基于变形控制的岩溶区基桩承载力研究

Study on Bearing Capacity of Piles in Karst Based on Settlement Control

深入分析了岩溶区基桩的承载机理及侧阻端阻的传递规律,建立了合理基桩侧阻端阻荷载传递模型,该模型可充分考虑桩周岩土体的加工软化和加工硬化型土的不同特性及桩端沉渣对基桩承载力的影响。在此基础上,根据桩侧土(岩)与桩端岩层阻力的发挥程度,推导得出了桩顶沉降量与桩顶荷载之间的关系式,从而通过桩顶沉降量来确定岩溶区基桩的竖向承载力。最后,结合自平衡静载试验,对理论方法进行了验证。实测荷载-沉降曲线与理论曲线吻合良好。

First, the bearing mechanism of piles in karst and load transfer regularity of side friction along the pile were analysed, and the rational load transfer models were established with consideration of the influences of the different behaviors of work-sorting or work-hardening soil （rock） and slime at the pile bottom on the bearing capacity of piles in karst. On this basis, the relation between the settlement of pile top and the vertical bearing capacity of pile was deducted accoMing to the development degree of the resistance force of soil （rock） along the pile and the end resistance at the bottom, so the vertical bearing capacity of piles can be determined by the allowable settlement of pile top. Finally, the theoretical method was verified by self-balance static loading test. The result shows a good agreement between theoretical curve and measured curve.