on the trench revetting.
4.2 Mechanical and Electrical Facilities
4.2.1 General
The facilities and equipment used on driving construction sites must correspond with the relevant accident prevention regulations as well as the generally accepted rules of technology such as, for instance, the VDE Regulations. Manufacturer's instructions are to be observed.
For the implementation of driving the following are to be employed
- measuring equipment for installation and for the accurate laying of the pipes according to height and lateral position
- pressure meters and, as far as is necessary from a technical process aspect, pressure monitors which are coupled with an overpressure valve. The pressure monitors must switch off when 90% of the permitted pressing force appropriate to the static calculation for pipes or pressing installation are achieved.
4.2.2 Driving Shield
The driving shield is to be designed to match the driven pipe, the driving technique and the surrounding soil. In general it consists of a reinforced concrete construction.
The driving shield must have at least the external diameter of the driven pipe including a pipe outer protection as necessary. Depending on the surrounding soil, the driving procedure and the injection of lubricating and support means, a very slight enlargement can be considered. This overcut can - referred to the half diameter - in particular with movement in curves be up to 20 mm, depending on the type of soil and nominal diameter, in special cases (e.g. rock, expansive clay), up to 30 mm. The selected overcut is to be justified and verified and be determined with the customer.
The shield is, with its components, to be dimensioned for the expected forces. It is to be so matched with the natural slope angle of the ground, if necessary with the construction of compartments or with a hood shaped design, that an uncontrolled penetration of the surrounding soil cannot take place. To minimise subsidences cavity filling is to be planned.
The driving shield may be fitted with facilities for the injection of lubricating and support agents for the reduction of skin friction.
4.2.3 Other Installations
According to the manner of driving, length of the driven stretch, material of the driven pipe and the type of surrounding soil, additional facilities such as pressure distribution rings, guiding installations and intermediate pressing station are to be employed.
4.3 Driven Pipes and Pipe Connections, Shafts
4.3.1 Pipes
At the time of the preparation/publication of this Standard there were no standards available in which the special requirements on driven pipes and pipe connections, for all materials which come into consideration, are regulated. General requirements are contained in Table 3:
Table 3: Material characteristic values for driven pipes
Material characteristic values3)
Material ATV Standard A
161, DVGW GW 312 Tab. 2
Other materials not listed in ° A 161/DVGW GW 312 Reinforced concrete Steel Vitrified clay + + +
Concrete DIN 4032, prEN 1916 + permitted oscillation ranges (2σA)
Steel fibre cement prEN 1916, DBV Advisory Leaflet: Bases for the
Dimensioning of Steel Fibre Concrete in Tunnel Construction
+ permitted oscillation range (2σA),
Fibre cement DIN 19850, prEN 588,
(except for asbestos cement)+ permitted oscillation range
(2σA), longitudinal compression strength
Cast iron
(ductile) DIN 28600 (DIN EN 545), DIN 19690 DIN EN 598) + permitted oscillation ranges (2σA), comp. stiffness (incl.
internal lining) Glass fibre reinforced
(GRP)(UP-GF) DIN 19565 + perm. oscillation plastics ranges(2σA),, longitudinal compression strength,
circular stiffness
Polymer concrete PA-I 3939 + permanent oscillation
range (2σA), longitudinal compression strength
PE-HD DIN 8075, DIN 19537, DIN 16961, DIN 19566, + longitudinal
compression strength. comp. stiffness
PVC-U DIN 8061, DIN 19534, PA-I 3840 + permitted. oscillation.
range (2σA), longitudinal comp. strength, circular stiffness,
circular flexural strength
The requirements on driven pipes and pipe connections with composite sections are determined by future operators taking into account the values of Table 3.
__________________
3) The complete table of all material characteristic values is given in Annex 1. Corrosion Protection
Driven pipes and their connections can be subjected to internal corrosion due to the substance being transported or external corrosion due to the surrounding earth or groundwater. A far as the materials employed are not sufficiently resistant, corrosion protection measures must be taken.
The following applies for pipes made from steel and ductile cast iron:
In general a cement mortar coating in accordance with DIN 2614 serves for internal protection.
External corrosion is dependent on soil and electrical parameters which can be assessed according to DIN 50929 Part 3 and DVGW Standard GW 9. The normal corrosion measures for pipelines are described in DIN 30675 Parts 1 and 2.
With driven pipes one must determine whether one is concerned with a jacket or a product pipe.
With jacket pipes one can dispense with outer protection if the product pipe is self carrying and the annular space is completely filled in accordance with DVGW Standard GW 307 or a rusting off addition is applied to the wall thickness in accordance with DIN 50929.
