The Methods For Analyzing Basal Upheaval Stability And General Stability Of Long Foundation Pits

The general stability and basal upheave stability of the foundation pits failure are the destruction of major accidents.The design of long narrow foundation pits don/t consider the structure space effect(Foundation pit width)which is not the real case such as long narrow subway foundation pits,Pipe jacking of foundation pit,Pipeline foundation pit and so on.This paper studies the general stability and basal upheave stability of the long foundation pits and the research methods of them,based on the reading the relevant literature at home and abroad.The two-dimensional solid model was established based on LimitState:Geo and ABAQUS to study general stability and basal upheave stability of the long foundation pits.This paper mainly completed following work:1?Study different insertion ratio,length and stiffness of retaining structure and support for basal upheave stability and general stability of the long foundation pits.Results show that the failure patterns of the long foundation pit character depends on foundation pit support form.Foundation pits with no support can occur general demolition,foundation pits with one support can occur overturn failure,foundation pits with two support can occur basal upheave failure,when supports have enough stiffness.2?The long foundation pits were determined by studying the change of displacement field and plastic strain field of the results of ABAQUS by changing load,mechanical parameters of sand,support friction between the soil retaining structure and soil and other factors.Results show that,the width of the long foundation pits has obvious restraining effect,which makes the long strip foundation pit more stable,and is not easy to produce the basal upheave and the general stability failure.3?The failure patterns of long narrow foundation pits were determined by changing mechanical parameters of sand,width of foundation pits and characters of retaining wall and support of numerical models by using LimitState: Geo,comparing the results of software and model tests.Results show that the opposite retaining wall of long foundation pits makes the long strip foundation pit not easy to damageThe foundation pits were classified according to the width.The two failure patterns of long strip foundation pit were presented.The safety factors was calculated based on the failure patterns of long foundation pits,and a large number of parameters were analyzed.The influence factors were found by using above three methods on the basal upheaval stability of long foundation pits.The analysis methods were raised about long narrow foundation pits,which provide the theoretical basis and a new theoretical basis for the long foundation pits.