水库滑坡-防治结构体系演化机理与稳定性研究

The reservoir landslide-stabilizing structure system, formed by the implantation of stabilizing structure in the reservoir landslide, exhibits a unique evolution process under the condition of reservoir operation. Its long term stability is directly related to the success of landslide control and the safety of reservoir. Therefore, it is of great theoretical and practical significance to study the evolution mechanism and stability of the reservoir landslide-stabilizing structure system. Supported by a large in-situ testing area in the Three Gorges Reservoir Region for geo-hazard research, this project applies the multidisciplinary comprehensive research methods to study the dynamic mechanisms of reservoir landslides, identify the evolution stages and establish a geological model for the coordinated action of landslide-stabilizing structure. Rheological tests of landslide rock and soil masses are conducted under dynamic seepage pressure to study the dynamic attenuation law of rheological parameters on account of structure degradation caused by water; so that the rheological mechanism of landslide rock and soil masses can be revealed. Based on the dynamic response of loads on stabilizing structures, the stress field, strain field and seepage field of landslide-stabilizing structure system and their interactions under reservoir operation are studied, as well as the characteristics of structure stress and resistance with time, so that a coordinated action model of the landslide-stabilizing structure system can be established and the evolution mechanism of reservoir landslide-stabilizing structure system is revealed. The evaluation method for the dynamic stability of reservoir landslide-stabilizing structure system is also put forward and the multi-parameter stability criterion with time is determined. Finally, the optimum structural design method for stabilizing structures considering water-induced degradation and rheological characteristics is proposed, providing theoretical references for the control of reservoir landslides.

水库滑坡防治结构植入形成的“水库滑坡-防治结构体系”在水库运行条件下具有独特的演化规律，其长期稳定性关系到滑坡防控成败和水库安全运行，该体系演化机理与稳定性研究具有重要理论意义和应用价值。项目依托三峡库区地质灾害大型野外试验场，应用多学科综合研究方法，研究水库滑坡动力学机制，判识水库滑坡演化阶段，建立滑坡-抗滑结构协同作用地质模型；开展动态渗透压力下滑坡岩土体流变试验，研究基于水致结构劣化的流变力学参数动态衰减规律，揭示岩土体流变机理。以防治结构荷载动态响应机理为基础，研究水库运行条件下滑坡-抗滑结构体系应力场、应变场与渗流场互响应特征及抗滑结构内力、抗力时效特征，建立滑坡-抗滑结构体系协同作用变形破坏模型，揭示水库滑坡-抗滑结构体系演化机理。提出水库滑坡-抗滑结构体系动态稳定性评价方法，确定多参量时效稳定性判据；提出考虑水致劣化流变特性的抗滑结构优化设计方法，为水库滑坡防控提供理论依据。

开展水库滑坡-防治结构体系演化机理与稳定性研究对保障水库滑坡有效防治与水库安全运行具有重要理论意义和应用价值。项目在水库滑坡演化机理、岩土体劣化与流变特性，水库滑坡-防治结构体系多场演化特征与协同变形机理、动态稳定性评价方法与结构优化设计方法等方面取得如下成果：（1）研发了水库滑坡-抗滑桩体系原位试验与物理模型试验技术，揭示了库水位波动下滑坡变形特征，将水库滑坡演化划分为四个阶段；揭示了水库初次蓄水对滑坡变形影响强烈的机理，发现了滑坡明显变形后具有自适应能力。确定了滑坡不同部位在各变形阶段的主控因素，提出了水库滑坡变形失稳的两种模式。（2）揭示了滑坡滑体碎石土和滑带土结构与力学参数在库水浸泡和干湿循环作用下的劣化规律、滑坡滑床红砂岩水力耦合下的力学特性及渗流规律。基于改进的剪切参数确定方法获取了滑坡碎石土剪切强度参数；将滑坡碎石土蠕变分为三个阶段。揭示了动态渗透压作用下滑带土在应变等速阶段后出现应变跳跃加速阶段的流变特性；建立了考虑动态渗透压影响基于元件模型理论的滑床红砂岩非线性蠕变本构模型。（3）揭示了水库滑坡-抗滑桩体系多场演化特征，将体系演化过程划分为初始变形、协同变形、非协同变形和破坏四个阶段；揭示了各阶段滑坡与抗滑桩的协同作用和荷载传递机制；提出了基于协同变形的滑坡应力计算和桩身变形计算方法；提出了滑坡桩后隆起越桩-前部牵引的水库滑坡-抗滑桩体系失稳模式。（4）提出了基于不平衡推力法和等效原理的牵引式、复合式滑坡等不同演化类型滑坡-抗滑桩体系动态稳定性评价方法，并提出了不同演化模式滑坡推力计算方法和滑坡安全系数取值修正方法；提出了考虑滑坡与抗滑桩协同变形的抗滑桩参数与布设方法；提出了动水压力型滑坡智能降排水设计方法。研究成果已成功应用于三峡库区马家沟滑坡、朱家店滑坡及西南锦屏库区呷爬滑坡、澜沧江营盘滑坡等的稳定性评价与防治，具有推广应用前景。