为了研究承压水体上切顶沿空留巷底板破坏特征，基于矿山压力、弹性力学理论，考虑了沿空留巷条件下沿倾向方向上一个工作面顶板提前垮落对上覆岩层的支承作用，分别构建了周期来压时采场底板力学计算模型，理论计算采后底板分别在走向方向与倾向方向的破坏形态;采用钻孔压水试验与直流电法观测等多种实测手段验证了奥灰承压水体上开采底板破坏深度。研究表明：① 理论计算采后底板沿工作面走向和倾向破坏形态：常规留设煤柱开采方式分别呈“勺形”和“倒马鞍形”、切顶沿空留巷开采方式均为“勺形”;② 常规留设煤柱开采方式底板破坏深度最大位置在工作面超前位置，切顶沿空留巷开采方式底板破坏深度最大位置在沿空留巷侧;③ 理论计算切顶沿空留巷开采较常规留设煤柱开采最大底板破坏深度减小1.8 m，减小百分比为13.8%，现场实测中切顶沿空留巷工作面底板破坏深度分别比条件相近的采用常规留设煤柱方式开采的董家河煤矿22507工作面、王村煤矿13506工作面底板破坏深度分别减小了2.06 m与1.86 m,减少百分比分别为19.1%与17.5%。理论计算与现场实测均表明切顶沿空留巷开采较常规留设煤柱开采方式底板破坏深度有着明显的减小，顶板定向切缝技术切断采空区部分顶板和巷道顶板之间的联系，使巷道上方一定范围内的顶板形成短臂梁结构，降低了煤壁侧的应力集中程度，无超前掘巷卸压效应和顶板切缝效应是导致切顶沿空留巷开采集中应力发生变化的主要原因，2者均有利于减弱超前集中应力及侧帮集中应力，降低了底板最大破坏深度。

In order to study the floor failure characteristics of the roof cutting and gob side entry retaining above the confined water body,based on the theory of mine pressure and elasticity,the supporting effect of the roof of previous working face falling ahead of time on the overlying strata along the dip direction under the condition of gob side entry is considered,and the mechanical calculation model of the floor of the stope under periodic weighting is constructed respectively.The theoretical calculation of the floor failure patterns in strike and dip direction along working face after mining is carried out respectively.The failure depth of the mine floor on the Ordovician limestone confined water body is verified by means of borehole pressure water test and direct current method observation.The results show that:① the theoretical calculation of the floor failure patterns in strike and dip directions along working face after mining:the conventional mining method of retaining coal pillars presents “Spoon Shape” and “Inverted Saddle Shape” respectively,and the mining methods of gob side entry are all “spoon” shape;② The maximum position of floor failure depth in conventional coal pillar mining method is in advance of working face,and the maximum position of floor failure depth is at the side of gob side in gob side entry mining;③ According to the theoretical calculation,the maximum floor failure depth of the gob side entry mining is 1.8 m less than that of the conventional coal pillar mining,and the reduction percentage is 13.8%.In the field measurement,the floor failure depth of the gob side entry working face with the roof cutting is 2.06 m less than that of the 22507 working face and 1.86 m less than that of the 13506 working face with the conventional coal pillar mining,respectively,the percentage reduction was 19.1% and 17.5%,respectively.Both theoretical calculation and field measurement show that the failure depth of the floor in the gob side entry mining is significantly reduced compared with that in the conventional coal pillar mining.The roof directional seam cutting technology cuts off the connection between part of the roof in the gob and the roadway roof,so that the roof in a certain range above the roadway forms a short arm beam structure,reduces the stress concentration degree of the coal wall side,relief pressure effect of no advance roadway and the effect of cutting roof seam are the main reasons that lead to the change of concentrated stress in gob side entry mining,both of them are beneficial to reduce the advanced concentrated stress and the concentrated stress of side wall,and reduce the maximum failure depth of floor.

1 工程背景

2 采场底板破坏力学模型

   2.1 切顶沿空留巷底板破坏力学模型

   2.2 留设煤柱底板破坏力学模型计算结果

3 现场实测

   3.1 底板钻孔布置

   3.2 钻孔压水试验

   3.3 钻孔直流电法观测

4 分析与讨论

   4.1 切顶沿空留巷与留设煤柱开采底板破坏深度比较(力学模型计算)

   4.2 切顶沿空留巷与留设煤柱开采底板破坏深度比较(现场实测)

5 结论