煤矿岩层移动建模方法及验证

摘要

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.%为了准确确定煤矿岩层移动数值模型的煤岩体力学参数,实现煤岩样力学参数与煤岩体输入参数之间的良好匹配,在分析Hoek-Brown强度准则及量化地质强度指标GSI围岩评价指标的基础上,利用Hoek-Brown强度准则与其等效Mohr-Coulomb强度参数的关系,建立一种基于Hoek-Brown强度准则的煤矿岩层移动建模方法,确定煤矿岩层移动数值模型的岩体力学参数.以某矿井为例,通过地表移动观测站观测数据和工作面矿山压力计算数据进行对比分析,结果表明:煤层支承压力峰值的计算值与模拟结果分别为17.50、18.52 MPa,峰值与煤壁的距离分别为16.21 m和15.00 m,两者的误差分别为5.51％和8.06％;模型的采空区应力恢复距为101.5 m(即0.36倍的采深),符合国内外现场经验认为的一般规律;在充分采动的情况下,数值模型与实测的下沉系数误差率为3.66％,移动盆地主断面下沉曲线的分布规律也相似,证明提出的建模方法具有可行性和实用性.