The interpretation of in situ soil tests

作者：C. Peter Wroth · 发表于：Géotechnique · 年份：1984 · DOI：10.1680/geot.1984.34.4.449 · 被引用次数：595 · 研究领域：Geotechnical Engineering and Soil Mechanics、Soil and Unsaturated Flow、Geotechnical Engineering and Soil Stabilization

The purposes of in situ testing are set out, and the difficulties of the interpretation of the observations are emphasized. These difficulties are due to the complex behaviour of soils together with the lack of control and of choice of the boundary conditions in any field test. One notable exception is the pressuremeter test, from which soil properties can be derived directly without recourse to empirical correlations. The discussion is concentrated on the measurement of undrained shear strength. The results obtained from different tests (triaxial, plane strain, direct simple shear, pressuremeter and vane) are compared by expressing them in terms of the undrained strength ratio s u /σ v0 ′ as a function of the friction angle φ. Special attention is paid to tests in which the principal axes of stress and of strain increment are free to rotate. In such tests, uncertainty exists regarding the definition of failure and the planes of maximum stress obliquity. To derive these functions Matsuoka's failure criterion is used. As a consequence a theoretical hierarchy of strengths is established which agrees qualitatively with experimental evidence. The importance to a designer of this variety of strengths is emphasized. A study is made of the piezocone and the interpretation of the pore pressures in terms of the overconsolidation ratio of the clay tested. A plea is made for the standardization of the equipment, the operation and the interpretation of in situ tests to obtain maximum ben...