一种基于块体化程度理论的裂隙岩体巷道顶板稳定性分级方法研究

Stability classification of roadway roof in fractured rock mass based on blockiness theory

岩体完整性是进行巷道顶板稳定性分级的一个重要指标,当前分级方法均是从一维角度对岩体结构进行描述,不能全面刻画出三维空间上顶板围岩的完整性。针对这一缺陷,引入裂隙岩体块体化程度理论,以块体化程度代替常规标准中表征岩体完整性的岩体质量RQD值和节理间距两项子指标,开展裂隙岩体巷道顶板稳定性分级研究,创新形成了一种适用于裂隙岩体顶板稳定性分级的BT分级方法。以块体百分比和块体体积曲线为基本依据,构建出裂隙岩体巷道顶板围岩块体化程度的解算流程;运用AHP法对稳定性影响因素权重进行了排序,制定出稳定性分级方法与标准。以铜坑矿92号矿体裂隙岩体试验区巷道顶板结构面调查数据和岩石力学参数为基础,运用传统分级方法 RMR法和BT法分别对各试验区巷道顶板稳定性进行评价,对两种分级结果进行比较分析,结果表明:与传统的RMR法相比,BT法在稳定性描述、分级准确性和安全管理指导作用等方面更为优越,更能够客观真实地反映出裂隙岩体巷道顶板稳定性。研究成果可为复杂裂隙岩体条件下的巷道顶板安全分级与管理提供更为可靠的科学依据。

Rock mass integrity is an important indicator for the stability classification of roadway roof, however, the current grading methods just describe from the one-dimensional angle of rock mass structure, which cannot fully reflect the integrity of the roof rock in three-dimensional. In order to overcome the limitation, the stability classification of roadway roof in fractured rock mass is studied by using blockiness as a rock mass integrity index instead of the two sub-indicators of rock mass quality RQD value and joint spacing in the conventional grading method, creating a kind of innovation especially suitable for the fractured rock mass stability classification methods called BT classification methods. According to the block percentage and block volume distribution curve, a solving process of the blockiness of the roadway roof surrounding rock in fractured rock mass is built. An AHP method is applied to determine the weights of the stability factors. The method and the standard of stability classification are constructed. Based on structure surface data and rock mass mechanical parameters of the roadway roof in four fractured rock mass experimental zones in the ore body No. 92 of Tongkeng mine, using the RMR method in the traditional classification methods and the new development method of roadway roof stability classification for each test area, two different classification results are comparatively analyzed, the results show： compared with the traditional RMR classification methods, BT method is more superior to the stability of the description, classification accuracy and safety management guidance, it can more truly and objectively reflect the fractured rock mass roadway roof stability. Research results can provide more reliable scientific basis for the condition of complex fractured rock mass of roadway roof safety classification and management.