Guiyang Shallow Buried Underground Excavation Subway Construction Caused By The Law Of Surface Deformation And Control Measures

With the rapid development of China’s economy,the demand for public transportation has also increased,and the construction of urban rail transit industry has gradually entered the blowout period.In recent years,China’s major cities have begun the construction of rail transit,mainly mainly subway,more and more new subway tunnels under the existing road projects began to appear.In this paper,based on the high-filling red clay weak formation project of Longshui Road under the second phase of Thesenlong Dark Digging Tunnel Section of Guiyang Metro Line 2,the construction impact and control measures of the existing municipal roads under the newly dug subway tunnel are studied by using the method of combining numerical simulation with the actual monitoring and measurement data on site,and the following conclusions are obtained:(1)The deformation law of the upper formation caused by the existing road construction under the newly constructed dark tunnel is studied,and the corresponding factors affecting the deformation of the formation are summarized.(2)Using numerical simulation method,the construction stability of the new dark excavation tunnel under the three different excavation methods of "up and down steps","reserved core soil method" and "CD method" is simulated,and through comprehensive comparative analysis of many aspects,it is suggested to use the "up and down step method" construction,which can speed up the construction progress and save investment.(3)The effect of surface grouting reinforcement in the project was evaluated by numerical simulation,and the width range of grouting reinforcement was simulated and optimized.The results show that after surface grouting,the deformation of the stratum and the force of the supporting structure have been significantly reduced,the strength of the surrounding rock has been significantly improved,and the width of the grouting reinforcement can be better controlled after appropriate widening Ground deformation can be optimized for construction accordingly.(4)Using numerical simulation methods to study the impact of different excavations on formation deformation,from the surrounding rock deformation,support structure force,surrounding rock stress and plastic area range and other aspects of comprehensive comparative analysis,it is recommended to optimize the use of 1 meter excavation into the ruler,0.154 D excavation ratio conditions for excavation,this method can save construction resources and speed up the construction progress.(5)Based on the analysis of the actual monitoring measurement data on the spot,the law of formation deformation is studied,and the measured data and other results are verified by comparison,which shows the rationality of the current construction scheme and the reliability of the numerical model.