Density of the soil in place by the Core Cutter Method
Density of the soil in place by the Core Cutter Method
Introduction: Introduction:
This test method sets out the procedure for the determination for the in-situ dry density of This test method sets out the procedure for the determination for the in-situ dry density of compacted soils in earth works and pavement layers.
compacted soils in earth works and pavement layers.
The core cutter method consists of driving a core cutter of known volume (1000 cm
The core cutter method consists of driving a core cutter of known volume (1000 cm33) into the soil) into the soil after placing it on a cleaned soil surface. The core cutter is usually provided with 2 mm high after placing it on a cleaned soil surface. The core cutter is usually provided with 2 mm high dolly. The driving of the core cutter is usually done !y hitting the dolly mounted on top of the dolly. The driving of the core cutter is usually done !y hitting the dolly mounted on top of the cure cutter with a suita!le hammer. Then the cutter filled with soil is removed and the e"cess soil cure cutter with a suita!le hammer. Then the cutter filled with soil is removed and the e"cess soil trimmed off. The cutter with the is weighed. The volume of the cutter is calculated from the trimmed off. The cutter with the is weighed. The volume of the cutter is calculated from the dimensions of the cutter and the in-situ unit weight is determined !y dividing the weight of the dimensions of the cutter and the in-situ unit weight is determined !y dividing the weight of the soil in the cutter !y the volume of the cutter. #f the water content of the soil in the cutter is soil in the cutter !y the volume of the cutter. #f the water content of the soil in the cutter is determined in the la!oratory$ the dry unit weight of the soil can also !e computed.
determined in the la!oratory$ the dry unit weight of the soil can also !e computed.
%or construction control$ this test method is often used as the !ase for acceptance of material %or construction control$ this test method is often used as the !ase for acceptance of material compa
compacted to cted to a specified density or to a specified density or to a percentage of a a percentage of a ma"imma"imum unit weight determined !y aum unit weight determined !y a standard la!oratory test method.
standard la!oratory test method. Objectives:
Objectives:
•
• &!'ective of this test is to determine the field density !y core cutter method.&!'ective of this test is to determine the field density !y core cutter method.
Apparatus: Apparatus:
The following apparatus are reuired (%igure 1). The following apparatus are reuired (%igure 1).
1)
1) The standThe standard densard density apparity apparatus consatus consisting oisting of steel cylif steel cylinder and dender and detacha!ltacha!le collare collar..
%igure 1 - pparatus for *ore *utter
%igure 1 - pparatus for *ore *utter +ethod.+ethod. 2)
2) !alanc!alance of 10 kge of 10 kg$ capaci$ capacity readaty reada!le and ac!le and accurate to acurate to at least 0.0t least 0.01 g.1 g. 3)
3) +iscell+iscellaneouaneous euipmes euipment such as rammer$ stnt such as rammer$ straight edgraight edge$ chisels for dige$ chisels for digging surroging surroundinundingg soil.
,) mall containers for moisture content determination.
) rying &ven / thermostatically controlled oven capa!le of continuously maintaining a temperature of 10 / 110 *0$ throughout the drying cham!er.
Procedure:
1) The core cutter was weighted (1) and calculated the internal volume from its
dimensions ().
2) The surface of the location to !e tested was prepared.
3) The core cutter with the collar on top was placed on the prepared surface and it was driven into the soil with a help of a hammer.
,) The surrounding soil was dug to take out the core cutter.
) The !oth ends of core cutter were leveled off with a straight edge and then it was weighted (2).
) The soil sample was removed from the core cutter and the material was mi"ed thoroughly secured and weighed with a representative$ sample for moisture determination.
) ample was kept in the oven for water content determination and after 2, hours it was weighed.
Observation:
• &!servations are given in nne" 1.
Calculations and result:
1. olume of the density apparatus in millimeters. 2. #n-situ density of the soil (at least for two trails)
4ulk ensity of the soil 5 !ulk 6 (2 / 1) in kg7m3
3. The ater *ontent of the oil and then the ry ensity of the oil ater *ontent w 6 +
+
ry ensity 5dry 6 5 !ulk
(1 + w)
Specimen Calculation:
• olume of the density apparatus 6
• #n-situ density of the soil
+ass of wet soil 6 6 4ulk ensity of the soil 6 6
• The +oisture *ontent of the oil
*an 8o9, +oisture content 6 6 *an 8o91: +oisture content 6 6
• verage moisture content 6
6
• The ry ensity of the oil • The +a" ry ensity
ry ensity 6
6
• The +a" ry ensity 6
• ;elative *ompaction 6
6
a) Trail 8o9 02
• #n-situ density of the soil
+ass of wet soil 6 6 4ulk ensity of the soil 6 6
• The +oisture *ontent of the oil *an 8o9 +oisture content 6 6 *an 8o92, +oisture content 6 6
• verage moisture content 6
6
• The ry ensity of the oil
ry ensity 6
6
• The +a" ry ensity 6
• ;elative *ompaction 6
6
Discussion:
&ne of the common methods of determining field density of fine-grained soils is core cutter method. 4ut this method has a ma'or limitation in the case of soils containing grained particles such as gravel$ stones and aggregates$ as the presence of coarse-grained particles will adversely affect the test results.
' (hy is it important to measure the field density) *ive e+amples#
amount of the compaction achieved during the construction. <nowing the field density and field moisture content$ the dry density is calculated. Therefore field density test is importance as a field control test for the compaction of soil or any other pavement layer.
