余震与降雨时序作用下震裂岩体破坏过程模拟方法及失稳力学机制研究

Strong earthquakes excitation on mountains can easily lead to shattered rockmass, which will develop to be collapses and landslides under aftershock and rainfall and bring in great harm, and the simulation method and mechanical mechanism are urgent breakthrough in theory and key technical problems. This project based on the geological research and experience on shattered rockmass, focus on Jinan bridge Huaping bank slope of Jinshajiang river, Yunnan. Through building geological structure models and mechanism patterns of earthquake and rainfall of shatter rockmass, dynamic evolutions of shatter rockmass mechanism characteristics under the earthquake and rainfall can be analyzed. Based on the analysis, the continuous-discontinuous coupling models, dynamic strength criterions, contact constitutive models, hydromechanical coupled models and high efficient parallel algorithms are integrated, and the simulation method for the whole crack through process from minor fractures to blocks to lose overall stability can be developed using the discontinuous deformation analysis (DDA) method. Combining the DDA simulations and model test data, the evolutions of fractures, displacements, stress and seepage field are studied; the timing effect of the excitation load, coupling effect of hydromechanical are explored; the approach to collaborative evaluation of minor key blocks and global stability are provided, and the instability mechanical mechanism of the shattered rockmass under the timing excitation of aftershock-rainfall and rainfall-aftershock are revealed. The results can provide theoretical and technical support for geological disaster prevention after the earthquake, and play an important role on promoting the development of rock mass dynamics and geological hazard controlling.

强震作用于山体易形成震裂岩体，在余震、降雨作用下失稳造成的崩塌滑坡危害巨大，其破坏过程模拟方法及失稳力学机制是亟待突破的理论与技术难题。本项目拟基于震裂岩体地质调查与经验认识，紧密依托云南金沙江金安大桥华坪岸坡工程，构建裂隙岩体地质结构模型与地震、降雨力学作用模式，分析余震、降雨下震裂岩体力学性质动态演化规律；以此为基础，集成连续—非连续耦合模型、动力强度准则、接触本构模型、应力渗流耦合与高效并行算法，基于DDA发展模拟岩体从局部裂隙贯通形成块体到整体失稳全过程的方法；结合DDA模拟与模型试验数据，研究裂隙、位移、应力、渗流场演化规律，探讨荷载作用时序效应、应力渗流强耦合效应，形成局部关键块体与整体稳定性协同评价方法，揭示余震—降雨、降雨—余震时序作用下震裂岩体失稳力学机制，从而为震后地质灾害防治提供理论与技术支持，在推动岩体动力学和地质灾害防治学科发展方面发挥积极作用。

强震作用于山体易形成震裂岩体，在余震、降雨作用下失稳造成的崩塌滑坡危害巨大，其破坏过程模拟方法及失稳力学机制是亟待突破的理论与技术难题。本项目紧密围绕裂隙岩体力学性质动态演化机理、局部裂隙贯通形成块体到整体失稳的模拟理论与方法、震裂岩体的失稳力学机制三个关键科学问题，依托云南省华丽高速公路金沙江金安大桥华坪岸坡工程、香丽高速公路岩羊村滑坡以及甘家寨滑坡震害实例，主要取得了三个方面的重要进展。首先，通过归纳工程场地降雨模式，给出地震荷载的简化形式，开展多方案的岩体动力学性质的试验，认识震裂岩体力学性质与破坏机理，从而提出裂隙岩体动力破坏强度准则。其次，通过实现随机不连续面三维网络模拟，提出三维复杂块体系统全空间识别方法，建立了连续—非连续的边滑坡数值分析模型；针对块体系统实现应力渗流耦合的DDA算法，针对单个块体提出地震与水压力共同作用下关键块体的动力响应分析方法；以此为基础，研发了集前处理、耦合计算、后处理为一体的局部块体与整体块体系统稳定性分析软件。最后，通过开展不同地震烈度与降雨条件下斜坡动力响应的物理模型试验，实现不同地质结构、地震与降雨作用时序下滑坡响应的多方案数值模拟，提出震裂裂隙对地震-降雨型滑坡的控制作用，形成了基于矢量和—DDA的滑坡安全系数计算方法，构建了基于尖点突变理论的滑坡动力破坏评价模型。.研究成果应用于金安金沙江大桥桥址边坡稳定性评价、岩羊村滑坡的长期稳定性监测；共发表论文20篇，主编行业团体标准1部；授权发明专利5项、软件著作权5项；培养研究生5名，1人入选中国科协青年人才托举工程项目资助、1人入选中国科学院青年创新促进会会员。项目研究为震后地质灾害防治提供理论与技术支持，在推动岩体动力学和地质灾害防治学科发展方面发挥积极作用。