循环荷载作用下淤泥质黏土软化试验研究

Experimental Study on Silt Clay to Soften under Cyclic Loading

针对连云港地区淤泥质黏土颗粒细、渗透系数小的特点,研究了循环荷载作用下土体的软化规律,提出该类土体软化指标。通过三轴循环荷载试验,得到累积轴向应变值和轴向应变值随着循环应力幅值比和固结压力的增大而增大;土样中平均孔压比随着循环应力幅值比的增大而增大;循环荷载的周期越大累积轴向应变和平均孔压值越大;在循环荷载作用初期,变形模量的弱化随着循环应力幅值比和循环周数的增大而更加显著。对试验数据进行分析,得出在风暴潮的波浪循环荷载作用下,连云港地区淤泥质黏土的模量和强度折减系数在0.75~0.80之间。

According to the silt clay characteristics which is fine particles and a small coefficient of permeability in Lianyun gang region, the soften law of the soil is studied and soil softening index is recommended under cyclic loading. Through triaxial cyclic loading test, the results are obtained, the accumulated axial strain and axial strain increase with the cyclic stress ampli tude ratio and the consolidation pressure increasing, average pore pressure ratio in soil increases with the cyclic stress ampli tude ration increasing, the accumulated axial strain and average pore pressure ratio increase with cyclic loading cycle increas ing. Weakening in the early stage of cyclic loading, deformation modulus is more significant as the increase of the cyclic stress amplitude ratio and the cycle number in initial stage. Analysis of test data, it is derived that silt clay in the modulus and strength reduction factor between 0.75 and 0.80 in the Lianyungang when storm surge wave cyclic loading take place.