斜井管片结构下方保护煤柱尺寸设计的离散元分析

发布时间：2018-03-15 17:43

本文选题：斜井　切入点：保护煤柱　出处：《北京交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,我国乃至世界上的大多数国家主要采用留设煤柱的方法来保护煤矿中的各类巷道。然而,此方法虽然可以对巷道起到良好的保护作用,但是同时保护煤柱的回收却较为困难,浪费了大量的资源。因此,研究护巷煤柱留设的宽度,使其既有利于受护巷道的稳定性与安全性,也能尽可能地提高矿区资源的回采率,具有普遍的经济效益与社会意义。新街矿区斜井井筒采用TBM工法进行施工。本文以新街矿区的煤层开采设计问题为背景,分析煤层开采过程中斜井管片结构的内力与位移的变化特征,确定保护煤柱的合理尺寸。经验公式法只笼统地涉及煤层的几何参数与力学性质,而数值模拟则可同时考虑煤层、岩层、斜井结构的几何特征与力学特征。本文采用离散元数值模拟的方法,主要研究内容与成果如下： (1)采用UDEC软件,选取斜井不同位置的断面,在3-1煤层中预先假设多个煤柱宽度值,模拟从远及近的分步开采过程。针对不同保护煤柱宽度,分析斜井结构的受力与变位,在煤柱宽度能使斜井结构满足安全性与稳定性要求的前提下,取其最小值作为斜井保护煤柱的建议宽度取值。在此过程中,发现回采工作面与斜井的水平距离越小,斜井结构受力状态越不利,变位也越大；斜井与开采煤层的竖向距离越大,斜井结构受力状态越有利,变位反而越大。同时,UDEC软件直接模拟得出煤层开采时,节理产生滑移的区域,获得岩层破裂角δ为76。。 (2)在二维模拟的基础上,结合斜井倾角6。,综合几何关系可得煤层工作面与斜井轴线在水平面上的夹角为1.53。,以该角度留设煤柱,采用与二维模拟分析类似的方法,对斜井落底处的一个回采工作面范围进行三维模拟(3DEC)。模拟结果表明：开采方向取工作面与斜井轴向平行时(有1.53°的夹角)对斜井结构的安全与稳定较为有利；先后开采的上、下煤层中的煤柱宽度取值之间影响很大,如上层3-1取40m,则下层5-1中最少需留86m,若3-1煤中取50m,则5-1煤中仅需67m。 (3)以三维固体模型为基础,采用完全流固耦合的方法,模拟流体在裂隙中流动时的煤层开采,将流固耦合模拟结果与三维固体力学结果进行对比分析,可以得出由于流体的存在,使得斜井结构受力较无流体时不利,位移反而变小,但同时位移不均匀程度加大,最终取代斜井结构的受力成为煤柱宽度取值的控制条件。
[Abstract]:At present, most countries in our country and even in the world mainly adopt the method of keeping coal pillar to protect all kinds of roadways in coal mine. However, although this method can play a good role in protecting the roadway, But at the same time, it is difficult to recover coal pillar and waste a lot of resources. Therefore, the study on the width of coal pillar retaining roadway is not only beneficial to the stability and safety of protected roadway, but also can improve the recovery rate of mining area resources as much as possible. It has universal economic benefit and social significance. The inclined shaft of Xinjie mining area is constructed by TBM method. Based on the design of coal seam mining in Xinjie mining area, the variation characteristics of internal force and displacement of inclined shaft segment structure during coal seam mining are analyzed in this paper. The empirical formula method only deals with the geometric parameters and mechanical properties of coal seam in general, while the numerical simulation can also consider the geometric and mechanical characteristics of coal seam, rock formation and inclined shaft structure. In this paper, the discrete element numerical simulation method is used. The main research contents and results are as follows:. 1) adopting UDEC software, selecting cross section of inclined shaft at different position, presupposing several pillar width values in 3-1 coal seam, simulating step by step mining process from far to near. According to different protection pillar width, the force and displacement of inclined shaft structure are analyzed. On the premise that the width of coal pillar can make the structure of inclined shaft meet the requirement of safety and stability, the minimum value is taken as the recommended width of pillar protection for inclined shaft. In this process, it is found that the horizontal distance between mining face and inclined shaft is smaller. The greater the vertical distance between inclined well and open coal seam, the more favorable the stress state of inclined well structure is, and the greater the displacement is. At the same time, the UDEC software directly simulates the coal seam mining. The fracture angle 未 is 76. 2) on the basis of two-dimensional simulation, combined with inclined angle of inclined shaft, the angle between coal seam face and inclined shaft axis in horizontal plane is 1.53.The coal pillar is set up with this angle, and a method similar to that of two-dimensional simulation analysis is adopted. A 3D simulation of a mining face range at the bottom of a inclined shaft is carried out. The simulation results show that when the mining direction is parallel to the axial direction of the inclined shaft (with an angle of 1.53 掳), the safety and stability of the inclined shaft structure is more favorable; The width of coal pillar in the lower coal seam has a great influence, such as 40m for upper layer 3-1, minimum 86m for lower layer 5-1, and 67m for 5-1 coal if 50m in 3-1 coal. On the basis of three-dimensional solid model, the method of complete fluid-solid coupling is used to simulate coal seam mining when fluid flows in a fissure. The results of fluid-solid coupling simulation are compared with those of three-dimensional solid mechanics. It can be concluded that because of the existence of fluid, the stress of inclined shaft structure is less than that of no fluid, and the displacement becomes smaller, but at the same time, the degree of non-uniformity of displacement is increased, so the stress of inclined shaft structure is replaced by the stress of inclined well structure as the control condition of the width of coal pillar.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD822.3

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