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为探寻饱和粉土的液化特性,利用GDS空心圆柱仪进行了一系列循环扭剪试验。在初始剪应力τs和循环剪应力τcy共同作用下,试样的最小剪应力τmin=τs-τcy存在3种类型:τmin<0,τmin=0和τmin>0。试验结果表明:当τmin≤0时,试样的孔压可以达到有效围压,其破坏模式为循环液化;当τmin>0时,试样的孔压始终达不到有效围压,其破坏模式为过大的累计应变。饱和粉土的循环强度随着初始剪应力τs与初始有效平均主应力0p′之比值SSR(初始剪应力比)的增加呈现出先减小后增大变化趋势,且SSR=0.1~0.15时的循环强度最低。当SSR≤0.1时,孔压比的发展模式随着循环剪应力比的增加由“快—平稳—急剧”的增长模式向“快—平稳”的增长模式转变;当SSR>0.1时,孔压比的发展呈现“快—平稳”的增长模式。
In order to explore the liquefaction characteristics of saturated silt, a series of cyclic torsional shear tests were carried out using a GDS hollow cylinder. Under the combined effect of initial shear stress τs and cyclic shear stress τcy, there are three types of minimum shear stress τmin = τs-τcy: τmin <0, τmin = 0 and τmin> 0. The experimental results show that when τmin≤0, the pore pressure of the sample can reach the effective confining pressure and its failure mode is cyclic liquefaction. When τmin> 0, the pore pressure of the sample can not reach the effective confining pressure all the time, and the failure mode Excessive accumulated strain. The cyclic strength of saturated silt shows a trend of first decreasing and then increasing with the ratio of initial shear stress τs to initial effective average principal stress 0p ’(initial shear stress ratio), and the cycle of SSR = 0.1 ~ 0.15 The lowest strength. When the SSR is less than or equal to 0.1, the development mode of pore pressure ratio changes from “fast-stationary-rapid” growth mode to “fast-stationary” growth mode with the increase of cyclic shear stress ratio. When the pressure ratio of the development of “fast - smooth ” growth model.