地铁荷载作用下水泥土应变监测模型试验研究

摘要

Cement soil reinforcement is widely used in metro construction in soft clay zones since it can effectively improve foundation strength and reduce settlement.Due to the initial consolidation of the compound soils caused by construction disturbance,the strain development and long term deformation is affected under the function of cyclic loading.A dynamic test is conducted on cement soil by means of an indoor GDS dynamic triaxial test,and the ef-fects of the cement mixing ratio and the initial consolidation degree on strain development are analyzed.Based on the research and experiment results,a strain development model considering the cement mixing ratio and initial con-solidation degree is established.The experiment results show:1)the lower the initial consolidation degree,the faster the strain development rate; 2)when the initial consolidation degree is low,the strain development rate of the ce-ment soil with a low cement mixing ratio is high;and 3)the strain development of cement soil is in a non-failure form,and it is approximately a linear relationship between the dynamic strain of the cement soil and the logarithm lgN of cyclic times under different consolidations.%在软粘土地区修建地铁等工程中,采用水泥土加固法可有效提高地基强度,减小地基沉降,因而其得到了广泛应用.在施工过程中,由于扰动影响使得复合土体存在初始固结度,在循环荷载作用下其应变发展规律会存在一定差异,进而影响其长期变形.文章通过室内GDS动三轴试验对水泥土进行了动力测试,分析了水泥掺入比和初始固结度对其应变发展的影响.综合已有研究和试验结果,建立了考虑掺入比和初始固结度的应变发展模型.试验结果表明:初始固结度低的试样,应变发展速率越快;当初始固结度较低时,掺入比小的水泥土应变发展速率较快;水泥土应变发展呈非破坏型,不同固结度下水泥土的动应变与循环次数的对数lgN之间近似呈线性关系.