超大采高综采面煤壁灾变的“尺度效应”与采高上限确定研究

The maximum support height of the full-mechanized hydraulic support in large mining height working faces applied in China has reached 7.2m. According to the survey, the problems of surrounding rock control such as coal-wall catastrophe etc, are ubiquity in super-high cut faces.This subject is aimed at selecting 4-6 domestic super-high cut working faces of different storage condition to study the microscale effects produced by length, angle, height, depth, coal physical and mechanical properties and other factors, which also studys the reasonable upper mining limit from the view of controlling coal wall instability and catastrophe. By using of the coal rock chromatography imaging system,the advanced support pressure morphology and effect on the coal wall damage in the large mining height working face are researched . And the crack field spatio-temporal evolution and its impact on the coal wall spalling and disaster in different layers of coal body in front of the coal wall mining are also measured by using of the borehole television.The research will analyze the distribution, frequency and energy release intensity of coal wall instability to search the quantitative relationship between the face catastrophic energy release intensity and the mining height by using of the portable microseismic monitoring system and its positioning function. Through the establishment of roof instability model, the method of support and the mutual strength in large mining height working face is determined.Based on the above research results,the law of scale effect of coal wall disaster in large mining height mechanized faces and the reasonable mining height limit set theory will be obtained.

我国实践的超大采高综采液压支架最大支撑高度已达7.2m，据调研，超大采高工作面普遍存在煤壁灾变等一系列围岩控制难题。本课题目的旨在从控制煤壁失稳乃至灾变角度研究我国超大采高综采合理的割煤高度上限，拟选取国内现有的4-6个不同赋存条件的超大采高工作面为研究对象，研究由于长度、倾角、采高、埋深、煤岩物理力学性质等因素变化所产生的各种微尺度效应。采用煤岩应力层析成像系统研究超大采高工作面工作面超前支撑压力形态及其对煤壁损伤的影响程度；采用钻孔电视实测煤壁前方不同层位煤体采动裂隙场时空演化规律及其对煤壁片帮乃至灾变的影响；采用便携式微震监测系统及其定位功能，研究不同采高条件下煤壁失稳发生的位置、频率和释放能量大小，探寻工作面灾变能量释放强度同采高之间的量化关系；建立超大采高工作面老顶失稳模型，研究超大采高工作面支架支护及护帮强度的确定方法，得出超大采高综采煤壁灾变的尺度效应规律和采高上限确定理论。

本课题目的旨在从控制煤壁失稳乃至灾变角度研究我国超大采高综采合理的割煤高度上限，通过选取国内有代表性的多个大采高工作面为研究对象，研究由于长度、倾角、采高、埋深、煤岩物理力学性质等因素变化所产生的各种微尺度效应。在课题实施过程中，理论始终和现场工程应用相结合，在阳泉、神东、四川攀枝花、潞安新疆公司等多个矿区进行了现场实测和数据采集。研究团队从宏观的覆岩垮落、能量释放到微观的卸荷与岩体损伤破坏等角度，研究了煤壁片帮冒顶乃至灾变失稳与采高之间的变化规律，揭示了采高的跃升给工作面围岩控制恶化带来的尺度效应规律，得出了尺度效应作用下大采高综采极限割煤高度和基于溃屈理论的大倾角大采高工作面极限极长度确定方法；从液压支架四连杆回转运动曲线唯一性原理，将支架失稳前的位态变化与围岩灾变的前兆信息结合起来，研究大采高采场顶板灾害预警指标及方法，提出了基于支架位态识别大采高采场顶板灾害预警指标及方法；提出了大采高极限开采强度概念，采用信息熵、属性识别法及逐步逼近原理与大数据相结合，研究了多因素耦合作用下特定煤层的极限开采强度评价模型及工作面相关极限参数计算方法。