腾晖矿软厚煤层接续回采矿压显现特征及煤柱稳定性研究

发布时间：2018-05-06 03:23

本文选题：接续回采 + 矿压特征　；参考：《中国矿业大学(北京)》2017年博士论文

【摘要】：近些年,随着我国国民经济快速、稳健发展,石油、天然气等重要能源的开发与开采强度日益提高,而煤炭资源作为重要能源之一,在推动经济发展的过程中,发挥着日益重要的推动作用;由于煤炭开采强度的不断加大,使得多数矿井煤层开采方式逐渐由传统“跳采”向“接续回采”转变,引起工作面接续紧张,矿压显现强烈;此时,接续工作面能否实现“安全、高效”回采,很大程度上取决于工作面间区段煤柱的稳定性,因此,采用多种研究手段,探究接续回采综放面、回采巷道矿压显现特征及成因,获得煤柱垂直应力场分布特征,建立煤柱稳定性力学条件,分析煤柱稳定性主要影响因素,揭示煤柱稳定性演化规律,确定煤柱合理留设方式,对进行类似工况条件下煤柱留设研究,实现矿井高效生产和促进我国经济稳定、健康发展具有重要推导意义。论文以腾晖矿接续回采综放面与区段煤柱为工程背景,综合采用现场调研、现场实测、室内试验、数值模拟、理论分析与工程类比研究手段,对上述主要内容进行较深入研究,获得主要如下成果:(1)通过现场调研,结合腾晖矿工程地质条件,采用估算法,得到了接续回采综放面支架架型:采用整体顶梁结构的正四柱式放顶煤支架,支架设计工作阻力为6000KN,确定了综放面基本参数:长度为155m,推进长度563m,采煤机截深600mm,采放比1:1.16,放煤步距0.675~0.945,为探究接续综放面矿压显现特征提供了合理分析依据。(2)探究了综放面“三测区”顶板来压,支架受力,立柱受力以及单体支柱受力特征,接续面矿压显现特征表现为:各测区,由下至上来压动载系数依次增大,矿压显现剧烈程度依次增高,工作面基本顶最小周期来压步距6.6m,最大周期来压步距17.6m,平均周期来压步距11.88m,工作面顶板垮落步距范围约8.5~15.55m,垮落步距范围与综放工作面周期来压步距较为吻合,超前支承压力峰值位置约44.05m,工作面支架工作状态较稳定,采动压力叠加效应与支架较低初撑力是上部测区来压程度较高的主要因素。支架初撑力频度与循环末阻力频度呈近似“正态分布”演化规律,支架工作状态较稳定,工作阻力有一定富余,采动压力叠加与支架低初撑力是上部测区来压强度剧烈的主要因素。前柱与后柱受力特性总体呈现较均衡性,局部出现前柱平均受力低于后柱,后柱受力不明显等反常特殊现象接续回采综放面“三区”矿压显现特征的形成,为进行双侧回采巷道矿压显现特征,与区段煤柱垂直应力场分布特征分析提供了重要依据。(3)采用室内试验研究与工程类比方法,2-103工作面煤岩层物理力学性质为:煤层物理力学性质较差,煤质偏软,顶板岩层物理力学性质较好,稳定性较高,煤岩样抗剪强度与剪切角度呈负相关,煤样抗剪强度受剪切角度影响程度明显高于岩样;运用钻孔应力监测系统,对原留设宽度煤柱垂直应力场进行现场实测,监测结果表明,煤柱支承压力影响深度约9m,监测范围内应力场可近似划分为应力降低区、应力升高区与弹性核区,可推知煤柱内部应力总体呈“双峰”分布特征;双侧回采巷道矿压显现特征,在时间与空间上具有同步性,但矿压显现剧烈程度存在显著差异性,邻近回采巷道支护轴向受力明显较高,是工作面推进速率、老顶岩梁运动状态、支承压力分布规律等多因素共同作用的结果。(4)采用现场监测手段,通过分析接续综放面回采过程中,双侧回采巷道锚杆(索)受力、围岩表面位移以及顶板离层演化特征,得到了回采巷道矿压显现特征,表现为:两巷支护轴力曲线整体呈现“凸变”和“凹变”演化特征,正巷支护受力曲线“凸变”和“凹变”幅度高于副巷;正巷支护受力、围岩位移程度较高与综放面上部测区来压剧烈程度高相一致,副巷支护受力与围岩位移程度低与下部测区来压剧烈程度低相一致,表明了矿压监测结果的合理性与可靠性。正巷围岩变形破坏主要受接续工作面采动影响,原支护方案与现有煤柱留设宽度,能够较好维护巷道掘采期间围岩稳定,煤柱宽度具有一定优化空间。(5)结合煤柱赋存特征,采用理论研究手段,基于突变理论尖点突变模型,结合泛函变分原理与弹塑性力学能量原理,构建了双侧采空区段煤柱总势能函数,揭示了弹塑性系统能量原理中驻值原理,与突变理论平衡曲面(临界点曲面)构造的相对应性,以及最小势能原理与突变理论中的分叉点集判别表达式具有的相关性,是区段煤柱稳定性力学判据建立的重要依据。根据区段煤柱总势能函数,得到了煤柱临界失稳状态的力学判据、煤柱稳定状态力学判据以及煤柱失稳状态力学判据,探究了煤柱稳定性的主要影响因素,为煤柱稳定性演化规律分析提供了理论依据。煤柱稳定性影响因素,主要包括煤柱高度,煤柱承受上覆岩层载荷、煤柱内部弱面倾角、煤柱弹性区与塑性区的宽度以及刚度比值,随着上覆岩层载荷增加,煤柱从稳定承载状态向失稳状态逐渐转变,煤柱失稳后,煤体呈现出“压硬性”特征,这一过程体现了尖点型突变模型的“突跳性”,煤柱稳定性与倾角呈负相关,随着角度增加不稳定程度逐渐提高,与室内煤岩样稳定性随剪切角度增加而降低的演化特征相类似;随着刚度比K增加,煤柱稳定性也逐渐提高。(6)数值模拟结果表明,接续工作面对煤柱稳定性的采动影响与弱面倾角呈正相关,弱面倾角逐渐增加,稳定性不断降低,垂直应力场分布形态整体逐渐由“双峰”向“单峰”逼近,塑性屈服区扩延程度逐渐提高,弹性核区宽度逐渐降低,煤柱侧帮位移具有不同形式与程度的变化和提高;演化特征与室内试验煤样抗剪强度与剪切角度增加呈负相关相一致,同理论研究结论较吻合,验证了数值分析结果具有一定合理性。(7)煤柱高度增加提高了接续工作面对煤柱稳定性的采动影响程度,两侧帮抵抗挠曲变形的能力逐渐降低,煤柱内部塑性屈服区有一定程度的扩延,垂直应力峰值向煤体内部具有不同程度转移,弹性核区宽度随煤柱高度的增加具有一定程度降低,煤帮位移量也具有不同程度增加;综合对比煤柱宽度、弱面倾角以及煤柱高度变化过程中塑性区、垂直应力场以及位移场演化特征,相邻工作面接续回采后对煤柱稳定性受巷道高度影响程度相对较低。(8)随着埋深逐渐增加,煤柱稳定性不断降低,接续工作面二次采动影响程度提高,煤柱非塑性区域逐渐缩小,煤柱两侧垂直应力峰值位置逐渐转移,弹性核区宽度减小,巷道顶板岩层、帮部煤体与底板岩层位移具有不同程度的增加,本工作面煤柱侧帮水平位移逐渐提高并大于上区段工作面煤柱侧帮水平位移,区段煤柱两侧帮表面水平位移随埋深的加大逐渐接近。(9)数值模拟结果表明,接续回采综放面区段煤柱留设应综合考虑相邻工作面巷道开挖和接续面回采对区段煤柱稳定性综合采动影响程度,宜选取宽煤柱留设方式,留设宽度范围为15m~23m,为提高煤炭资源回采效率,合理煤柱留设宽度为19m。接续回采综放面区段煤柱稳定性受煤柱宽度、煤柱内部弱面倾角以及煤柱埋深影响程度较高,煤柱高度对稳定性影响程度相对较低,数值模拟与理论研究结果具有一定程度上的一致性。(10)采用塑性区理论计算法与载荷估算法,所得煤柱留设宽度理论值与数值模拟结果较为接近,进一步获得合理煤柱留设宽度范围为19m~21m,确定接续回采综放工作面区段煤柱合理留设宽度为19m。现场应用表明,煤柱宽度优化后,仍能较好维护接续综放面推进过程中,回采巷道围岩的稳定性,提高了煤炭资源回收效率,满足了矿井“安全、高效”的生产要求。
[Abstract]:In recent years, with the rapid and steady development of our national economy, the development and mining intensity of important energy sources, such as oil and gas are increasing, and coal resources, as one of the important energy sources, play an increasingly important role in promoting economic development. Because of the increasing intensity of coal mining, most coal mines have been made. The mining mode is gradually changed from the traditional "jump mining" to "continuous recovery", which causes the continuous tension of the working face and the intensity of the ore pressure. At this time, the stability of the coal pillar is largely determined by the "safe and efficient" recovery of the continuous working face. Therefore, a variety of research means is adopted to explore the continuous mining fully mechanized caving face and return. The vertical stress field distribution characteristics of coal pillar are obtained, the characteristics of