矿区采煤引起的重力异常变化研究

发布时间：2019-06-04 13:35

【摘要】：任何物体在地球表面或附近空间都受到地球重力的作用,地下物质分布不均匀将会引起重力场变化。随着矿产从地下采出,形成采空区,也会导致地面重力场发生变化。在开采沉陷区进行重力勘查时,随着煤炭资源不断从地下采出,将引起地表不断下沉,这种采空区随时间由下向地面不断发展的过程中,将导致地面重力值发生动态变化。因此,在煤矿区研究开采引起的重力异常变化规律,对采空区位置探测及矿区大地水准面精化研究等具有重要意义。本文利用开采沉陷理论分析了采空区残余空洞大小及分布特征,针对煤矿开采沉陷的特点,以现有的重力异常理论模型为基础,利用高斯公式对其进行数学变换,将三重积分变换成二重积分,并采用有限元法实现数值计算。同时,利用Matlab2014a软件平台进行模拟计算,探讨了影响有限元数值计算精度的因素,发现其精度与单元大小、计算方法及计算点至单元体的距离等密切相关。为了更好地发现重力异常与地质异常体之间的关系,利用Matlab编写了重力异常正演GUI程序,能够准确地展现出地质异常体产生的重力异常。煤矿开采引起的地面沉陷按照概率积分法计算模型求取,并利用上述重力异常正演程序计算出工作面开采前、后的地面沉陷及相应的重力异常变化,通过回归分析得出重力场与地面沉陷的关系模型。同时,计算出采空区残余空洞引起的重力异常附加值。依据重力场的可叠加性,得到工作面开采及地表沉陷所引起的重力异常变化。本文的研究改进了重力异常计算模型的适用性,建立了煤矿开采沉陷与重力异常的关系模型,具有一定的理论和实用价值。
[Abstract]:Any object on or near the earth's surface is affected by the earth's gravity, and the uneven distribution of underground material will cause the gravity field to change. With the mining of minerals from the underground, the formation of goaf will also lead to the change of ground gravity field. When gravity exploration is carried out in the mining subsidence area, with the continuous mining of coal resources from the underground, the surface will continue to sink, and the goaf will lead to dynamic changes in the gravity value of the ground in the process of continuous development from down to the ground with time. Therefore, it is of great significance to study the variation law of gravity anomaly caused by mining in coal mining area for the detection of goaf position and the study of geoid refinement in mining area. In this paper, the size and distribution characteristics of residual voids in goaf are analyzed by using mining subsidence theory. According to the characteristics of coal mining subsidence, based on the existing theoretical model of gravity anomaly, the mathematical transformation is carried out by using Gao Si formula. The triple integral is transformed into double integral, and the finite element method is used to realize the numerical calculation. At the same time, the simulation calculation is carried out by using Matlab2014a software platform, and the factors that affect the accuracy of finite element numerical calculation are discussed. It is found that the accuracy is closely related to the size of the element, the calculation method and the distance from the calculation point to the element body. In order to better find out the relationship between gravity anomaly and geological anomaly body, the forward GUI program of gravity anomaly is compiled by Matlab, which can accurately show the gravity anomaly produced by geological anomaly body. The surface subsidence caused by coal mining is calculated according to the probability integration method, and the surface subsidence and the corresponding gravity anomaly change before and after mining are calculated by using the above gravity anomaly forward program. The relationship model between gravity field and ground subsidence is obtained by regression analysis. At the same time, the abnormal added value of gravity caused by residual voids in goaf is calculated. According to the superposition of gravity field, the abnormal variation of gravity caused by mining and surface subsidence in working face is obtained. In this paper, the applicability of gravity anomaly calculation model is improved, and the relationship model between mining subsidence and gravity anomaly is established, which has certain theoretical and practical value.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD821;P312

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