Study Of Cyclic Properties Of Saturated Clays Under Undrained Condition

The properties of saturated clay under cyclic loading are very important problemthat should be carefuly considered when people design and analyze differentgeotechnical structures. With the fast development of economy, there are many newproblems in coastal cities and inland cities where lots of structures were built on deepsoftc lays. To guarantee these buildings'safety avoiding accidents, it is meaningful tostudy properties of saturated soft clays under repeated loading.This article first uses the principle of vacuum preloading to prepare the saturatedsoft clay, seeking to prepare the process of preparation of soil samples to improveuniformity of means.Further, through cyclic triaxial tests control of the cycle of stress test, researchingthe cyclic properties of disturbed soft clays under the UU condition. The cyclictriaxial tests were conducted under one confining pressure, cyclic strength and thecyclic accumulative strain versus the number of cycles,static stresses and cyclicstresses were determined under different combined static and cyclic stresses, andestablish its relationship. Then by comparing the UU cyclic properties of disturbedand undisturbed saturated soft clay, we can draw the conclusion of comparing withthe undisturbed saturated soft clay, the UU static strength of disturbed saturated softclay was significantly reduce, the rate of reducing about 50 percent above, it was alsocan draw that there will produce a pore pressure in saturated soft clay under cyclicloading which will soft the soil strength, and the rate of undisturbed saturated softclay change obviously versus the number of cycles while the rate of disturbedsaturated soft clay is not significant.Finally, under the premise of simulating the 0 K consolidation, cyclic triaxialtests were conducted using disturbed saturated soft clay samples under three differentconfining pressures, studying cyclic strength and the cyclic accumulative strain versusconfining pressures,the number of cycles,static stresses and cyclic stresses. And candraw that by arbitary selection of 12 cycle of destruction, the cohesive force willgradually decreased with the number of cycles increase, while the internal frictionangle also show the same features. Through further research we can found that theCoulomb-Mohr criteria can be used to describe the cycle of destruction of saturatedsoft clay under CU condition. By the research of cyclic accumulative strain, when thecycle of destruction less than 2000, we can draw that the confining pressures have a effect on cyclic accumulative strain, while the cycle of destruction more than 2000, itcan not consider the effect of confining pressures on cyclic accumulative strain.