Research On Deformation Of Adjacent Existing Roads By Foundation Pit Excavation

In recent years,construction land resources have become increasingly scarce,and the construction of urban high-rise buildings and underground spaces and related ancillary facilities has continued with the development of China's infrastructure construction and the expansion of land resource development scale.However,with the increasing density of buildings in the urban center,the excavation of building foundation pits will inevitably cause a certain degree of interference to the surrounding complex environment.The excavation and support process of building foundation pits will be safe for nearby existing facilities.The impact of the excavation and support of building pits on the safety and stability of nearby existing facilities has become a key issue that people cannot ignore.Issues related to the influence of the excavation and support process on adjacent existing roads as the starting point in this paper.Based on the induction of the deformation mechanism of the foundation pit and the form of urban road damage,a foundation pit project in Zhaoqing,Guangdong Province is used as a case.The finite element software AQAQUS is used to establish the foundation pit and road model,analyze the deformation characteristics of the foundation pit retaining structure and roads,and change the five factors of pile diameter,pile spacing,embedded depth,pit bottom reinforcement and driving load.An orthogonal experiment is designed to analyze the influence of each factor on the existing road subsidence.The specific research content and results are as follows.(1)The numerical simulation method was used to simulate the excavation and support process of the foundation pit,and the deformation results of the foundation pit supporting structure and the adjacent existing road were obtained.The results show that the maximum settlement of the road occurs near the outer edge of the roadway on the side of the foundation pit,and the settlement value is basically the same as the maximum value of the soil settlement curve at the corresponding location.(2)By comparing the simulation data with the monitoring data,it is found that although the results have a certain deviation,the overall change trend is similar,indicating that the numerical analysis method can better reflect the deformation of the foundation pit and the road.(3)By simplifying the model and changing the values of pile diameter,pile spacing,embedded depth,pit bottom reinforcement and driving load of the envelope structure,the effects of changes in various parameters on the existing road deformation are analyzed systematically.Among them,the change of the pile spacing of the retaining piles has less influence on the road settlement.(4)Through the design of orthogonal tests,the range analysis of each influencing factor is performed and the indexes are optimized,and The influence of each parameter on the road settlement was determined from the largest to the smallest in the order of pit bottom reinforcement,embedded depth,pile diameter,and driving load.Figures [49] tables [22] references [56].