块体理论中结构面相交算法优化研究

针对传统块体理论中结构面无限延伸的假定和部分有限结构面理论的不足,提出了一种新的结构面相交关系的判定方法。在结构面有限延伸的前提下,选择结构面圆盘模型进行分析。在判定两结构面是否相交的计算中,回避了线段与圆形直接求交的困难,选择投影法,即求得两结构面交线矢量的法平面,根据法线在法平面投影为一点、圆形域在对应法平面投影为线段的特点,分别计算垂足和两圆心投影点的距离并与圆形域半径进行比较,分析交线和圆形结构面域的包含关系,进而对结构面相交与否进行判断。并利用此原理提出了块体分析工作中野外实测结构面的筛选方法,经由判别矩阵的筛选,剔除原无限块体理论不能分辨的、实际延伸很短、并不与其他结构面相交,或虽与其他结构面相交,但对形成块体没有贡献的结构面。新算法简化了块体计算的工作量,大大提高了效率,对结构面数据量大的块体分析工作尤为明显。

Research on optimization of intersection algorithm of structural plane in Block Theory

In view of the shortcomings of traditional block theory and the assumption of infinite extension of structural plane, a new determining method of structure intersection relationship is presented. On the basis of the finite extension of the structural plane, we conduct analysis by the model of structural plane disc. In calculation of the intersection of two structural planes, the difficulties of direct intersection calculation of line and circle are avoided. It chooses projection method. First, the normal plane of intersection vector of the two structural planes is obtained, and according to facts that the projection of the normal line and cir-cle region in the normal plane are a point and a line segment respectively, so the distance between the pedal and the projection of two circle center is calculated and compared with the radius of the circular region, so we can analyze the inclusion relationship between the intersection line and the circular structure, and then judge the intersection of the structure planes. Using this princi-ple, the selection method of in-situ structure planes in block analysis is put forward. By the selection of discriminant matrix, we ignore those short extended planes, not distinguished by traditional block theory, that do not intersect with other structural planes, or those however intersect with other planes but do nothing contribution to the formation of the blocks. This new algorithm simplifies the workload of further block calculation, greatly improves the efficiency of block analysis with large quantities of struc-tural planes.