大型地下立交动态施工过程3D有限元分析

3D Finite Element Research on Dynamic Construction Mechanics for a Large-sized Underground Interchange

互通式地下立交是大型复杂的地下空间交通工程,目前国内外在这方面的研究和可供借鉴的成果还很少。互通式地下立交一般处于城市化水平高,地面建筑密集,地下管网复杂,路网不易改造的城市中心区,地下立交不同横断面处的地下空间结构形式是不同的,既有平交、双洞合一的大断面,也有双洞上下正交,动态施工力学复杂,影响因素众多。结合重庆市渝中区朝天门大型互通式地下立交可行性研究,通过三维弹塑性有限元数值模拟,对地下立交的平交(15°)和上下正交两种情况钻爆法动态施工力学进行研究,以检验可行性研究提出的方案的合理性,为地下立交施工方案优化提供科学依据。

The underground interchange is a large and complicated underground traffic project. At present, the researches on the underground interchange and the achievements in this field are rare. The underground interchange is usually located in the urban center where the urbanization level is high, the ground buildings are condensed, the underground pipe- network system is complicated and the road network system can not be reconstructed easily. At different cross sections of the underground interchange, the layout forms of the underground space are different. There is not only the double excavations crossed in a plane or combined into one tunnel, but also the form that the double excavations are located vertically from each other. There the dynamic construction mechanics is complicated and the influencing factors are multitudinous. In conjunction with the feasibility study of the large underground interchange at Chaotianmen in Yuzhong District of Chongqing and by 3D elasto - plastic finite element numerical simulation, this paper presents the researches on the dynamics mechanics with the drill - blast tunneling method when the tunnels are crossed in a plane （ with an angle of 15° ） and the tunnels are vertically located. These researches can test the reasonability of the scheme in a feasibility study and then can offer some scientific basis for the construction scheme of the underground interchange.