Seismic Response Analysis Of Shallow Buried Soil Utility Tunnel In Baotou Area

Baotou area is located in the Yinchuan-Hetao seismic zone and the northeast earthquake area,which is a high seismic risk area.But it is also listed as the first utility tunnel pilot project in China,with the total length of utility tunnel planned in the city of 227.12 km.As an important urban lifeline facility,the seismic research of utility tunnel must be solved.At present,the study on the seismic response of the utility tunnel in high-intensity areas is still in its infancy in China.In this paper,the finite difference software FLAC3 D is used to conduct a numerical simulation study on the seismic response law of the shallow buried utility tunnel in baotou area.This paper has completed the analysis of the following aspects to provide theoretical support and technical reference for the seismic design and construction decision of the utility tunnel in baotou areaFirstly,the development history and research trends of utility tunnel at home and abroad are summarized,and the operation situation of utility tunnel in baotou area is elaborated;The time-history seismic wave of SeismoSignal is adjusted with the software of SeismoSignal,and the results show that the modified seismic wave effectively reduces the residual displacement,saves the computation time,and makes the numerical simulation results more accurate.Secondly,according to the actual engineering projects,the establishment of a comprehensive numerical model of utility tunnel in clayey silt,silty clay and silt pipe gallery soil as a variable,analyzes the comprehensive utility tunnel of the acceleration response,displacement response structure parts,displacement response of the seismic peak acceleration time,the structure of the utility tunnel as an index,such as stress reaction results show that the silt in the acceleration and the maximum stress of pipe rack structure,and the X,Z stress plays a main role in the state of stress,can be in the soil around the utility tunnel laid the flexible damping layer,improve the condition of stress is larger.The structural displacement of the utility tunnel in the silty clay is the largest and the joints at the end of the structure appear.Finally,select the rectangular cross section,rectangle,circular cross section,and other forms of utility tunnel section as a variable,the comprehensive analysis of different cross section pipe rack displacement response,structural stress response and distribution of plastic zone,the result shows: the circular cross section utility tunnel uniform stress and minimum stress,can be reduced by adding flat shape header at the bottom of the plastic damage of soil;For the stress concentration phenomenon of rectangular and quasi-rectangular cross-section utility tunnel,the junction of the utility tunnel can be set in the form of haunching,and the appropriate place to add reinforcement or steel fiber to prevent concrete tensile crack.