循环荷载作用下土的动力特性及隧道工后沉降分析

选取重塑砾质黏土作为试验土样,采用室内动三轴试验系统研究循环荷载作用下土体的模量弱化规律,并考虑多重因素下隧道工后沉降公式拟合。实验表明:累积应变与累积孔压随围压与动应力比的增大而增大,并在振动10000次达到稳定趋势,而模量模量弱化幅值呈现相反的规律。在不同激振频率下累积孔压,累积应变随频率增大而减少,模量的弱化幅值随频率增大而减小。在前人的基础上进一步考虑了激振频率对累积应变,和累计孔压公式进行拟合得到相关参数。研究成果对砾质黏性土的动力特性以及隧道工后沉降预测提供了有价值的参考。

Dynamic characteristics of soil under role of cycle load and settlement analysis after tunnel construction

The paper selected remodeling gravelly clay soil as test sample,and used the indoor dynamic triaxial testing system to research the modulus regular of soil under cyclic load weakening, and considered the fit of settlement formula after tunnel construction under multiple factors. Experiment showed that accumulated strain and cumulative pore pressure increases with the increase of confining pressure and dynamic stress ratio and reaches a steady after vibrating 10,000 times, while the modulus weakening amplitude shows the opposite rule. If the pore pressure is cumulated at different excitation frequencies,the cumulative strain decreases with the increase of frequency, the weakening amplitude of modulus decreases with the increase of frequency. On the basis of previous research,the paper further considered the effect of excitation frequency on accumulative strain,and fitted the cumulative pore pressure formula to get relative parameter. The result can provide a valuable reference for the prediction of dynamic characteristics of soil frail shield and the settlement of gravel cohesive soil after tunnel construction.