微型桩组合结构抗滑机理模型试验研究

Experimental Study on the Anti-Sliding Mechanism of Micro-Pile Composite Structure

针对框架梁连接的微型桩组合结构,采用模型试验与有限元分析相结合的方法,对微型桩桩后土压力和桩身水平位移进行测试和分析,研究微型桩组合结构抗滑机理。结果表明:采用框架梁连接的微型桩组合结构,其抗滑机理除了表现在微型桩组合结构增强了滑带的抗剪能力外,各排微型桩还承受较大的弯矩和土体抗力作用;依据模型试验结果,将碎石土受到的土压力采用矩形分布时,运用桩—土相互作用的有限元分析方法计算桩身弯矩和桩身水平位移是合适的,各排微型桩桩身水平位移的理论分析结果与实测结果较为吻合;在模型试验条件下,施加35.49kPa的滑坡推力时作用在第1—第3排桩上的剩余滑坡推力分别达到2.46,2.11和1.01kN·m-1,剩余滑坡推力比为2.44∶2.09∶1。

In view of the micro-pile composite structure linked by frame beam, model tests together with finite element analysis were adopted to test and analyze the earth pressure behind micro-pile and the horizontal displacement of pile shaft as well as study the anti-sliding mechanism of micro-pile composite structure. The results show that, for the micro-pile composite structure linked by frame beam, its anti-sliding mechanism is evident that each row of micro-pile is under large bending moment and soil resistance in addition to enhancing the slip shear capacity. According to the results of model tests, when the soil pressure on the gravel soil is of rectangular distribution, it is appropriate to calculate the bending moment and horizon- tal displacement of pile shaft by means of pile-soil interaction finite element analysis method. The theoretical analysis results of the horizontal displacement for each row of micro-pile agree well with the measured ones. Under the conditions of model test, after the landslide thrust of 35.49 kPa being applied, the residual landslide thrust on the piles from the first to the third rows is respectively 2.46, 2.11 and 1.01 kN·m^-1 , and the ratio of residual landslide thrust is 2. 44 ： 2.09：1.