Interaction And Safety Analysis Of Excavation Of Adjacent Double Foundation Pits

In the process of China's continuous urbanization,some city-specific problems are gradually exposed.Among them,the rapid population growth and limited land have made urban traffic more and more congested,and the problem of the mismatch between the planning level of transportation infrastructure construction and the scale of urban development has become increasingly acute.As the most effective way to solve urban traffic problems,the degree of perfection of subway transportation has become an important factor that determines the level of urban development.But with the construction of subways and the construction of urban complexes.The subway is bound to be adjacent to the city's shopping malls and other places and even imagined.This will cause adjacent double or multiple foundation pits to be excavated simultaneously or successively.The excavation of many adjacent double or multiple foundation pits has become a difficult point in the excavation process.In this paper,the excavation of the deep foundation pit of the main station of Line 4 of the main station of Line 4 and the transfer station of Beiyangying Street Station of Shenyang Metro to the auxiliary pit of Line 10 is used to study the double foundation pit opening during the construction of the deep foundation pit.The mutual effects of digging.The main research work of this paper is as follows:(1)Based on the characteristics of the deep foundation pit retaining system and the deformation mechanism of the surrounding soil during the excavation of the deep foundation pit,the related theories of the impact of deep foundation pit excavation on the surrounding environment are introduced.(2)On-site monitoring of the foundation pit and analysis of the on-site monitoring data,summarize the changes in the deformation of the retaining structure,ground settlement,and building settlement during the construction of the deep foundation pit.And use MIDAS / GTS NX to establish the main deep foundation pit project of Line 4,the soil outside the pit and the deep foundation pit project attached to Line 10,and compare the calculated value of the software simulation with the measured value to verify the accuracy and applicability of the model.(3)Change the working conditions of the model and relevant calculation parameters,and simulate and analyze the deformation rules of the retaining structure under different construction sequences.The impact of the newly excavated deep foundation pit on the existing deep foundation pit,and the difference between the double foundation pits.The effect of distance on the retaining structure of double foundation pits and the effect of different excavation depths on spacing.Find out the safe distance for excavation between double foundation pits.Finally,the linear relationship between the maximum horizontal displacement of the retaining wall and the spacing of the foundation pit is obtained.It can be considered that when the two foundation pits are constructed at the same time,the distance between the two foundation pits is about 2 times the excavation depth of the foundation pit.When the distance exceeds 4 times the excavation depth,there is almost no effect between the double foundation pits.Therefore,when double foundation pits are excavated at the same time,the mutual influence range of the double foundation pits is related to the depth of the foundation pit,and the spacing should be at least twice the depth of the foundation pit.