vertical stress field distribution of coal pillar are obtained, the stability mechanics condition of coal pillar is established, the main influencing factors of the stability of coal pillar are analyzed, the evolution law of the stability of coal pillar is revealed, the rational retention mode of coal pillar is determined, and the study on the retention of coal pillar under the condition of similar working conditions is carried out to realize the efficient production and promotion of the mine. China's economic stability and healthy development have important derivation significance. In this paper, with the engineering background of fully mechanized caving face and Qu Duanmei column in Tenghui mining, the main contents of the main contents are studied by field survey, field measurement, indoor test, numerical simulation, theoretical analysis and engineering analogy. 1) through the field investigation and combined with the engineering geological conditions of Tenghui mine, the support frame of the fully mechanized caving face is obtained by using the estimation method. The four column top coal caving support with the whole roof structure is used. The design resistance of the support is 6000KN. The basic parameters of the fully mechanized caving face are determined: the length is 155m, the propelling length is 563m, the cutting depth of the coal mining machine is 600mm, the production and discharge ratio 1:1. 16, the coal step distance 0.675~0.945 provides a reasonable analysis basis for exploring the characteristics of the ore pressure of the fully mechanized caving face. (2) to explore the top plate pressure of the "three measuring areas" of the fully mechanized caving face, the force of the support, the force of the column and the stress characteristics of the single pillar, and the characteristics of the pressure manifestation of the continuous surface are as follows: the pressure dynamic load coefficient in each test area is increased in turn and the ore pressure is in turn. The intensity of the apparent intensity is increased in turn, the minimum period of the basic top of the working face is 6.6m, the maximum period is 17.6m, the average period is 11.88m, the range of the roof caving distance is about 8.5~15.55m, and the range of the fall distance is in agreement with the cycle distance of the fully mechanized caving face, and the peak position of the forward support pressure is about 44.05m. The working state of the support is more stable, the superposition effect of the mining pressure and the lower bracing force of the support are the main factors of the higher pressure degree in the upper test area. The frequency of the bracing force and the frequency of the end resistance of the support are approximately "normal distribution", and the working state of the support is more stable, the working resistance has some surplus, the overlay of the working pressure is superimposed and the support is low. The initial bracing force is the main factor of the intense pressure in the upper test area. The stress characteristics of the front column and the rear column are generally more balanced, the local front column average force is lower than the rear column and the rear column is not obvious. It provides an important basis for the analysis of the vertical stress field distribution characteristics of the section coal pillar. (3) the physical and mechanical properties of the coal strata in the 2-103 working face are: the physical and mechanical properties of the coal seam are poor, the coal quality is soft, the physical and mechanical properties of the roof rock are better, the stability is higher, the shear strength and shear angle of the coal and rock samples are the shear strength and the shear angle. The degree of shear strength of coal samples is significantly higher than that of rock samples. The vertical stress field of the original width coal pillar is measured by the borehole stress monitoring system. The monitoring results show that the depth of supporting pressure