集约式微型桩群水平承载性能试验研究

 对矩形布置的集约式微型桩群支护体系采用分级加载的方法，进行水平荷载原型试验及数值计算，研究滑坡推力作用下集约式微型桩群抗滑作用机制，并分析桩间土体参数、桩身强度、桩排间距等设计参数变化对桩群水平承载性能影响的敏感程度。结果表明，在滑体介质为粉质黏土的地层中，当滑坡推力超过某一定值时前排桩才会发挥支挡作用，桩群前方土压力峰值的位置深于桩群内部，微型桩群与土体水平荷载分担比约为7：3；控制最佳排间距，相比优化其他设计参数对提高集约式微型桩群水平承载力、减小桩顶位移效果明显。试验成果为深入分析集约式微型桩群的抗滑机制和优化工程设计提供了参考。

EXPERIMENTAL STUDY ON THE LATERAL LOAD-CARRYING PROPERTIES OF INTENSIVE MICROPILES

In order to study the micropiles anti-slide mechanism by the step loading method on rectangular arranged intensive micropiles retaining system，a full scale lateral loading test and a numerical calculation on it were performed. On the basis of prototype test，a finite element model is established to analyze the lateral bearing capacity of the pile group by changing the design parameters like soil parameters，micropile elastic modulus，pile spacing and row spacing. According to the results，the front-row piles will not play the role in retaining until the landslide thrust force exceeds a certain value for a stratum of silty clay；the position of the earth pressure peaks in front of piles is deeper than the earth pressure peaks inside of piles；the lateral load bearing rate of the soil and the pile is 7∶3. Controlling the piles in optimal row spacing was more effective than optimizing other parameters in enhancing the lateral bearing capacity and reducing displacement of pile tip. The test result provides reference for further analysis on anti-slip system of intensive micropiles and optimization of engineering design.