The Influence Of Foundation Pit Precipitation And Excavation On Settlement Of Adjacent Buildings

With the accelerated process of city, new projects which build in original buildingsare more and more. The excavation of deep foundation pit in dense buildings andunderground shallow water area, must consider the influence of dewatering offoundation pit, excavation process on adjacent buildings. Precipitation provides a goodenvironment for the construction of foundation pit excavation, reinforcement,supporting structure stability and reduce the water pressure has great effect on thesurrounding soil. At the same time, precipitation will also make the seepage field offoundation pit excavation become more complex, may cause the disaster flowing soil,sand flow, piping, also make the groundwater level decline due to lateral soilconsolidation caused by surface subsidence. Therefore must pay attention to theinfluence of foundation excavation and dewatering of foundation pit and surroundingbuildings. Based on a foundation pit project in Handan City, because of excessiveprecipitation excavation adjacent building settlement caused by accident, as follows:(1) Movement rule of groundwater in soil, the seepage effect which produces to theretaining structure, soil consolidation settlement, interaction between soil-water,combined with the deep foundation pit engineering project scope determinedprecipitation landing funnel.(2) Analysis caused by dewatering of foundation pit adjacent soil consolidationsettlement rules. The calculation of soil Terzaghi’s one-dimensional consolidation theory,Biot’s consolidation theory consolidation difference based on whether the impact, fortotal stress change generated in the process of consolidation, summarizes themechanism and influence factors of consolidation settlement, get the influence law onthe settlement of foundation pit engineering precipitation area adjacent to the ground.(3) In combination with the construction data of foundation pit engineering,statistical analysis of precipitation and the monitoring data, found from the law ofsettlement of foundation pit excavation, the precipitation caused by the building, toexplore the excavation and precipitation caused by time and space effect of groundsettlement.(4) Numerical simulation using FLAC3D software, establish the numerical modelof foundation pit engineering. By using the numerical model, the deformation of foundation pit excavation, dewatering of foundation pit are caused by building valueand also consider deformation caused by excavation and precipitation value distortionbetween value and the actual monitoring. The results show that considering deformationcaused by excavation and precipitation values can be better fitted with the measuredvalues, and is not equal to the distortion caused by considering two respectively andvalue, so the need for the design of foundation pit dewatering considering the impact onthe surrounding environment.The results of this study can provide a reference for design and construction of thesame type of foundation pit engineering.