of the coal pillar is about 9m, and the stress field in the monitoring range can be approximately divided into the stress reduction area and the stress elevation area. With the elastic core area, it can be concluded that the internal stress in the coal pillar is generally "Shuangfeng" distribution characteristics, and the characteristics of the ore pressure in the bilateral mining roadway have the characteristics of synchronism in time and space, but there are significant differences in the intensity of the ore pressure, and the axial stress of the adjacent mining roadway is obviously higher. It is the advancing speed of the working face and the movement state of the old roof rock beam. (4) by means of on-site monitoring, through the analysis of the stress of the bolt (cable), the displacement of the surrounding rock surface and the evolution characteristics of the roof separation in the recovery of the fully mechanized caving face, the characteristics of the ore pressure in the mining roadway are obtained, which are shown as follows: the axial force curve of the two roadway support is the whole. With the characteristics of "convex change" and "concave change", the amplitude of "convex change" and "concave change" of the supporting force curve of the roadway is higher than that of the vice alley. It shows the rationality and reliability of the monitoring results of mine pressure. The deformation and failure of the surrounding rock of the roadway is mainly affected by the mining of the continuous working face, the original support scheme and the existing coal pillar width are retained, which can better maintain the stability of the surrounding rock during the mining and mining, and the width of the coal pillar has a certain optimization space. (5) combining the characteristics of the coal pillar, the theoretical research means is adopted. The total potential energy function of the coal pillar in both sides of the goaf is constructed in combination with the functional variational principle and the principle of elastoplastic mechanical energy, which reveals the principle of the stationing in the energy principle of the elastoplastic system, the relative stress of the equilibrium surface (critical point surface), and the principle of minimum potential energy and the catastrophe theory. The correlation of the discriminant expression of the bifurcation point set is an important basis for the establishment of the stability mechanics criterion of the section coal pillar. According to the total potential energy function of the section coal pillar, the mechanical criterion of the critical instability state of the coal pillar, the mechanical criterion of the stability state of the coal pillar and the criterion of the instability state of the coal pillar are obtained, and the main influence of the stability of the coal pillar is explored. It provides a theoretical basis for the analysis of the stability evolution of the coal pillar. The factors affecting the stability of the pillar include the height of the pillar, the loading of the overlying strata on the pillar, the angle of the weak surface in the coal pillar, the ratio of the width and stiffness of the elastic zone to the plastic zone, and the stability of the coal pillar to the unstable state with the increase of the load of the overlying strata. Gradually change, after the coal pillar is unstable, the coal body presents the "pressure hard" characteristic. This process embodies the "sudden jump" of the cusp model. The stability of the coal column is negatively correlated with the dip angle. With the increase of the angle, the instability degree increases gradually, which is similar to the evolution characteristics of the stability of the coal and rock samples with the increase of shear angle. The stability of coal pillar is increased gradually as stiffness ratio K increases. (6) the results of numerical simulation show that the effect of recovery on the stability of coal pillar has a positive correlation with the weak angle