Modeling methods and verification of rock strata movement in coal mine

In order to accurately set up the coal and rock mechanics parameters of the rock strata movement numerical model for the coal mine and to realize a good match between the mechanic parameters of the coal and rock specimen and the input parameters of the coal and rock mass, based on the analysis on the Hoek-Brown strength criterion and the evaluation index of the quantitative GSI surrounding rock, the relationship between the Hoek-Brown strength criterion and the equivalent Mohr-Coulomb strength parameters were applied to determine the rock mechanics parameters of the rock strata movement numerical model for the coal mine,and thus the rock strata movement numerical modeling method of the coal mine was established based on the Hoek-Brown strength criterion. Taking a certain mine as an example, a comparison analysis was conducted on the observation data of the surface movement observation station and the mine pressure calculation data of the coal mining face. The results showed that the calculation value of the seam support pressure peak and the simulation results were 17.50 MPa and 18.52 MPa individually. The peak value and the distance to the coal wall were 16.21 m and 15.00 m and the error of the above two was 5.51% and 8.06%. The model stress recovered distance of the goaf was 101.5 m (0.36 times than the mining depth) and could meet the site experiences at home and abroad as a general law. Under the condition of the full mining, an error rate between the numerical model and the measured subsidence coefficient was 3.66% and the distribution law of the cross section subsidence curve for the movement basin was similar. The above results clearly showed that the understanding of the numerical model and the actual information was the same and the feasibility and practicability of the modeling method were verified.