皖北矿区回采巷道动态权值分类及其差异化支护

Dynamic weight classification and differentiated support on mining roadway in Wanbei minefield

皖北矿区回采巷道支护设计很大程度上依赖于技术人员的工程判断力和实践经验,导致有些巷道支护效果不佳,有些设计参数偏于保守,制约着矿井安全高效水平的提高。因此,在考虑层位岩性、节理裂隙、开采深度等因素基础上,定义了巷道顶板、底板及煤帮的稳定性判别指标。基于关键层理论,计算出顶板垮断极限层的层序数和采空区悬顶长度,推导出临界煤柱宽度计算式,从而确定了护巷煤柱稳定性判别指标,并进行了巷道围岩综合评价和整体分类。采用计算机数值模拟,拟合出分类指标与围岩塑性率的函数关系,计算了随围岩条件动态变化的分类指标权值,并依据基本顶来压当量及围岩塑性率函数的斜率变化,确定了围岩次分类的判别条件。结合皖北矿区回采巷道支护的成功实例,构建了包含巷道围岩力学参数、支护参数及其支护效果等信息的样本数据库,在综合考虑巷道类型及服务年限、区域类型、整体分类及围岩次分类基础上,优选试验巷道的支护方案,实现回采巷道支护决策安全可靠、经济合理。

The supporting design practices on mining roadway in Wanbei minefield heavily relies on engineering judgment and experience of technicians. As a result, some design parameters of mining roadway are poor and design parameters are conservative, which restricted the improvement of mine safety and production efficiency. Therefore, on the base of overall consideration on layer and lithology, joint fissure, mining depth, etc. , the stability index of roadway roof, roadway floor and coal rib are de-fined. Based on the key strata theory, strata number of caving limits layer and the width of unsupported roof in the goaf are calculated, the formula of critical width of coal pillar is derived and , thereby, the stability index of coal pillar is determined. Based on this, the stability index of roadway roof, roadway floor, coal rib and coal pillar are regarded as classification index, the comprehensive evaluation of sur-rounding rock and global classification are carried out. The computer numerical simulation is adopted to march the relationship between the plastic ratio of surrounding rock and the global classification index. Index weights which dynamically change with the conditions of surrounding rock are calculated and , according to equivalent weighting of the main roof and the slope of curve of plastic ratio of surrounding rock, the criterions of sub-classification are determined. Combined with successful examples of mining roadway support in Wanbei minefield, a sample database of mining roadway including roadway type, area type, mechanical parameters of surrounding rock, support parameters, and supporting effect, etc. is established. On the base of overall consideration on roadway type, service time, area type, global classi-fication and sub-classification, the support plan of testing roadway is optimized to ensure support deci-sion safe, economic and reasonable.