With product pipes particular requirements have to be placed on the sheathing which take into account loading with driving. The following applies:
a) Driven pipes made from ductile cast irons:
PE sheathing in accordance with DIN 30674, Part 1,
Cement mortar sheathing in accordance with DIN 30674, Part 2. b) Driven pipes made from steel:
PE sheathing in accordance with DIN 30670, PP sheathing in accordance with DIN 30678.
If required additional protection using cement mortar.
With particularly high shear loading with driving, special sheathing with increased resistance to peeling are applied. Feed trials in accordance with, for example, AfK Recommendation No. 1 are normal for the assessment of the sheathing following driving. Comparative measurements using external probes in accordance with DIN 50925 can be used for the verification of the effectiveness of an additional cathodic corrosion protection.
4.3.1.1 Basic Determinations
Details on material characteristic values of the pipe materials as well as methods for verification can be taken from Table 3. Requirements of dimension and function as well as their monitoring and marking are still to be determined. With regard to dimensions the following are to be differentiated:
- dimensions to be provided by the manufacturer, - general binding dimensions and tolerances.
4.3.1.2 Manufacturer's Details
The manufacturer of driven pipes must give details on - internal pipe diameter,
- external pipe diameter (maximum value), - type of connection,
- dimensions in the area of the connection,
- construction length (average value determined at the internal diameter from largest and smallest jacket length between the pipe faces).
In addition, details are to be given on - quality assurance
with regard to the observance of the given details and the general binding requirements in accordance with Sect. 4.3.1.3.
4.3.1.3 General Binding Dimensions and Tolerances 4.3.1.3.1 Construction Length Tolerances
Table 4: Construction length tolerances in mm
DN All materials4) ≤ 800 ± 5 > 800 to ≤ 1200 ± 8 > 1200 + 25 - 10 4.3.1.3.2 Perpendicularity of Faces
The perpendicularity is of particular significance for the transfer of the driving forces and the dimensioning of the pressure transmission rings.
The deviation from the perpendicular is defined as the sum of the deviation of the overall point reflection (image) from the perpendicular (opposite jacket line) and the deviation from the perpendicular within the wall thickness s.
Perpendicularity of the faces is defined at each end of the pipe, in accordance with the Fig. 1, as ∆a = max. a - min a.
Measurement takes place against a firm wall which is perpendicular to the pipe axis. If there is no significant surface perpendicular to the pipe axis available as reference surface ∆a can also be determined by double measurement at 180° of the rotated pipe against any sloped surface5).
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4)
One may deviate from the requirements of Table 4 with welded pipe connections.
5)
Measurement procedures for the determination of deviation from perpendicularity, suitable for the construction site, are described in Annex 2.
Fig 1: Perpendicularity of the faces
Table 5: Permitted deviations from the perpendicular in mm
DN reinforced concrete, Concrete,
steel fibre concrete
Fibre-
cement Vitrifiedclay Steel Cast iron
(ductile ) GRP (UP-GF) Polyme r concret e PE-HD PVC-U ≤ 200 4 0.5 1.0 1.0 1.0 1.0 2.0 1.0 > 200 ≤ 300 4 0.5 1.0 1.6 1.0 1.0 1.0 1.0 > 300 ≤ 1000 6 0.5 1.0 1.6 2.0 1.0 1.0 2.0 > 1000 ≤ 2800 8 0.5 - 1.6 3.0 1.0 1.5 - > 2800 10 - - -
The requirements according to Table 5 apply analogously also for pipes with non-scheduled perpendicular face surfaces (e.g. for curved routes).
4.3.1.3.3 Deviation from the Straight
The deviation of a mantel line from the straight may, independent of the construction length of pipes, be a maximum of:
Table 6: Permitted deviation from the straight in mm
DN All materials
≤ DN 1000 5
DN 1000 to ≤ DN 2000 10
> DN 2000 15
The deviation is measured over the complete length of pipe. For steel driven pipes 1.5 mm per metre construction length may not be exceeded.
4.3.1.3.4 Deviation of the Pipe External Diameter
Table 7: Permitted tolerances of the maximum external pipe diameter in mm
DN All materials6)
other than concrete, reinforced concrete, steel fibre concrete and
vitrified clay
Concrete, reinforced concrete, steel fibre
concrete Vitrified clay ≤ 300 + 0 - 10 400 + 0 - 10 + - 12 0 500 + 0 - 15 600 + 0 - 15 + 0 800 + 0 - 12 - 8 - 24 + 0 1000 + 0 - 30 > 1000 ≤ 2800 - 16 + 0 - 14 + 0 - > 2800 + 0 - 24 - 20 + 0 - 4.3.1.3.5 Invert Conformity
The permitted deviation from the invert conformity (stepping) is given in Table 8 as percentage of the nominal diameter. Moreover it is limited to 30 mm.
