西部鄂尔多斯矿区强矿压显现及顶板运动规律

Strata Movement Law and Strong Ground Behavior in Western Ordos Coalfield

矿山压力显现研究对于围岩控制与动力灾害防治必不可少。为研究西部鄂尔多斯矿区矿压显现及顶板运动规律,基于红庆梁矿现场调研,分析了强矿压显现演化规律及其原因,建立了"软岩基本顶+砾岩关键层"的覆岩结构及相应的计算模型。基于采空区矸石压缩变形理论,确定了下部垮落岩体对砾岩层的支承荷载参数并推导了砾岩层破断步距表达式。研究结果表明:受上覆硬厚砾岩层运动影响,300~340 m推采范围为工作面强矿压显现区域,支架大面积泄液与煤壁大面积片帮为强矿压主要显现形式,最大片帮深度达1.5 m。采空区垮落岩体对砾岩层有一定的支承作用,影响砾岩层的弯曲下沉及其破断步距,在此条件下的砾岩层运动过程可分为3个阶段,分别为未触矸阶段、持续弯曲下沉阶段、砾岩层破断阶段。模型计算的砾岩层破断步距为306.9 m,现场验证为320m。上述研究可为相似地质条件下的超前支护设计和矿压显现控制提供参考。

To understand the ground behavior is essential for surrounding rock control and dynamic disaster preven⁃tion,the evolution law and causes of strong ground behavior in wester Ordos Coalfield are researched through in-situ investi⁃gation in Hongqingliang Coal Mine.Then,the overlying strata structure of“soft main roof+conglomerate key strata”is es⁃tablished as well as the corresponding analytical calculation model.Based on the theory of gangue compression and deforma⁃tion in goaf,the supporting load parameters of the lower collapsed rock mass to the conglomerate layer are determined and the expression of the fracture step distance of the conglomerate layer is derived.The results show that under impact by the movement of the overlying hard and thick gravel layer,the stoping range from 300 m to 340 m experiences the strong ground behavior in the mining face.Large area drainage of support and large area of coal wall spalling are the main forms of strong mine pressure,with the maximum spalling depth up to 1.5 m.The caved rock also supports the conglomerate strata,affecting the bending and sagging process.The evolution process of the conglomerate strata can be divided into three stages,i.e.un⁃touching gangue stage,continuous deformation stage and conglomerate breaking stage.The theoretically calculated caving span of conglomerate strata is 306.9 m,and the field investigation is 320 m.The results can provide a reference for advanced support design and ground pressure control under weakly cemented strata condition.