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煤矿灾后巷道混杂坍塌体结构分类研究

A classification framework for heterogeneous debris structures in post-disaster coal mine roadways

  • 摘要: 煤矿发生安全事故后,巷道坍塌堵塞现象极为普遍,如何快速研判混杂坍塌体内部结构、打通救援通道是现场迫切需要解决的问题。目前,没有指导混杂坍塌体结构快速研判的方法,现场需要花费大量时间混杂坍塌体结构,制约了救援时效性,不利于救援通道的快速打通。为此,采用案例分析的方法开展了灾后巷道混杂坍塌体结构特征及其影响因素研究,建立灾害类型、围岩岩性和支护类型3个维度,每个维度依据其内在属性提取差异化指标,灾害类型维度分为渐进破坏和触发破坏2个指标,围岩岩性维度分为硬岩、中硬岩和软岩3个指标,支护类型维度分为锚杆/索支护系统、钢构和复合支护3个指标,3个维度不同指标组合得到18种混杂坍塌体结构类型及其特征,得出一种灾后巷道混杂坍塌体三维特征快速分类法,分类结果以代码(111−233)表示,第1位数表示灾害类型,1=渐变破坏型,2=触发破坏型;第2位数表示围岩岩性1=硬岩,2=中硬岩,3=软岩;第3位数表示支护类型1=锚杆/索支护系统,2=钢构,3=复合支护。对某矿113101工作面胶运巷冒顶事故案例进行精细化分析,采用灾后巷道混杂坍塌体三维特征快速分类法对其灾后混杂坍塌体进行分类,分类结果是“131型”,主要特征是软岩塑性流动形成均匀致密堆积,锚杆被岩体包裹呈散落分布,金属网拉伸变形覆盖底部;采用颗粒流数值模拟软件对事故坍塌特征模拟,其模拟结果为软岩塑性破坏,锚杆和锚索在岩体中变形或断裂,金属网拉伸变形覆盖表层,模拟结果与“131型”分类结果特征分析基本吻合。并对两例案例进行应用,分类结果分别是“121型”和“132型”,且两例案例中混杂坍塌体结构特征与事故现场勘察结果吻合,验证了分类结果的合理性,证明了灾后巷道混杂坍塌体三维特征快速分类法的可行性,该方法可为煤矿事故应急救援中混杂坍塌体内部结构的快速研判与救援通道打通提供科学支撑。

     

    Abstract: In the aftermath of safety accidents in coal mines, the pervasive phenomenon of roadway collapse and obstruction poses an urgent on-site challenge: namely, the expeditious assessment of the internal structure of heterogeneous debris and the creation of rescue channels. At present, there is a paucity of methods to guide the rapid assessment of heterogeneous debris structures, resulting in a significant amount of time spent on-site evaluating these structures. This has the effect of delaying rescue timelines and hindering the rapid establishment of rescue passages. In order to address this issue, a case analysis approach was adopted in order to study the structural characteristics of post-disaster roadway heterogeneous debris and the factors that influence them. A three-dimensional framework was established, comprising disaster type, surrounding rock lithology, and support type. Each dimension was characterised by a set of indicators based on the inherent properties of the disaster. The disaster type dimension includes two categories: gradual failure and triggered failure. The surrounding rock lithology dimension includes three categories: hard rock, medium-hard rock, and soft rock. The support type dimension includes four categories: bolt/cable support systems, steel frame support, and composite support. The amalgamation of disparate indicators across these three dimensions engenders 18 distinct types of heterogeneous debris structures and their characteristics, thereby precipitating a rapid three-dimensional classification method for post-disaster roadway heterogeneous debris. The classification results are denoted by alphanumeric codes (111−233), where the first digit indicates the disaster type (1 = gradual failure, 2 = triggered failure), the second digit indicates the surrounding rock lithology (1 = hard rock, 2 = medium-hard rock, 3 = soft rock), and the third digit indicates the support type (1 = bolt/cable support system, 2 = steel frame support, 3 = composite support). A detailed analysis was conducted of a roof fall accident in the haulage roadway of the 113101 working face of a specific mine. The rapid three-dimensional classification method was used to categorise the heterogeneous debris left behind by the disaster, resulting in a classification of '131'. Key characteristics include uniform and dense accumulation due to the plastic flow of soft rock, bolts scattered within the rock mass and enveloped by it, and stretched metal mesh covering the bottom. Particle flow numerical simulation software was used to simulate the collapse characteristics of the accident. The simulation results indicated plastic failure of the soft rock, as well as deformation or fracture of the bolts and cables within the rock mass and stretched metal mesh covering the surface. These simulation results largely align with the characteristics of the “131” classification. The method was applied to two further cases, resulting in classifications of ‘121’ and ‘132’. The structural characteristics of the heterogeneous debris in both cases were consistent with the results of the on-site investigation, thereby validating the classification and demonstrating the feasibility of using this rapid, three-dimensional method to classify heterogeneous debris on post-disaster roadways. This method can provide scientific support for rapidly assessing the internal structure of heterogeneous debris and clearing rescue channels during emergency response operations in coal mine accidents.

     

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