Table 8: Permitted deviation from invert conformity
DN All materials
All 1 %
4.3.2 Pipe Connections 4.3.2.1 Components
4.3.2.1.1 Plug-in Connections
Plug-in connections for driven pipes consist of constructional elements to ensure - sealing against water and other media,
- shear force stability, - transfer of axial forces,
- corrosion proof joint sealing (with non-corrosion resistant pipe materials with internal liner).
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6)
4.3.2.1.2 Welded Connections for Steel Pipes
For welded connections the following apply additionally to 4.3.2.1.1 (e.g. according to DIN 1626 or DIN prEN 10217-1).
- seam preparation for butt welding, bevel angle for joint sides 300 ± 5o - step height 1.6 mm ± 0.8 mm,
- the welder employed must have a valid welding certificate according to DIN EN 287-1.
Weld seams carried out on driven pipes are to be tested as non-destructive; for jacket pipes a sampling test applies. DIN EN 25817 applies for weld seam quality.
4.3.2.2 Manufacturer's Details
The manufacturer is to provide comprehensive details, including detailed drawings, on the
- dimensions and tolerances - materials
of connections including the pressure transfer ring as well as on - quality assurance
with regard to the observation of their own details and the general binding requirements according to 4.3.2.3.
4.3.2.3 General Requirements 4.3.2.3.1 Sealing
The connections for wastewater pipes and, if required, jacket pipes of gas and water pipelines must be sealed against:
Under operational conditions
- an internal water overpressure of 0.5 bar (for water catchment areas 2.4 bar with factory acceptance testing),
- an external water overpressure of 0.5 bar (to be agreed as necessary for greater depths in groundwater).
Under Construction conditions
- an internal air overpressure in accordance with the requirements.
With higher external pressures due to lubricants the position of the sealing agent may not, through this, change. The extent of the requirement is to be agreed in individual cases.
The requirements on sealing of product pipes for gas and water are laid down in DVGW GW 462/I, G 462/II, G 463, G 472 and DIN 4279.
4.3.2.3.2 Deflection Capability
Connections must, with loading in accordance with Sect. 4.3.2.3.1, must remain sealed with the maximum permitted deflection. This results - in deviation from DIN 4060 - from the change of the average joint gap width about the half thickness of the pressure transfer ring according to Sect. 4.3.2.3.4, however, at least by the values of Table 97).
Table 9: Deflection capability in mm per m construction length
DN Max. deviation a ≤ 200 > 200 to ≤ 500 > 500 t0 ≤ 1000 > 1000 25 15 10 5 Fig 2: Deflection Fig 2: Bends
4.3.2.3.3 Shear Force Stability
The connections must remain tight under loadings according to Sect. 4.3.2.3.1 with the application of shear load/movement according to DIN 4060; 1988, Sect. 4.2.1.2.
4.3.2.3.4 Transfer of Axial Forces
When a pressure transfer ring is used for the transfer of axial forces the following applies for its thickness
guidance value Dj of 0.1s.
Special consideration is to be given to bent route lines or gaping joints.
______________________
6)
Pressure transfer rings made from materials with the smallest possible lateral extension are used for the transfer of axial forces, for which knotless wood and chipboard have proved themselves.
Other materials for pressure transfer rings must correspond with the specifications of the pipe manufacturer and must be matched with the configuration of the pressure transfer ring and the pipe material
The width of the pressure transfer ring may not exceed the minimum wall thickness at the front face. Slight offsets are recommended.
4.3.2.3.5 Design of Pipe Connections, Joint Seals
Pipe connections (plug-in connections) have an external seal (for examples see Figs 3 and 4).
Independent of a later implementation of an internal sealing the pipe connections must be so designed and manufactured that, with correct driving, all functions can be taken on by the external seal.
To this belongs at least
- sufficient anchoring of the guide rings in/on the driven pipe, - measures to avoid lateral infiltration.
Fig 3: Sketch of the principle of a pipe connection with single-sided fixed guide
ring with pipes made from concrete, steel-fibre concrete and reinforced concrete
The joints of the external seal are tested for watertightness on completion of driving - with manned driving individually. If with this there are leaking pipe connections a functioning internal joint sealing in accordance with Table 10 is to be installed in agreement with the customer. A testing of the subsequently installed joint sealing is to be carried out in each case.
With manned pipe driving an internal seal closure can be carried out if this is necessary for operational reasons, such as, for example, with sewers.
With reinforced concrete driven pipes a front support shoulder of the seal chamber can be produced at the tip from concrete or other materials (collar rings).
Fig 4: Sketch of principle of a pipe connection with loose guide ring
Only such sealing agents may be used with which a mutual influence between pipe material and sealing agent is excluded. Suitability is to be verified.
