【作者】 彭作为；

【导师】 周创兵；

【作者基本信息】 武汉大学 ， 岩土工程， 2004， 硕士

【摘要】 本文以金沙江向家坝水电工程右岸进水口高边坡稳定性问题为研究目标，以极限平衡法中的Sarma法和三维弹塑性有限元分析为手段，对进水口高边坡在各种工况和各种可能的不利荷载组合下的稳定性进行了较详细的分析和评价。对边坡拟采用的设计方案、施工方案、以及加固措施的正确性进行了论证。主要内容包括以下几方面： （1）利用Sarma法分析向家坝水电站右岸地下厂房进水口边坡稳定性，考虑边坡开挖、施工爆破造成的节理裂隙或卸荷裂隙贯通、持续暴雨或水库水位骤降及施工因素对边坡稳定性的影响。并针对具体的边坡形态和节理分布特征，研究进水口边坡的局部稳定性问题。 （2）采用三维弹塑性有限元方法，建立了向家坝水电工程右岸包括进水口边坡和引水隧洞、地下厂房、尾水隧洞等地下结构的三维整体有限元分析模型，对向家坝水电工程进水口边坡开挖锚固进行较为精确的模拟，根据现有的资料，在此基础上得到进水口边坡的变形和应力分布规律。根据有限元计算结果，对边坡的整体稳定性和局部稳定性分别进行了相应的分析评价。 （3）在上述三维整体有限元分析模型的基础上，从应力应变分布规律变化的角度，分析评价了引水隧洞和地下厂房等地下结构的开挖对进水口边坡稳定性的影响。 （4）依然在三维整体有限元分析模型的基础上，通过在不同程度上弱化进水口边坡反倾结构中软弱夹层的力学参数和弱化岩性较差而且对边坡稳定影响较大的T₃³岩层力学参数，分析评价了反倾结构对进水口边坡稳定性的影响。 （5）通过上述对进水口边坡稳定性的分析评价，提出了几条在设计、施工以及运行过程中改善边坡稳定性的建议。 研究表明： 向家坝水电工程右岸引水隧洞进水口边坡在各种工况、各种可能的不利荷载组合下都能保持其整体稳定性。但是，由于受两组优势节理面的切割，在施工和运行期间，可能会出现局部的块体失稳。 向家坝进水口和边坡开挖以及锚固过程中，没有过大的拉应力和塑性变形区。进水口边坡大多数还是处于压应力状态，仅在边坡马道局部出现较小的拉应力，边坡开挖卸荷显著的深度为3～8米。结果说明向家坝进水口边坡开挖是稳定的。 向家坝进水口边坡拟采用系统锚秆进行支护，锚杆支护是边坡逐步开挖时逐步施加的。岩体内锚杆主要承受拉剪作用，进口边坡处锚杆承受的最大拉应力为54.6lMPa，最大剪应力为3O.02MPa，只要加固及时，边坡的卸荷松弛变形可以得到限制，且当边坡出现局部出现较大变形时，锚杆支护作用可以得到进一步发挥。从进水口边坡系统锚杆在施工、运行过程中的受力状况计算分析结果看，进水口边坡拟采用的逐步开挖逐步锚固的施工顺序是科学合理的。 引水隧洞和地下厂房的开挖，对进水口边坡的位移和应力分布都有一定的影响，但是从计算所得的影响范围和量值看，其影响有限，不会破坏进水口边坡的整体稳定性。 进水口边坡的反倾结构有利于边坡的稳定，即使将反倾结构中软弱夹层的力学强度锐减，进水口边坡仍然能维持其整体稳定性。更多还原

【Abstract】 Taking the stability of the high slope of the intake of Xiangjiaba hydropower station as research target, the limit equilibrium method and 3D Elasto-viscoplastic finite element method as research measure, this paper analyzes and appraises the stability of the high slope under different work conditions. The result proofed the design scheme, construction scheme and anchorage scheme. The main study contents as follows:(1) Analyze the stability of the high side slope of intake by Sarma method. In this course, some adverse influencing factors as slope excavation, joint fissure caused by blasting, prolonged storm rainfall and rapid drawdown have been considered. Then, based on the shape of slope and distribution characteristics of joints, study the local stability.(2) Using 3D FEM, three dimensional finite element model of the high slope is presented in this study, analyze the global 3D stress and deformation distribution, considers the effects of excavation, anchoring and different work conditions. Evaluate the stability of the slope, based on the stress and deformation result.(3) Analyze the influence to the stability of the slope that caused by excavation for seepage tunnel and underground power plant.Evaluate the influence to the stability of the slope caused by counter-inclined structure.(4) In order to improve the stability of the slope and ensure the safety in the engineering construction and operation, Some proposals on engineering measures been presented.Studies show that the high side slope of the intake of Xiangjiaba hydropower station will be stable in integer under possible work conditions. But the slope maybe crippling in period of construction and operation because of the cutting by tow clusters joints. In the process of excavation and anchoring: there is not oversize tension stress and plastic zone in rock mass of the slope, the obvious off-load depth is about 3 to 8 meters. The results indicate that the slope can hold stability in excavation period, the design scheme and sequence of excavation and anchoring are rational.The slope of intake will be bolted by systematic bolts. By the calculation, we can get conclusions as follows: the max tension stress on bolts is 54.61MPa, and the max shearing stress is 30.02MPa; the off-load deformation can be control effectively if anchoring istimely; the more deformation which present in local slope rock-mass will make further use of bolts.Excavation for seepage tunnel and underground power plant take some harmful effect to the slope, but it will not damage the slope’s integral stability. Counter-inclined structure is propitious to slope holding stability. The slope of intake still hold stability after the mechanical parameter be diminished drastically.更多还原