| The development and distribution of rock mass fissures are affected by many factors,resulting in the development of fissures that are both random and uncertain.Therefore,certain statistical methods and statistical software should be adopted for the statistics of rock mass fissures.This project adopts the method of combining survey line method and Dips software.Two survey lines are laid on the left bank and right bank of the dam site area.For the large-scale faults passing through the survey line,the statistics are classified according to the scale of fracture development;for small and medium-sized joints Fissures are measured by statistical window method and Dips software is used for analysis and statistics to comprehensively determine the dominant development direction of rock mass fissures in the dam site area.According to the above measurement data,the RQD value method is used to evaluate the integrity of the fractured rock mass in the survey line;the visible length of the fracture,the characteristics of the structural plane,the distance between the same groups and the line density are analyzed by the method of mathematical statistics to analyze the connectivity performance between the fractures and the development of the fractures The level of permeability of the rock mass on both sides of the dam site is preliminarily determined.In this paper,the geometric parameters of fractures,including occurrence,trace length,gap width and gap spacing,are statistically analyzed,and the general rules of fracture development and distribution are obtained.The seepage coefficient of rock mass is obtained by field pressure water test method and geometric parameter method,and the seepage field of fractured rock mass is given for the simulation of dam site area,and the seepage field and the proposed dam body are simulated by using the continuous medium model.Based on the simulation results of seepage field,a conclusion can be drawn:（1）The main developed rock strata in the dam site area are relatively simple,mainly limestone dolomite.According to the statistics and analysis of the fractures exposed on the left and right bank of the group in the left bank is:（1）70～90°∠60～90°;（2）250～270°∠42～75°;（3）160～178°∠60～86°.The right bank:（1）340～350°∠50～85°;（2）160～170°∠60～80°.（2）The fractured rock mass permeability in the dam site has a certain regularity in the vertical development,and the fractured rock mass integrity degree on both sides is mainly poor and general.With the increase of the buried depth,the fractured rock mass permeability presents a relatively undeveloped state,which is relatively weak,and presents a decreasing trend with the increase of the depth.According to the results of the analysis of fractured rock mass permeability of rock mass in dam site area,mainly micro porous～weakly permeable strata within a minimal permeable zone distribution,using the permeability tensor with hole water pressure test data of composite permeability coefficient was 0.0747 in the left bank of the dam site area m/d,on the right bank of dam site area of 0.0443 m/d,the revised comprehensive on the left bank is on the right bank.Under different working conditions.（3）To the dam site area of seepage flow field simulation results show that the dam site area natural condition of seepage a maximum speed of 1.24 x 10-6 cm/s,water seepage velocity under the condition of 1.03 x 10-3 cm/s,seepage velocity increased nearly 1000 times on the order of magnitude,the dam site zone seepage velocity part focused on the left bank of dam site area,as the change of reservoir dam shoulder position seepage velocity.（4）The proposed dam simulation design parameters,design water core wall insulation parameters by 5%,the design water core wall by 5%,to simulate the working condition of three parameter increases by about 5%,the permeability of speed of the order of magnitude of the increase in around 10-4,permeability parameters by 5%when the dam has no obvious change,so the proposed dam design parameters adopted by 5%of water wall can also have very good anti-seepage effect,selecting parameters of smaller water core wall is helpful to save costs.（5）The seepage field of dam site area stress state does not change significantly under three conditions,in the dam site area full of high shear stress zone,according to the simulation results can be seen that the slope of the right most dangerous section of the body in a stable state,the strong limy dolomite weathering about 0.2 m thickness of surface displacement is larger,but the volume is small,the seepage field of dam site area is not enough to build the state of the seepage field change. |
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