Study On The Improvement Of The Response Displacement Method For Underground Strutures Under Complex Site Conditions

With the rapid development of urbanization and science and technology,the status of urban ground transportation is not optimistic.Simply relying on ground transportation can no longer fundamentally solve traffic pressure.Metro-based urban rail transportation has become the main source of people's development and use of underground transportation space.form.However,in the process of earthquake,the seismic response of ground structure and underground structure is very different.The seismic design method that completely depends on ground structure can not explain the seismic response of underground structure.Based on the existing seismic design methods for underground structures,this paper combines theoretical analysis with numerical simulation to describe in detail the calculation process of six seismic design methods for underground structures,and compares various calculation methods.The applicability of various calculation methods;for the reactive displacement method calculation method of the calculation of the diversity of principles,the sensitivity of the various parameters of the analysis;Finally,the reaction displacement method to improve,the specific conclusions are as follows:(1)The calculation principle,calculation process and applicability of six methods including FLAC dynamic time history analysis method,general reaction displacement method,integral reaction displacement method,finite element reaction acceleration method,forced reaction displacement method,and Pushover method are introduced in detail.(2)Six types of underground structure seismic design methods have been compared and the two types of underground structures(two-story three-span rectangular structure and two-layer three-span dome structure)have been compared in four different working conditions in different soil layers and different overburden thicknesses analysis.(3)The sensitivity analysis of the four main calculation parameters in the reaction displacement method was performed,and the influence of each calculation parameter on the deformation of the structure was obtained.(4)A method for determining the formation reaction displacement based on the equivalent acceleration and a method for determining the foundation spring based on the thin layer method are proposed.The examples are verified.The results show that the improved reaction displacement method has high calculation accuracy and is close to the dynamic time history method.