岩溶区高铁桥梁桩基沉降计算及参数影响分析

本文结合郑徐客专徐州特大桥工程,对桥梁桩基础下伏土层厚度和下伏层溶洞直径对群桩基础沉降影响进行分析。结果表明,群桩沉降变形主要由桩端下卧土层的压缩引起,下卧土层越薄沉降越小;溶洞孔径的大小对群桩基础总沉降影响不大;当相邻两墩台分别采用摩擦桩与嵌岩桩作为基础形式时,嵌岩桩的工后沉降远小于摩擦桩的工后沉降。因此,有必要对坐落于软土地基上摩擦型群桩基础进行加固处理,以满足工后差异沉降要求。

Settlement Calculation and Parameter Analysis for Pile Foundation of High-speed Railway Bridge in Karst Area

According to the Xuzhou special bridge construction of Zhengzhou-Xuzhou High-speed Railway,this paper made an analysis on the influence of the thickness of underlying soil layer and the dimension of cave span in the lower limestone layer of the pile foundation on the settlement of the pile group foundation.The result shows that the settlement of pile group foundation is mainly caused by the compression of the lower part of the pile group foundation,and the thinner soil layer is,the smaller the settlement of the pile group is.The size of the cave span has little effect on the total settlement of the pile group foundation.When the friction pile and the rock-socketed pile are used in the two adjacent pile foundations,the settlement of the rock-socketed pile is much smaller than that of the friction pile.Therefore,it is necessary to strengthen the soft soil foundation with friction group pile,so that the settlement can meet the requirements of post-construction differential settlement.