Details:

Creators:
Townsend F.C. ; Anderson J.B. ; Rahelison Landy
Townsend F.C. ; Anderson J.B. ; Rahelison Landy Less -
Corporate Creators:
University of Florida. Dept. of Civil and Coastal Engineering
Corporate Contributors:
Florida. Department of Transportation
Subject/TRT Terms:
[+]
Field Tests Finite Element Method Footings Foundation Engineering Insitu Test Methods Soils
Publication/ Report Number:
Report no. RPWO-14
Resource Type:
Tech Report
Geographical Coverage:
Florida
Corporate Publisher:
Florida. Department of Transportation
Abstract:
The study looked critically at insitu test methods (SPT, CPT, DMT, and PMT) as a means for developing finite element constitutive model input parameters. The first phase of the study examined insitu test derived parameters with laboratory triaxial tests at three sites. These were used to develop baseline input parameters which were verified by simulating the triaxial tests using two finite element codes. Conclusions drawn from these conclusions are: (1) FEM simulations of triaxial test stress-strain curves produced excellent results. (2) the hardening models (PLAXIS-Hardening Soil and PlasFEM-Sandler Dimaggio) simulated the non-linear behavior better than the Mohr-Coulomb or Drucker-Prager models. (3) In general, Esub50 triaxial test modulus values agreed with those estimated from DMT and PMT unloading tests, and (4)FEM simulations of field PMT curves using triaxial test based parameters were unsuccessful. It was necessary to increase the triaxdial Esub50 values by Omega=1.3078e [to the power of 0.0164p[subl]R{squared}=0.8515, where Omega is the triaxial E[sub 50] modulus multiplier and p[sub 1] is the PENCEL limit pressure. The second phase of the study was to predict the deformations of a cantilevered sheet pile wall (unloading case) and the deformations of a 2-m diameter shallow footing (loading case). The third phase was to predict the deformations of a 2-m diameter shallow footing (loading case). Conventional analyses methods were compared with FEM using insitu test derived input parameters. Conclusions were: (1) convential analyses (CWALSHT) under-predicted wall deformations unconservatively, while wall deflections were accurately predicted using the Hardening Soil Model with input parameters estimated from SPT correlations and "curved matched" PMT values. (2) Fundamentally, the stress history of a soil profile, i.e., OCR or preconsolidation pressure, must be known for any settlement prediction either using conventional or finite element methods. (3) Of the conventional methods for estimating settlements (CSANDSET), only the SPT based D'Appolonia, and Peck and Bazaraa methods provided reasonable estimates of the observed settlement. (4) The conventional DMT method, which correlates OCR values, slightly overestimated measured settlements. (5)None of the insitu test derived input parameters (SPT, CPT, DMT and PMT) coupled with FEM Mohr-Coulomb or Hardening Soil models, accurately predicted the shallow footing settlements.
Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:3c8767b2ee9af34cdbd842bd49ae5dd8625cce12e29fe7aacc2f9840435028d5
Download URL:
https://rosap.ntl.bts.gov/view/dot/14969/dot_14969_DS1.pdf
File Type:

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