Table 10: Internal sealing for driven pipes
Sealant
1. Adhesive 2. Compressive
two component sealing agent elastomers
Final joint width b mm min 10 mm joint depth t mm Single layer t ≥ 12 + b/3 Double layer t ≥ 2(12 + b/3)8) t ≥ 2b
Properties of the face surface
Dry (moisture content < 5 %),
grease and dust free Grease free, moisture independent
Correct outcrops and holes Remarks
If backfill material used enlarge depth
of joint correspondingly Immediate sealing effect, compression of ring 20 %
to 60%, working independent of temperature
Notes BPG9) DIN EN 681-1
Processing according to details of the sealing agent manufacturer
________________
8)
Only with particularly high loadings
9)
BPG = Bau- und Prüfgrundsätze des Instituts für Bautechnik, Berlin (Construction and Test Principles of the Institute for Construction Engineering, Berlin)
4.3.2.3.6 Material for Connections (Guide rings)
The coupling of driven pipes must consist of one of the following materials or combination of materials:
- pipe material (standardised or registered for that medium - gas, water, wastewater - to be transported),
- stainless steel in accordance with DIN 17440, DIN EN 10088-1, - coated steel (e.g. rubber elastomer),
- construction steel in accordance with DIN EN 10025, e.g. S 235 JR (only for manned driving with rusting off addition in accordance with DIN 50929-3, based on assessment according to DVGW GW 9).
Couplings made of steel with galvanised surface protection or with polymer coatings < 1000 µm are not permitted.
4.3.2.3.7 Materials for Sealing Agents
External sealing - insofar as they are made of elastomers -must meet the requirements in accordance with DIN EN 681-1.
Internal sealing for sewers produced by manned driving must meet the requirements of the relevant Construction and Test Principles of the German Institute for Construction Engineering (DIBt).
4.3.2.3.8 Delivery Condition
The pipe connections - if required including the pressure transfer rings - are to be delivered by the pipe manufacturer and, as far as possible, are to be pre-assembled. 4.3.3 Packaging
Driven pipes for non-manned driving are - if necessary with pre-assembled connections - to be delivered packaged. The packaging must be matched to the demands of road transport and storage at the construction site and allow single piece removal.
For delivery and storage of pipes made of reinforced concrete DIN 19695 applies, for steel pipes the DIN Standard Specifications contained in the Technical Regulations of the DVGW.
4.3.4 Marking
Driven pipes and connections are, as a minimum, to be marked with - manufacturer's identification,
- date of manufacture, - nominal diameter,
- test symbol, approval mark or DIN symbol (insofar as relevant), - certification/monitoring markings,
4.3.5 Connections
As no branch fixtures can be fitted with driven pipes, connections to road drains and domestic connections are to be made through boring and subsequent attachment. For this, laid down components known from laying in open construction and in the appropriate pipe standard specification are to be used.
The manufacturer of driven pipes has to provide the necessary information for this. 4.3.6 Quality Surveillance
Observation of the requirements laid down in Sects, 4.3.1, 4.3.2, 4.3.4 and 4.3.5 is to be checked by surveillance monitoring consisting of self-monitoring and monitoring by an outside agency. Basis for this procedure is DIN 18200.
Scope and frequency of tests - insofar as they are not regulated through standard specifications or admissions - are to be laid down by the outside monitoring agency. 4.3.7 Shafts (Manholes)
Shafts for wastewater sewers and drains from driven pipes must correspond with DIN 19549 and the thereupon based material related standards for shafts. For the interface between driven sewers and drains and shaft structure the following, in addition applies: - in the area of a double joint a non-driving component may be employed which, in
accordance with ATV Standard A 127, is dimensioned for loading in open trenches and which is connected to the neighbouring driven pipe using a pre-fabricated connection.
- with driven pipe lengths < 1.00 m the connector can be dispensed with, whereby in or on the shaft wall a jointed connection is always planned.
5 Preparatory
Planning
The subsoil conditions, existing structures, supply and disposal facilities as well as the and groundwater conditions influence the choice of driving procedure, the necessary installations and the implementation of the pipe driving.
Therefore, in the planning stage and before the start of construction, it is necessary to obtain sufficient information and to make available the appropriate documents. The planning of third parties is also, if necessary, to be taken into account.
Before carrying out the pipe driving the maximum permitted deviations from the planned height and lateral position of the driven stretch are to be determined. With this, it is necessary to take into account that the pipeline, with the application of tolerances,
- meets its given tasks and
- does not endanger other structures and installations.
is maintained and other structures are not prejudiced.
