Research On The Subgrade Settlement And Controlling Measures Of High-speed Railway During The Under-passing Of Shallow Metro Tunnel Construction

With the gradual formation of high-speed rail network, a large number of traffic engineering crossing high-speed railways will appear. Due to the characteristics of the high-speed railway, new roads and railways cross the existing or under construction of high-speed Cross railroad should give priority to choose the program that high-speed rail under-pass the roads or railways. The embankment settlement of the high-speed rail is the key technical issues. Study on the control technology of the subgrade settlement caused by under-crossing tunneling to ensure the safety of high-speed rail and meet the needs of the construction is of great significance and practical value. This paper studied on the basis of the previous settlement mechanism of the embankment settlement caused by the tunnel construction, and in accordance with the relevant domestic and international norms of the subgrade settlement and track deformation of the high-speed railway to make the control standards of the subgrade settlement and track deformation, analyzes the different influence factors in under-crossing project of high speed railway embankment settlement and track deformation, according to the ideas of the based on the control of subgrade settlement and track deformation, we put forward the feasibility of the indicators under-passing the high-speed railway, and based on this indicators system we study on the feasibility of under-passing indicators in soft soil under using different auxiliary method. This paper mainly completed the following research work:(1) According to the deformation regularity of strata caused by tunnel excavation, this paper analyzes the interaction between strata-embankment-orbit, and analyzes the mechanism of embankment settlement and rail deformation caused by the deformation of strata.(2) By referring to the domestic and foreign relevant norms of subgrade settlement and rail deformation, combined with the control standard in the actual project, according to the safety, adaptability, economic principle, this paper is proposed to the control standards of subgrade settlement and track deformation under the tunnel excavation under-passing the high-speed railway.(3) According to the characteristics of metro tunnel undercrossing the high-speed railway project, analyzes the factors affecting the high-speed railway subgrade settlement and track deformation in crossing project. This paper uses the numerical simulation software FLAC3D to simulate and analyze the different factors, and analyzes the space-time distribution of the subgrade settlement and track deformation under the tunnel excavation undercrossing the high-speed railway.(4) According to the control theory of the high-speed railway embankment "Zero settlement after construction", we put forward the feasibility of the indicators under-passing the high-speed railway based on the control of subgrade settlement and track deformation, and based on this indicators system we study on the feasibility of under-passing indicators in soft soil under using different auxiliary method to provide guidance for the under-passing the high-speed railway projects in the future.