【作者】 沈中超；

【导师】 沈军辉；

【作者基本信息】 成都理工大学 ， 地质工程， 2008， 硕士

【摘要】 两河口水电站是雅砻江中下游的控制性水库电站工程,对整个雅砻江梯级电站的开发影响巨大。在坝前左岸雅砻江一级支流庆大河近沟口左岸边坡部位布置有导流洞、泄洪洞、放空洞等泄水建筑物进口。该边坡变形明显,除浅部存在规模较大的倾倒弯曲—拉裂变形体外,深部还存在卸荷拉裂变形及蠕滑变形现象。研究该工程边坡的变形破坏机制,评价工程边坡的稳定性,对工程边坡设计及加固,保障电站的正常运行等具有重要的实际意义。本文在庆大河进水口边坡的基本地质条件、斜坡岩体结构、变形破裂迹象等研究基础上,对边坡的变形破坏模式及成因机制进行分析,并建立其变形破坏机制的概念模型。运用刚体极限平衡理论对边坡进行稳定性计算与评价。采用UDEC二维离散元软件对其变形过程进行模拟,验证其变形破坏规律。运用FLAC3D三维有限差分软件对该边坡开挖前后的应力、应变进行模拟计算,并分析边坡的稳定性。根据变形体不同部位的变形情况,开挖深度,稳定状况等因素提出相应的工程措施建议。具体内容及成果如下:(1)结合野外调查资料,较全面的总结了庆大河进水口边坡的岩体结构特征,并初步建立了地质结构模型。将边坡岩体质量分为Ⅲ、Ⅳ及Ⅴ类,且主要以Ⅳ和Ⅴ类为主,同时将结构面分为Ⅲ、Ⅳ、Ⅴ级结构面,并对其性状特征进行了详细的描述。根据边坡的破坏模式及变形的程度,将变形体主要分为Ⅰ、Ⅱ、Ⅲ、Ⅳ四个区,分别阐述了各区变形特征,并分析了变形体的成因机制。即边坡底部岩体主要受薄层变质粉砂岩控制,在长期的物理作用下,薄层变质粉砂岩发生破坏,前缘临空条件得到改善,随着河谷的下切、边坡地形切割程度及坡度的增大,导致上部顺板理面发生倾倒变形。(2)通过上述地质分析与判断,详细阐明了可能失稳的不利块体组合模式,并采用极限平衡法对工程边坡整体稳定性进行计算和评价。计算结果表明,工程边坡整体稳定性主要受控于fb13-4、fb13-6及f6,存在以fb13-4为底滑面,以fb13-6或f6为后缘拉裂面的块体破坏,自然工况下稳定性较差,在暴雨或地震等不利工况下极易失稳。采用随机块体赤平投影分析法对边坡局部块体稳定进行分析和评价。计算结果表明,洞脸边坡易形成以裂隙③或裂隙④为底滑面,以裂隙①或②为后缘拉裂面的随机块体破坏。洞侧边坡无不利结构面组合,其稳定性较好。(3)采用UDEC二维离散元软件对边坡的变形过程进行数值模拟,分别从应力、位移、裂隙张开度以及位移矢量分析自然状况下在不同计算步时的变形特征,并加监测点监测开挖坡面的位移情况,定量的分析其开挖后边坡的变形情况,进而进行稳定性评价。评价结果表明,边坡开挖后,仍存在底部顺板理面发生倾倒—弯曲变形,顶部顺层面产生滑移拉裂破坏的破坏模式。(4)采用FLAC3D快速拉格朗日有限差分程序对边坡进行数值模拟,计算边坡在开挖前、后应力应变、剪应变增量及塑性区范围等,并分析其稳定性。计算结果表明,在断层附近出现塑性区和剪应变增量带,其稳定性较差。(5)在野外地质分析基础上,结合前述计算结果,对边坡稳定性进行综合评价,根据评价结果,对边坡不同部位提出相应的预应力锚索、锚拉桩、防护网及排水等针对性工程措施建议。更多还原

