Research On Load Characteristics And Construction Mechanics Of Similar Rectangular Pipe Jacking

With the development of our country’s economy and the acceleration of city’s municipal construction,major and medium-sized cities are committed to building a three-dimensional and comprehensive modern transportation system.The demand and requirements for the construction of urban underground space are also constantly increasing.Traditional open-cut construction methods can no longer meet the needs of the current project.In order to ensure the smooth flow of urban roads,more and more non-excavation techniques are used in the construction of urban municipal projects,including the top-pipe project.This article relies on the rectangular pipe jacking project of Sichuan University’s pedestrian traffic channel at Chengdu South Road,and studies the load characteristics,construction mechanics,and the effect of excavation on the formation deformation of the rectangular pipe jacking.The following main research results have been obtained:(1)The complicated relationship between contact with soil during the jacking process of rectangular pipe jacking is analyzed,and the various loads acting on the pipe section of the rectangular pipe jacking are analyzed in detail.The forces of the pipe section were divided into two discussions: unloading arch theory and soil column theory.The formulas for calculating the frictional resistance of the pipe section and the soil are given.the theoretical calculation formula for the jacking force of the rectangular jacking pipes under different depths is deduced.From the four aspects of the top pipe section parameters,the grouting of the pipe wall,the soil parameters of the pipe section and the construction factors,the influence on the top thrust was analyzed.(2)Through the establishment of a three-dimensional numerical model,the top tube internal forces,formation deformation,tube-soil contact pressure,tube-to-nodal contact pressure,and tube-soil friction resistance under different jacking distances during the construction of rectangular pipe jacking were studied.The law of change reveals the construction mechanics behavior of the rectangular pipe jacking.(3)Through the establishment of a three-dimensional numerical model,the excavationprocess of rectangular pipe jacking was simulated using the shear failure criterion of rock and soil,and the effects of different excavation modes、different jacking speeds and different reputation on the excavation of excavation of the pipe jacking project were studied.The numerical simulation results give a reasonable excavation mode and jacking speed.(4)Relying on practical engineering,various construction difficulties encountered during the actual construction of a class of rectangular pipe jacking were analyzed,and the surface deformation was analyzed in conjunction with field monitoring measurement data,revealing that the type of rectangular pipe jacking in different stages during the construction process The effect of the distance on the ground surface.