Study On The Influence Of Underground Excavation On Adjacent Buildings

Since the 21st century,the process of urban modernization in China has been accelerating gradually.Underground transportation and skyscrapers have become two important symbols of prosperity of a city.In the process of urban modernization,a large number of new metro projects are near existing buildings and foundation pit projects,and there are also frequent safety accidents.This paper summarizes the basic theory of the interaction between adjacent engineering construction,and on the basis of ABAQUS numerical analysis software,combined with practical engineering examples,simulates and calculates the excavation process of metro tunnel with adjacent frame structure and the excavation process of foundation pit with adjacent grounding Metro tunnel,so as to analyze the interaction between metro tunnel construction and existing frame structure,and the excavation process of foundation pit with existing one.The main research work and results are as follows:(1)The adjacent construction of underground engineering can be divided into three categories:first,the construction of new projects near existing tunnels;second,the construction of new tunnels near existing tunnels;third,the construction of two or more tunnels at close distance at the same time;and the interaction between underground structure-stratum-superstructure interaction system is mainly due to the damage of ground displacement caused by soil excavation.The foundation of a building transfers the influence of foundation damage to the superstructure,which causes the overall settlement,inclination and cracking of the superstructure.(2)Applying ABAQUS numerical analysis software to simulate the ground settlement law of tunnel excavation and verify the Peck settlement curve;at the same time,studying the influence of tunnel excavation when the ground frame structure is adjacent,it is found that within a certain range,the ground settlement value,the horizontal displacement of the column foot of the ground frame structure and the vertical displacement of the foundation increase gradually with the increase of the depth of the tunnel;but with the increase of the depth of the ground frame structure,the vertical displacement of the foundation increases With the increase of tunnel diameter,the ground settlement value,horizontal displacement of column foot and vertical displacement of foundation of ground frame structure increase gradually.(3)The dynamic change law of ground settlement,foundation settlement and frame structure deformation in the whole process of tunnel excavation is simulated with an engineering example of tunnel excavation with adjacent upper frame structure,and the influence of frame structure foundation form,tunnel excavation method and their adjacent positions is discussed.It is found that when the integrality of frame structure foundation form is better,CRD is adopted in tunnel excavation.The closer the distance between the axis of the long side column of the frame structure and the axis of the tunnel,the greater the impact of the tunnel excavation,and the greater the inclination of the frame structure.(4)Combining with the engineering example of excavation of foundation pit of near-grounding Metro tunnel,the law of plastic strain zone expansion behind the wall and the law of surface settlement,horizontal displacement of diaphragm wall and tunnel displacement change during the whole process of excavation of foundation pit are simulated.The disturbance of surrounding soil of tunnel caused by excavation of foundation pit,the different influence of adjacent position of the two and excavation mode of foundation pit are discussed.It is found that the soil of foundation pit excavat The greater the disturbance degree and the closer the tunnel is to the foundation pit,the greater the impact of the foundation pit excavation;and the symmetrical zonal excavation can reduce the impact of the foundation pit excavation.