Intelligent inversion method of in-situ stress field for a complicated engineering geological body

The in-situ stress is the original stress in the geological body forming from the geological structure and gravity. It is an important factor which influences the stability and instability of the geological engineering. Due to the long geological tectonic setting and geological evolution, the in-situ stress field is a function of time and space, thus it is very difficulty for us to make accurate inversion the in-situ stress field. Taking Jinchuan mine as the engineering background and with the aid of in-situ stress measurement in Jinchuan mine, the in-situ stress field was inverted. First the 3D numerical mode of geological engineering body in Jinchuan mine was established, and the relation between in-situ stress and rock mass parameters and coefficients of horizontal pressure was obtained by orthogonal numerical analysis and genetic programming (GP). Then the optimization mode was established which takes the sum of squares of differences between the measured initial stress and calculation initial stress up to the minimum value as the objective function. The rock masses parameters and coefficients of horizontal pressure would been obtained by solving the optimization model using genetic algorithm. Finally, the initial stress field can be obtained when the 3D numerical analysis is carried out again by inputting the parameters of rock masses and coefficients of horizontal pressure. Based on comparing inverting in-situ stress with the measured values for the 4 gauging points, the maximum and minimum error of the principal stress is 16% and 0.62% respectively. The results show that the method of intelligent inversion of in-situ stress field can be applied for complicated geological engineering body to simulate in-situ stress field and the accuracy meets the engineering demand. © 2016, Harbin Institute of Technology. All right reserved.