Design and Construction Technology of Back System of Two-way Jacking Pipe in the Same Starting Well
According to the situation of two or more pipe jacking operations in the underground pipe gallery project,based on the pipe jacking engineering example of the comprehensive pipe gallery EPC project of Danxia Road in Nanchang,the technology of two-way pipe jacking operation in the same originating well was analyzed and studied.A numerical calculation model was established to analyze the stress of the relevant structural system.Combined with the finite element numerical simulation method,the stress characteristics under different construction sequences were compared.The results show that:under the same load condition,the maximum bending moment of the back wall when pushing two pipes on one side is larger than that when pushing symmetrically.The back structure meets the requirements of stress and stability in each engineering process.The feasibility of using rib type back wall as back support,distributing the reaction force of main jacking cylinder through the back of steel boxed box,and setting double row and two-way back system in the large jacking launching well is verified.The construction and demolition technology of the back wall structure is further proposed,and then verified by the deformation monitoring of the back wall in the actual project.