水力钻孔煤体破裂特性及瓦斯渗流规律研究

The topic is based on the process technology of preventing device of hydraulic drill, which is self-developed and remote controlling, to study the coal broken degree during the hydraulic drilling process and fracture's evolution process and the gas' movement law after drilling and so on. Then we discuss the prevention mechanism through hydraulic drilling, and optimize the technological parameters of prevention. By this way, we can get the best effect about the prevention and control of coal and gas. We can research on coal's changes of physical and mechanical properties by high pressure water jet and the static effect leve by verifying and inspecting the outburst prevention effect through experimental analysis and the on-site monitoring or other technical means. At the same time, we can discuss deformation of coal formed in the coal and impact range, we can not only supervise gas pressure and gas content and so on, but also verify and inspect the outburst prevention effect; according to failure characteristics of surrounding rock and fracture distribution, we can determine the gas flow path and deduce the gas seepage equation after hydraulic drill, we can decide the different coal seam characteristics of outburst prevention technique of hydraulic drilling, we can improve and optimize the construction technology, and also can make the corresponding measures about safety by testing on-the-spot and numerical simulation and other means to study the change of coal characteristics during the drilling process.

课题基于自行研制的远程控制水力钻孔防突技术装置，研究水力钻孔过程煤体破坏程度、裂隙演变过程以及钻孔后瓦斯运移规律等，探讨水力钻孔防突机理，优化防突技术参数，达到防治煤与瓦斯的最佳效果。通过实验分析以及现场监测等技术手段，研究煤体在高压水射流冲击压力和水准静态作用下物理性能和力学性能的变化；同时探讨煤体水力钻孔后，煤体内部形成超前孔洞周围煤体的变形情况以及冲击影响范围，监测瓦斯压力、瓦斯含量等变化情况，验证和检验防突效果；依据围岩破坏特征和裂隙分布规律，确定瓦斯流动轨迹，推导水力钻孔后煤体内瓦斯渗流方程；通过现场测试、数值模拟等技术手段研究整个钻孔工序中煤体特征的变化，确定不同煤层特征下水力钻孔防突技术参数，改进和优化防突技术施工工艺，制定相应的安全防护措施。

课题基于自行研制的远程控制水力钻孔防突装置，在深入研究分析水力钻孔过程中煤体破坏程度、裂隙演变过程以及钻孔后瓦斯运移规律等基础上，通过数值模拟分析、理论计算和现场试验等技术手段，优化装置性能和关键技术参数，最终定型螺旋钻杆-快速接头式水力钻孔防突装置。该装置通过井下测试以及效果检验，证明了水力钻孔装置能够实现煤与瓦斯突出煤层掘进工作面卸压增透和防突的效果。.在深入分析高压水射流结构及特点的基础上，研究了高压水射流在煤体内部形成超前孔洞周围煤体的破裂特性以及冲击影响范围。阐述高压水射流冲击后煤体围岩应力发生的变化，最终形成了孔口较大的漏斗状煤体破碎槽孔；同时由于围岩应力的作用，煤体受压变形，促使煤体裂隙进一步发育，扩大瓦斯释放范围，达到了大面积卸压的目的，进一步完善了高压水射流破煤防突机理。多次工业现场试验表明，水力钻孔后，改变了孔槽周边煤样提特征，煤体裂隙进一步发育，为瓦斯排放提供了通道，瓦斯突出危险性进一步降低。.通过数值模拟分析、电镜扫描、现场检测等手段，进一步研究了掏槽孔洞周围煤体完整性的破坏情况和裂隙发育分布情况，检验了水力钻孔过程中煤体破裂情况和措施的防突效果；分析了煤体水力钻孔后煤层渗透率变化，建立了描述煤层瓦斯渗透率非线性方程；并根据瓦斯渗流理论得出水力钻孔后煤体内瓦斯渗流方程。通过数值模拟分析和工业现场测试，研究了在不同开采条件下：煤体强度、煤层围岩特征等，水射流冲击力、掏槽角度、掏槽位置、掏槽孔径等关键参数。确定了不同煤层特征下实施水力钻孔防突的关键技术参数，改进和优化防突技术施工工艺，制定相应的安全技术防护措施。