Stability Analysis Of The Great Wall Overlying On The Shallow Double-arched Tunnel

With the development of the underground engineering, more and more problems onthe adverse geological conditions and existing building safety are ocruring. The inducedstress caused by the underground excavation is the root reason that generates deformation,failure and instability for the buildings and structures.So, the stability analysis of the GreatWall overlying on the shallow double-arched tunnel is very important for the engineeringpractice.The engineering background is the shallow double-arched tunnel with the overlyingGreat Wall, which is one part of coastal road from the Shihe bridge to the Hebei-Liaoningborder. Based on the technical requirements of the shallow double-arched tunnelunderlying the Shanhaiguan Great Wall during congstruction and opertation period, thethree-dimentional numerical model is established using the finite element software ofMIDAS-GTS. According to the model, the mechanism of influence on the Great Wall bythe stress relief during construction period is analized, and the stability of the Great Wallby the vibration load of vehicle during the opertaion period is studied. The mainresearches in the essay are as follows:(1) According to the general situation of engineering and the requirements of thenational related department, the construction method of shallow-buried double-archedtunnel through the Great Wall and the reinforement scheme are proposed to insure thesafety of ancient Great Wall.(2) The difficulties and key points of the tunnel excavation are stated in detail, andthe interaction relationship of the tunnel, the surrounding rock and the Great Wall isexplained. Based on the analysis, the effects of tunnel construction on the Great Wall isachieved by the stratum deformation and its transmission.(3) The response mechanism of tunnel under the static and dynamic loads issystematically analyzed, and the dynamic time-load curve of vehicle crossing the tunnelduring its operation is given.(4) According to the geological conditions and tunnel construction method, thethree-dimensional numerical model of tunnel excavation is established.Using the Coulomb -Mohr failure criteria, the mechanical behaviors of the Great Wall during the tunnelexcavation with two kinds of supporting scheme are studied individually and compared.(5) Based on the three-dimensional numerical model of tunnel during the operationperiod, the impact of vehicle vibration load on the Great Wall under the condition oftwo-way transport service is studied and the time-history curve of mechanical effect of theGreat Wall is obtained. The stability of the Great Wall proves the reliability of thesupporting scheme of the Great Wall.