水电能源开发中的关键工程地质体力学问题

Key problem of engineering geomechanics in hydroelectric energy exploitation

本文首先讨论了能源开发建设所面临的工程问题和科学问题,简述了工程地质体力学的内涵和应解决的核心问题.特别介绍了笔者研究团队最近几年的研究成果,提出了相关科学问题的研究方向.主要内容包括:传统固体力学中关于点破坏的概念,研究地质体有很大的局限性,论述了用破坏程度描述地质体破坏状态的合理性,以及基于监测与数值模拟相结合的破坏状态概念—破裂度;基于破裂演化原理,讨论了工程地质灾害的两个防灾理念,强调了状态判断的合理性及数值模拟方法的重要性;讨论了地质体稳定性分析方法的评价标准,并对目前常见的几种评价方法做了简要的评述;提出了数值模拟地质体的非连续、非均匀性的两尺度力学模型和计算框架;论述了代表性体积单元尺度上的应变强度分布函数,该函数比本构关系表征材料的破坏特性更为合适;综述了地质体孔隙裂隙渗流及与破裂场耦合模型的计算模型;结合汶川地震次生地质灾害的现象,指出了拟静力计算方法的不合理性,介绍了关于地震作用下地质体边坡稳定性的数值模拟新方法.

Engineering and scientific problems confronted in hydroelectric energy exploitation and construction are discussed, and the concept and key problems in engineering geomechanics are introduced. The research work by the team of the authors in recent years is reviewed and research interests in relevant scientific fields are proposed, which includes： （1） The theory of ＂failure on a point＂ in traditional solid mechanics is inadequate to describe geological body, and the concept of ＂fracture degree＂ is proposed, rationality as well as the operation method with field monitoring and numerical simulation are discussed. （2） Two disaster prevention concepts in geologic hazards based on fracture evolution are introduced, rationality of state evaluation and importance of numerical simulation are emphasized. （3） Evaluation criteria of stability analysis for geological body are discussed and comments are made for some of the common methods. （4） Two scale mechanical model and computational frame for numerical simulation of discontinuum and heterogeneity in geological body are presented. （5） Distributive function of strain strength in representative volume element are expounded, which is more appropriate to describe fracture of material than traditional constitutive relationship and parameters. （6） Seepage model for fractured porous media and fracture coupled model are reviewed. （7） According to secondary geological disaster in Wenchuan, irrationality of pseudo-static method is pointed out, and a new method with numerical simulation for stability analysis of geological body subjected to seismic loads is introduced.