复杂采空区三角网模型剖面轮廓线提取方法

 采空区是矿山安全生产面临的主要灾源之一，准确获取采空区剖面等信息是实施采空区灾害防治及空区周边资源安全开采的重要基础，而采空区三角网模型剖面轮廓线提取是采用可视化方法实现采空区剖面准确获取的前提。在分析目前常用的三角网模型剖面轮廓线提取方法（即最小距离法、扇形区域法和凸包算法）运用于提取边界复杂的采空区剖面轮廓线时存在缺陷的基础上，对传统的方法进行了改进，形成了适用于复杂边界采空区三角网模型剖面轮廓线的提取方法--凸包压入法。首先以垂直于任意坐标轴的平面剖切采空区三角网模型得到轮廓线的无序点集，提取无序点集的凸包线作为初始轮廓线，然后将包络于初始轮廓线内的点按张角最大的原则全部添加到轮廓线中，获得完整的剖面轮廓线，形成采空区剖面。实际应用表明，研究形成的算法能够快速有效地提取复杂采空区的剖面轮廓线，可准确获取复杂采空区剖面，具有很好的实用价值。

Extraction of Sectional Contour Lines of Goafs using Triangulation Model

Goafs are one of the main hazards for mine safety and production. Accurate information of goaf profile is an important basis for safe exploitation of mining resources and prevention of goafs' disasters. Contour line extraction by using goaf triangulation model is the premise for accurately obtaining the profile by visual method. The defects of currently used triangulation sectional contour extraction methods are analyzed, including the minimum distance method, fan-shaped regional method and convex hull algorithm applied to extract the sectional contour line of goafs which have complex boundaries. This paper aims to improve the conventional methods and proposes an advanced extraction method named convex hull penetration method for the extraction. First, it extracts the convex hull line of unordered point set obtained in the plane vertical to arbitrary axis using the triangulation model; then it obtains a complete cross-section contour line by putting points of the initial contour line into the contour line following the principle of maximum opening angle; finally it forms the profile of the goaf. The application shows that this method has practical values in efficiently extracting the sectional contour lines of complex goafs and accurately obtaining the profile.