Effect Of Slurry Shield Construction Of The Pipeline

Relying Jiangsu Jiang Chengjiang West Road over the river tunnel project, the construction of large diameter slurry shield disturbing effect on the soft soil layer. First, to explore the surface longitudinal settlement law shield tunneling, to verify the cause of the four stages of soil disturbance on the basis of previous studies, the proportion of the different stages of the degree of soil disturbance come in soft soil layer construction. Secondly, based on the theory of large diameter slurry shield construction characteristics and transverse settlement trough does not consider the rate of incision the pressure the under-voltage rate and grouting pressure overpressure formation caused by loss, proposed GAP parameter correction formula. Peck formula to apply to amend and based on the analytical solution of the Sagseta theory, field data to verify that:the equivalent strata loss caused by factors take into account the quality of construction, the rate of incision pressure under-voltage and grouting pressure overpressure rate greater settlement value calculation results with the measured data is more consistent, and theoretically more reasonable. Finally, the use of the Python language program written to the ABAQUS finite element software, the establishment of a three-dimensional finite element model, the use of cell life and death shield construction stiffness migration simulation of the construction process, and consider nonlinear deformation of the soil in the numerical calculations. By numerical simulation:horizontal, vertical, vertical displacement trends in accordance live, close to the maximum settlement amount with the measured data; Then, investigate the effect of shield construction of the pipeline:Using Python programming language written ABAQUS finite element software, create a three-dimensional finite element model, the use of cell life and death functions to achieve the simulation of shield construction stiffness migration of the construction process, and in the numerical calculation Consider the nonlinear distortion in the soil. Get:the top soil layer of concrete pipeline depth positions affected by the pipeline, soil displacement is not significantly less than the impact of concrete pipeline soil, and in the depth of the position of each point below the line will move closer to the settlement, eventually tends to coincide. As well as to increase the stiffness of the next line lying layer deposition can inhibit the role of the pipeline, through reasonable grouting lying layer stiffness under increasing pipeline, the pipeline can be achieved to reduce sedimentation purpose of reducing the impact of construction on the pipeline. Compared to soil stiffness increases above the pipeline, increasing the stiffness of the lower layer of the pipeline lying settlement more effective inhibition of the pipeline. It can be obtained by numerical calculation:In the process of promoting Shield, when just below the shield forward to pipelines, sewer settlement is maximized. Calculating the maximum value obtained by using the settlement model UH compared with larger deformation of the Mohr-Coulomb model, using the model UH deformation curve and the measured curve is closer to the deformation, the deformation amount of the measured data using the Mohr-Coulomb model is smaller. In addition, with the decrease of the shield and the vertical distance pipelines, pipeline settlement gradually increasing it has a direct relationship with the underlying layer to reduce the stiffness of the pipeline. Therefore, the vertical distance between the shield and pipeline safety were discussed. And, analyzed and summarized by pipeline through the process of shield protection measures for pipeline and emergency measures.Finally, increase the upper soil layer, E, C, C,Ф values can effectively reduce the settlement of soft soil layer, reducing the shield construction soil disturbance, which demonstrated, reduce soil disturbance for the purpose of reducing the settlement can be achieved through the surface of the soil grouting reinforcement.