基于层次分析法的坝基岩体质量量化分类OA

The engineering geological classification of dam foundation rock mass in current hydraulic and hydropower codes is a qualita-tive evaluation scheme based on a multi-index system.In practical application,it has problems such as poor discrimination,inconven-ience in comparison and relatively conservative evaluation.To accurately carry out quantitative classification of dam foundation rock mass quality in hydropower projects,the implicit evaluation indexes in the scheme are sorted out,and four indexes including uniaxial compres-sive strength of rock,rock mass integrity coefficient,spacing of structural planes and characteristics of structural planes are selected as the main quantitative factors for evaluating dam foundation rock mass quality based on expert opinions collected through questionnaire sur-veys.After reassigning the initial scales of the factors given by experts,the importance ranking of evaluation factors is determined.Then the weight of each factor is calculated by the Analytic Hierarchy Process(AHP),and a quantitative classification system of hydropower dam foundation rock mass is constructed by referring to the framework of RMR classification system.The results show that the corrected weight coefficients of uniaxial compressive strength of rock,rock mass integrity coefficient,spacing of structural planes and characteristics of structural planes are 0.10,0.45,0.15 and 0.30,respectively.Through practical comparison and verification,the consistency rate be-tween quantitative classification and original qualitative classification reaches76.8%,indicating that the quantitative scheme of dam foun-dation rock mass is basically feasible.Aiming at the problem of high scores in the quantitative evaluation of"mosaic-cataclastic struc-ture"and"cataclastic structure"rock mass,it can be solved by downgrading the corresponding types of structural planes.