浅埋暗挖过街地下通道施工方案的数值模拟

Numerical simulating on underpass by shallow tunnel construction method

针对银川市区采用明挖法修建过街地下通道存在的问题,采用数值模拟的方法探讨了浅埋暗挖技术应用于城市过街地下人行通道的施工方案.根据工程勘察设计资料,利用FLAC-3D软件,建立了银川市区北京路西桥巷过街地下通道浅埋暗挖法施工的数学模型,并对中隔墙法(CD)和十字隔墙法(CRD)两种工法的施工过程进行了数值模拟.计算结果表明,十字隔墙法在地表沉降、拱顶位移、水平收敛位移、塑性区分布等方面均优于中隔墙法.从地下通道施工过程的稳定性及控制地表沉降的角度考虑,采用十字隔墙法比较合适.由于银川市区已建和在建的地下通道均采用明挖法施工,数值模拟结果的准确性还无法得到工程实测数据的验证.

For the deficiency of the traditional open-cut method to underpass in Yinchuan City Street, the rational construction procedure of shallow tunnel method is discussed by using numerical simulation method. The numerical model of the underpass for the cross of Beijing road and Xiqiao street in Yinchuan urban is established by FLAC-3D software based on engineering survey and other design information. The underpass construction process of CD （center drift）and CRD （cross drift） methods are simulated. Results show that CRD method is more excellent than CD＇s in some aspects, such as surface settlement, vaulted displacement and the horizontal convergence displacement, plastic zone distribution and more. From the point of view of stability of underpass construction process and control of the surface settlement, CRD method is prospective in underpass construction. Because underpass constructions of the Yinchuan city have used open-cut method, the accuracy of the numerical simulation results can not get the project measured data validation yet.