大断层控制采场水平应力演化与矿震关系研究

Study of relation between horizontal stress evolution and mine tremor in stopes controlled by large faults

以河北某矿典型大断层控制采场为背景,采用理论分析、数值模拟、现场实践等方法,探索大断层控制采场水平应力演化规律及其与矿震发生的关系,并提出相应的减震开采设计方法,建立关键层水平集中力近似估算模型。研究结果表明:开采覆岩破裂运动伴随水平应力释放和转移的演化过程,采场周围存在明显的水平应力"增压(载)区"和"卸压(载)区",持力层的水平应力集中主要来源于覆岩破裂区水平应力释放;水平集中力能够在顶板两端形成"反力矩",阻止其支承端部拉伸破坏并增加极限跨度,是形成关键层大范围悬顶和诱发强矿震的主要原因;采用"窄工作面+条带开采技术+合理开采强度"开采设计,能降低水平应力转移程度,从而实现控制顶板运动和矿震防控的目的。

Based on a stope controlled by a large fault in a mine in Hebei Province, the relationship between horizontal stress evolution and mine tremor was studied using the methods of theoretical analysis, numerical simulation, in situ test, etc. Corresponding mining design methods were proposed to reduce mine tremors, and an approximate estimating model of horizontal concentration stress was established. The results show that fracture of the overlying strata is accompanied by the evolution process of horizontal stress release and transfer. There exist evident “pressure-increase” area and “pressure-decrease” area of horizontal stress, and horizontal stress concentration of the bearing stratum is mainly from horizontal stress release. The “counter torque” formed by horizontal concentration stress at both ends of the roof can prevent tensile failure in the ends and increase the limit span. The “counter torque” is the main cause to form a wide range of hanging arch and induce strong mine tremor. The designed method of “narrow long wall panel ＋ skip mining technology ＋ reasonable mining intensity” can reduce the extent of horizontal stress transfer and thus achieve the goal of controlling roof movement and mine tremor.