For sewers and drains only controllable pipe driving methods should be employed. The values of the maximum deviations from the nominal listed in Table 11 should not be exceeded. For operability a gradient reserve should be planned.
Table 11: Max. deviation in mm from the nominal for drains and sewers
DN Vertical Horizontal < 600 ≥ 600 to ≤ 1000 > 1000 to < 1400 ≥ 1400 ± 20 ± 25 ± 30 ± 50 ± 25 ± 40 ± 100 ± 200
5.1 Inventory of Available Structures and Facilities
Details are to be obtained on the position and condition of - cables, - pipelines, - sewers, - manhole shafts, - foundations, - artificial cavities,
- anchors and injected bodies,
- other remaining structural facilities in the area of the site,
as well as other structures, insofar as these influence or interfere with driving or, through these, the usage and condition can be endangered. In cases of doubt the precise situation is to be determined through exploration or search channels or other suitable measures.
Necessary dislocations are to be initiated in good time. If necessary existing facilities are to be secured through suitable measures.
It is recommended that the condition of the existing structures and facilities is determined through perpetuation of evidence.
All planning documents must be available on the construction site.
5.2 Subsoil and Groundwater Conditions
Details on the subsoil and its characteristics as well as on the groundwater conditions are necessary for
- structural calculation of pipes and trenches
- selection of the driving procedure and the implementation, of the pipe driving.
The available generally recognised rules of technology for the implementation of the investigations and their evaluation are summarised in
- DIN TAB 113 - Reconnaissance and Investigation of the Subsoil and in
- DIN TAB 36 - Earthworks and Foundations.
The construction site conditions are to be so investigated that a classification in accordance with the General Technical Contract Conditions for Construction Services (ATV), DIN 18319 "Pipe Driving Projects" is possible (see also 5.2.2).
5.2.1 Details for Structural Analysis
The following are required for the structural calculation of driven pipes in accordance with ATV Standard A 161/DVGW GW 312:
- type of soil with details on the group or specific gravity above and below water and the angle of internal friction,
- level of groundwater, maximum/minimum, in construction and operating states,
- arrangement of details in calculation principles in accordance with ATV Standard A 161/DVGW GW 312 "Static Calculation of Driven Pipes",
- loading and installation conditions in accordance with ATV Standard A 161/DVGW GW 312, Sect. 3.3.
5.2.2 Details for Procedures and Implementation of Pipe Driving
According to the requirements of the individual case the following are to be given for Loose soil
- borehole log,
- grain shape and distribution,
- compaction density or consistency, - max. and min. groundwater level, - shear stability,
- modulus of elasticity and earth pressure coefficient, - permeability coefficient,
- degree of contamination of the soil, ground-air and groundwater, - conditions for waste disposal,
- aggressive effect of soils and groundwater, - organic soils.
Rock
- borehole log and description of the condition, - fault line and spatial orientation,
- hardness and removal ability, - single axis compression strengths,
- amount of water, groundwater level maximum and minimum, - degree of contamination of soil, ground-air and groundwater, - conditions for waste disposal,
In difficult cases additional details on, for instance, unfavourable strata, slopes, swell pressure, are necessary and are to be made available in the form of loading details through supplementary investigations.
Attention is drawn to the General Technical Contract Conditions for Construction Services (ATV), DIN 18319 "Pipe Driving Projects".
5.3 Details on Settlement
Taking into consideration the subsoil and groundwater conditions, the height of cover, the usage of the terrain of the driven length and the structures above and/or in the area of influence of the driven length details are to be made on permitted settlement.
If required, safety measures are to be determined.
5.4 Cover
Attention is drawn to Table 1 for non-directed driving.
With steered driving increased settlement is to be expected with H < 1.0m or < De and advanced lifting cannot be excluded.
In order to avoid possible damage greater cover should, if necessary be selected.
5.5 Structural Calculation, Driving Forces
Before the start of the implementation of construction the load bearing capacity of the pipeline taking into account the driving forces must be verified or provided initially. The structural calculation of pipes to be installed in loose soil using the pipe driving procedure takes place in accordance with ATV Standard A 161/DVGW W 312.
For pipes which are driven in rock engineering considerations are to be made in individual cases taking into account the characteristics of the mountain
An estimation of the expected driving forces as a function of the site accuracy should be carried out within the scope of planning.
For the installation of pipes dimensioned for driving in start and end shafts or trenches in open construction different structural conditions are to be taken into account for this by matching of the support.
Pipes for connection lengths, which are laid in open construction, are to be dimensioned in accordance with ATV Standard A 127.
