近距离煤层协同机理对下层煤巷道位置的优化

Optimization of roadway location in lower coal seam from synergy mechanism of contiguous seam mining

近距离煤层的上层煤回采导致下层煤所处的应力环境复杂,回采巷道位置选择成为制约煤层安全回采的技术难题。通过数值计算研究了近距离煤层开采时下层煤内部应力分布及应力变化率演化规律,分析了下层煤内部应力变化率与上煤层残留煤柱尺寸之间的关系,提出了通过设计初期优化上层煤保护煤柱尺寸提供下层煤的回采和巷道维护时空先决条件,实现了上下煤层安全高效回采的协同机理。从应力变化率、应力集中程度和采区整体设计三方面对下层煤回采巷道位置进行了优化,验证了在上层煤残留煤柱正下方布置回采巷道的可行性。研究结果成功应用于现场工程实践。

The upper coal mining in the contiguous coal seam results in the complicated stress environment in the lower coal seam, and the choice of the roadway position is a technical problem for safe extraction. Through numerical simulation, evolution law of stress distribution and stress rate in the lower coal seam was studied for contiguous seam mining, the relationship between stress rate in the lower coal seam and the size of upper coal pillar was analyzed, and synergy mechanism that provides spatial and temporal prerequisite for the protection of the lower coal seam mining and roadway maintenance by optimizing the size of upper coal pillar in the initial design was put forward to realize the high efficient and safety mining. Roadway location in the lower coal seam was optimized through stress rate, stress concentration degree, and the mining area design, and feasibility for roadway to be located under the residual coal pillar was verified. The results were successfully applied to the engineering practice.