【作者】 肖尧；

【导师】 付小敏； 聂德新；

【作者基本信息】 成都理工大学 ， 岩土工程， 2011， 硕士

【摘要】 在我国铁路、交通、水电工程建设中,存在大量高陡岩质边,边坡稳定性分析是很复杂课题。随着20世纪我们水电行业发展,水电工程增多,规模的扩大,经常要在较为复杂的地质条件下建坝,对各类高边坡人工开挖,此类高边坡稳定性问题,势必为关注的重点之一。合理分析和评价对工程有非常重要作用,为大坝安全施工和运行提供依据。本文结合卡拉水电站左岸坝肩边坡稳定性的研究评价,从区域地质环境、坝区工程地质条件、岩体质量及参数、稳定性分析及评价到结论进行研究。左岸工程地质条件复杂,岩体结构经过不同时期、不同规模构造运动的改造,同时受外营力的表生作用,岩体结构复杂。作者在边坡地质环境和边坡岩体结构的基础上,以坝肩边坡稳定性为分析的重点,对坝肩边坡的变形破坏模式及控制因素,通过多种方法获得岩体力学参数指标,重点对自然边坡稳定性及开挖后边坡稳定性作出系统分析和评价。具体研究内容和成果如下:(1)对边坡地质环境调查分析,左岸坝肩边坡主要出露地层为第四系坡积层、崩坡积及上三叠统杂谷脑组T3Z。上三叠统杂谷脑组岩性主要为变质砂岩、板岩、大理岩三个大组。在边坡上游约1Km处出露陡倾断层F115,但对工程边坡稳定性无影响。左岸坝肩边坡出露少数小断层和长大倾坡外裂隙对工程稳定性起控制作用。工程边坡坡体结构为:弱风化下带-微新岩体为反向中、厚层层状结构,弱上-强风化带为反向碎裂-块裂结构。(2)在边坡岩体结构特征和风化、卸荷的基础上,结合左岸坝肩边坡地表调查和平硐统计分析,提出左岸坝肩边坡两种破坏模式:在中上部高程处主要以倾倒弯曲变形为主,中下部高程处主要沿SW向硬性结构面滑移-拉裂变形破坏为主。(3)运用边坡岩体质量分级研究结果,在现场定性分析的基础上,结合现场获得岩体各项指标,采用SMR分级法和修正CSMR分级法,定量分析边坡岩体质量并作评价和分析,边坡岩体质量以Ⅲ1、Ⅲ2级岩体为主,在边坡表部和弱带发育区出现Ⅳ级岩体,其中大部分为Ⅲ级岩体,在平硐底部出现Ⅱ级岩体。(4)结合岩体质量分级的结果,选取依照《水力发电工程地质勘察规范》(GB50287-2006),获得各类岩体的抗剪强度和变形模型;通过室内单点三轴试验分析,获得边坡岩体抗剪强度;依据中国水电顾问集团华东勘测设计研究院现场大量直剪试验和变形试验,综合分析选取参数。在以上三种方法获得岩体参数的基础上,综合给出边坡岩体抗剪强度、变形模量的参数建议值。(5)在规范和工程类比的基础上,通过野外调查,获得边坡自然坡比,最后通过分析最大自然坡比与边坡的关系,结合卡拉水电站左岸坝肩边坡特点,确立了未来边坡的最佳开挖坡比值。(6)研究边坡可能构成潜在欠稳块体,在此分析边坡边界条件的基础上,获得左岸坝基边坡总的控制边界,然后对具体工程边坡进行确定性判断,分析计算稳定性。分析顺层发育的层间挤压带或剪切带、断层及拉开长大的卸荷拉裂缝。(7)沿SW组结构面卸荷拉裂缝为滑动边界的潜在块体用多种方式,采用地质分析、赤平投影、块体理论、slide极限平衡理论及phase有限元方法,对坝肩边坡的稳定性进行系统的分析,考虑在天然、暴雨、地震工况下进行计算分析。边坡开挖后,岩体稳定性变化较小,需要一定的加固处理。更多还原

【Abstract】 Combining with Carla hydropower station in the abutment on the slope stability research subject,in the regional geological environment characteristics anddam engineering geological conditions and problems based on the analysis,using data collection and analysis、field geological investigation、testing and theory and numerical analysis,it left the abutment stratigraphic lithology,the rock mass structure and rock quality and parameters, the abutment slope rock mass stability of system analysis and evaluation,the research results obtained as follows:(1)Left bank mainly by the abutment slope Triassic miscellaneous valleybrain group of metamorphic sandstone、slate、marble constitutes . Slope upstream about the exposed steep for the F115 pour fault slope stability have no influence ,the slope of the exposed in small faults and grew up outside pour slope facing the stability of the slope structure within control function ,one of the slope to is SW main control structure surface.(2)Weak weathering with until slightly under the new and the weak unloading segment the slope rock mass structure for the slope of sloping in thick~ thick layer structure ,weak to strong weathering strong on unloading zone of slope for poured in fractured ~ chipped structure . The left side of the abutment upper failure modes for dumping bending deformation and fracture ,the failure mode for the mid-lower along to rigid structure of SW sliding surfaces of deformation and failure mode of sliding- ripping.(3)According to the classification and the fixed CSMR with SMR grading methods,On the slope rock mass quality quality grading results indicate ,inⅢ1、Ⅲ2 slope grade rock primarily ,slope rock massⅡlevel for the deep .(4)According to indoor and outdoor tests and material ,with reference to”the hydroelectric engineering geological investigation standard“comprehensive analysis ,got the slope rock mass physical mechanics parameters advisable values . (5)According to slope lithology, structure, each rock group of physical mechanics characteristics and natural slope gradient ,and design slope spatial characteristics comprehensive analysis, identified Carla hydropower station in theabutment slope excavation left than the suggested value best slope.(6)According to slope deformation damage phenomenon and failure mode, and controlling structure characteristics of weak surface comprehensively analysis ,search out slope potential unstable block;Then the geological analysis and limit equilibrium and finite element method,consider however, heavy rains, earthquake condition of the abutment design, left the excavation system slope stability analysis and calculation,the results show that the slope stability is bad, need local do appropriate reinforcement.更多还原