【作者】 张和生；

【导师】 刘鸿福；

【作者基本信息】 太原理工大学 ， 矿产普查与勘探， 2013， 博士

【摘要】 煤炭开采造成地表移动与变形具有一定的规律,且这一规律性在平原地区的研究已较为成熟,而在丘陵及山区,煤炭开采造成的地表破坏规律与平原地区具有明显的不同,若能对开采后山区地表移动与变形的破坏规律进行较为有效的预计,是完全可以减少地面建构筑物破坏,同时对合理开发地下煤炭资源是有实际意义的。就西气东输管线而言,长度已达5万km以上,仅一、二、三线工程干线总里程近1.5万km,且已建成的一线管线工程有近1千km途经陕西神府、山西的河东,霍西,沁水、河南焦作、山东兖州、江苏徐州及两淮等煤炭基地,其地下埋藏有丰富,甚至是优质的煤炭资源,为此研究地下煤炭资源开采后地表变形对输气管线的影响,保证输气管线正常运行和煤炭资源有效开发,具有较大的实用价值。本文在系统分析煤炭开采引起的岩层移动与变形在平原所表现的一般特征及山区所表现的特殊特征条件下,就地表移动与变形预计方法进行了概述,指出了山区地形条件下,地下开采引起的地表移动与变形是复杂的,且地表移动与变形规律至今仍是人们研究的难题之一。对此,论文利用BP神经网络非线性特征的特点,针对东山煤业所处的山区地形条件,就其某一工作面的实测观测站资料,在融入地形及其他因素(包括预计点的位置、预计点所在坡度及坡向、开采条件与地质因素等)后,构建了各因素量化指标及山区开采沉陷3层结构的BP神经网络预计模型,并通过对地表移动与变形的预计结果与实际观测数据的对比,表明所构建的BP神经网络模型与实际地表变形是基本相一致的,这表明利用BP神经网络进行山区地下开采沉陷预计是可行的。其次,本文利用GIS中几何与属性数据相关联的特性,以DTM为基础,借助于ANSYS大型数值分析软件,构建了山区地表移动与变形预计的FLAC3D模型,实现了快速建立山区开采沉陷预计的FLAC3D模型。据此结合西山煤电马兰矿的某工作面实际开采进行了两个主断面地表移动与变形的数值模拟预计,获得了该工作面两个主断面的移动与变形分布云图及等值线图,并通过与该工作面地表移动观测站实测移动与变形资料的对比,给出该数值模拟的预计与实测地表变形时基本一致的结论,表明FLAC3D数值模拟方法可以应用于山区地表移动与变形的预计,同时两种方法各有优缺点,BP神经网络及数值模拟都具有时间短、工作量小、效益高的优点,但BP神经网络仍是一种表象预计,需要大样本,同时不能直观反映岩体内部各岩层的移动变形情况,而FLAC3D不仅直观反映地表移动与变形,还可以反映岩体内部的移动与变形,更具有实用性。但两种方法都可以用于山区地表移动变形的预计。此外,论文以西气东输管线山西某段实际资料为研究背景,针对已发生地下采煤造成输气管线变形的情况,系统地整理了输气管线与地表变形的实际观测资料,并结合实际地形和地表下沉及水平变形量,总结出管线变形与地表移动变形之间的关系是：管线的拉伸、压缩整体指向坡体的下方,而管线压缩范围大于其拉伸范围；管线变形量是小于地表变形的。对此,本文利用数值模拟FLAC3D,结合西气东输管线下方实际煤炭赋存条件,构建了管线与工作面三种不同的空间布局关系,并分别进行了数值建模及模拟,结果是：①在以管线中心点为监控剖面的模拟中,给出了距该剖面上不同开采位置处管线的应力分布,表明管线受开采影响时,其应力分布呈现出由小变大再变小的规律性；同时给出管线的压缩与剪切应力是按顺时针方向变化,并且以剪应力为主；②在对管线整体受地下开采的模拟中,以开采推进距管线不同距离时,对管线的下沉、水平位移动态趋势进行了分析,表明了三种空间关系下,管线在垂直位移、水平位移方面呈现出不同的表象,总体呈现出全管线在平行管线方向上,水平位移基本呈对称分布,而垂直管线方向水平位移呈不对称分布,并以指向下坡方向为主的规律；垂直位移分布随开采的进行,位移逐渐增大,然后达最大,再减小的趋势,基本以开采中心为对称分布的特点；③论文综合分析后,选取了斜交空间关系最有利于管线安全运行的结论,为今后管线下方进行煤炭资源的开采,同时又保证管线的正常运行提供了依据。更多还原

