客运专线深大排桩围护基坑安全影响因素及对策分析

为系统分析深大排桩围护基坑的安全影响因素，结合成绵乐客运专线双流机场段基坑工程，利用结构变形现场监测数据进行了设计参数与施工工序的安全影响分析，并提出了增强基坑工程安全性的技术对策。研究结果表明:排桩围护结构主要呈现桩顶与桩底变形小、中间变形大的“大肚状”形态，其中，围护结构刚度与旁载主要影响围护桩的变形量，支撑类型与放坡平台对变形形态和变形量都有影响，而施工工序主要影响围护结构的变形速率，施工质量则是直接与工程安全相关；根据“长条形基坑分段、大基坑分块”的设计施工原则，加强施工安全监管与信息化技术，可大大降低深大基坑的技术风险。

Analysis on Countermeasures and Factors Affecting Safety of Row Pile Retaining Deep and Large Foundation Pit along Passenger Dedicated Lines

In order to systematically analyze the factors affecting safety of row pile retaining deep and large foundation pit, the analysis on effect of design parameters and construction process on safety was carried out and the technical countermeasures regarding safety enhancement for foundation pit was proposed, which was combined with the project of foundation pit along Shuangliu Airport section of Chengdu-Mianyang-Leshan Passenger Dedicated Lines and made use of on-site monitoring data with respect to structural deformation. The research results show that the row piles retaining structure mainly presents a shape of ＂potbelly＂, i. e. small deformation at pile top and pile bottom and large deformation in the middle, wherein the rigidity of the retaining structure and side load mainly affect extent of deformation of the supporting piles; the type of supporting and the slope setting stage impact both shape and extent of the deformation ; the construction process mainly have an influence on rate of the deformation; and the construction quality is related to the safety directly. According to the construction principle of ＂ long column foundation pit in segments and large foundation pit in blocks＂, the supervision on safe of construction and information technology are intensified to reduce technical risks on deep and large foundation pit greatly.