动单剪分析饱和粉土的液化性

CYCLIC SIMPLE SHEAR TESTS RESEARCH ON LIQUEFACTION OF SATURATED SILT

利用Shear Trac-II-DSS动单剪测试系统,研究了邯郸地区饱和粉土的液化性。结合Seed简化理论中等效的原则,将地震剪应力时程等效成周期剪应力和周期次数,得到了地震剪应力与抗液化剪应力关系曲线;初步确定了该地区粉土液化深度为2m左右,初始液化区域为2～6m;当埋深较浅时,抗液化强度比等效地震剪应力要大;随着埋深增加抗液化强度和等效地震剪应力均增大,且抗液化强度增加的幅度比等效地震剪应力增幅要小;当达到一定深度时,抗液化强度等于等效地震剪应力,出现初始液化现象;随着埋深进一步增加,抗液化强度增加的幅度比等效地震剪应力增幅要大,最终导致粉土不液化。该结论可为今后的工程设计提供参考。

Through analyzing the tests result from Shear Trac-II-DSS Cyclic simple shear tests, the liquefaction of saturated silt in Handan city were investigated. Combined with H. D. Seed simplified the- ory of equivalent principle, the seismic shear stress time history is equivalent to the cyclic shear stress and cycle times, this paper get the relationship curve of seismic shear stress and the anti-liquefaction shear stress. The area of initial liquefaction depth below the surface of about 2m was obtained by the curve and the initial liquefaction area is 2- 6m. When the depth is shallow, the liquefaction resistance is stronger than the equivalent seismic shear stress. With the increasing depth, the silt liquefaction strength increase is smaller than the equivalent seismic shear stress increases. Reach a certain depth, the lique- faction strength equal to the equivalent seismic shear stress, silt will occur initial liquefaction. With the increase of buried depth, the liquefaction strength increase will be greater than the equivalent seismic shear stress increase. At last, it will not lead to liquefaction. This conclusion can provide reference for the engineering design.