【作者】 朱继良；

【导师】 黄润秋；

【作者基本信息】 成都理工大学 ， 地质工程， 2006， 博士

【摘要】 数百米级岩石高边坡的开挖及其稳定性问题是目前我国大型水电工程建设中所遇到的重大工程技术问题。本文针对小湾水电站高达近700m的人工高边坡，通过大量现场跟踪施工的地质调查工作，结合系统的变形监测和三维有限元数值模拟分析，较为系统的揭示了大型人工高边坡开挖施工过程中，边坡所发生的以变形和卸荷破裂为代表的一系列地质-力学响应过程，进而探讨了此类边坡的变形稳定性问题。论文取得了以下主要研究成果： (1)首次针对高达数百米的复杂人工高边坡，系统揭示了边坡在开挖过程中所表现的变形和破裂行为，建立了一套对大型复杂岩石高边坡开挖过程地质-力学响应的系统认识，尤其是揭露和认识了开挖过程中若干有别于传统认识的新现象和新规律；形成了较为完整的分析和评价方法；积累和丰富了大型复杂岩石高边坡开挖工程的认识与经验，为今后类似工程的建设提供了理论指导与工程借鉴。 (2)紧密跟踪施工开挖过程，对揭露的各种结构面进行详细的地质编录和描述。在现场编录的基础上，进行系统的资料分析与整理，形成了对开挖边坡岩体结构特征较为系统和深入的认识。 (3)系统研究了复杂地质条件和高地应力环境下，岩石高边坡大坡比、强开挖所表现的变形响应，揭示了此类边坡变形响应的基本规律及特殊的表现，研究表明： ①高边坡开挖过程中，边坡的变形与开挖过程有较强的同步性；变形主要受开挖卸荷影响，以侧向水平卸荷回弹变形为主，垂直变形指向下，但量值很小，约为水平变形的9％～20％，变形矢量总体呈近水平的俯角，而不是通常有限元计算得出的指向上的仰角。 ②随开挖的进行，坡体的变形随开挖面的远离表现出总体衰减，最终稳定的响应特征，典型的变形响应曲线有三个阶段：即开挖后2～4个月的“变形快速增长阶段”，对应开挖面至测点的高度约为70～120m；开挖后18～22个月内“变形缓慢增长阶段”，开挖面距测点的高度为220～300m；此后，变形处于“稳定”阶段，不再受开挖过程的影响。 ③边坡开挖过程中，当出现大规模水平退坡开挖或大面积“揭底”开挖时，水平开挖面将产生强烈的垂直卸荷回弹，其程度可使上部大更多还原

【Abstract】 The excavation and stability of the hectometers high rock slope are currently an important technical problem of the water conservancy project construction in China. Through the abundant geological investigation of construction tracing in situ-site, combining with the systematical deformation inspection and 3D numerical simulation, the slope with height of 700m in Xiaowan Hydroelectric Station is studied to present a series of geological and mechanics feedbacks such as deformation and unloading fracture during the process of the excavation of this large scale slope. Then, the stability of this kind of slope is discussed. The main results are showed as follows:(1) Based on the research of the hectometers high slope being artificial and complex, its deformation and fracture behavior during the process of excavation is systematically presented, whose geology & mechanics responding mechanism is obtained. Especially, several new phenomena and rules being different to the traditional ones are disclosed. Then, a rounded analyzing and evaluating method about large scale complex rock slope is formed, the experience of excavation is accumulated, which is helpful to the construction of the similar project in the future.(2) all kinds of geological structural planes being exposed are carefully recorded and described by means of closely tracing the process of excavation. On the basis of the documentation in situ-site, the structure characteristics of rock mass are deeply researched and systematically presented.(3)the reactive deformation of high rock slope with great sloping更多还原