Proceedings of the Deep Mixing 2015 Conference, (DFI)
Seismic Performance of Soil-Cement Grid Supporting a Structure over Soft Clay
Mohammad Khosravi, Virginia Tech, United States; Ross W. Boulanger, University of California, Davis, United States; Daniel W. Wilson, University of California, Davis, United States; Shuji Tamura, Tokyo Institute of Technology, Japan; C. Guney Olgun, Virginia Tech, United States; Yongzhi Wang, University of California, Davis, United States
This paper describes the centrifuge model construction procedure for a soil-cement grid supporting a structure over soft clay and the system's dynamic response to shaking motions of varying intensity. The soil profile consisted of soft clay partially reinforced using a soil-cement grid with an area replacement ratio, Ar, of 24% and an Improvement Depth / Grid Spacing ratio of 2.40. The centrifuge test included a single degree of freedom structure on the reinforced soil portion and was subjected to 13 different earthquake events with peak accelerations ranging from 0.02 to 0.55g. The test showed that centrifuge models of soil-cement grid reinforced soil could be constructed using trenching and excavation technique and the results could be used to examine system-level performance, including the effects of grid cracking. The issue of concern was how cracking patterns observed in the soil cement panels could be related to the imposed shaking and response of the structure. Excessive settlement of the structure was observed when the shaking was strong enough to rock the structure, causing local crushing of the soil-cement panels under the footing. The damaged soil-cement grids did, however, continue to support the static loads of the structure.
|article #2085; publication #1013 (DM-2015)|