深埋节理岩体多裂隙扩展及非连续变形机理研究

For rock mechanics and engineering safety research, mechanism of multi-cracks expansion and discontinuous deformation with high geostress in deep jointed rock masses, is a problem urgently to be solved. Combined with deep hydro-power station's (such as Jin'ping and Dagangshan, etc.) monitoring data of crack expansion and deformation, similar rock specimen's compression tests and cavern excavation model test considering influences of discontinuities' parameters, geostresses' environment and loading's rate (or unloading's rate) are done in this project, energy accumulation-dissipation mechanism is introduced at the same time. Characteristics of discontinuous deformation with high geostress in deep jointed rock masses are analyzed, process of multi-cracks expansion and energy dissipation behavior are studied, multi-cracks' initiation, expansion, break through and evolution law are analyzed, thus multi-cracks expansion's strength criterion and energy constitutive model are established. Based on the above study results, algorithms of multi-cracks expansion and reinforcement are developed, in order to improve the discontinuous deformation analysis efficiency and computational reliability for jointed rock masses, especially the intermittent jointed rock masses. Cavern excavation process in deep hydro-power station is simulated with the developed DDARF. By the comprehensive research means of test, theoretical analysis and numerical simulation, mechanism of multi-cracks expansion and discontinuous deformation with high geostress is revealed. This project will be able to provide theoretical basis for establishing discontinuous deformation analysis system in deep jointed rock engineering.

深埋节理岩体高地应力条件下的多裂隙扩展及非连续变形机理，是岩体力学与工程安全研究的一个亟待解决的难题。本项目结合锦屏、大岗山等深埋水电站现场监测资料，开展考虑地应力环境、加卸载速率、温度等影响因素的类岩石试件压缩试验和洞室开挖模型试验，并引入能量积聚-耗散理论，分析高地应力条件下节理岩体非连续变形特征，研究多裂隙扩展过程及能量耗散行为，深入分析其萌生、扩展、贯通及最终的破坏模式和演化规律，建立深埋节理岩体多裂隙扩展强度准则和能量本构模型。基于研究成果改进和研发多裂隙扩展及加固止裂算法，提高节理岩体尤其是断续节理岩体非连续变形分析的效率和可靠度，并对深埋洞室开挖围岩裂隙扩展和非连续变形进行DDARF数值研究。通过试验研究、理论分析和数值模拟等综合研究手段，共同揭示高地应力条件下节理岩体多裂隙扩展及非连续变形机理。本项目将为深埋节理岩体工程非连续变形分析体系的建立提供理论依据。

深埋节理岩体的多裂隙扩展及非连续变形机理，是岩体力学与工程安全研究中需要解决的难题。项目结合锦屏、大岗山等深埋水电站现场监测资料，开展了节理多参数、围压、温度、加卸载以及“X”型节理对岩体裂隙扩展影响的压缩试验，分析了不同条件下岩体的裂隙扩展过程和破裂形态，研究了其非连续变形特征。结合加卸载试验，研究了裂隙扩展过程中的能量耗散行为，考虑了加卸载过程中能量的耗散引起岩体强度的变化，建立了卸载过程中弹性模量与加载过程中弹性模量的关系方程，进而提出了岩体裂隙扩展过程中的能量本构模型，通过该模型计算所得的围岩劈裂区平均深度与现场监测结果最为接近。基于非连续变形分析软件已有的研究基础，进一步调试和完善了前处理建模耦合（同时保证建模精度和计算效率）、本构模型、多裂隙扩展、加固止裂以及锚固失效判断等算法，并将其嵌入到DDARF中，提高了节理岩体尤其是断续节理岩体非连续变形分析的效率和可靠度。通过试验研究、理论分析、数值模拟等多种研究手段，共同分析了节理岩体的多裂隙扩展及非连续变形机理，项目对推动我国岩体科学研究、加快深埋工程建设具有重要的学术意义和工程价值。