5.6 Preferred Nominal Sizes for Product Pipes and Jacket Pipes
The preferred nominal diameters of pipes for wastewater sewers and drains, for drinking water supply and gas supply are given in Table 12:
Table 10: Preferred nominal diameters for driven pipes
DN Wastewater Drinking water Gas
32 40 50 80 x x x x x x x x 100 150 200 250 300 400 500 600 800 x x x x x x x x x x x x x x x x x x x x x x x x x x 1000 1200 1400 1600 1800 x x x x x x x x x x x x x x x 2000 2200 2400 2600 2800 x x x x x x 3000 3200 3400 3600 3800 4000 x x x x x x
5.7 Start and Finish Shafts
In the wastewater network start and finish shafts are, if possible, to be so arranged that these, with the employment of prefabricated shafts or shaft components, can be utilised immediately or after completed assembly, as access manhole shafts. These shafts should be used for the junction with domestic connections. The junctions and transitions within the shaft are to be designed conveniently from a flow technology aspect.
6 Implementation
6.1 Competent Firms
Only competent firms, which have experienced personnel and suitable facilities, may be entrusted with the implementation of pipe driving.
With the driving of product pipes for gas and water the firm must be additionally in possession of the DVGW Certificate for Pipeline Constructors in the appropriate Group in accordance with DVGW GW 301.
Verification for tasks on sewers and drains is considered as effective if the firm is in possession of the appropriate certificate of the Quality Community "Quality Protection Sewer Construction".
6.2 Requirements on Implementation
6.2.1 General
All facilities and operating methods must correspond with the Accident Prevention Regulations (UVV) and the generally recognised safety and industrial medical rules. Driving is to be permanently monitored with regard to the driving forces, the type of soil involved, in particular with regard to contamination, as well as the driving installation. If obstacles which cannot be reduced and removed, escapes of gas, inadmissible deviations from the planned pipe axis, inadmissible driving forces, chipping at the front face of the pipe or cracks in the pipes occur, driving is to be suspended until the determination of the necessary measures. The owner is to be informed. Suitable measures are to be determined mutually.
Driving is to be so carried out that a functionable and watertight pipeline results. The driven pipes, pipe connections and seals are to be examined for the requirements placed on them and for freedom from damage before being lowered in the start shaft. Vitrified clay driven pipes are, in addition, to be subjected to a test pressure of 15 bar with a muff test equipment at both ends.
Should the driven pipeline be employed as product pipeline then it must correspond with the required test pressure and the further demanded requirements. The stability and watertightness tests are to be carried out according to the relevant regulations, standards and advisory leaflets.
6.2.2 Driving Protocols
With non-manoeuvrable, unmanned systems, e.g. press boring method, the position of the pipe length is to be measured and recorded at intervals which are to be laid down. With manoeuvrable pipe driving with unmanned systems the following driving parameters - as far as procedurally possible - are to be continuously, measured and recorded:
- driving forces,
- deviations according to height and to lateral position, - rolling,
- driven lengths.
With press boring and shield driving the parameters are to be recorded in driving intervals of max. 200 mm lengths or max. 90 secs. duration are to be measured automatically and recorded mechanically. With this, it is to ensured that, with the pressing of the driving presses and the removal tool, each respective maximum pressure appearing during an interval is recorded. With the remaining parameters the mean value from the last interval is to be recorded.
Alternatively, continuously working graphic measurement recorders are also permitted. With pipe driving with manned systems the measured pressing forces of the main and the intermediate press stations are to be continuously recorded and compared with the calculated values. Deviations are to be justified. A protocol is to be made on the position of the pipe length. With this the vertical and lateral position of the cutting shoe and the
first pipe is to be monitored as a minimum every two metres and after every installed pipe; the result is to be shown in a diagram. Additional monitoring of the survey system is to be carried out regularly at suitable intervals.
The pressure is to be measured with the use of lubricants.
The customer is to be informed immediately when contamination is suspected.
The protocols must contain the date as well as show details on the position of the construction site, soil and groundwater conditions.
6.3 Measurement and Steering Installations
The employment of non-manoeuvrable or manoeuvrable pipe driving depends on the requirements with regards to laying accuracy.
With non-manoeuvrable pipe driving the direction of driving is predetermined before the start of work in the start shaft or start trench by the careful erection of the mechanical driving facilities. In particular with longer driven stretches and/or unfavourable or changing soil conditions larger deviations can occur.
With manoeuvrable pipe driving the following parameters must be measured in the area of the driving machinery and/or driving shield:
- vertical deviation, - horizontal deviation, - roll,
- slope, - driven path.
For this, optical equipment, laser equipment and bubble levels can be used to measure vertical deviations; optical equipment, laser equipment, gyroscopes to measure horizontal deviations and inclinometers to measure slope and roll. In addition the paths of the control cylinders are to be measured. Steering pressures must be indicated.
