| The seepage and penetrate deformation of the reservoir and dam area with loose rock is the major engineering geology problem Shanxi Hengquan Reservoir. Thus ascertaining the seepage situation, distributive scale, seepage quantity and the stability of the dam penetrating deformation will be related to the design, construction as well as the regular operation and bring into the play of the dam in the future.After drilling holes and exploration wells along the axis of dam and carrying out tests including geophysical prospecting, grain distributing site-test, original sample and huge scale disturbed loose sample indoor- test, water pressing test, single hole and group holes water pump tests etc., on the basis of datacollection and field investigation, the article has obtained several accomplishments of following aspects:1 > The seepage features of dam and reservoir area of Shanxi Hengquan Reservoir have been determined.The surface stratum with depth of 10~20m which is mainly consisted of cobble soil with huge gravel or gravel soil shall be divided as two strips, including i) the first strip with width of 296m and average depth of seepage strip of 19m is the dam foundation of left bank and is classified as strong seepage area with the penetrating factor of 21.3m/d; ii) the second strip with width of 364m and average depth of seepage strip of 13m is the dam foundation of right bank and is classified as strong seepage area with the penetrating factor of 81 m/d.There are total five strips divided for the strong weathering bedrock of the dam foundation with depth of 20~30m and inhomogeneous seepage performance. They are: i) The first strip with width of 250m and average depth of seepage strip of 35m is classified as moderate seepage area with the penetrating factor of 0.8m/d; ii) The second strip with width of 80m is divided vertically as two layers according to the seepage performance. They are up-layer which is classified as moderate seepage area with the average depth of 15m and penetrating factor of 3.3m/dand lower-layer which is classified as moderate seepage area with the average depth of 15m and penetrating factor of 0.8m/d. The weighted seepage factor for the whole second strip shall be 2.05m/d; iii) The third strip with width of 105m and average depth of seepage strip of 30m is classified as moderate seepage area with the penetrating factor of 0.8m/d; iv) The fourth strip with width of 165m is divided vertically as two layers according to the seepage performance. They are up-layer which is classified as moderate seepage area with the average depth of 20m and penetrating factor of 2.5m/d and lower-layer which is classified as moderate seepage area with the average depth of 10m and penetrating factor of 0.8m/d. The weighted seepage factor for the whole fourth strip shall be 1.93m/d; v) The fifth strip with width of 60m is divided vertically as three layers according to the seepage performance. They are up-layer which is classified as strong seepage area with the average depth of 8m and penetrating factor of lOOm/d, middle layer which is classified as moderate seepage area with the average depth of 12m and penetrating factor of 2.5m/d and lower-layer which is classified as moderate seepage area with the average depth of 10m and penetrating factor of 0.8m/d. The weighted seepage factor for the whole fifth strip shall be 27.93m/d and is strong seepage area.With kaminsiji approximate equation, the seepage quantity of dam foundation has been estimated and following results have been obtained, including the seepage quantity for loose stratum of Quaternary System of 77434.0m3/d, strong weathering stratum of bedrock of 10408.7m3/d and the total seepage quantity for dam foundation of 87842.7m3/d. Among which, the loose stratum of Quaternary System is the main seepage stratum.2 s The distributing scale, structure and components of stratum for the loess mesa of left bank and ancient river course have been ascertained. The ancient river course has been determined as the main pass way of the around dam seepage and seepage quantity for different seepage sections have been calculated.i) The loose penetration layer of ancient river course of left bank with the depth of 15-3Om is thinning gradually from front to back of mesa. The seepage strip is classified as moderate seepage area with the width of penetration strip is about 950m and equivalent seepage factor is 3.3m/d. With the average depth of 25m and average seepage factor of 0.8m/d, the strong weathering bedrock of ancient river course is classified as moderate seepage area.ii) The total seepage quantity of left bank has been calculated to 2680.5m3/d with hydraulic approximate equation. Among which, the seepage quantity for ancient river course is 2077.8m3/d. The assumed total seepage quantity shall be 1591.1m3/d after adopting effective anti-seepage measures for ancient river bank of left bank.iii)The around dam seepage quantity of right bank has been calculated to 151.9m3/d with qiubuyi equation.3 > Total three methods, namely standard equations, experience and test, have been adopted to compare and analyze the dam foundation seepage deformation type. Therefore it has been determined that the major dam foundation seepage deformation type is water creep and floating earth is the minor type. The critical hydraulic gradient and allowable hydraulic gradient for seepage have also been determined, i.e. i) the critical hydraulic gradient of dam foundation seepage damage of floating earth type is 1.2 and water creep type is 0.3; ii) the allowable hydraulic gradient of dam foundation seepage damage of floating earth type is 0.6 and water creep type is 0.15. The total allowable hydraulic gradient of dam has been suggested to adopt 0.15. iii) The average hydraulic gradient for natural dam foundation is calculated to 5.10-7.14 with equation, which is larger than theallowable hydraulic gradient of 0.15. So it is possible to occur seepage deformation damage.4 s According to the engineering point of view, the limited unit method has been adopted to calculate the assumed seepage quantity for dam foundation, left and right dam shoulders which will be treated effectively. The calculated results are the total seepage quantity of dam foundation of 5390. Im3/d, around seepage quantity of left bank of 1589.06m3/d, around seepage quantity of right bank of 5.25m3/d, the annual seepage quantity of the whole reservoir area of 2.549 million m3 which is matching to the planning seepage quantity of 2.47 million m3 for drainage basin hydrology equilibrium. Thus the calculation of seepage quantity of reservoir area is essentially accurate. In addition, the limited unit method has also been adopted to analyze the stability of seepage of dam after adopting assumed anti-seepage methods and it has been proofed by results that the dam is stable and the assumed treating methods are reasonable and effective.5 > The dam seepage treating methods have been put forwarded in the article. It is suggested that slot and hole plastic concrete anti seepage core shall be adopted for dam foundation and surface stratum of ancient river course of left bank; curtain grouting along the axis of dam for strong weathering bedrock fordam foundation and both banks and the bottom of curtain shall be beneath the lower limit of water seepage ratio of lOLu of the bedrock.By the research of reservoir and dam seepage and penetration deformation for Shanxi Hengquan Reservoir, the article has ascertained the geology features, distributing scale and seepage quantity of the seepage area, analyzed the seepage deformation types and the seepage stability of the dam, put forwarded the anti seepage treating methods, provided reliable geology basis foe design and construction and had practical directing significance for seepage and penetration deformation problems for loose rock reservoir and dam in Shanxi Province.
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