武汉长江盾构隧道洞口浅埋段施工地层稳定性数值分析

Numerical Analysis on Ground Stability during Construction of Shallow-buried Portal Section of Wuhan Yangtze River Crossing Shield-driven Tunnel

武汉长江隧道工程采用直径11.37m泥水盾构施工,盾构始发段地质条件复杂,隧道覆土厚度7m左右,同时受加固区与地面建筑影响,地层应力状态非常复杂,而对开挖泥水压力的设定一般都采用简单土压力理论计算值,但与实际地层压力分布差别较大。现采用数值模拟方法分析始发掘进过程引起的地层位移规律,以此来确定开挖面的合理泥水压力、泥浆比重等,对指导施工具有一定的意义。

Wuhan Yangtze River crossing tunnel is constructed by means of slurry shield machines with 11.38m diameter. The geology of the launching section of the tunnel is complex, with the thickness of the overburden being about 7m. Influenced by the consolidation zones and surface buildings, the stress condition of the ground is also very complex. In normal cases, the slurry pressure is determined on basis of simple ground pressure theory, which results in values that are much different from the actual distribution of the ground pressures. In the paper, numerical analysis is made on the pattern of the ground displacements induced by launching and boring of shield machines so as to determine the proper slurry pressures acting on the working faces and the unit weight of the slurry. The paper can provide reference for the construction of the tunnel.