岩溶对高铁桥梁桩基沉降影响分析

Analysis of the Influence of Karst on Pile Foundation of High-Speed Railway Bridge

摘要: 本文结合郑徐客专工程，分析了下伏土层的厚度和溶洞跨径等对墩台群桩基础沉降的影响，并分析了当相邻墩台采用两种类型桩基础时，两者之间的差异沉降特点，从中找出下伏土层加固的方法与施工措施。结果表明，群桩沉降变形主要由桩端下卧土层的压缩造成；溶洞跨径基本上对群桩基础的总沉降影响不大；当相邻两墩台基础分别采用摩擦桩与嵌岩桩时，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的要求。

Abstract: According to Zheng Xu special railway line for passenger transportation project, this paper analyzed the influence of the thickness of the soil layer beneath the pile foundation and the cave span in the lower limestone layer on the settlement of the pile foundation and the post-construction settlement. At the same time, this paper analyzed the characteristics of differential settlement when the adjacent piers and towels adopt two different types of pile foundation. Then the method and construction measures of the lower soil reinforcement were found out and the corresponding construction technology was put forward. The results show that the settlement of pile group is mainly caused by the compression of the lower part of the pile foundation. The size of the cave span basically has little effect on the total settlement of the pile group foundation. When the adjacent two piers use the friction pile and the rock-socketed pile, it is necessary to reinforce the foundation of the friction pile on the soft soil foundation to meet the requirement of post-construction differential settlement.