【作者】 吕金昕；

【导师】 黄润秋； 巨能攀；

【作者基本信息】 成都理工大学 ， 岩土工程， 2010， 硕士

【摘要】 拟建的其宗水电站位于云南省迪庆州与丽江市交界的金沙江中游河段位置。坝区岩体主要为泥盆系中统的千枚岩,板岩和千枚岩夹结晶灰岩。为满足水工布置要求,引水洞出口边坡开挖高度300m,坡比1:0.75,同时在边坡的下部还需开挖7根引水隧道。如此高陡的千枚岩边坡稳定性如何?开挖引水隧洞对边坡稳定性影响多大?成为工程设计部门关心的关键技术问题。论文针对这些问题,在现场调查分析引水洞出口边坡的岩体结构特征,并在室内岩石试验的基础上,对千枚岩岩体的微观结构、物理力学性质进行研究。结合边坡岩体结构特征分析了边坡可能的变形破坏模式,采用数值模拟方法对开挖边坡的稳定性及隧道开挖对边坡稳定性的影响进行分析。具体内容及成果如下:(1)现场地质调查表明边坡整体岩体结构总体属于镶嵌结构,结构面以Ⅳ、Ⅴ级为主。Ⅳ级结构面主要包括北东向的陡倾结构面、北西向的中等倾角结构面;Ⅴ级结构面即千枚岩中发育的石英片理、板理;绢云母片理面等原生结构面。(2)薄片鉴定结果显示千枚岩主要含有石英、绢云母绿泥石与碳酸盐等矿物,千枚岩微观构造特征在一定程度上显示软岩类岩石的微观破裂现象。室内试验得知,千枚岩岩体各向异性明显,岩类内聚力变化不大,但内摩擦角存在较大差别。(3)结合边坡的岩体结构特征,确定边坡开挖后可能出现的变形破坏模式,边坡可能的变形破坏模式为:浅层滑移-拉裂变形破坏、深层滑移-压致拉裂变形破坏。在定性分析基础上,通过数值模拟计算及刚体极限平衡分析边坡的稳定状况。结果表明,边坡在天然状况下稳定性较好,整体失稳的可能性较小。工程开挖后总位移最大部位位于坡表顶部位置;但在暴雨、地震工况下,边坡顶部具有沿结晶灰岩与千枚岩的地层分界面发生局部失稳的可能性。(4)针对边坡-洞室体系组合开挖对边坡稳定性影响分析表明:引水隧硐开挖,对边坡整体稳定性的影响是相当有限的,应力应变发生改变的地方都主要集中在6倍洞径的围岩范围内,对边坡整体稳定性影响不大。更多还原

【Abstract】 The Station is located the middle reaches of Jinsha River which is seated at the junction of Diqing Prefecture and Lijiang City of Yunnan Province. Mainly rock mass in the system of Devonian phyllite, slate and phyllite folder crystalline limestone. To meet the requirements of hydraulic layout, excavation of diversion tunnel exit height of 300m, slope ratio of 1:0.75, while the lower part of slope excavation of seven needed diversion tunnel, So high and steep slope stability phyllite what? Excavation of diversion tunnel on the slope stability is their impact? Engineering design sector as the key technical issues of concern. Paper solve these problems, the investigation of diversion tunnel at the scene of rock mass slope of the outlet structure characteristics, and indoor rock on an experimental basis, on the Phyllite Body of the microstructure, physical and mechanical properties were studied. Combination of structural characteristics of rock slope analysis of the slope deformation and failure modes possible, by numerical simulation of the excavation slope stability and the tunnel excavation on the slope stability analysis. The key contents and conclusions are as follows:(1) The field geological survey shows that rock structure of the overall slope are generally belongs to the mosaic structure which structural planes are mainlyⅣandⅤlevel. TheⅣlevel structural planes are mainly including to NE steep angle structural plans and to NW medium angle structural plans, andⅤlevel structural planes are original structural plans which are quartz foliation developped in phyllite and foliation plane developped in sericite.(2) The results of thin section shows that minerals in phyllite are mainly contained quartz, chlorite-sericite and carbonate. To a certain extent, the micro-structural characteristics of phyllite appears micro-fracture phenomenon on micro soft rocks. And laboratory test shows that phyllite is significantly anisotropy and has little changed in cohesion, but there is a big difference on internal friction angle.(3) Through analysis on rock structure characteristics of the slope, to determine the main factors on slope stability and possible slope failure modes. There are including shallow slip-crack and deformation failure, deep slip-pressure crack failure. Based on qualitative analysis, by numerical simulation and rigid body limit equilibrium to analysis situations of slope stability. Slope stability is good in natural conditions and it is less likely overall instability. The largest part of total displacement is located on the top of the slope surface after excavation, but on the top of the slope which along with the part of layer interface between crystalline limestone and phyllite have the possibility to occured local instability in the rain and earthquake conditions.(4) Dealing with slope stability analysis of slope-cavern combination system on excavation indicates that the influence on slope stability is very limited for small spacing and small diameter of diversion tunnel excavation, and the changed place of stress and strain are mainly concentrated in the 6 times hole diameter of the surrounding rock mass. The deformation influenced by the excavation that the position is on the general cavity export.更多还原