增压型地质构造破断区诱发煤与瓦斯突出特性研究

Tectonic structures play an important role in controlling coal and gas outburst, but there has not formed a unified understanding of the mechanism that how different types of tectonic structures control coal and gas outburst. Basing on previous studies，we find that pressure increasing tectonic structures are more easily to induce coal and gas outburst, the mechanism and icriterion are necessary to further study. We propose to use self-developed three-dimensional hydraulic loading outburst simulation apparatus, by the coal roadway driving which is more prone to happen outburst as the typical similar simulation experiment model, to reveal the initial stress distribution and gas occurrence rule of the coal seam with pressure increasing tectonic structure broken zone, to exploration the superimposed effect of the mining stress field and the tectonic stress field in front of the tunneling face, to expound the control mechanism of the superimposed stress field to the gas flow field. It will reappear and validate the experiment results from micro angle with the gas-solid coupling software RFPA2D-GAS which can simulate the failure process of gassy coal and rock. And in the coal mine field, the influence of tectonic structures to outburst is tracked and analyzed; In addition, the suppression effect of the pressure decreasing tectonic structure to outburst is also analyzed contrastively, and the pressure increasing tectonic structure criterion is given. The research can not only deeply reveal the mechanism of coal and gas outburst induced by tectonic structure, but also can provide some new coal and gas outburst prediction and control methods. So it has important theoretical meaning and realistic valve to coal mine safety production.

地质构造对突出起重要作用，但不同形态地质构造的诱突机制迄今没有形成统一的认识，仍在探索。前期研究认为增压型地质构造比减压型地质构造更具突出的条件，可以此为切入点开展研究，深入揭示地质构造诱突机制。拟运用自制的三维液压加载突出模拟装置和具有含瓦斯煤岩破裂过程模拟功能的力学软件RFPA2D-GAS，以含增压型地质构造破断区煤层掘进为典型模型进行模拟实验，研究煤层初始应力的异常分布和瓦斯赋存特征，揭示掘进面前方围岩采动应力场与构造应力场的叠加特性及其对瓦斯流动的控制效应，并现场跟踪研究地质构造影响突出情况，最终提出增压型地质构造破断区诱突机制。并研究减压型地质构造对突出的影响，综合对比分析，提出增压型地质构造的辨识依据，初步提出其危险性消除原理。项目研究不仅有助于更深入地揭示地质构造诱发突出机理，还可为地质构造影响下瓦斯突出预测预报和防治提供新的方法，对煤矿安全生产具重要理论指导意义和实用价值。

我国煤矿瓦斯地质条件复杂，煤与瓦斯突出（简称“突出”）是煤矿安全生产的重大威胁。随着开采深度的增加，突出灾害日趋严重。深入揭示突出机理，对合理制定防突措施，保障煤矿安全生产具有重要意义。大量突出地点的地质构造调查资料表明，几乎所有的瓦斯异常涌出或突出都与地质构造的影响有关。但是，人们对究竟何种形态的地质构造更容易引起突出仍还存在争议，在地质构造诱发突出机理方面还未形成统一的认识。本项目采用多学科交叉理论分析、实验室试验和仿真分析以及现场跟踪考察等方法，研究了增压型地质构造的赋存特征、诱突力学演化特性、辨识依据和相应防控方法。研究结果表明：增压型地质构造的形成是一个动静态结合特殊的过程，它与采掘过程、构造形态、地应力、煤层瓦斯赋存和透气性密切相关；其边界围岩受到压应力作用，质地坚硬透气性低，内部结构松软，富含承压瓦斯，这为煤与瓦斯突出的发生提供了有利的条件。受构造应力场的影响，增压型地质构造破坏区附近煤岩体的初始应力高于正常区域，为正常区域煤岩初始应力的1.5-1.7倍；采掘过程中，工作面前方的集中应力场与构造应力场相叠加，造成增压型地质构造围岩应力进一步增加，可达正常区域煤岩初始应力的2倍以上。采掘至增压型地质构造破坏区附近时，其围岩发硬，透气性低，卸压特性不明显，内部瓦斯压力得以保持，形成异常高的应力梯度和瓦斯压力梯度，这是诱发突出的最根本原因，也是增压型地质构造的辨识依据。在复杂瓦斯地质条件突出煤层中采掘时，要确保预测孔、措施孔和检验孔穿透增压型地质构造破坏区的边界围岩，以掌握前方待采掘区域突出危险性的准确信息，减少误判。项目成果丰富了突出机理理论和防控方法，可为采掘工作面过复杂构造带瓦斯动力灾害预防提供理论和技术参考。