284 / 2024-03-14 20:49:27

A Novel Approach Using CASM-Based Interpretation of Pressuremeter Test Data

loading and unloading,critical-state soil,pressuremeter test

3、深地工程与能源利用 > 1、深部岩土力学基础理论

    In-situ tests, integral to geotechnical engineering research, frequently encounter variations in soil parameters caused by instrument disturbances. Particularly in the case of pressuremeter tests, where loading data is susceptible to disturbance from the insertion of the pressuremeter, interpreting soil intrinsic properties through unloading or loading-unloading data tends to be more reliable. Most models reflecting soil undrained characteristics using unloading or loading-unloading curves are based on perfectly plastic stress-strain relationship. However, the total stress analysis based on a perfectly plastic model cannot account for the effects of stress history or strain hardening/softening. According to the semi-analytical solution based on the unified state parameter model for clay and sand (CASM) for the complete expansion-contraction of spherical and cylindrical cavities under undrained conditions, this paper proposes a novel method for interpreting loading-unloading data of pressuremeter tests.. Validation of this approach is conducted through self-boring pressuremeter (SBP) tests in Fucino clay, demonstrating its effectiveness in obtaining soil parameters such as initial effective horizontal stress, undrained shear strength, and initial overconsolidation ratio. The results of the study indicate good agreement between theoretical curves and experimental data, highlighting the potential for more accurate results compared to traditional interpretation methods.