Analysis Of Seismic Response Of Underground Structure And The Adjacent Ground Building

ABSTRACT:As China’s economic development and social progress, urban underground space is vigorously developed to improve the bearing capacity of the city’s. Under the background of urban underground space development, underground and surface structures are getting closer, the dynamic interaction between the two can not be ignored, they are a complex dynamic interactive system. On the one hand, due to the presence of large underground structures, the surface movement difference in free field motion, thereby affects the seismic response of the ground structure. On the other hand, due to the presence of ground structures, the structure vibration can be radiation in the soil to change the motion of the ground soil, and the seismic response of underground structures is precisely determined by the movement of surrounding ground soil. In order to improve the seismic safety of our cities, in-depth study the dynamic interaction between underground structures and ground adjacent buildings is very necessary.This paper establishes an overall analysis model which is considering the dynamic interaction between the underground structures and the adjacent buildings, applying the finite element software ABAQUS to complete the numerical simulation. Based on testing and verifying the reasonableness of dynamic boundary, inputting seismic wave, nonlinear contact, soil-structure interaction, it analyzes the influence of underground structure in different deep on the surface of the seismic motion, the effect of interaction under the condition of different depths of underground structures, different relative positions of the buildings and different frequency of incident wave, and though the orthogonal test, identified the primary and secondary relationships of the main factors.(1) When there is no ground construction, greater impact on the depth of underground structures on surface seismic movement (surface displacement and acceleration), with the increase in tunnel depth, surface seismic movement increase firstly and then decrease, and gradually levels off.(2) In a certain depth of tunnel, different incident frequency impact on the surface seismic significantly, in the same incident wave frequency, when the buried depth of the tunnel and the tunnel diameter ratio is in the range of1-2, surface seismic response changes obviously, when depth and diameter ratio exceeds2.5, the surface seismic response gradually levels off.(3) When there is ground construction, the mutual influence on seismic response of ground buildings and underground structures increase firstly and then decrease and gradually leveled off with increasing spacing between the two, and increases with depth of underground structures, mutual influence increase firstly and then decrease, and tended to the case without underground structures.(4) The mutual influence above also related to the frequency of the incident, when the incident wave frequency is in the1～10Hz, the mutual influence on seismic response of ground buildings and underground structures decrease with the increase of the incident frequency, and gradually leveled off.(5) Through the orthogonal test, selects quasi level method to analyze the whole underground structures and surface buildings in the statistical method of four factors (base rock, depth of underground structure, frequency of incident wave, relative positions between the underground structure and surface buildings) and three levels, draw on various factors affect the size of the seismic response of underground structures is:depth of underground structure>relative positions between the underground structure and surface buildings>frequency of incident wave>base rock, for surface buildings, the effect size of the seismic response is:depth of underground structure>frequency of incident wave>relative positions between the underground structure and surface buildings>base rock.