软弱土地基深基坑坑底加固对邻近地铁隧道的保护作用分析

Study on Protection of Deep Foundation Pit Strengthening to Adjacent Metro Tunnels in Soft Soil

软粘土地基土体力学性质差,在软粘土地基中进行深基坑施工,易对周边环境产生影响。本文通过杭州地区典型软粘土地基中深基坑工程案例分析,研究了软弱土地基中深基坑坑底加固方式对减少基坑变形的作用,及其对邻近地铁结构的保护作用。研究结果表明:对坑内软粘土进行加固,能有效增强坑内土体强度和刚度,减小坑内土体变形,尤其是采用满堂加固,加固后的坑内土体在坑底形成了一道强有力的加固土支撑带,能大幅减小围护结构和周边环境变形。

Due to the poor mechanical property of soft soil, construction of deep foundation pit in soft soil can easily influence the adjacent environment. Based on a case study of a deep foundation pit in typical soft soil in Hangzhou, the influence of strengthening methods on how to decrease the deformation of foundation pit was analyzed, and the protection on the adjacent metro tunnels was studied. Results shows that the strengthening of soft soil, especially by the ground reinforced method, can effectively improve the shear strength and the stiffness of soil, and reduce the deformation of the soil inside the pit. A strong support strap is formed at the pit bottom after strengthening, which can drastically reduce the deformation of both the retaining structure and the environment.