立交工程软弱土层基坑防护结构受力分析

随着城市规模的不断扩大和铁路的快速发展,市政道路与铁路立交工程逐渐增多。高规格的市政道路使铁路地道越做越大,同时,新建高速铁路严格的沉降控制对工程实施提出了更高的要求。为了确保市政设施及铁路的安全,必须对越做越大的基坑工程进行有效的防护。以典型的高水位、软弱土层、大面积的基坑工程为例,采用钻孔灌注桩为防护结构主体,用冠梁、桩间腰梁、水平内撑、水平斜撑等方式对基坑工程进行了加强。对施工过程中结构的受力与变形情况进行了详细的分析。经现场实际实施,支护系统稳定安全。

Analysis of the Loaded Forces of the Protective Structure for the Foundation Pits of a Grade Separation Project in the Soft and Weak Stratum

With the continuous expansion of the size of cities and the rapid development of railways,there will be more and more municipal-highway-and-railway~grade-separation projects to be built. High-standard municipal highways make increasingly big- ger railway underground passages to be built. Meanwhile, the strict requirements of newly-built railways in controlling the set- tlement pose a higher demand for the accomplishment of projects. To ensure the safety of both municipal facilities and railways, the increasingly larger foundation pit projects should be effectively protected. With typical high-water-level, large-area founda- tion pit projects in the soft and weak stratum as practical examples,foundation pit protects are strengthened in the paper by u- sing bored piles as the main bodies of the protective structure, and in the form of crown beams, inter-pile mid-beams, internal level struts and level oblique struts. The states of the structure being force-loaded and deformed during construction are ana- lyzed in detail in the paper. Through the practical application of the protective system, it is found that the protective system is both stable and secure.