Study On The Buildings Deformation Around Expansive Soil Foundation Pit

In recent years, with the rapid development of urbanization, many big cities faced to many challenges such as traffic and lack of land, the construction of metro became the best way to solve those problems. At the same time, the construction of subway laded to a lot of deep foundation pit projects,which is surrounded with dense buildings in the cities. The space of their construction is narrow. So the design of foundation pit project and special soil problem in construction is more and more outstanding. It greatly influenced the safety of foundation pit construction and the protection of foundation pit's surrounding buildingsAs a kind of expansive soil,The main characteristic of the old clay in Wuhan district is swell-shrink deformation. All kinds of researches from domestic and foreign about characteristics of expansive soil and its soil improvement theory method have been thorough. But the studies on the deformation of swelling soil foundation pit's surrounding buildings are less. This paper analyses the engineering properties and deformation mechanism of the old clay comprehensively, and the influence of foundation pit excavation to the surroundings. In addition,by the way of settlement monitoring data to build a statistical analysis model, explaining the possibility that using Elman neural network forecast model to process and feedback monitoring data. On the base of analysis above, Taking the deep foundation pit project of optical valley square station of Wuhan metro line 2 as an example, introducing that damage and crack appear more or less surrounding buildings ground under the geological condition of Wuhan district old clay and influence of foundation pit excavation. Then finding out the factors of building settlement and deformation and proposing to take corresponding construction technology and management measures. At last, the aim of Controlling affected buildings'settlements and protecting buildings are reached.In the end, through the analysis and summary of the control measures of this engineering practice case, the research measures and conclusions can be used as reference for the similar engineering conditions in the construction of subway foundation pit.