Research Of The Elastic-plastic Displacement Back Analysis Of Rock Model

During the geotechnical calculating, the mechanics character is very complex for its special material. Using appropriate model and parameters is very important to the result of calculation. This paper use the commonly system identification theory, as to the special medium martial-rock, do some researches based on the works got before.In practicality project, the elastic-plastic characters of rock already satisfied the needs. So in this thesis, the elastic-plastic model of rock has been analysis. The main content is as follows:(1) As to choosing parameter during identification, found a FEM model which can use structural parameter to calculate the sensibility of point displacement.(2) Discussing the universality principle of system identification, and applying it to identifying rock.(3)Based on the Strain space, derive the formula of the elastic-plastic constitutive equations of rock, got the state parameter and structural parameter of system identification, and found the objective function of system identification by least squares techniques.(4) Comparing the traditional optimize method and genetic algorithm on the choosing problem of objective function optimization, and compare with a mathematic function.(5) Associating NN and genetic algorithm, using Fortran programme the calculation program to identify the elastic-plastic model.(6) Based on result got before, identify the model and estimate the parameters of wall rock of seepage tunnel of jipin second hydroelectric station, validate the rationality of the methodogical in the paper.