Application And Performance Analysis Of Prestressed Anchor Rods In Deep Foundation Pit Construction Of Subway

In the process of rapid urbanization,the problems caused by the backwardness of the transportation infrastructure and the development of the city have received more and more attention.The construction of subway transportation lines has become the main means for cities to ease traffic pressure.A large number of deep foundation pit projects have also emerged throughout the country.The deep foundation pit of the subway has obvious regional characteristics,the construction conditions in the city are harsh,and the safety and quality requirements of the project are higher.Therefore,using reasonable enclosure structure and support method to limit the deformation of deep foundation pit of subway and reduce the adverse impact caused by construction has become an important factor to be considered in the construction of deep foundation pit.Prestressed anchor support has been widely used in deep foundation pit engineering,but theoretical research on prestressed anchor support is insufficient.Combined with actual engineering,numerical simulation analysis of prestressed anchor support can continue to optimize its support.The effect is optimized.Based on the excavation of the foundation pit of the Beidaiying Street Station of Shenyang Metro Line 1 0,this paper analyzes the deformation law and causes of the enclosure structure through the combination of actual monitoring data analysis and finite element model simulation data analysis.A method for improving the stability of the envelope by optimizing the prestressed anchor support was explored.The main research work is as follows:(1)Understand the project overview and be familiar with the construction plan,support plan,monitoring plan,and carry out on-site monitoring of the foundation pit,and use the monitoring data to summarize the deformation law and force characteristics of the retaining pile,the surface,the prestressed anchor support,etc.Analyze the reasons.(2)Through the theoretical analysis and data query to understand the characteristics,categories and advantages of prestressed anchors,to study the factors affecting the effect of prestressed anchors and the way of impact.(3)Establishing the finite element model to simulate the deformation of the foundation pit,using the measured data to modify the model,analyzing the deformation law and deformation reasons of the foundation pit,and deeply studying the specific influence effect of each parameter on the prestressed anchor support effect,which is the prestressed anchor.Rod optimization design provides a reference.(4)Through simulation analysis,it can be used as a reference for the optimization of prestressed anchor support of similar deep foundation pits:the anchorage section of prestressed anchor should be anchored in a more stable soil layer,and the ideal anchorage length is 8m.Between 12m,the ideal anchoring angle is 10 degrees to 20 degrees,the prestressing can improve the supporting effect,and it is generally suitable to apply the prestress between 150kN and 200kN.Under the same conditions,the increase of the foundation pit width requires higher support,and the influence of the foundation pit width cannot be ignored during design.