土压力监测在高填方下刚性桩复合地基沉降分析中的应用

Application of earth pressure monitoring in the analysis of settlement for composite foundation with rigid piles under high fill

本文通过对京津二通道(五环路—天津)高速公路高填方路基下CFG桩基础的土压力观测数据进行分析,对比高填方路基下的沉降观测数据及理论计算的最终沉降量,对柔性基础下刚性桩复合地基承载力变化情况进行了研究。通过实例分析了柔性基础下刚性桩复合地基的桩土应力比变化情况,指出了影响桩顶、桩间土压力变化的影响因素,说明了因为土压力计感应膜的位置差异造成的桩间土土压力的"欠读"现象(即测读值偏小),并指出了通过改变垫层刚度来增加刚性桩复合地基的基础刚度这一调节桩土应力比的手段。

Through analyzing the field testing data of the earth pressure of the CFG pile foundation under the high fill subgrade for the second highway from Beijing to Tianjin（Fifth Ring Road to Tianjin boundary）,the settlement data and the final theoretical calculation settlement data are contrasted,and the bearing capacity variation of the composite foundation with rigid piles under the flexible foundation are studied.Based on the example,the variation of the pile-soil stress ratio of the composite foundation is analyzed,and the factors to influence the pressure variations of the pile top and the soil between piles are pointed out.The ＂less reading＂ phenomenon of earth pressure between piles which is caused by the location difference of the sensing membrane of the soil manometer is explained,and the means to regulate the pile-soil stress ratio which could increase the stiffness of the composite foundation through changing the cushion stiffness are presented.