It is to be ensured that measurement and control facilities are so installed that they are separated from the start trench walls and shoring planks which can have their location changed through force or load inputs.
6.4 Removal and Conveyance
6.4.1 Types of Removal
Depending on the soil type and the pipe diameter the following types of removal of the existing soil at the working face are possible:
removal by - hand,
- mechanical aids, - boring head,
- full section machinery - hydrostatic pressure jets - blasting10)
6.4.2 Removal Conditions
It is to be ensured and checked that no more soil is removed from the working face than the driving cross-section produces. With unstable soils it is to be prevented, with suitable measures, that soil collapses, e.g. through installation of compartments, hood shield, support at the working face (earth pressure, hydraulically, compressed air). The removal of driving obstacles in front of the cutter from an accessible shield may only be carried out under the protection of special auxiliary and safety measures.
6.4.3 Conveyance
For the horizontal conveyance of the loosened soil the following types of conveyance, in general, come into consideration:
- bucket conveyance, with or without tracks, by winching or electrically driven tractors, - conveyor belt,
- screw conveyor,
- hydraulic conveyance (flush conveyance), - pneumatic conveyance,
- special procedures. 6.4.4 Filling of Cavities
Cavities between driven pipes and surrounding soil as well as cavities in the surrounding soil which have resulted from driving must be filled with suitable material.
With the employment of soil displacement procedures and horizontal rammers with open pipe (see Sect. 2.2.2.1) a back-filling can be dispensed with if, due to the soil relaxation, damage can be excluded.
6.5 Exit and Entry Opening
With the start of the driven stretch and on breaking into the end shaft or end trench, special measures are necessary for the support of the working face to avoid soil and possibly groundwater engulfment. For this the following, for example, come into consideration:
- auxiliary constructions with additional horizontal or vertical revetting, - temporary groundwater sinking with tongued-wall sealing,
- injection of surrounding soil, - inlet and outlet locks.
6.6 Drainage
Certain driving methods are suitable in groundwater so that, with this, drainage tasks, if required, are limited to a single pumping out of the groundwater for the production of an underwater concrete base for the start and end shafts or trenches.
________________
10) Technical blasting certificate required.
- open drainage, - closed drainage, - combined drainage, - compressed air, - hydrostatic support,
- special procedures (e.g. freezing techniques). 6.6.1 Open Drainage
Insofar as soil type and water intrusion allow and the manoeuvrability is not prejudiced, the water can be diverted through the driven pipe to the pressing shaft and pumped out from there. A flushing out of the working face is to be prevented by suitable measures. 6.6.2 Closed Drainage
Lowering of the groundwater is to be so dimensioned and carried out that the groundwater level during the whole driving time is lowered sufficiently below the base of the start and end shafts or trenches insofar as the shafts or trenches and exit openings are not made watertight through constructional measures. At the end shaft or trench the groundwater level is to be lowered sufficiently below the pipe base before driving breaks into the end shaft or trench. During driving the groundwater level in the area of the working face is to be lowered sufficiently.
The groundwater levels are to be checked before and after driving, e.g. through sounding pipes.
A closed drainage away from the working face should be carried out only in exceptional cases for the removal of stratum water and then only temporarily. With this, suitable measures are to be taken to prevent an outflow of soil.
6.6.3 Combined Drainage
A combination of closed and open drainage is possible. 6.6.4 Drainage Using Compressed Air
Employment comes into question for both unmanned as well as manned pipe driving. Should personnel be employed under overpressure then the "Regulation for Work under Compressed Air - Compressed Air Ordnance" is to be observed.
Pipes for manned driving under compressed air must have an internal diameter of at least 1.60 m in the atmospheric range. Minimum dimensions in accordance with the Compressed Air Ordnance for locks 1.60 m, 1.80 m for working spaces.
Personnel locks are to be so equipped and so operated that external assistance can be brought in at any time with danger in the working chamber and all persons who are in the working chamber can withdraw into the lock at all times. Therefore, as a rule, at least two series locks are to be planned.
With all compressed air driving with which working chambers are arranged in the area of the shield, i.e. the rearward pipe length is in free air, an emergency lock (cup lock) is
to be held permanently at the shaft or trench in order that a pressure balance can be achieved in the shortest time in the atmospherically extended pipeline.
The leading pipe and the shield and or the driving machine are to be connected together up to the lock, resistant against extension. During pipe changing in the start shaft or in the start trench recoil is to be prevented by a suitable stop device until the safe take-over of the rearwards force from the compressed air in the working space by the skin friction. 6.6.5 Liquid Stabilisation
Liquid stabilisation of the working face in general assumes a completely mechanised removal of the soil. The pressure and the viscosity of the support liquid is to matched to the height of the groundwater level, the characteristics of the existing soil, the earth covering and other constructional conditions.
