Influence Research Of Stability Of Existing Access Line Tunnel During Shield Construction In High Groundwater Level Area

In this paper,according to the characteristics of a shield construction project in a high groundwater level section of the Guangzhou Metro,the Midas GTS software and RBF neural network were used to carry out the stability analysis of the high groundwater level section at a short distance through the section line,and to explore different seepage environments The stability control method of the next exit line is as follows:(1)Using the method of combining engineering monitoring and numerical analysis,the construction deformation law of the section line under the high groundwater level is analyzed.The study found that the finite element model considering the fluid-solid coupling effect predicts the cumulative settlement of the vault of the outgoing line.Both curves are consistent with the law of the settlement groove curve,and the trend is consistent.The coupled model fits the actual shield construction excavation process well.(2)Using the finite element model corrected by the monitoring data,the stability study of the shield construction under the outgoing section was carried out.The study found that the vertical displacement of the vault and the bottom of the arch and the concentrated disturbance range of the shield machine are larger than that of the non-coupling model,and the main stress of the segment is reduced.It can be seen that the presence of the seepage field has a greater impact on the stability of the outgoing line.In the design and construction,in order to ensure that the outgoing line is less disturbed,the influence of the seepage field needs to be considered.(3)Using numerical analysis methods,a study was conducted on factors affecting the stability of shield tunnel construction under the exit section.The study found that within a certain range,the elevation of the earth cabin pressure,the grouting pressure,and the vertical displacement are all reduced to varying degrees;when the water level depth increases,the vertical displacement increases and the stability of the outgoing line decreases.(4)Using the RBF neural network based on the Python platform for the construction parameters: multi-dimensional coupling analysis of soil cabin pressure and grouting pressure and water level depth,the shield of the tunnel stability of the outgoing line and the new line under different seepage environments is studied Parameter control method.