深基坑近距离开挖对广州某高压电缆顶管隧道的 影响

由于邻近施工的影响,一些高压电缆顶管隧道出现了变形、裂损和接头张开渗漏等问题。采用数值模拟方法,研究了深基坑工程近距离开挖时(L/D_e≤0.75)可能对广州某高压电缆顶管隧道产生的影响。结果表明,由于深基坑工程支护结构的刚度和基坑开挖深度都较大,顶管隧道的位移主要表现为竖直方向上的"向上隆起";隧道横断面径向变形很小,可以忽略不计。在目前的基坑支护方案及其与电缆隧道的净距(L=12 m)条件下,顶管隧道结构的水平、竖向位移和径向收敛都较小,没有超出相关规范的要求;但当净距L减小至2~5 m时,顶管隧道的上浮将可能超限。

Influence of Nearby Deep Excavation on a Pipe-Jacking Tunnel of High-Voltage Cables in Guangzhou

Affected by adjacent construction,the deformation,cracking,opening and leakage of joint of pipe-jacking tunnels are found out.The effects of nearby deep excavation(L/D e≤0.75)on a pipe-jacking tunnel of high-voltage cables in Guangzhou are studied by numerical simulation method.Results show that vertical displacement of cable tunnel is obviously observed rather than lateral displacement.This might be attributed to the large stiffness of supporting system and large excavation depth.The radial deformation of cable tunnel is relatively small and can even be ignored.According to the current design scheme of retaining structure and the net distance between excavation site and tunnel(L=12 m),the displacement and radial deformation of pipe-jacking cable tunnel are controllable.However,when the net distance L reduces to 2~5 m,the uplift of cable tunnel may exceed the allowable limit.