盾构地铁隧道穿越电缆隧道扰动规律研究

Study on the disturbance law of shield subway tunnel through cable tunnel

在邻近地下电缆隧道处进行地铁盾构施工,周围土体受到扰动,土体应力重分布进而导致电缆隧道产生位移,结构破坏变形。为研究盾构隧道穿越对电缆隧道的扰动规律,从盾构隧道和电缆隧道的空间位置关系、净距及电缆隧道的截面尺寸3个方面进行大量数值模拟,得出不同工况下的受力和变形曲线,在此基础上对电缆隧道的环形和纵向安全系数进行验算,并得到随间距变化二次衬砌与结构最小安全系数的关系曲线,从而提出了两种工况下施工安全保护距离。研究得出以下结论:(1)电缆隧道的竖向位移与纵向拉应力随间距的减小而增大,随截面尺寸扩大,电缆隧道承受的纵向拉应力随之扩大,产生的沉降值减小;(2)二次衬砌结构最小安全系数随间距的减小而减小,随截面尺寸的扩大而减小;(3)相同条件下,斜下45°平行侧穿的安全保护距离要小于垂直下穿工况,安全性更高。

In the adjacent underground cable tunnel construction process,the surrounding soil is disturbed,and the soil stress redistribution leads to the displacement of the cable tunnel and deformation of the structure.In order to study the disturbance law of shield tunnel crossing on cable tunnel,a large number of numerical simulations are carried out from three aspects:spatial position relationship between shield tunnel and cable tunnel,clear distance and cross-sectional size of cable tunnel,and the force and deformation curves under different working conditions.On this basis,the annular and longitudinal safety factors of cable tunnels are checked,and the relationship curve between secondary lining and the minimum safety factor of the structure is obtained with the change of spacing,so as to propose the construction safety protection distance under two working conditions.The main conclusions are:(1)The vertical displacement and longitudinal tensile stress of the cable tunnel increase with the decrease of the spacing,and with the expansion of the cross-section size,the longitudinal tensile stress of the cable tunnel expands accordingly,and the resulting settlement value decreases.(2)The minimum safety factor of the secondary lining structure decreases with the decrease of the spacing and decreases with the expansion of the cross-section size.(3)Under the same conditions,the safety protection distance of diagonal 45°side penetration is less than that under the vertical underpass condition,and the safety is higher.