Study On Rock Mechanics Parameter Back Analysis And Construction Mechanics Problem In Underground Chamber

In this paper, based on simulation modeling laws of geometry, constitutive relations, stress conditions and construction, a simulative calculation model has been proposed by considering the mechanical problems during the underground chamber construction and adopting constitutive models of enveloping type which can consider elasto-plastic materials and their cracking. The model can describe rock multi-media characteristic consider the interrelation of shoring structure and stratum reflect some influencing factors, for example: faultage interlayer joints, construction process and so on. Regularly riled criterion and constitutive model to rock mass are described in this paper. Sometimes four-parameter yield criterion which may degenerate to other regularly yield criterions in some certain conditions are described, too. In this paper, the dominated equations formed from nonlinear FEM are derived through incremental theory, and the corresponding formulations of iterative method for solving the nonlinear dominated equations are described.In this paper, regularly back analysis methods' computational theories and steps are summarized and viewed, including conjugate gradient method, DFP method, simplex method. Their merits and disadvantages are described, too. In factual engineering, it is invaluable to eliminate the reading errors in some certain degrees by using the relative displacement. Based on DFP optimum back analysis in the excavation of underground chamber, the corresponding object function and formulation are derived in this paper.To maintenance the stability of underground chamber, the problems have always been discussed about how to take reasonable excavation method. Based on analytical method of construction mechanics, the simulative computational FEM formulations about multi-stage excavation of underground chamber are prescribed. For some underground chamber construction, the stability of surrounding rock different excavation method and so on have been studied.Based on the calculated results, the stability of surrounding rock of some underground chamber is evaluated. The rationality of excavation method and shoring project is evaluated. It has been proved rationale and feasible to use different shoring project and shoring parameter for different surrounding rock type.