Several challenges in advanced laboratory testing of geomaterials with emphasis on unconventional types of liquefaction tests

Abstract

On advanced laboratory testing of geomaterials with emphasis on unconventional types of liquefaction tests, it is attempted to report some of the past and recent challenges in developing/improving laboratory stress–strain soil testing apparatuses and relevant control/measurement techniques. They include a) local measurements in triaxial tests on prismatic/cylindrical specimens and torsional shear/triaxial tests on hollow cylindrical specimens, b) non-destructive evaluation of particle crushing and inter-particle sliding based on AE measurements, c) special types of liquefaction tests using motor-driven loading devices on specimens with thin sandy layer as well as those consisting of segregated layers with direct/indirect evaluation of local deformation, and d) other special types such as large deformation tests, tension tests and long-term tests. The general lessons learned from these challenges are as follow. Some of the “element” test results need to be analyzed and interpreted as boundary value problems in terms of the stress/strain non-uniformities and the specimen heterogeneity. Possible effects of system compliance should be properly considered as well. Each of the variety of laboratory stress–strain test methods has its specific advantages and limitations. By developing an original way of application, the limitation may turn into an advantage.