of the coal pillar, the weak angle gradually increases and the stability decreases, and the distribution of vertical stress field is gradually approaching from "Shuangfeng" to "single peak", and the expansion of plastic yield zone is extended. The width of the elastic core area is gradually increased, the width of the elastic core area is gradually reduced, and the lateral displacement of the coal pillar has different forms and degrees of change and improvement. The evolution characteristics are in agreement with the increase of shear strength and shear angle in the laboratory test, which is in agreement with the theoretical research conclusion, which proves that the results of numerical analysis are reasonable. (7) the height of the coal pillar is increased. With the increase of the effect of the recovery on the stability of the coal pillar, the ability of both sides to resist flexure deformation gradually decreases, the plastic yield zone in the coal pillar has a certain degree of expansion, the peak of the vertical stress is transferred to the coal body, and the width of the elastic core area decreases to a certain extent with the increase of the height of the coal column. The displacement is also increased in varying degrees; the comprehensive comparison of the width of the coal pillar, the weak angle of the weak surface and the evolution of the plastic zone, the vertical stress field and the displacement field in the process of the height change of the coal pillar, and the relative low influence of the stability of the coal pillar on the stability of the coal pillar after the successive recovery of the adjacent working face. (8) the stability of the pillar is constantly increasing with the gradual increase of the buried depth. In addition, the effect of two times on the mining face increased, the non plastic area of the pillar gradually reduced, the peak position of vertical stress shifted gradually on both sides of the pillar, the width of the elastic core area decreased, the roof rock of the roadway, the displacement of the coal body and the bottom rock layer increased in different degrees, and the horizontal displacement of the side side of the coal pillar was gradually increased and greater than that of the coal pillar. The horizontal displacement of coal pillar side helps the horizontal displacement of the coal pillar on both sides of the section. (9) the numerical simulation results show that the retention of the coal pillar in the section of the continuous mining fully mechanized caving face should take into consideration the comprehensive mining influence degree on the stability of the coal pillar of the adjacent working face, which should be selected. The width of the width of the wide coal pillar is 15m~23m, in order to improve the coal mining efficiency. The reasonable coal pillar retention width is 19m. continuous mining fully mechanized coal pillar, the stability of the coal pillar is affected by the width of the pillar, the weak angle inside the coal pillar and the depth of the coal pillar's buried depth is higher, the influence degree of the coal column height to the stability is relatively low, and the numerical simulation and the numerical simulation The theoretical results are consistent to a certain extent. (10) the theoretical calculation method of plastic zone and the load estimation method, the theoretical value of the retention width of the coal pillar is close to the numerical simulation results, and the reasonable width of the retention of the coal pillar is 19m~21m, and the rational retention width of the coal pillar in the continuous recovery recovery working face area is 19m.. The field application shows that after the coal pillar width is optimized, it can still maintain the stability of the surrounding rock in the mining roadway, improve the efficiency of coal resource recovery, and meet the production requirements of "safe and efficient" in the mine.

【学位授予单位】：中国矿业大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD32

【相似文献】