红层软岩隧洞围岩稳定性分析及分类方法改进  

Discussion on Stability Analysis and Classification Method Improvement of Soft Red-Bed Rock Mass

作　　者：曹荣国 胡相波[1] CAO Rongguo;HU Xiangbo(China Water Resources Beifang Investigation,Design and Research Co.Ltd.,Tianjin,300222)

机构地区：[1]中水北方勘测设计研究有限责任公司,天津300222

出　　处：《水利水电工程设计》2024年第2期33-36,共4页Design of Water Resources & Hydroelectric Engineering

摘　　要：以亭子口灌区一期工程(Ⅳ标段)为工程实例,选取小洞径隧洞较典型的工程地质条件类型,运用工程地质分类法、RMR法、Q系统围岩分类方法分别对红层软岩隧洞围岩稳定性进行分类,由此避免因单一方法造成的系统偏差,对本工程隧洞围岩有了更系统的认识,评价了各方法适用性,并指出各方法分类过程中侧重的分类指标及存在的问题。为改进工程地质分类方法并建立本项目专门的围岩分类方法提供了技术参考和思路:(1)对于小洞径完整软岩岩石强度指标权重可适当降低;(2)对于无结构面发育的围岩,其结构面产状与洞向组合关系指标减分项数值可适当缩小;(3)对本工程水理性质敏感的软岩,因围岩干燥状态和遇水后的工程性质差异巨大,工程地质分类法低估了软岩有水后的劣化影响,故地下水指标权重可适当增大;(4)洞径的影响可加入评分系统中,以某一标准洞径作为零分项,超出该洞径范围实行加、减分。按照以上思路改进工程地质分类对规范的修订有较高参考价值。Taking the first phase of the Tingzikou irrigation project(SectionⅣ)as an engineering example,typical engineering geological conditions of small-diameter tunnel is selected.The engineering geological classification method,RMR method,and Q-system rock mass classification method are used to classify the stability of the surrounding rock of soft red-bed rock tunnel.This approach helps to avoid systematic bias caused by a single method,providing a more systematic understanding of the surrounding rock of the tunnel in this project.The applicability of each method is evaluated,and the classification indicators and problems emphasized during the classification process of each method are pointed out.It provides valuable technical references and ideas for improving engineering geological classification methods and establishing a specialized surrounding rock classification method for this project:(1)For small-diameter tunnel,the weight of intact soft rock strength indicators can be appropriately reduced;(2)For surrounding rocks without structural plane development,the deduction item of the structural plane occurrence and tunnel direction combination relationship can be appropriately reduced;(3)For the soft rock in this project that are sensitive to hydraulic properties,there is a significant difference in engineering properties between the dry state and the water-bearing state,and the engineering geological classification method underestimates the deterioration effect of soft rock after water-bearing,so the weight of groundwater indicators can be appropriately increased.(4)The influence of tunnel diameter can be incorporated into the scoring system,with a certain standard tunnel diameter as the zero-score item,and scores are added or deducted when exceeding this tunnel diameter range.Improving the engineering geological classification according to the above ideas will also be of high value for revising the specifications.

关 键 词：红层软岩 围岩分类 围岩稳定性 指标权重 

分 类 号：TU457[建筑科学—岩土工程]