The Impact Of Site Condition And Ground Building On Seismic Response Of Underground Structure

With the continuous progress of the development of economy and society,living space of human being is needed,so underground space has been developed.However,with the economic progress and development,effects of earthquakes and other disasters have become increasingly frequent.Such as the Jiuzhaigou Earthquake,Wenchuan Earthquake and the Great Hanshin Earthquake,and these earthquakes have caused enormous losses on society and economy.The adjacent surface building also affects the stability of the underground structure.Therefore,it is necessary to analyse the seismic design of the underground structure.Based on the previous research,some crucial issues related to the seismic response of underground structures are summarized.And in different site condition,the model of soil-underground structure system is built.At the same time,the dynamic response of the underground structures under horizontal seismic excitations is discussed.In order to analyse the influence of buried depth on the underground structure,this paper also set up six different depth three-dimensional model of soil-underground structure.And the dynamic influence of buried depth on the underground structure is analyzed under seismic excitation.For the impact of aboveground buildings on underground structures,a three-dimensional finite element model of underground structure-soil-ground buildings is established.The dynamic response of underground structures under different height and different space position of adjacent surface buildings are studied respectively.The main research contents of this paper are concluded as follows:(1)Using the finite element software ADINA to build the three-dimensional soil-underground structures whose buried depth is 10 m and site condition is single homogeneous soft soil.The dynamic response of the structure under the seismic excitation has been studied.It analyses the part of maximum seismic response in the underground structure.And it selects some key nodes in the part of maximum seismic response as a reference point for further working conditions.(2)Based on the soil-underground structure theory,the finite element model has been established under different site conditions.Under horizontal seismic excitations,the dynamic response of underground structures is analyzed under different site conditions,including the soft soil,sand,upper part of the structure with sand sandwich and lower part of the structure with sand sandwich.The lower part of the structure with sand sandwich has great impact on the structure.(3)Under the condition of different buried depth,the basic rule and the influence degree of acceleration,displacement and stress response of underground structure under earthquake excitations are studied under the condition of different buried depth.Under the condition of shallow buried,the underground structure in the soil presents a certain response law with the increased buried depth.(4)A three-dimensional finite element model of the underground structure-soil –adjacent surface buildings has been established.It firstly compares and analyzes the dynamic response law and influence degree of the underground structure under the earthquake excitations,with the ground building and no ground building.Secondly,based on the model of the underground structure-soil–adjacent ground buildings,the dynamic influence and longitudinal responses of underground structures under different height of the building and the relative position between the building and the underground structure are analyzed.Finally,according to the results,the model of serious seismic response is added isolation trench between ground building and underground structure in surface,and dynamic response of different depth of the underground structure is analyzed and compared.