【Abstract】 Surface movement and deformation caused by coal mining follows some regularity which has been studied more maturely in plain regions, while such regularity in hilly and mountainous areas is obviously different from in the plains. More efficiently prediction of such regularity after coal mining, could perfectly help to reduce the damage of ground buildings, and is practically significant to reasonably exploit the underground coal resources.The total length of the West-East Gas Transmission Pipeline (WEGTP) is up to50,000km, and it is close to15,000km only for the first, second and third pipeline projects. The first pipeline projects have been built, nearly1,000km of which passing through numerous coal bases such as Shenfu of Shaanxi Province, Shanxi Province (e.g. Hedong, huoxi, Qinshui), Jiaozuo of Henan Province, Yanzhou of Shandong Province, Xuzhou of Jiangsu Province, Huainan and Huaibei of Anhui Province. There have rich underground coal resources of good quality in these regions. Therefore, it has a great value in use to investigate the impact of ground deformation on gas transmission pipelines after fully underground mining, thereby guaranteeing normal operation of these pipelines and efficient development of coal resources.The present study systematically analyzed general characteristics of rock formations during movement and deformation in plains and its special features in mountainous areas, presented an overview of the prediction methods for ground movement and deformation, and then pointed out that the ground movement and deformation caused by the underground mining is very complex. So far, it has remained one of the major challenges to examine and reveal the regularity. In this study, we investigated in depth the regularity of surface movement and deformation due to the underground mining.First, the thesis utilized nonlinear features of BP nerve network to specially analyze the measured data of some working plane from Dongshan Coal located in the mountainous areas. In order to quantitatively build and measure all factors and then to construct a3-layer structure model of BP nerve network for mining subsidence in the mountainous regions, we considered the terrain and other factors including prediction points (location, slope and slope direction), mining conditions, geological factors and so on. Through contrast of the ground movement and deformation between the expected results and actual observations, we found that the BP neural network model was generally consistent with the actual surface deformation, indicating it is feasible to develop a design of underground mining subsidence based on BP nerve networks for the mountain areas.Second, a FLAC3D model has been built to predict the surface movement and deformation in mountainous regions by using the feature that the geometry is associated with the attribute data in GIS, on the basis of the DTM and the large numerical analysis software ANASYS, thus rapidly achieving in construction of the FLAC3D model of mining subsidence in mountain regions. Through combining the actual mining of Malan in Xishan coal and electricity of Shanxi Province, therefore, numerical simulation and prediction for movement and deformation were conducted for two major sections in order to obtain distribution cloud images and contour maps which are associated with their movement and deformation. Through contrast with the measured ground movement and deformation data, it is concluded that prediction of the numerical simulation is expected to be consistent with the measured surface deformation, indicating that the FLAC3D numerical simulation method can apply to prediction of the ground movement and deformation in mountainous regions.The above mentioned two methods have their own advantages and disadvantages, respectively. Although the BP nerve network and numerical simulation are relatively fast, workload small and efficiency high, it is still only an appearance design, needs big samples, and cannot intuitively reflect movement and deformation of the internal rock body. In contrast, the FLAC3D model can intuitively reflects movement and deformation for both the ground surface and the internal rock body, so that it has more practicality than the BP nerve network. Either of them can be used to predict ground movement and deformation in mountainous areas.In addition, this thesis used the real data and actual information from some part of the WEGTP in Shanxi for research background to systematically arrange the observed data from deformation of gas transmission pipelines and ground movement deformation. Considering volume of the actual terrain deformation, surface sinking and horizontal deformation, we have established a relationship between the pipeline deformation and the ground movement and deformation as follows:Stretch and compression of a pipeline overall points to bottom of the slope body, while the pipeline compression range is greater than its stretch range, and volume of the pipeline deformation is less than surface deformation volume.In the text we utilized the numerical simulation FLAC3D to build three different kinds of spatial distribution relationships between pipelines and work profiles according to the actual coal conditions below the WEGTP. Corresponding numerical modeling and simulation were respectively conducted, and the results are as follows:(1) Simulation made in a control surface at the center of the pipeline presented its shear stress distribution from different mining locations, which indicated a regularity of the stress change from small to large and then to large change due to effects of mining.(2) To simulate effects of underground mining on integral pipelines, we analyzed the move trend of pipeline sinking and horizontal displacement when mining advances from different distance from the pipeline. Three spatial relationships were indicated. Pipelines have different appearances for their vertical and horizontal displacements. Overall, the horizontal displacement paralleling the pipeline generally showed symmetric distribution, while it was not symmetric when perpendicular to the pipeline direction and mainly pointed to the downhill direction. The vertical displacement slowly increased, reached the maximum, and then decreased, demonstrating symmetrical distribution features around the mining center.(3) In this thesis we took the permissible deformation of WEGTP into consideration, and concluded that the oblique spatial relationship between pipeline and displacement is the most conducive to the pipeline operation after a comprehensive analysis, thus providing sufficient basis for exploitation of coal resources under the pipeline in future and guaranteeing the normal operation of the pipeline.更多还原