Study Of Rain Infiltration On Stability Of Unsaturated Pit Supporting Structure

With the rapid increase of the country’s economic strength, The high-rise buildingshas been rapid development in many cities in the country with more and more deepfoundation pit support engineering, Pile anchor as has its unique advantages, hasbecome one of the most commonly used in deep foundation pit support one of thesupporting structure.However, Foundation for the loess areas of the current construction,rainfall infiltration is usually one of the main occasions of non-saturated soil slopeinstability. So that, the study about the influence of the rainfall infiltration to the slopestability and supporting structure is becoming an important part of the study on pit slopereinforcement engineering.I have read a lot of information to find that the present study unsaturated soil slopeinstability article under rainfall more basic expression of failure regularity and highintensity rainstorms of a slope failure is one of the main reasons of the slope failure.However, there is only a few studies for the supporting conditions of the pit in the cityon the rainfall infiltration, but it can not copy the slope failure mechanism to simulatethe pit, pit following its own characteristics with respect to the general slope:1. Deepfoundation pit slope is generally90°vertical slope in the city, surface general concretesurface layer can prevent the infiltration of rain water, the ordinary slope is generallyinclined slope, slope surface receiving more rainwater, and the rain will scour the solpe;2.Anchor Piles Bracing pit, due to the presence of anti-slide pile role, the overalldamage to deeper slip surface the ordinary slope slip surface shallow;3.The pit slopesoil are generally dense in the city with slower rainfall Infiltration, ordinary the slope soil generally more looser with high rainfall infiltration rate, the slope seepage fieldchanges very fast in rainfall infiltration.This paper take a Deep Foundation of Xian as the research object, study itssupporting structure stability under rainfall conditions. Main course of the study are asfollows:(1) by reading a lot of literature, books and domestic and foreign relevant journalsof pit slope deformation and stability under rainfall conditions, Then the characteristicsof the deep pit slope’s soil are analyzed and the concept of matrix suction in unsaturatedsoils is introduced, shear strength of unsaturated soil and the soil water characteristiccurve are also described; Secondly, the mechanism influencing of the slope deformationof deep pit excavation under rainfall infiltration is introduced, the process of rainfallinfiltration into deep pit excavation， factors of the slope deformation and Theunsaturated soil Galerkin percolation theory are discussed,so slope and support andearth are seen as a body to study.(2) Combined with the project of a deep pit slope at Xian area,based on MIDASfinite element software,and establish rainfall analysis model according to the actual size.After model established, instantaneous rainstorm and continuous rain in two differentsoil permeability coefficient simulation, analysis under different conditions of soil porewater pressure variation with rainfall duration.(3) Combined with pit Supporting conditions, to utilize MIDAS finite elementsoftware foundation supporting model, follow the conditions of the seepageanalysis,analyze influence variation of the foundation pit slope stability factor, boltaxial force and row pile bending in different work conditions.