Failure Forecast Of The Underground Structure Under Complicated Load

According to the theoretical analysis and numerical simulation calculations methods, the theoretical calculation model and numerical simulation method of the failure forecast for the underground structure (take shaft lining for example) under complicated loads had been studied and discussed. The failure factors and the mechanism of the underground structure under complicated loads had been analyzed. The bearing loads of the shaft lining had been analyzed at length, and at the same time the feasibility and necessity of the adding principle had been indicated when the bearing loads of the shaft lining had been theoretically analyzed. The theoretical calculation formula of the shaft lining under diversified loads had been deduced. According to space axisymmetric question , the theoretical calculation model of failure forecast of the shaft lining under complicated loads had been established based on elastic theory. When the model were applied to an project, using linear regression, the linear equation about vertical additional force and the depth had been obtained. For the first time the formula about the three direction stress of the shaft lining acted by gravity, soil and vertical additional force changing along depth z and radial r had been obtained. After the elastic-plasticity theory had been expatiated briefly, the elastic-plasticity stress-strain model and failure rule suit for reinforement concrete shaft lining in thick alluvium had been pointed out, the calculation model of numerical simulation method of the failure forecast of the shaft lining under complicated loads had been established. Consider shaft lining as a space axisymmetric question, take two dimension element for the numerical simulation of shaft lining failure and based on this, the time, location and development of the shaft lining failure had been forecast. The change of the stress and strain had been analyzed when the shaft lining failed, and favorable results had been obtained.