The Mechanism And Failure Governance Research Of Deep Foundation Pit Engineer-ing Waterproof Curtain

In recent years, many tall buildings is built in our country, therefore, a number of problems of deep foundation pit engineering appears and the scale and depth of deep foundation pit is increasing. At the same time, a lot of all sorts of problems needed to resolved appears. Foundation pit is not only the problem of stress field changing, displacement field changing but also it is a problem of complex seepage field affecting. To the stability and safety of foundation pit and its surrounding environment, so in the design of foundation pit engineering calculation we must consider the safety of foundation pit, check water and seepage stability. Better performance waterproof curtain can effectively prevent the foundation pit lateral of the underground water level drops, sequentially ensure the safety of foundation pit engineering, reduce the impact on foundation pit process and surrounding environment.This topic based on in foundation pit engineering of Wenshan central city construction projects. In the topic, according to the excavation process of waterproof curtain local failure condition, modeling analysis, studying the effect of waterproof curtain to foundation pit excavation.. In order to find an ideal cemented-soil mixture ratio, and apply the experiment result to the engineering example to governing the failure of waterproof curtain in engineering project, we take the geotechnical experiment to find the permeability changing regular of different dosage of cemented-soil and admixture (fly ash and slaked lime) in composite cemented-soil under the different age. Using FLAC3D finite difference analysis software, modeling, analysis, calculation. And then we contact the failure and governance of waterproof curtain results with results of the numerical simulation analysis to research their influence on excavation engineering. Mainly including the following aspects:(1) Introducing and analysis the Wenshan central city construction projects and waterproof curtain local failure condition and reason appearing in excavation process.(2)According to experiment methods of soils for different dosage of cement and admixture infiltration experiment of cemented-soil under different age. Analysing changing regular of permeability coefficient fo different dosage of cement and admixture of cemented-soil under different age for 3 days,7 days,14 days,21 days, 28 days. To find the ideal cemented-soil admixture ratio to govern the waterproof curtain failure under this geological condition.(4)Establishing finite difference model, numerically simulating the basic condition of excavation process, the failure and governance of waterproof curtain contacting with engineering practice, the research analysis influence of foundation pit excavation and the failure and governance of waterproof curtain of foundation pit.