裂隙岩体块体化程度评价方法的若干问题修正

块体化程度是评价岩体完整性的一种新指标，能从三维角度表征岩体破碎程度，但目前该方法仍存在未充分考虑岩体切割程度及块体规模、未限定基础应用条件、块体化程度等级划分不合理等缺陷。针对上述缺陷，深入分析了其产生原因，并借鉴岩体切割程度、三维块度模数、体积RQD等计算原理，限定了块体体积百分比相关概念，提出了考虑岩体完整性块度尺寸效应的块体体积综合百分比计算方法，确立了块体化程度等级及分级指标取值依据，建立了修正的块体化程度评价方法。通过对比块体化程度评价修正方法、岩土工程规范对岩体完整性的划分结果，分析了修正方法的合理性。分别以广西铜坑矿锌多金属矿体、乌东德水电工程的块体研究数据为基础，开展了修正块体化程度评价方法的实例验证，结果表明：利用修正块体化程度评价方法计算的铜坑矿+255 m中段4#试验区岩体块体体积百分比为11.18%，属轻度块状化岩体；乌东德水电站PD49-1平硐、PD4支硐块体体积百分比分别为12.847%、10.168%，均属于轻度块状化岩体，岩体完整性程度为较完整级别。与现有块体化程度评价方法比较，修正方法计算的块体体积百分比能够更准确地从三维角度表征真实岩体的完整性。研究成果对精确刻画岩体三维完整性具有重要意义。

Correction of the problems of blockiness evaluation method for fractured rock mass

Blockiness is a new index to evaluate the integrity of rock mass, and it can represent the degree of rock mass fracture in three dimensions. However, current blockiness evaluation methods have not considered the cutting degree of rock mass, the size of the block, unrestricted basic application conditions and unreasonable ratings of blockiness levels. In this study, the causes of these limitations were analysed in-depth. Moreover, the concept of block volume percentage was defined referring to the calculation principles of the rock mass cutting degree, three-dimensional (3D) block modulus and volume RQD. A comprehensive percentage calculation method of block volume was proposed, in which the scale effect of rock blocks was considered. The ratings of blockiness levels and the values of the classification index were determined, and the improved blockiness evaluation method was developed. By comparing the rating results of the modified blockiness evaluation method and the Chinese codes for geotechnical engineering, the rationality of the modified blockiness evaluation method was analysed. Based on the Tongkeng Zn polymetallic orebody and Wudongde Hydropower Project, the case studies of the modified blockiness evaluation method were conducted. The results showed that the block volume percentages of No. 4 testing area at the 255 m level in the Tongkeng Zn polymetallic orebody, the PD49-1 adit and PD4 branch adit in Wudongde Hydropower Station were 11.18%, 12.847% and 10.168% by using the modified block evaluation method, respectively. In addition, they all belonged to slight-blockiness categories, and the rock mass was moderately integrated. Compared with the conventional blockiness evaluation method, the block volume percentage calculated by the modified blockiness evaluation method can more accurately represent the integrity of the rock mass from a 3D perspective. The findings in this study are significant for accurately characterising the 3D integrity of rock mass.