Settlement data has been collected using settlement points, horizontal inclinometers, and magnet extensometers along the I-15 rreconstruction alignment since construction began in 1998. This data is presented and interpreted detailed in several publications and
reports available from UDOT. This report relies on the settlement profile measured at 200 South Street in Salt Lake City.
Flint and Bartlett (2005) have used the settlement data to back calculate HNLE model parameters for the Bonneville clays at 200 South and I-15 and the Lime-Cement treated site at I-80 and I-15. In this report, tThey back calculated the drained HNLE parameters using soil layering properties and geophysical measurements only. No triaxial laboratory testing was available for their evaluation. The FEA program Sigma/W was used to model the surface settlement resulting from the determine the various soil properties from tfoundation layers and calibrated to that settlementhe settlement data. The sequencingstaging of the embankment construction was included in the analysis Figure . Figure 18 shows the embankment geometry and stagingsequencing used in the evaluationsanalysis by Flint and Bartlett (2005).
Figure 18 - 200 South Embankment - From Flint and Bartlett (2005)
The measured settlement dataprofile at the end of primary consolidation was plotted for the 200 South Street Array and compared to thesettlement estimates made with linear elastic (LE) Limit Equilibrium mmethods and consolidation properties developed for the during design of the I-15 Rreconstruction Project. These soil data and constructiondesign estimates appear in the following tables and figures, as well as the results of their calibrationback-calculation of HNLE parameters by Flint and Bartlett (2005). Figure 19
also shows Notice that only the Sigma/W analysis of Flint and Bartlett (2005), which included the calibrated calibrated HNLE model parameters. This Sigma/W analysis with the HNLE model provided the best matched to the actualmeasured settlement dataprofile.
from the Sigma/W analysis.
Table 3 shows the typical HNLE soils properties from the Duncan et.al (1980) library that Flint and Bartlett (2005) used to begin their FEA. The soil profile was divided into 6 layers, as was done in this report for the North and South Temple Street sites along I-15.
Table 3 - Typical HNLE Properties for 200S
After a series of iterations, Flint and Bartlett developed calibrated model properties that are shown in Table 4. Note that the failure ratio is the same for each soil. This is because the settlement data did not need strength parameters to do the calculations, which the failure ratio is dependant on. Figure 19 shows the results of the analysis re-run using the calibrated soil parameters.
Table 4 - Calibrated HNLE Properties
Layer K Kb Kur m n Rf
Upper Alluvium 60 40 240 0.60 0.5 0.7
Upper Bonneville 30 20 120 0.45 0.2 0.7
Interbeds 50 40 220 0.60 0.5 0.7
Lower Bonneville 50 40 190 0.45 0.2 0.7
Deeper Alluvium 110 120 430 0.25 0.0 0.7
Cutler Dam 70 50 300 0.45 0.2 0.7
Figure 19 - 200 South Settlement Data and Estimates - After Flint and Bartlett (2005)
The HNLE model parameters developed directly from the triaxial testing done as part of this report can be input into the Sigma/W models constructed by Flint and Bartlett to show how well the laboratory testing represents the real worldmeasured field behavior of the soils. The summary of the HNLE parameters to be inputted into the Flint and Bartlett Sigma/W model is found in Table 5. These revised values were used to re-run the
Table 6 shows a comparison of the HNLE parameters developed by this report and those used by from Flint and Bartlett (2005). The results from of this report are presented in the first column for each parameter. The results from Flint and Bartlett (2005) are shown second column for comparison. For plots of the triaxial test data regression, see the appendix of this document.
Table 6 - Comparison of Triaxial and Back Calculated Parameters
K Kb m n Rf
Upper Alluvium 50 60 30 40 0.6 0.60 0.57 0.5 0.7 0.7 Upper Bonneville 50 30 24 20 0.77 0.45 0.57 0.2 0.7 0.7
Interbeds 75 50 23 40 0.78 0.60 0.78 0.5 0.7 0.7
Lower
Bonneville 39 50 29 40 0.77 0.45 0.35 0.2 0.7 0.7 Deeper Alluvium NA 110 NA 120 NA 0.25 NA 0.0 NA 0.7
Cutler Dam NA 70 NA 50 NA 0.45 NA 0.2 NA 0.7
The information in Table 6, was input into the finite element computer program SIGMA/W for analysis of the embankments. The embankment loading was modeled sequentially to simulate construction loading of the Bonneville deposits. The first analysises have several phases, each phase divided into embankment construction steps.
