复杂岩溶地层考虑压曲效应的桩基竖向承载力研究

Research on Vertical Bearing Capacity of Pile Considering Buckling Effect in Complex Karst Area

以杭州轨道交通16号线上泉车辆基地桩基为工程背景,采用数值模拟和静载试验相结合的方法,对覆盖性岩溶地层下的桩基竖向承载力进行研究。采用ANSYS建立桩、土、溶洞耦合的三维有限元模型,对岩溶地层下的钻孔灌注桩的基桩承载力进行了数值分析,得出桩身范围内溶洞的存在降低了土体对桩身的约束而产生了压曲效应,降低了桩身实际抗压承载力,并且溶洞越大压曲效应越明显,桩基竖向承载力的消弱越多。同时,结合桩基静载试验对数值分析的结果进行验证,保证了结果的有效性。

With the construction and development of rail transit,there are more and more cases of rail construction under karst geological conditions,among which the overburden karst geology is the key difficulty that needs to be studied.Taking the pile foundation ofthe Shangquan depot of Hangzhou Rail Transit Line 16 as the engineering background,the vertical bearing capacity of the pile foundation under the covering karst stratum was studied by the method of combining numerical simulation and static load test.ANSYS was used to establish a three-dimensional finite element model of the coupling of piles,soil and karst caves,and the bearing capacity of foundation piles of bored piles under karst strata was numerically analyzed.The buckling effect was produced due to the constraint of the karst cave,which reduces the actual compressive bearing capacity of the pile body,and the larger the karst cave,the more obvious the buckling effect,and the more weakened the vertical bearing capacity of the pile foundation.At the same time,the results of the numerical analysis was verified by the static load test of the pile foundation,which ensures the validity ofthe results and provides a reference for the design ofthe pile foundation in the karst area.