| Fractured rock flow as a key scientific research and engineering applications,has been widespread concern in domestic and foreign scholars and research,reflected in many of its need for the further development of applied sciences and engineering some of the major practical problems.The difficult and hot spots of fractured rock reseach is important to strike a coefficient of infiltration and percolation model selection.In this paper,Kajiwa hydropower station in terms of the actual project as an example to study the geological structure Overview dam area, hydrogeoiogical conditions of the dam area and focus on the development of cracks in bedrock, strike a coefficient of infiltration and seepage simulation.The development and distribution of fractured rock affected by many factors,showing both random and certainty.Rock fissures development and distribution of the main methods of statistical probability model and non-identified model law.Based on large quantity of fractures measuring data,the geometric characteristic parameters can be described by statistical model analysis.Based on the fractures measuring data of limited outcrop,we can get the probability distribution model of each geometric parameter of representative fractures by probability model.Similarly,the crack development and distribution of the impact of the rock permeability coefficient also show the same randomness and uncertainty,to strike a major infiltration coefficient of a Field Test,fractured measurement,inversion and the fracture network Seepage numerical method.Fractured rock groundwater seepage There are three main numerical model:Equivalent Continuous medium model,discrete fracture network model,the fissurespore double medium model.The last two models can be as accurate portrait of fractured rock flow,has developed rapidly in recent years,but use only small-scale study.The equivalent continuous medium model regards fractured rock as continuous medium,whether in theory or in solving methods are the basis of maturity and experience in the development of intensive use of large-scale study.In this paper,the geometric parameters of the fissures,including the occurrence,trace length, width and spacing gap conducted statistics,that the fracture and distribution of the general law and application of non-deterministic model,in the reproduction of the indoor rock dam area Fracture network.Application of water pressure test at the scene and the geometric parameters of the law to strike a rock permeability coefficient,the bedrock for the dam area of groundwater seepage field of simulation to set the parameters,the analysis of infiltration coefficient of scale effect and to strike a typical unit on the basis of,The equivalent of a continuous medium model of the dam area bedrock groundwater seepage field in the simulation.Drew the following conclusions:1,The terrane of dam site area is layered rock group,rock permeability is characterized by the EC(O1r)thick layer permeable rock and weak permeable rock,major flooding of two is O1r2 and O1r4 Sub-layer,the weak rock O1r3 flooding include thin permeable sandstone layer of rock,on the whole,as depth increased,the penetration decreased significantly.2,The dam site groundwater main received supplies of precipitation of exposed area and mountains near the dam site area water district groundwater recharge,Supply conditions are relatively poor,and recharge is litter.Rainfall along the surface cracks and weathered layer weeping at the recent steep angle unloading fissures infiltration,the infiltration of groundwater along the main movement in the discharge zones across the relatively Geshui rock,bottom-up movement,therefore,in the wood River(Regional erosion base level)below,the aquifer rock "partial" for the confined aquifer characteristics.3,Fractured the dam area in accordance with its size,extend the length and causes can be divided into four:Ⅱ-level structure - fault,the fault extends more than 200 m,broken centimetres in width from a few dozen to several hundred centimeters from.Ⅲlevel of the structure - of the wrong zone,steep angle fault zone extended length of 60～70 m,large,up to 200 m;alleviate the dip in the wrong zone extended length of 50～60 m,large, up to 100 m.ⅣV-class level and structure of the surface - large cracks and small cracks.The cracks extend for 2～10 m,no such fracture filling and filling of thin.Small fissures extending less than 2 m,no filling or filling of thin,very wide gap.One large and small fracture of both the randomness also of the law,namely,the development of small cracks basic geological structure of the regional impact of the strong performance of the structural advantages of features, structural advantages in the development of fissures within the group Show strong randomness.4,According to the Field measured data show that the main dam area fractured bedrock of the following groups:(1)Left Bank:①110～140°∠65～90°②280～320°∠75～90°③10～40°∠35～50°;(2)right bank:①120～145°∠70～90°②305～320°∠75～90°③10～50°∠30～40°④90～110°∠75～90°.NNW and to which groups most of NNE.5,Respectively,on the fractured geometry parameters statistics,draw the following conclusions:(1)trace length:Zuoyou An fracture to＜1 m in a very short cracks and 1～3 m short fissures mainly,and with the increasing depth,the cracks Trace length show the first increase after decreasing trend.(2)Gap Width:Generally speaking,the left and the right bank of Adit fissures measuring point gap width of the same statistics,the wide gap to＜0.1 mm wide gap cracks and fissures of 0.25 to 0.5 based,gap-＜0.5 mm fracture of the 97.8-95.1%%,Cracks are confined.The right bank of the wide gap over a fractured left bank of development,Zuoyou An chamber within the wide gap measure on the whole with the increase in depth and smaller,while a local oscillation.(3)pitch:Dam Area rock fissures wide pitch to pitch-based,with a wide spacing than the middle of the pitch.Fracture density increases with the depth will remain basically unchanged.6,Fractured geometry parameters that statistics:the occurrence of cracks available Fisher distribution,Bingham distribution,Bivariate Fisher distribution,and other forms of description, description of this paper,Fisher,trace length with normal distribution,the wide gap with the normal number,spacing With negative index distribution.7,Fractured rock permeability coefficient characteristics:(1)water pressure test results showed that the permeability coefficient with the increase in the depth decreases,which is due to the increase in depth with the formation,weathering,unloading role gradually weakened and stress Growing,the open fracture of the depth gradually worsen until the closure.When the depth greater than 100 m,permeability coefficient gradually stable,mostly in the 0.04 m/d,rock permeability is weak,can be seen as isotropic media.Test of the dam area permeability coefficient was lognormal distribution,in order to better characterization and description of layered permeability changes with depth,we follow the Sub-depth and the probability of the relationship between the permeability coefficient will be divided into the multi-level domain.(2) infiltration of calculation showed that the penetration depth and value of trends and changes in water pressure test basically the same,the certification of the water pressure test the credibility of the results.Dam Area layered aquifer permeability of the rock group with little difference, vertical rock layers show the infiltration of anisotropy,anisotropy factor K1/K3 in general between 2 to 30,with the increase in the depth Weakened to the opposite sex,and more isotropic. The analysis,the formation Dam Area Comprehensive Test points with the depth of penetration of the increased volume and significantly reduced the local level up to 90 m below the depth, comprehensive measurement points of infiltration of K0 less than 0.2 m/d.8,Fractured rock permeability coefficient show strong scale effect through the cracks of the infiltration of increasing the scope of the results showed that infiltration of fracture increased with the increase of pilot-scale fluctuations,and obtained a typical unit of volume For the 30*30 *30m3.9,Due to meet typical element of the presence and penetration of the conditions of symmetry,applications for medium model of fractured bedrock groundwater seepage were simulated,the paper adopted the groundwater simulation program "Visual MODFLOW3.1", respectively,to simulate the dam area Under natural conditions after the water seepage and flow characteristics of the original design and optimize the design of the programme impervious to leakage of the programme,the results showed that the original design programmes to meet the requirements of anti-seepage.In this paper,the fractured bedrock groundwater seepage field simulation of the general method are systematic studyed and summed Up。A variety of media are applied to calculat the infiltration parameters,permeability tensor method of typical unit of fracture is put forward.
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