旧采区围岩破坏及应力分布规律数值模拟研究

发布时间：2018-05-18 19:14

本文选题：旧采区二次回采 + 三维数值模拟　；参考：《太原理工大学》2015年硕士论文

【摘要】：本论文以晋煤集团天安圣华煤业有限公司3#煤层旧采区二次回采首采工作面的实际地质资料为基础，通过理论公式计算、RFPA数值模拟相结合的方式，，研究了：旧采区不同情况下遗留煤柱状态，及旧采巷道状态，并对两者的影响因素进行了分析；旧采区二次回采掘进时与旧采巷道的安全煤柱宽度以及应力、位移分布规律；旧采区二次回采采煤工作面初次来压分布规律。通过对上述内容的研究，得出了以下结论：（1）利用理论分析和三维数值模拟方法研究了煤柱状态，得出了：①旧采区的遗留煤柱大部分处于稳定状态；旧采巷道大部分以空巷、空区为主。②巷宽、巷高、煤柱1、2宽度对遗留煤柱及旧采巷道的状态均有一定的影响，遗留煤柱状态主要受煤柱本身宽度的影响，接下来是附近巷道巷高、巷宽的影响；旧采巷道状态主要受本巷巷高及巷宽的影响。（2）通过二维数值模拟的方法，研究了旧采区巷道掘进工作面的应力、位移分布变化规律。得出了：①随着旧采巷道断面的增大，安全煤柱宽度增大，空巷时煤柱的安全宽度为5m,空区时煤柱的安全宽度为15m，冒落区时的煤柱安全距离为20m；②二次掘进时，工作面应力基本上都比开挖前要降低、位移比开挖前要大，旧采巷道断面越大，应力、位移变化率越大。③在煤柱宽度小于与大于安全煤柱宽度时，应力、位移分布规律差别十分明显。小于安全煤柱宽度时，应力降低区域很大，位移只存在一个较大的峰值；大于安全煤柱宽度时，应力降低区域较小，一般存在两个位移峰值。④当煤柱宽度超过安全煤柱宽度后，应力、位移变化率变化不大（3）通过理论分析与二维数值模拟方法研究了直接顶和顶煤初次来压分布规律，得出了：①按照理论计算得出的正常回采初次来压步距为8.13～11.50m，采用数值模拟方法得出的初次来压步距为11m。②从应力分布图中可以看出，来压时的应力分布规律与未来压时的规律明显不同，来压时最大应力值明显比未来压时的最大值大，且最小值明显比未来压时最小值小。③随着旧采巷道断面的增加，二次回采受到旧采巷道的影响也越大，主要表现在，初次来压步距越来越小；最大应力越来越大，应力集中系数也越来越大；工作面首次出现破裂的步距也越来越小；工作面前方的空顶距离越来越大，回采难度也相应的增大；应力降低范围也越来也大。④当旧采巷道断面一定时，随着距离的增大，旧采巷道对工作面的影响趋于稳定，即旧采巷道对工作面的影响存在一临界值，超过该值，继续增大距离，二次回采初次来压分布规律基本不变。
[Abstract]:This paper is based on the actual geological data of the secondary first mining face in the coal seam old mining area of Tianan Shenghua Coal Industry Co., Ltd., Jin Coal Group, and combines the numerical simulation of RFPA with the theoretical formula. The paper studies the status of coal pillar and roadway in old mining area, and analyzes the influencing factors of them, the width, stress and displacement distribution of safe coal pillar during secondary mining excavation and old roadway in old mining area; Distribution of the first pressure in the secondary mining face in the old mining area. Through the study of the above contents, the following conclusions are reached: 1) by using theoretical analysis and three-dimensional numerical simulation method, the paper studies the status of coal pillar, and concludes that most of the remaining coal pillars in the old mining area of 1 / 1 are in a stable state, and most of the old roadways are empty roadway, the main goaf is 2. 2 roadway width, and the roadway is high. The width of pillar 1 ~ 2 has a certain influence on the status of the remaining coal pillar and the old mining roadway. The state of the remaining coal pillar is mainly affected by the width of the coal pillar itself, and the next is the height and width of the roadway nearby. The state of the old roadway is mainly affected by the height and width of the roadway. 2) by means of two-dimensional numerical simulation, the stress and displacement distribution of roadway excavation face in old mining area is studied. It is concluded that with the increase of the section of the old roadway, the width of the safe pillar increases, the safe width of the pillar in the empty roadway is 5 m, the safe width of the pillar in the empty area is 15 m, and the safe distance of the pillar in the caving area is 20 m when the coal pillar is driven twice. The stress of working face is basically lower than that before excavation, the displacement is larger than that before excavation, the bigger the section of old roadway is, the greater the stress and displacement change rate is. 3. When the width of coal pillar is smaller than that of safe pillar, the stress is larger than that of safe pillar. The law of displacement distribution is quite different. When the width of coal pillar is smaller than that of safe coal pillar, the region of stress decrease is very large, and the peak value of displacement exists only, and when the width of coal pillar is larger than that of safe coal pillar, the region of stress decrease is smaller. Generally, there are two peak displacement peaks. 4. When the width of coal pillar exceeds the width of safe pillar, the change rate of stress and displacement does not change much. Through theoretical analysis and two-dimensional numerical simulation, the first pressure distribution of direct top coal and top coal is studied. It is obtained that the first step distance of normal mining is 8.13 ~ 11.50 m calculated according to the theory. The initial pressure step distance obtained by numerical simulation method is 11m.2, which can be seen from the stress distribution diagram. The law of stress distribution in the coming pressure is obviously different from that in the future. The maximum stress value in the coming pressure time is obviously larger than the maximum value in the future pressure time, and the minimum value is obviously smaller than the minimum value in the future pressure time. 3. With the increase of the section of the old mining roadway, the minimum stress distribution law is obviously smaller than that of the future pressure time. The influence of the old roadway on the secondary mining is more and more, mainly in the following aspects: the first pressure step is becoming smaller and smaller; the maximum stress is becoming larger and larger, the stress concentration factor is becoming larger and larger; the distance between the first breakup of the working face is also becoming smaller and smaller. The gap distance in front of the face is getting larger and larger, the difficulty of mining is also increasing correspondingly, and the decreasing range of stress is also increasing. When the section of the old roadway is fixed, the influence of the old roadway on the working face tends to be stable with the increase of the distance. That is to say, there is a critical value for the influence of the old roadway on the working face, beyond which the distance continues to increase, and the distribution law of the first pressure in the secondary mining is basically unchanged.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD323

【参考文献】