厚基岩采场弱胶结岩层动力溃砂机制研究现状与展望

Research status and prospect on the mechanism of dynamic sand inrush atweakly cemented strata in working face with thick bedrock

我国西部矿区黄陇、宁东两大煤炭基地发生的采场顶板溃水溃砂与强矿压显现叠加灾害是一种厚基岩采场顶板弱胶结岩层动力溃砂灾害。该灾害类型在表象、物源和动力源上均不同于以往浅埋、近松散层采场的非动力溃水溃砂灾害,是一种新型的采场顶板灾害。由于该类型灾害突发性强、破坏性大、冲击力大,对安全生产带来严重威胁,致使如何有效防控灾害的再次发生成为许多矿区亟待解决的难题。目前揭示灾害形成的内在机制、探明其中蕴藏的科学问题是建立灾害防控技术体系的基础和关键。通过挖掘灾害形成的表象、物源和动力源特征,分析事故矿区覆岩结构、地层条件及相关研究现状,研究得到硬岩下方支承压力和基本顶载荷分布对弱胶结地层劣化的响应规律、硬岩破断作用下劣化弱胶结地层溃涌的动力形成机制和通道演化规律等2个关键科学问题是揭示灾害形成机制的瓶颈。因此,关于灾害形成机制研究形成了弱胶结地层遇水劣化对影响因素的反馈特征及响应关系、上硬岩层和基本顶受力条件随弱胶结地层劣化的变化规律、劣化弱胶结地层溃涌动力机制和增量载荷作用下通道演化规律等3个主要研究内容,并且提出了从根本上改变灾害发生客观条件的硬岩超前预裂和弱胶结地层注浆改性的综合主动防控技术思路。研究成果将为采场顶板溃水溃砂和强矿压显现并发灾害构建防控技术体系提供借鉴,保障西部煤田大规模安全开发。

The superposition disaster of roof water and sand inrush and strong ground pressure in Huanglong and Ningdong coal bases in western mining areas of China is a dynamic sand inrush disaster of weakly cemented strata in working face with thick bedrock.This type of disaster is different from the water and sand inrush disasters in shallow and near loose layer working face in occurrence,material source and power source.It is a new type of roof disaster.Because this type of disaster is sudden,destructive and powerful,which poses a serious threat to safe production,how to effectively prevent and control the recurrence of disasters has become an urgent problem in many mining areas.At present,the understanding on the internal mechanism of disaster formation and the studies on the scientific problems are the basis and key to establishing the technical system of disaster prevention and control.This paper analyzes the overburden structure,formation conditions,and related research status in the accident mining area,and obtains the response law of bearing pressure and basic top load distribution under a hard rock to the deterioration of weakly cemented formation.Two key scientific problems,such as the dynamic formation mechanism and channel evolution law of degraded weakly cemented formation under the breaking action of hard rock,are the bottleneck to reveal the formation mechanism of disaster.Therefore,the research on the formation mechanism of disasters has formed three main research areas including the feedback characteristics and response relationship of the deterioration of weakly cemented strata when encountering water to the influencing factors,the variation law of the stress conditions of upper hard rock,and basic roof with the deterioration of weakly cemented strata,and the collapse dynamic mechanism of degraded weakly cemented strata and the channel evolution law under incremental load.The comprehensive active prevention,and control technical approaches of hard rock advanced splitting and weak cemented stratum grouting modification are put forward to fundamentally change the objective conditions of disasters.The research results will provide theoretical support for the development of a prevention and control technological system for the water and sand inrush of roof and concurrent disasters of strong ground pressure,and ensure the large-scale safe development of Western coalfields in China.