Leakage Evaluation Of Karstic Rock Based On Stochastic Structure Model And It's Application In Shuibuya Dam

Seepage control in karstic rock mass is one of the most important problems in hydroelectric engineering and mining engineering as well as traffic engineering. At present, permeability assessment and leakage analysis of multi-layer karstic rock mass are mainly qualitative, while seldom quantitative. Based on the field measurements in the horizontal grouting galleries of seepage control curtains on the left bank of the Shuibuya Hydropower Project on the Qingjiang river, a quantitative analyses of the permeability coefficient and seepage amount are conducted in this paper, which will provide a theoretical basis for the study of seepage and seepage control treatment of karstic rocks.Following issues are addressed in the paper:â‘  Based on the in-situ measurements of fissures and karstic cavities in grouting galleries with the traditional methods and digital photograph, some qualitative and quantitative analysis are carried out to study the karstic characteristics of rock mass, which lead to a karstic intension partition of rock mass. Then a karstic model is built based on the analysis of the spatial characteristic, distributing rule and controlling factor of rock mass.â‘¡ The technique to build plane and spatial stochastic structural mode is studied. Based on the statistic analysis of fissures and karstic cavities in grouting galleries, a stochastic structural model is set up.â‘¢ The concept of equivalent permeability coefficient based on the stochastic structural model and its formula is put forward. With the parameters of fissures and karstic cavities extracted from the stochastic structural model, the equivalent permeability coefficient of karstic rock mass is calculated. These calculated equivalent permeability coefficient is summarized and then the rule of permeability of the karstic rock mass is gotten. The correlation analysis of calculated equivalent permeability coefficient and the result of pressing-water test is also carried out.â‘£ At last, the seepage amount of rock masses is estimated under four different conditions of seepage control measures with the help of a software for groundwater analysis. The existing formula for calculating the seepage amount of karstic conduits is revised. The seepage amount of rock masses in the measured grouting galleries is...