Study On The Micro Disturbance Construction Technology Of High-speed Railway Environment Under The Shield Of Water Rich Sand Layer In Loess Area

When the earth pressure balance shield machine is driving in the water rich sand layer in the loess area,it is easy to have problems such as too fast abrasion of the shield cutter,difficulty in establishing the earth chamber pressure,and large ground settlement.Based on the first underground high-speed railway culvert project of water-rich sand shield in loess area,this paper adopts the methods of indoor geotechnical test,numerical analysis and field excavation test,and systematically studies the environmental micro disturbance construction technology of water-rich sand shield under high-speed railway in loess area from three dimensions of soil improvement,shield machine adaptability transformation and stratum reinforcement measures.At the same time,based on the intelligent monitoring,the rationality of a series of technologies is verified,and the control method of environmental micro disturbance parameters based on the speed confidence interval of cutterhead is preliminarily proposed,which can be used as an effective method of environmental micro disturbance control for the water rich sand layer EPB shield passing through the high-speed railway.The main research contents of this article are as follows:(1)Risk analysis of shield tunneling through high-speed railway.Midas finite element analysis software is used to simulate the construction process of shield tunneling under the culvert of high-speed railway passenger dedicated line.The environmental disturbance risk is analyzed from the perspective of surface settlement law and culvert structure deformation law,which provides effective reference for the research of environmental micro disturbance construction technology and the formulation of intelligent monitoring scheme.Midas finite element analysis software is used to simulate the construction process of shield tunneling under the culvert of high-speed railway passenger dedicated line.The environmental disturbance risk is analyzed from the perspective of surface settlement law and culvert structure deformation law,which provides effective reference for the research of environmental micro disturbance construction technology and the formulation of intelligent monitoring scheme.(2)Study on micro disturbance construction technology of high-speed railway under shield.In this paper,based on the project of water-rich sand layer earth pressure balance shield passing through the culvert of high-speed railway in loess area,using the research methods of soil improvement test,numerical analysis and field tunneling test,the micro disturbance construction technology of water-rich sand layer shield passing through the high-speed railway environment in loess area is systematically studied from three dimensions of soil improvement,shield machine adaptability transformation and stratum reinforcement measures.It can provide more scientific theoretical guidance for the safety construction of similar projects.(3)The rationality analysis of the micro disturbance technology in the environment of shield tunneling through high-speed railway.Based on the intelligent monitoring system of "Leica ts50 magnetic suspension type automatic total station + supporting equipment",the real-time monitoring is carried out for the shield tunneling under the high-speed railway passenger dedicated culvert project,and the rationality of environmental micro disturbance construction technology is evaluated from the perspective of settlement deformation control effect and shield mechanical parameter control effect.Based on the in-depth analysis of the variation and deviation ratio of the speed parameters of cutter head with large data base,the control method of environmental micro disturbance parameters based on the confidence interval of the speed of cutter head is preliminarily proposed,which can be used as an effective method for the control of environmental micro disturbance of the high-speed Railway under the water rich sand layer EPB shield.