6.6.6 Special Procedures
Special procedures are permitted insofar as their suitability can be proved.
6.7 Stabilising and Lubricating Means
With the injection of a suspension with thixotropic properties, e.g. bentonite suspension, the friction resistance between pipe and soil occurring with driving can be significantly reduced in cohesionless loose soil and in soils with only a slight cohesion, e.g. gravel and sand soils. Care should be taken to achieve as even as possible a coating over the whole pipe jacket surface. Injection pressures, viscosities and quantities used are to be continuously monitored and so chosen that damage to the pipeline and neighbouring structures is avoided.
With inaccessible sections the suspension can be injected at the boring head or into the annular gap in the area of the driving machine follower; with accessible sections, via injection nozzles in the driven pipes, which subsequently are to be permanently sealed against pressure.
The environmental friendliness of stabilising and lubricating means must be verified in both solid and fluid condition.
A side effect of the use of lubricating means can be the reduction of the top surface settling through filling of the annular gap.
7
Pipe Driving under Railway Property of the German Railways
Company AG (DB AG)
The following regulations give the status on the Rules and Standards of the German Railways Company (DB AG)11).
7.1 General
The crossing of pipelines within the railway property of the DB AG are, as far as possible, to be carried out using installation procedures which exclude or keep to a minimum changes to the track layout and which disturb rail traffic only to a minor extent.
Safety of rail traffic must be ensured at all times. The minimum cover height (Upper edge railway sleeper - upper edge pipe) in accordance with DS 804 50 and DS 836 may not be undercut (hc ≥ 1.50 m and ≥ = di). All metallic pipes are to be coated with an effective corrosion protection. The driving procedure may not damage the corrosion protection. For intersection with gas and water pipelines within the property of the Federal German Railway the "Gas and Water Crossing Standards" DS 180 of the German Railways apply. With intersection of cable protection pipes, wastewater sewers and drains the Technical Rules of DS 180 are to be applied analogously.
The applicant will be notified of the necessary documents for a crossing construction measure by the Regional Area of the DB AG.
The permitted driven pipes will be designated by the DB AG
Additional requirements will be laid down by the DB AG for crossings of railways with a track speed > 160 kph.
Under certain conditions driving tasks must be carried out, without interruption, in day and night shifts and on Sundays and holidays. With interruptions of the driving, measures are to be taken which prevent an endangering of the railway operation - e.g. through collapse of the working face. In addition care is to be taken to provide, to a sufficient degree, observation of the driven stretch and the location of the track. According to the significance of the stretch of railway technical metered observation of the track is to be applied.
This can be necessary, for instance, - with non-cohesive soils (fluid sands) or
- to avoid longer disruption of the rail traffic.
_____________________
11)
Respective regulations are to be observed for pipe driving under installations outside the responsibility of the DB AG.
7.2 Protective Measures
monitoring by the DB AG is possible at all times.
Before the start of construction the Regional Area of the DB AG, in agreement with those responsible and taking into account the local conditions, determines whether or which special measures for the protection of the rail traffic are to be taken.
7.2.1 Operational Protective Measures
As operational protective measures for rail traffic the following come mainly into consideration:
- continuous surveillance and technical measurement monitoring (perpetuation of evidence procedure) of the track bed for height and direction during driving and control of the track bed during the subsequent period up to the consolidation of the soil,
a) without imposition of slow travel, b) with imposition of slow travel.
the necessary measurement protocols are to be presented to the Regional Area for evaluation.
- installation of small auxiliary bridges or strengthened small bridges with limitation of the permitted maximum speed of trains (max v usually between 60 and 90 kph). As a rule no speed limitation is necessary for track safety without a trench under the track. - speed limitations will be laid down specially by the DB AG, but are especially to be
expected on stretches of the main network.
- installation of auxiliary bridges (with slow driving zones). 7.2.2 Constructional Protective Measures
As constructional protective measures for the reduction of disruptions of the track bed, the following come into consideration:
- selection of an installation procedure with which only small disturbances are to be expected,
- the avoidance of settling,
- stabilisation of the soil through injection,
- the prevention of soil collapse at the working face,
- large cover heights which allow a formation of an arch over the pipes,
- avoidance of overcut or implementation of as small as possible an overcut beyond the pipe diameter (including outer cover),
- injection of a bentonite suspension during driving and pressing of the overcut with cement-bentonite mixture on completion of the driving,
- avoidance of curved travel under the track, - continuous driving,
- immediate piping is necessary with pipe driving under rail tracks.
7.3 Track Bed Changes
Limiting values of the track bed change, which can serve as indication for the intervention threshold, are to be worked out.
