【作者】 周洪福；

【导师】 聂德新；

【作者基本信息】 成都理工大学 ， 地质工程， 2008， 博士

【摘要】 赛格水电站左岸为三叠系白云岩,右岸为石炭系玄武岩,中间为白云岩/玄武岩接触断层破碎带岩体。怒江深大断裂从坝址区外围通过,区内断裂构造发育,岩体完整性受到一定的影响,其中玄武岩钻孔揭露岩芯平均RQD仅33%;白云岩中细微裂隙极为发育,裂隙间距普遍在数厘米,甚至1cm以下,岩体表观结构呈碎裂状,钻孔岩芯RQD值多在10%以下;白云岩/玄武岩接触断层破碎带规模较大,其中钻孔揭露铅直最大厚度在35-40m,带内断层泥、糜棱岩厚度较大。表观现象如此破碎的岩体,能否用作高混凝土重力坝的坝基岩体,无论是理论意义还是工程意义都较为重大。为此,本论文主要从以下几个方面对这一问题进行了研究:(1)根据坝址区钻孔揭露的断层破碎带位置,利用三维模型技术和构造地质分析方法,研究分析了坝址区断层破碎带的空间展布特征,得到了坝址区主要断层破碎带的空间位置、产状、规模。(2)通过现场调查和室内的资料分析,得到了白云岩特殊性质的成因机制,研究结果表明:白云岩虽然裂隙间距很小,但是由于裂隙被钙质充填胶结,使得碎裂的白云岩由非连续介质向连续介质转变,与传统意义上的碎裂结构岩体有着本质的不同,本论文将其定名为“充填胶结碎裂岩体”。(3)分别对覆盖层以下坝基白云岩和玄武岩进行了岩体结构划分和岩体质量分级,论证了岩体质量分级主要指标之间具有较好的相关关系。(4)现场和室内试验结果表明:在不受或者轻微受到外界扰动的情况下,玄武岩和“充填胶结碎裂”白云岩具有高波速、高模量、高完整性系数、高抗剪强度参数、低渗透性的特点。进入弱风化以后,岩体的力学参数达到Ⅲ级及以上岩体的标准。而河床部位断层破碎带的力学参数较低,需要进行特别处理。(5)以力学指标为核心,从岩体质量、岩体风化程度、岩体渗透性等指标分别选取了建基面的位置,突破了以往单纯依靠风化带选择建基面的限制。经过综合分析,不考虑河床地段破碎带和影响带,确定的建基面位置最低处为ZK115号钻孔处,高程为646.74m。(6)三维数值分析结果表明,当不对坝基断层破碎带进行任何处理时,11坝段将会出现明显的不均匀沉降,大坝的稳定性较差,不能满足工程的需要。采用钢筋混凝土板和混凝土塞并同时提高破碎带变形模量的综合处理方法以后,可以有效降低大坝的不均匀沉降,提高11坝段的稳定性系数至2.3-2.4之间,能够满足大坝的稳定性要求。更多还原

【Abstract】 There are Triassic dolostone in left and Carboniferous basalt in right and fault belt rock mass between dolostone and basalt in Saige Hydropower Station. The research region have many fault and Rock mass integrality be effected because of the NuJiang deep and major fault. The RQD of basalt is only 33% and RQD of dolostone even under 10%. The dolostone that the space of discontinuities is universal several centimeter even under 1cm is very cataclastic apparently because there are many discontinuities in rock mass. The size of fault belt rock mass between dolostone and basalt is large. There are many fault gouge in fault belt rock mass with thickness of 35-40m in borehole. Can these rock mass that surface textures so cataclastic will be as foundation of high concrete gravity dam. It will be important theory and project significance. Therefore, the main contents of this dissertation are:①According to position of fault belt rock mass by borehole disclosing, getting the distribution, thickness and orientation of main fault belt rock mass make use of three-dimensional model and method of tectonic geology.②According to field and indoor investigations and analysis, found out especial formation mechanism of dolostone. According to result of research, dolostone with small space between discontinuities is differs from the common cataclastic rock mass because the discontinuities are filled and cemented with calcium, make the dolostone from discontinuous medium features to continuous medium features. In this dissertation, these new special structure rock masses were named filling cementation cataclastic rock mass.③Rock mass structure and rock mass quality of dolostone and basalt are evaluated under overburden layer. Demonstrate these quantifiable indexes have the perfect correlativity. ④According to field and indoor investigations and tests, under the conditions of non-disturbance or slight disturbance, basalt and filling cementation cataclastic dolostone have high longitudinal wave velocities, high modulus of deformation, high sound degree coefficient, high shear strength and low osmosis. Rock mass mechanical parameters of basalt and dolostone achieve or exceed criterion of grade III enter into weakly weathering belt. But mechanical parameters of fault belt rock mass in river-bed are low, and need to be treated.⑤By making the rock mass mechanical parameters as kernel, select the rock mass of dam foundation by index of rock mass quality, rock mass weathering and rock mass osmosis, and broke through the limitation of dam foundation rock mass selection only based on weathering zones. At last made sure the lowest of selected dam foundation rock mass to bed rock roof is 646.74m in the position of ZK115 without regard to the fault belt rock mass in river-bed.⑥According to result of three-dimensional FEM analysis, stability of dam 11 is low because of unequal settlement when don’t treat the fault belt rock mass in river-bed. Stability coefficient of Dam 11 can be achieved 2.3-2.4 and reduce unequal settlement effectively by making use of integrative prevention measures that are board of concrete with steel, plug of concrete and increase of modulus of deformation of fault belt rock mass.更多还原