珠三角深厚软土区公路隧道深基坑施工安全控制研究

Research on Construction Safety of Deep Foundation Pit of Highway Tunnel in the Pearl River Delta

摘要: 珠三角地区的软土具有含水量大、压缩性高、承载力低等特性，对基坑工程的设计和施工都提出了更高的要求，深基坑支护设计和施工面临诸多挑战。因此，本文以珠三角公路隧道深基坑工程为背景，分析了基坑施工状况，重点介绍了施工中存在安全问题。釆用岩土有限元分析软件对该工程的开挖过程进行模拟,分析基坑边缘的堆载和支护时机对基坑稳定性影响。结果表明：基坑边缘荷载控制在20 kpa以内，荷载离基坑边缘距离超过5 m，钢支撑及时架设，可大大减小桩身位移值。研究结果对类似软土公路隧道深基坑的开挖具有一定的借鉴意义。

Abstract: The soft soil in the Pearl River Delta area has the features of high water content, high compressi-bility and low carrying capacity, etc., which have put forward stricter requirements for the design and construction of foundation pit project. There are many challenges in the design and construc-tion of deep foundation pit engineering. Therefore, this paper, taking foundation pit excavation in the section of highway tunnel, analyzed the present situation during excavation of foundation pit. The geotechnical finite element analysis software simulated the excavation of foundation pit, which analyzed the influence of pile load and support timing on foundation pit stability. The results show that: the load of the foundation pit edge is within 20 kpa; the distance of the load from the foundation pit edge is over 5 meters; the steel support was erected at the first half of the excavation. The results can be used for reference to other similar venues construction.