Study On Environmental Effects Of Deep Foundation Pit Excavation Of Wenzhou City In Wenzhou Deep Soft Ground

With the development of urban construction,a large number of deep foundation pits of subways continue to emerge.For areas like Wenzhou that are so expensive,the impact of the excavation of the deep foundation pit on the surrounding environment and houses cannot be ignored.Coupled with the nature of the special deep muddy strata in Wenzhou,the impact of foundation pit excavation on the surrounding environment is even more difficult to control.However,the research on the influence law of the deep foundation pits in Wenzhou area on the surrounding environment is still scarce.Therefore,this paper studies the influence law of the deep foundation pit excavation in Wenzhou area on the surrounding environment by comparing the two aspects of the actual measurement analysis and indoor model test of the S1 line airport section of Wenzhou city railway.Through the analysis of measured data and model tests,the following conclusions are drawn:(1)The measured data shows that when the foundation pit is excavated,the surface settlement curve shows an obvious “pot bottom type”,and the impact range is about 3.5 times the depth of the foundation pit excavation.The deformation of the underground continuous wall presents “swelling”,and the maximum deformation position is at the bottom of the pit.Before the second steel support of the deep soil is completed,the deformation is basically consistent with the ground connection wall.However,after the second steel support is completed,the deformation rate is significantly faster than the ground connection.(2)Through the similar relationship between on-site conditions and model tests,the similarity principle is used to determine the single-value relationship,and the model test is introduced.Compared with the prototype test,it compensates for the single lack of loading mode,and more comprehensively analyzes the influence of different loading methods on the deep foundation pit excavation process.(3)The model test shows that the ground settlement curve and the measured result curve are in the same way,but the maximum position of the surface settlement of the model test is small and the field is measured.The entire excavation process of the first two steel support constructions,whether it is actual measurement or model test,the rate of surface settlement deformation is very fast.The distance of the ground wall loading will affect the horizontal displacement of the ground wall.The additional earth pressure generated by the loading around the model test is irregularly distributed along the excavation depth,and the influence of the maximum excavation depth of the foundation pit is relatively large.