紫坪铺水电站溢洪道边坡运行期长期稳定性评价

【作者】 涂国祥；

【导师】 黄润秋；

【作者基本信息】 成都理工大学 ， 地质工程， 2005， 硕士

【摘要】 紫坪铺水电站位于岷江上游河段。电站泄洪主要依赖于紧邻右坝端、沿右岸条形山脊布置的开敞式溢洪道及两条泄洪排沙洞。为修建溢洪道,必需对其内侧山体进行大范围、大方量的开挖,形成长近500米、高达200余米、坡角约30°～60°的高边坡。区内出露三叠系上统须家河组(T_3xj)的一套湖沼相含煤砂页岩地层。受即金沙坝向斜的影响,岩体结构较为破碎,层间错动明显,断裂构造发育。在这样一种复杂的地质环境和工程条件下,溢洪道内侧边坡的长期稳定性问题是一个关系到能否保证溢洪道安全运营的关键问题,因此研究溢洪道内侧边坡运营期间的长期稳定性具有极为重要的意义。 本文在大量现场调查和室内软岩流变试验分析的基础上,从溢洪道内侧边坡所处的地质环境和工程条件入手,在详细分析边坡的岩性组合、岩体结构、工程开挖期间的变形破坏迹象及其机制后,得出了影响边坡长期稳定性的两个关键性因素,即地下水和软弱岩体的流动变形。而后较为深入的研究了地下水影响边坡岩体变形破坏的作用机理,并运用有限元数值模拟方法重点研究了水库蓄水后和库水位升降过程中边坡地下水位变化特征以及渗流场特征,运用FLAC^3D软件重点研究了水库蓄水后边坡变形发展趋势,最终结合上述研究成果给出了运营期间边坡长期稳定性的建议评价方法,并运用这一方法对溢洪道内侧边坡运营期间长期稳定性作出了较为科学、合理的评价,取得了以下主要研究成果。 （1） 分析了工程开挖条件下边坡岩体变形破坏模式及其形成机制。 （2） 初步研究了软弱岩体流变特性及其对边坡长期稳定性的影响。 （3） 深入分析了在库水水位变动条件下,边坡地下水渗流场的动态变化规律,及其对边坡长期稳定性的影响机理和影响程度。 （4） 进一步分析了运营期间边坡变形特征及其发展趋势。 （5） 分析研究了溢洪道内侧边坡潜在最危险破坏面和破坏模式,并评价了其长期稳定性。更多还原

【Abstract】 The dam for Zipingpu hydroelectric power station is loacated in the upriver of Minjiang River. The ability of the station to discharge flood is beared mostly on the draining runnels and the spillway which is closed to the right shoulder of dam, and was built along the bar-ridge. During the period of construction, the inside mountain of spillway was excavated largely and deeply, forming a high-cliffy slope called the inside slope of spillway, with the length near 500m, height near 200m, and angle of slope between 30° -60° . The exposed rock in study area is a suite of sandstone and shale, which belong to the Xujiahe group of Trias. The structure of the slope’s rock mass is comparative cracked, controlled distinctly by the lithology of the slope, slidding along bedding plane obvioursly. Because of such complex geology environment and construction condition, during the period of impounder, the long-term stability of the inboard slope will be a key problem for the safety of whole station in the period. So it’s a very important and essential to study the inboard slope’ secular stability of the spillway.In this paper, the author has investigated the geology environment and construction conditions, and has finished the rheology test for the weak rock mass, and has analyzed the characters of slope’s lithology, structure, and characters of failure during period of construction. On those base, the author has worked out the key factors which control the stability of the slope, namely groundwater and creeping of weak rock mass. After so on, the mechanism how the groundwater effects the failure of rock mass was studied comparatively deeply, and the author has simulated the character of seepage field and the level of groundwater of the slope in the process of reservoir’s water level ascending and dropping with the method of finite element , and has simulated the trend of the slope’s deformation since the reservior will have stored water with FLAC^3D. In the end, on the base of above studying, the author brings forward the method for evaluating the long-term stability of slope, and works out the comparative scientific and credible result for the inside slope’s stability. As a whole, in this paper, the author has acquired the following outcome.1. Analyzed the rock mass’s failure modes and mechanism of the slope during the period of construction.2. Pilot studied the creeping characteristic of weak rock mass and the mechanism that affecting the slope’s stability.3. Studied deeply the dynamic characteristic of seepage field and the mechanism that affecting the slope’s stability. during the period of product.4. Studied ulteriorly the trend and characteristic of the slope’s deformation during the period of product4. Analyzed every section’s long-term stability status of the slope.更多还原