地下采空诱发顺层岩质斜坡变形破坏特征研究

为揭示地下采空诱发顺层岩质斜坡变形失稳的机制,采用底摩擦模型模拟试验方法,以重庆市鸡尾山地质条件为试验对象,研究不同开采顺序(顺坡开采、逆坡开采)、煤柱留设(上下边界矿柱、区段或水平矿柱)情况下,地下采空区不同空间分布诱发其上覆岩层的变形破裂响应特征。结果表明:1)地下采空区分布不同,其上覆岩层变形破裂响应特征也不同;2)软弱夹层是顺层斜坡的潜在滑动面,同一矿山地质条件、不同采空区影响下的软弱夹层可分为凹形、凸形、S形、反S形4种类型;3)地下采矿形成采空区后,岩体破坏规模及程度主要受地质环境和开采方式的控制,地下采空影响下类似含软弱夹层缓倾斜顺层斜坡的变形机制为弯曲-断裂、滑移-拉裂。

Deformation and fracture response characteristics of the bedding rock slope under the impact of the goaf

The paper intends to focus itself on the exploration of the deformation fracture mechanism of the consequential rock slope declining induced by the mining goaf.For this purpose;the authors took the geological conditions in Chongqing Jiweishan Mount Mine as the experimental study sample through a bottom friction model.The simulation experiment has been laid out to trace the characteristic deformation fracture response of the strata in the goaf in different situations.For instance,we have taken into account the mining sequences (mining along and against the slope) and coal pillars(top-down-direction boundary pillars,the section coal pillars and level coal pillars) in the paper.The results of our experimental simulation study demonstrate the following features:(1) The deformation fracture response characteristics of the overlying strata may differ from case to case in the goal,which may lead to the difference of the stabilities of the slopes.In such cases,it is more likely for the mining activities against the slope to induce landslide risks as compared with the mining situation in the opposite direction of the slope with the same mining geological features.Moreover,coal pillars and their locations can also serve as the influential factors to contribute to the stability of the slope area.Therefore,both the factors should be taken into account when studying the stabilities of the slopes.(2) It is also necessary to take into account the soft interlayer,which is also the potential factor leading to the instability.For example,there is a coal mine,whose soft interlayer can be divided into 4 types:the concave,the convex,the positive S-shaped and the reversed S-shaped one,when study goes on with the effects of the various goaf areas,which are by nature useful to predict the stabilities of the rock involved.(3) We have also investigated and examined the scope and the extent of destruction.Since the rock mass has resulted in primarily regulated geological environment,we have studied the recovery methods for the underground mining situations.Facts tell us that the rock mass that has been exposed and deformed in the mined-out tunnel direction,thus implying trends to get dangerously intensive crack,rupture and even collapsing.Furthermore,under the strong impact of the underground mining,the deformation tendency of similar slow-going declining slope including the soft interlayer crack will be inevitably leading to bendfracture and extrusion-slip-tension crack.