Abstract
A substructure on-line testing (SOT) system was developed for the purpose of conducting a quantitative simulation of the behavior of horizontal subsurface layers subjected to earthquake motions (SH wave) under undrained conditions. In this method, a computer analysis of the seismic response and a pseudo-dynamic loading test which estimates the restoration force of the materials were combined with a computer on-line data processing system. With the SOT system, which was devised to analyze the overall seismic response behavior of subsoils, an on-line test was adopted only for layers demonstrating complicated hysteretic behavior with respect to restoration force, while a numerical model was applied to the remaining layers. The following tests were conducted in order to verify this system : 1) The reliability of a series of 6 hollow torsional shear apparatus installed in the SOT system was verified by comparing the test results with the results of cyclic undrained simple shear tests conducted by Tatsuoka et al. (1989); 2) A test on a quasi-elastic specimen was conducted based on the SOT system using a test algorithm developed for this study, and an elastic analysis was carried out using the modulus of elasticity obtained from this test. Based on a comparison between the respective results of the test and the analysis, the reliability of the test algorithm was verified; 3) Using the system thus verified, a seismic response liquefaction test on a saturated sandy subsoils was conducted, which showed that the SOT system developed in this study was capable of accurately simulating the seismic response of a level subsoils.
