【作者】 伊小娟；

【导师】 胡卸文；

【作者基本信息】 西南交通大学 ， 地质工程， 2011， 硕士

【摘要】 随着国家经济的发展,经济重心逐渐向西部转移,由于西部特别是西南的水电资源十分丰富,使得水电资源开发的潜力很大,但是由于西部特殊的地理环境,大型水电站的硐室群大部分处于深山峡谷区,使得其常处于较高的初始应力中,并且受到地形及构造活动带的影响,使得其地质条件十分复杂。在复杂地质作用下,使得岩体物理力学性质发生改变,尤其处在山体深部的岩体具有与其相地质环境条件相适应的力学性质。本文以锦屏一级水电站大理岩、溪洛渡水电站玄武岩、大岗山花岗岩室内及现场试验为依托,系统分析了与深部岩体有关的室内岩块及现场岩体的变形及强度特征。1.岩石室内试验表明岩石的力学指标与物理指标存在着一定的关系,岩块的力学性质主要受到岩石本身的性质(强度、风化程度、紧密程度)的影响,且围压对岩块的变形及强度特性有一定的强化作用；2.分析岩体现场试验,岩体的变形及强度参数受到岩体的结构、风化程度以及地应力条件的影响,一般的岩体风化程度越低、岩体完整性越好、所处的地应力越高,其变形及强度参数越高；3.通过对岩体变形及强度特性影响因素的探讨,认为岩体所赋存的应力状态及岩体的紧密程度对岩体的变形特性影响相对显著,而岩体的结构对岩体的强度特性影响相对显著；4.选取新鲜大理岩及玄武岩为研究对象,研究不同地应力相同结构条件下岩体的力学特性差异,普通大理岩现场变形模量高出了107%-60%,而斑状玄武岩的则低了15%；在相同试验条件下,新鲜普通大理岩变形模量要高于斑状玄武岩,这与室内试验相差较大,室内大理岩岩块变形模量与斑状玄武岩变形模量之比为0.5,而现场为1.11-1.23；说明岩体的变形特性主要取决于岩体所赋存的地应力条件；5.与变形试验相比,大理岩的抗剪(断)摩擦系数均要低于玄武岩,其室内峰值强度摩擦系数约是玄武岩的0.68,而现场抗剪断强度约是玄武岩的0.8；大理岩岩体的抗剪断摩擦系数要高于室内岩块三轴试验得到的摩擦系数,其高出约7.5%,增长幅度明显小于变形参数；说明岩体的强度特性受岩体所赋存的地应力条件影响较小：6.选取弱风化花岗岩及玄武岩为研究对象,分析相同应力不同结构条件下岩体力学特性的差异。分析其变形试验结果,相同试验条件下的玄武岩变形模量要高于花岗岩,其纵波波速也高于花岗岩纵波波速,说明其变形特性主要取决于岩体自身的紧密程度；7.由于玄武岩受到层间及层内错动带性质的影响,使得玄武岩的抗剪(断)摩擦系数低于花岗岩；而其抗剪(断)粘聚力要高于花岗岩,其主要原因是岩体的粘聚力主要取决于岩体连续部分的特性及岩石本身的物理性质,而玄武岩岩块本身的强度要高于花岗岩,因此玄武岩的抗剪(断)粘聚力要高于花岗岩。通过以上室内及现场试验分析,岩石的力学性质主要取决于岩石的强度,而现场岩体的力学性质则主要取决于岩体所赋存的应力条件及岩体的结构特征。更多还原

【Abstract】 With the national economic development, economic center of gravity gradually shifts to the west. Because south-west’s plentiful hydropower resources, making it has the great potential for development of hydropower resources. But due to the special geographical environment of west, the caverns of large hydropower stations are often located in the high geostress filed which are strongly influenced by high mountains and geological structure, and making it has very complicated geological conditions. The complex geological conditions make the physical and mechanical properties of rock changes, and particularly the rock mass deep in mountain has the mechanical properties adapted to its geological environment.In this paper, based on the marble of Jinping hydropower station, basalt of Xiluodu Hydropower Station, granite of Dagangshan laboratory and field tests, systematically analyses the rock and rockmass deformation and strength characteristics relate to the deep rock mass.1.Rock laboratory tests show that there is certain relationship between the mechanical index and physical index, and the mechanical properties of rock mainly are influenced by the nature of the rock (intensity, degree of weathering, degree of compactness), and confining pressure has certain reinforcement on the deformation and strength characteristics of rock2. Field test shows that the deformation and strength parameters of rock mass are influenced by its structure, the degree of weathering and geostress conditions. Usually the rock mass has higher deformation and strength parameters with the lower degree of weathering, more integrity rock mass and the higher geostress conditions;3.Analyzing the factors influencing the deformation and strength characteristics of rock mass, the deformation characteristics is close related to the geostess conditions and close level of rock mass, and the rock mass structures influence relatively significant to the strength characteristics.4. Researching differences in mechanical properties of rock mass with the same structure and different stress conditions based on the fresh marble and basalt rock mass, the deformation modulus of rock mass is higher 107% to 60% than the rock while porphyritic basalt is lower 15%.With the same test conditions, the deformation modulus of new ordinary marble is higher than the porphyritic basalt, and the laboratory deformation modulus ratio of 0.5while the site for 1.11-1.23. It shows that the deformation characteristics of rock mass depend on its geostress conditions.5. Compared to the deformation test, the friction coefficient of marble shearing test is lower than the basalt, and the laboratory friction coefficient of peak intensity is about 0.68 of basalt, while the field is about 0.8. The shearing friction coefficient of marble rock mass is higher about 7.5% than the rock, significantly less than the growth rate of deformation parameters. It shows that the geostess condition of rock mass is relatively smaller influence to its strength characteristics.6.Researching differences in mechanical properties of rock mass with the different structure and same geostress conditions based on the moderately weathered granite and basalt rock mass, rock deformation test results show that the deformation modulus of basalt is higher he granite with the same experimental conditions, and the longitudinal wave speed is also higher than the granite. It indicates that the deformation of rock mass depends on its degree of compactness.7. Due to the influence of bedding fault and interlayer faults zones in basalt, making shearing friction coefficient of basalt is lower than granite, and shearing cohesion of basalt is higher than the granite. The main reason is that the cohesion depends on the characteristic of continuous part and physical properties of the rock itself, and the strength of basalt rock is higher than granite. Therefore the shearing cohesion of basalt is higher than granite.The above analysis shows that the mechanical characteristic of rock mainly depends on the rock strength, and the mechanical characteristic of rock mass mainly depends on the geostress condition and rock mass structure.更多还原