【Abstract】 Two middle and lower reaches of the Yalong River Hydropower Station is the controlling power plant reservoir engineering,the whole cascade Yalong tremendous impact on the development of power plants.In an upstream tributary of the left bank of the Yalong river near Mizonokuchi-Left Slope site layout a diversion tunnel,the spillway,such as emptying discharge structure of imports.The slope deformation obviously,with the exception of the shallow existence of large-scale dumping of bending-Latin America fissile body,there are still deep disposal of fissile-Hela and creep deformation phenomenon.Slope project to study the mechanisms of deformation and damage,assessment of slope stability,the slope of the project design and reinforcement to ensure the normal operation of power plants,and so have important practical significance.This paper in-river intake slope of the basic geological conditions,the slope rock structure, deformation and fracture on the basis of signs,and so on,the slope of the patterns and causes deformation and damage mechanisms for analysis and the establishment of mechanisms of deformation and damage its conceptual model.Use of rigid limit equilibrium theory of slope stability calculation and assessment.UDEC using two-dimensional discrete element of its software to simulate the deformation process,verification of its deformation and damage. FLAC3D use of three-dimensional finite difference software excavation of the slope before and after the stress and strain of simulation and analysis of slope stability.According to deformation of different parts of deformation,the depth of excavation,stable conditions and other factors to the corresponding measures proposed.Details and results are as follows:(1)of the field survey data,more comprehensive summed up the slope-river intake structure of the rock,and initially established a geological model.Slope quality will be divided intoⅢ,ⅣandⅤcategory,and the major categories toⅣandⅤmainly at the same time,the structure of divided intoⅢ,Ⅳ,Ⅴ-level structure,and its characters features a detailed description of According to the slope failure mode and the extent of deformation,deformation will be divided into the main bodyⅠ,Ⅱ,Ⅲ,Ⅳfour areas,respectively,on the district deformation features and analysis of the causes of the deformation mechanism.That the slope at the bottom of metamorphic rock major TLC siltstone control,in the long-term physical effects,TLC metamorphic siltstone in damage,to improve conditions for the invading front,with the valley of the incision,cutting degree slope terrain And the slope of the increase,leading to the upper-plate in the dumping grounds of deformation. (2)through the geological analysis and judgement,to elaborate on the possible instability of the adverse combination of block model and adopt the ultimate balance of the project slope stability of the overall calculation and assessment.The results show that the slope of the overall stability of the main controlled by fb13-4,fb13-6 and f6,there to the end of fb13-4 for the sliding surface to fb13-6 or f6 for the post-edge fracturing of the block damage,The poor stability of the natural condition,in heavy rain or earthquakes and other adverse condition vulnerable instability. A randomized block Chek projection analysis of the partial block slope stability analysis and evaluation.The results show that the slope face-to-form④cracks or fissures③the end of the sliding surface to crack①or②margin for the post-fracturing of the block were damaged.No adverse side-slope of portfolio structure,its good stability.(3)UDEC discrete two-dimensional element software on the slope deformation process of numerical simulation,from stress,displacement,and crack open displacement vector analysis of the situation in different natural step when calculating the deformation characteristics,and increase the monitoring points Excavation of the slope of the displacement monitoring the situation,quantitative analysis of the slope after the excavation of the deformation and then a stability evaluation.Evaluation results showed that the slope excavation,there are still at the bottom with a plate of dumping grounds-bending deformation,a top-level slip fracturing damage failure mode.(4)use of finite difference FLAC3D fast Lagrangian procedures to simulate the slope, calculated slope in the excavation before and after the stress and strain,shear strain increment and plastic area,and to analyse its stability.The results show that the fault in the vicinity of a plastic zone and shear strain increment zone,its poor stability.(5)in the field of geological analysis,based on the results of the foregoing,the slope stability comprehensive evaluation,based on the evaluation results,the slope corresponding to different parts of the prestressed cable,anchored Pile,protection and drainage networks,such as Targeted measures proposed.更多还原