偏心顶力下多室沉井结构受力分析

Structure Stress Analysis of Multi-Chamber Open Caisson Under Eccentric Jacking Force

偏心顶进力荷载作用下,多室沉井作为顶管始发井时,结构的受力与变形特性非常复杂。以深圳市固戍水质净化厂二期工程大型沉井为对象,通过数值模拟研究不同的偏心顶力作用下多室沉井结构的工作性状,得出多室沉井结构的受力特性及变形规律。在此基础上提出相应的技术处理措施,即在沉井内隔墙之间浇筑支撑墙,对比分析采用支撑墙之后沉井结构的受力特性和变形规律,验证措施的有效性及可行性。结果表明:顶管施工会使多室沉井结构产生平面上的扭转以及竖直方向上的倾斜,增大沉井结构局部应力,最大主拉应力超过混凝土抗拉强度标准值;浇筑支撑墙后,沉井变形和受力得到明显改善,最大主拉应力减小到1.3 MPa。

Under the action of eccentric jacking force,when the multi-chamber open caisson is used as the starting well of pipe jacking,the stress&deformation characteristics of the structure are very complex.Taking the large open caisson of the second phase project of Gushu Water Purification Plant in Shenzhen as the object,the working behavior of the multi-chamber open caisson structure under different eccentric jacking forces is studied by numerical simulation,and the stress characteristics&deformation law of the multi-chamber open caisson structure are obtained.On this basis,the corresponding technical treatment measures are put forward,that is,the support wall is poured between the internal partition walls of the open caisson.The stress characteristics&deformation laws of the open caisson structure after the support wall is used are compared&analyzed to verify the effectiveness&feasibility of the measures.The results show that:the pipe jacking construction can make the multi-chamber open caisson structure produce plane torsion&vertical inclination,increase the local stress of the open caisson structure,and the maximum principal tensile stress exceeds the standard value of concrete tensile strength;after pouring the support wall,the deformation&stress of the open caisson are obviously improved,and the maximum principal tensile stress is reduced to 1.3 MPa.