Figure 18 demonstrates the phases and geometry. The analysis begins with an elastic analysis with no embankment to determine the in-situ stress state. The analysis then continues with the loading from the original 1960’s I-15 embankment. The first phase of I-15 reconstruction at 200 South is next, noted as “Phase I”. Finally, the second phase of I-15 reconstruction is modeled. This modeling progression is done for each set of HNLE model parameters.
Figure 20, shows the comparison of the HNLE model parameter results for the original I-15 embankment at 200 South prior to the I-I-15 reconstruction. In Figures 20 through 22, the “matched” settlement profile is from Flint and Bartlett (2005). The “lab” settlement profile is the results from this report using the laboratory determined values for the HNLE model. It can be seen that the two analyses match quite well. From Figure 20, the two analyses match well. Figure 21 shows the comparison of the HNLE model parameters results for the Phase I I-15 reconstruction at 200 South Street. Once again, From Figure 21, the two analyses match well.
Figure 20 - Existing I-15 Embankment Analysis Comparison
Figure 21 - Phase I of Reconstruction Analysis Comparison
From Figure 21, it can be seen that the laboratory triaxial HNLE parameters provide a good estimate of the measured field settlements at the 200 South Street array. In addition, observed. Thethe HNLE results from this report compare well with to the calibrated parametersthe modeling developed by Flint and Bartlett (2005). However, except that the maximum settlement at the toe of the embankment is slightly less for the analysis performed in this report using run with the laboratory-determined HNLE hyperbolic model parameters. This latter e lab parameter analysis was reanalyzedre-run with the HNLE parameters for the Upper Alluvium altered to better agree align with the HNLE parameters found for the underlying layers. The assumption is that some parameters, such as K and m, will be different than those for the Bonneville deposits, but not significantly differentso. This result is shown as the “parametric” profile in Figure 22. Table 6 includes the parameters for the Upper Alluvium used in the re-analysis. Figure 22 shows that altering the HNLE model parameters, from those found in the calibration done by Flint and Bartlett to those that align with the laboratory testing, the surface settlements match the observed settlements much closer.
Finally, the results of the HNLE model analysis from laboratory triaxial testing can be compared to the actual measured surface settlement data for the 200 South site for the I-15 reconstruction. Figure 23 shows a plot of the measured surface settlements (black line) compared to the HNLE analysis results for this report (red line).
Figure 23 - Comparison of Measured Data and HNLE Models
Conclusions
Laboratory triaxial testing of carefully sampled specimens of Bonneville clay from the locations of the I-15 bridges over North and South Temple Streets in Salt Lake City were conducted to determine appropriate Duncan et al. (1980). Hypberbolic mModel parameters for estimating settlements from new embankment and MSE wall construction.
The laboratory test data was used to develop the parameters, and finite element modeling of the 200 South Street case history from the I-15 Reconstruction settlement monitoring was done. This finite element modeling showed that the use of laboratory determined HNLE model parameters reasonably matched the observed settlements at the 200 South Street array..
Acknowledgements
The authors of this report wish to express thanks to the following individuals:
Clifton Farnsworth for his I-15 settlement data and .
Kleinfelder Inc. for use of their constant humidity room to store Shelby tubes of clay samples.
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Appendix
Figure 24 - General Trend of all Initial Tangent Modulus Data
Figure 25 - General Trend of all Bulk Modulus Data
Figure 27 - Comparison of Triaxial Test Results to Calibrated HNLE
2 = sensitive and soft clays
2 = sensitive and soft clays
Figure 29 - South Temple CPT Data
Figure 30 - Stress:Strain Plot for B1 -14.00
Figure 31 - Stress:Strain Plot for B1 15.46
Figure 32 - Stress:Strain Plot for B1 15.48
Figure 33 - Stress;Strain Plot for B1 17.22
Figure 35 - Stress:Strain Plot for B2 13.3
Figure 37 - Stress:Strain Plot for B3 7.1
Figure 39 - Stress:Strain Plot for B3 8.7
Figure 41 - Stress:Strain plot for B3 11.56
Figure 43 - Stress:Strain Plot for B3 17.260
Figure 45 - Stress:Strain Plot for B3 18.532
Figure 47 - Stress:Strain Plot for B4 6.25
Figure 49 - Stress:Strain Plot for B4 11.07
Figure 51 - Stress:Strain Plot for B6 16.84
Figure 53 - SIGMA/W In-Situ Stress Analysis
Figure 54 - SIGMA/W Existing Embankment Analysis
Figure 56 - SIGMA/W Phase II Anlysis