【作者】 郭喜峰；

【导师】 尹健民；

【作者基本信息】 长江科学院 ， 岩土工程， 2009， 硕士

【摘要】 西部地区岩石工程都面临高地应力引起的施工风险与运行风险,地应力测量与相关研究则显得尤为重要。特别是大型水电工程一般处在地质条件复杂的高山峡谷区,地应力不仅是地下洞室与坝基开挖中控制失稳、岩爆与变形的先决条件,也是指导方案布置与支护设计的基础条件,所以都开展了大量的地应力测试与相关研究。本文以金沙江白鹤滩水电站应力场为研究对象,针对坝区一系列实测地应力资料,开展了以下工作:(1)分析了复杂地质条件水电工程特有的河谷应力场的主要影响因素,重点对地应力场数值模拟分析方法进行了文献综述。(2)阐述了基于边界位移法、应力场由自重应力和构造应力组成假设和三维有限元正演模拟法的多元回归反演方法,建立了反映白鹤滩坝区复杂地形、复杂地质构造和多相岩层的三维有限元地质模型,从实测应力数据反演获得白鹤滩工程区的地应力场。并从反演结果计算值和实测值的吻合程度,说明了反演模型的合理性。(3)在实测应力资料和回归反演结果基础上,详细展示了白鹤滩水电站地应力分布特征,给出了工程重点部位最大、最小水平主应力和垂直应力随深度的变化关系、以及不同比选坝线的应力剖面图。总体而言,河谷岸坡和河谷底部应力分布规律具有河谷应力场的一般分区特征,但复杂地形、岩层和构造等方面的影响也十分明显。更多还原

【Abstract】 Rock engineering in west China faces high risks through its construction and operation phases due to the problems of high insitu stress, so stress measurement and relevant study reviews very important. In particular, large hydropower projects are always located in high valleys and in mountainous regions, the determination of in-situ stress field is of major significance, not only for the prevention from potential failure, rock burst, large deformation and instability of underground powerhouse and dam foundation excavation, but also for the arrangement and design of support and reinforcement scenario. That’s why stress measurement and stress field analysis become necessary for hydropower projects. This paper takes in-situ stress field in BaiHeTan hydropower station for example, and the major studies are as follows:(1) Main influence factors of specific valley stress field in hydropower projects under complicated geological conditions were analyzed, and numerical methods on simulation of in-situ stress field were emphatically summarized(2) The basic principle of multivariate feedback regression based on boundary displacement method, hypothesis of in-situ stress field consisting of gravity stress and structural stress, 3-D FEM forward simulating is summarized. 3-D FEM geological simulation model of BaiHeTan hydropower station reflecting complex terrain, geological structure and multiphase rock layer was established, and then in-situ stress field of project area was obtained from inversion of measurement in-situ stress. Degree of stress values anastomosis between simulating and field measurement illustrates the rationality of inversion model.(3) Based on the measured data and results of feedback regression, distribution features of in-situ stress in BaiHeTan hydropower station were showed in detail, the relationships of horizontal principal stress and vertical stress values along depth were studied, and the stress profile of different axis were presented. In general, distribution of in-situ stress in bank slope and bottom of valley accordance with general zoning characteristics, but the influences of complex terrain, rock layer and structure are obvious.更多还原