条带开采煤柱长期稳定性评价及煤柱设计方法

煤柱在地下水、风化作用等多种因素的作用下会发生剥离和尺寸缩减,使煤柱发生渐进性失稳破坏。基于煤柱的渐进性剥离行为和剥离体的堆积特性,建立了煤柱的非均匀剥离模型;分析了煤柱剥离的影响因素、煤柱安全系数与煤柱剥离的关系,建立了条带煤柱长期稳定性评价方法;讨论了采出率、地表沉陷控制和煤柱长期安全系数的协同关系。分析表明:煤柱的剥离与煤的碎胀系数、休止角和采宽采厚比有关,可利用剥离角确定煤柱的极限破坏程度。煤柱的宽高比越大,剥离对其稳定性的影响程度越小。该模型适用于条带煤柱长期稳定性评价。

Long-term stability evaluation and coal pillar design methods for strip mining

The coal pillar will peel and scale down under the effects of underground water,weathering,etc.,leading a progressive pillar failure.Based on the progressive peeling behaviors of coal pillar and properties of peeled coal deposit,this paper established a non-evenly peeling pillar model；the factors affecting pillar peeling and the relationship between pillar peeling and safety factor had been analyzed；a long-term stability evaluation method for strip pillars had been proposed；finally,the synergic relationships among recovery ratio,subsidence control and safety factor has been discussed.Analysis results shows that the pillar peeling is affected by bulk factor of coal,angle of repose and width-height ratio of mining tunnel,and the degree of pillar peeling can be determined by peeling angle.The increase of pillar width-height ratio can reduce the effects of peeling angle on pillar stability.This model can be utilized in long-term failure risk evaluation for strip pillars.