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对地铁隧道周围软黏土进行加固,已应用于地铁隧道沉降的治理,但是对软黏土加固后的动力特性研究还不够深入。通过对上海地铁隧道周围加固软黏土进行GDS试验,系统探讨循环荷载振动频率、循环动应力幅值、初始偏应力及围压对动弹性模量的影响。试验结果表明:随着循环振动次数的增加,动弹性模量的衰减过程可分为急剧衰减阶段和缓慢衰减阶段,且缓慢衰减阶段的时间要明显长于急剧衰减阶段;循环荷载振动频率对动弹性模量有显著影响;随着循环应力幅值、初始偏应力、围压的增大,动弹性模量都有了很大的提高,但其变化对动弹性模量的衰减速率并无显著影响。采用对数函数对试验数据进行回归分析,建立了加固软黏土在循环荷载作用下动弹性模量衰减模型,较好的反映了动弹性模量的衰减规律。
The reinforcement of the soft clay around the subway tunnel has been applied to the settlement control of the subway tunnel. However, the research on the dynamic characteristics of the soft clay reinforcement is still not deep enough. Through the GDS test on the reinforcement of soft clay around the subway tunnel in Shanghai, the influence of cyclic loading vibration frequency, cyclic dynamic stress amplitude, initial deviatoric stress and confining pressure on dynamic modulus of elasticity was discussed systematically. The experimental results show that with the increase of the number of cyclic vibration, the decay process of dynamic elastic modulus can be divided into a sharp decay stage and a slow decay stage, and the time of the slow decay stage is obviously longer than the sharp decay stage. Modulus of the elastic modulus has a significant impact; with the cyclic stress amplitude, initial deviatoric stress, confining pressure increases, the dynamic elastic modulus has been greatly improved, but its change has no significant impact on the rate of decay of dynamic elastic modulus . The logarithmic function was used to analyze the experimental data. The dynamic elastic modulus attenuation model of the reinforced soft clay under cyclic loading was established, which better reflects the attenuation law of dynamic elastic modulus.