基于自由面上环路对应节理无限切割的关键块体搜索

关键块体理论在评价工程裂隙岩体稳定性中得到了广泛应用。然而，一方面岩体中节理数量众多，关键块体的搜索将耗费较多机时；另一方面，极少数偶然出现的块体识别也会极大地增加计算量。因此，开发有针对性和灵活的关键块体搜索方法就非常重要。首先将研究区域分解成凸子区域，找出自由面上的闭合环路，然后利用环路的组成节理以及与其相交节理进行空间无限切割来识别该环路是否对应关键块体。该方法针对性强，能较好地适应人为规定的判别条件，如搜索楔形体以及后缘切割限定等，并能顺利实现凹面体的关键块体搜索，且编程实现简单。以某挂帮矿的顶柱为实例进行关键块体的搜索，验证了上述方法的可行性。

Key block searching based on joints infinite cutting of closed loop on free surface

The key block theory is widely used in stability evaluation of engineering fractured rock mass.The searching method of key block should be of pertinence and flexibility due to large amount of joints and huge calculations caused by the searching of very few occasional blocks.Firstly,the researching region is decomposed into convex sub-regions;and all closed loops on free surfaces of research region are found out.Then the primary joints that form the closed loop and relevant joints that intersect with the primary ones are regarded as infinite plane to cut the region into convex blocks,among which the key block associated to closed loop will be identified.With better pertinence and programmability,this method can fit some artificial conditions very well such as wedge searching and limitation of trailing cutting.It can also search concave block successfully.Finally,an example of top pillar is presented to show the effectiveness of the above-mentioned searching method.