地铁荷载下隧道周围加固软黏土应变累积特性

Characteristics of Strain Accumulation of Reinforced Soft Clay Around Tunnel Under Subway Vibration Loading

摘要:

通过对上海地铁四号线海伦路站附近隧道周围加固软黏土进行应力控制的循环三轴试验,研究了列车循环荷载作用下加固软黏土的累积变形特性.充分考虑土体围压、固结比、轴向循环压力的大小及频率的影响,得到了加固软黏土在各个因素综合影响下的残余应变的变化规律.通过研究发现,可以用对数关系曲线来描述加固软黏土残余应变随振动次数的变化情况.通过回归分析,确定了各影响因素对预测模型参数的影响.

Abstract:

Based on the dynamic triaxial tests of the reinforced soft clay around the tunnel nearby the Hailun Road station of Shanghai Metro Line 4,the characteristics of strain accumulation caused by subway vibration loading are explored by taking into account the influence of confining pressure,consolidation ratio,cyclic loading amplitudes and vibration frequency,and the change law of residual strain influenced by each factor is obtained.The logarithmic function form is adopted to describe the relationship between the residual strain and the vibration number.Besides,the model parameters are determined with the regression analysis.The research results are not only of great importance to the reinforcement of the soil around subway tunnels,but also of great theoretical value and practical meaning to the longterm settlement prediction of soft clay around tunnel under subway vibration loading.