广州岩溶地区深基坑开挖对周围环境影响的研究

Field investigation of deep excavation of metro station on surrounding ground in karst region of Guangzhou

以广州地铁9号线在岩溶地区施工深基坑为例,研究岩溶地层基坑施工对周围环境的影响。该车站基坑长259.7 m,宽18.7 m,深15.8 m。基坑深度范围内包括溶洞和砂层,溶洞地层富水、稳定性差、物理力学性质差,砂层厚0~15 m,有较大的渗透性,基坑施工过程中对地下连续墙的侧向位移和地面沉降进行了监测。监测结果表明,基坑开挖结束时地下连续墙的最大侧向位移为12 mm,地面沉降的最大值为10.1 mm,基坑开挖过程中对周围环境的影响很小。研究成果可为今后类似工程施工提供经验借鉴。

This paper presents a case history of an investigation into the responses of the surrounding ground to the deep excavation of a metro station of Metro line 9 in the karst strata of Guangzhou, China. The metro station is 259.7 m long by 18.7 m wide by 15.81 m deep. The construction site mainly consists of two typical strata of the karst strata and sand layer. The karst strata, with poor mechanical properties and low self-stability, is a geological formation shaped by the dissolution of the carbon limestone. The thickness of sand layer is 0 ? 15 m, which is of high hydraulic conductivity. During the field test, lateral deflections of the diaphragm wall and ground surface settlements were monitored. The test results show that the maximum lateral displacement of diaphragm wall is 12 mm and the maximum ground surface settlement is 10.1 mm. The monitoring results indicate that during construction there is minimal impact on the surroundings. Such field monitoring may allow for the formation of a database to guide the future engineering practices.