Deformation Control And Numerical Simulation Analysis Of A Deep Foundation Pit Support In Shenzhen

With the continuous promotion of urbanization and the increasing population density in cities,only surface land can no longer meet people’s needs.Therefore,people have begun to explore underground spaces.In recent years,the concept of environmental protection and green development has been deeply rooted in people’s hearts and has become a global theme.In urban areas,in order to get closer to this theme and protect the environment,there has been a wave of underground space excavation.Urban underground engineering has become a focus of geotechnical engineering,and the construction of various underground facilities inevitably involves issues such as excavation,support,and groundwater control of underground engineering and foundation pits.The natural conditions in different parts of China are different,resulting in significant differences in the distribution of strata and groundwater related situations.Before excavating a deep foundation pit,it is necessary to conduct a detailed investigation of the distribution of groundwater level,strata,and pipeline burial in the project site.Based on these conditions,the design,calculation,and research of deep foundation pit support must be carried out to ensure the safety and smooth progress of the project.Before designing specific foundation pit support engineering,this article first reviews the relevant research results of current deep foundation pit support.Then,taking the Huawei Production Center G area renovation project as an example,the geological conditions of the project are complex,the surrounding buildings(structures)are dense,and there are many municipal pipelines.Therefore,the form of deep foundation pit support has been selected and the foundation pit plan has been designed.Further numerical simulations were conducted,including the horizontal displacement of the pile top,the bending moment of the pile body,the horizontal and vertical displacement of the foundation pit,and the axial force of the anchor cable.Then,the influencing factors of the pile anchor support structure were analyzed,including four aspects: pile spacing,pile length,pile diameter,and anchor cable pre stressing.It was found that all four factors have an impact on the row pile and anchor cable support structure.The results show that as the spacing between piles decreases,the horizontal displacement of the support piles also gradually decreases.As the pile diameter increases,the maximum horizontal displacement gradually decreases,but when the pile diameter exceeds a certain limit,the decrease in horizontal displacement is very small.The pre applied force of the anchor cable decreases,and the maximum horizontal displacement of the support pile increases.The depth corresponding to the bending moment reverse bending point and the maximum horizontal displacement value of the pile body gradually shifts upwards.As the length of the pile increases,the maximum horizontal displacement of the support pile decreases.However,when the length exceeds a certain limit,the amplitude of horizontal displacement changes decreases,and the impact on the deformation of the support pile is not significant.Finally,by comparing the actual monitoring data and the numerical simulation deformation data,the rationality of the support scheme design is verified.It is suggested that the four factors of pile spacing,pile length,pile diameter and anchor cable preload should be comprehensively considered in the design optimization.Through this study,it can provide effective reference for the design and research of related deep foundation pit engineering in the future.