水库运行条件下滑坡岩土体流变特性对抗滑工程效果影响研究

Rheological properties of rock and soil under dynamic seepage pressure are crucial in the analysis of long-term stability of landslide anti-sliding engineering. These rheological properties are not considered in current design of landslide anti-sliding engineering. Therefore, it is urgent to carry out research on influence of rheological properties on landslide control effect under reservoir water fluctuation. Research is conducted by taking the typical landslide anti-sliding engineering in Three Gorges Reservoir as example. Engineering geological conditions of this landslide should be first investigated. The mechanical charateristics test for unsaturated soils are done to determine the mechanical properties of unsaturated soils. the rheological tests of the sliding zone soil,sliding body gravel soil, and rockmass fixing of anti-sliding piles under dynamic seepage pressure are done, the the rheological charateristics and mechinism of rocks and soils are examined to obtain their rheological constitutive model and long-term strength. The numerical simulation based on unsaturated seepage theory, physical model test and in-situ monitoring methods shall be used in theis research. Firstly, the comback analysis is used to determine parameters of the landslide and anti-sliding structure. Then, the deformation & failure rule and stability of landslide anti-sliding engineering system under reservoir operating condition are summarized regardless of rheology. Based on rheology theory, the nonlinear time effect on deformation and failure of this system and its long-term stability are investigated, and the internal force and the long-term strength of the landslide anti-sliding structure system are studied. Based on the above research, the effect of rheological properties of rock and soil on the internal force and the long-term stability of this system are analyzed. This research aims to evaluate the effect of rheological properties on anti-sliding engineering, and present correction method of the safety coefficient in anti-sliding pile design by considering rheological influences. The research achievement could be benefit for landslide-anti-sliding pile design in reservoir area.

动态渗透压力下滑坡岩土体流变性质影响抗滑工程的长期稳定，目前滑坡治理设计未考虑岩土体流变特性，急需开展水库运行条件下岩土体流变性质对滑坡治理效果影响的研究。选择三峡库区典型滑坡－抗滑工程,查明工程地质条件，进行非饱和土性质试验，研究非饱和土力学特性；开展动态渗透压力下滑带土、抗滑桩嵌固段岩石及滑体碎石土流变试验，研究岩土体流变机理，确定流变本构及长期强度。采用基于非饱和理论数值模拟、物理模型试验与现场监测相结合的方法，进行滑坡与防治结构参数智能反演；模拟分析不考虑流变时水库滑坡-抗滑结构体系变形破坏规律及稳定性；基于流变理论，模拟分析水库滑坡-抗滑结构体系非线性变形破坏时效规律及长期稳定性，研究抗滑结构体系内力及长期强度变化规律；分析岩土体流变特性对滑坡-防治结构体系内力及长期稳定性的影响，评价其对抗滑工程效果影响；提出考虑流变影响的抗滑桩设计安全系数修正方法，为库区滑坡治理设计提供依据。

本研究以我国长江三峡库区典型滑坡为例，研究典型滑坡岩土体流变特性和非饱和强度性质，建立了滑坡岩土体流变本构模型，确定了流变强度参数和非饱和土剪切强度参数；研发了水库运行条件下滑坡-防治结构大型物理模型试验技术，构建了滑坡-防治结构野外多场信息监测平台，揭示了水库运行条件下滑坡-防治结构变形破坏规律，提出了水库运行条件下滑坡-防治结构体系稳定性评价方法；基于流变理论，模拟分析滑坡-抗滑结构体系非线性变形破坏时效规律及长期稳定性，提出了抗滑桩受荷段土压力和嵌固段岩体抗力分布的概化模型，总结了滑坡-抗滑结构体系结构内力及长期强度变化规律，提出了考虑岩土体流变特性的强度折减法评价滑坡-抗滑桩体系长期稳定性评价方法；采用模型试验和数值模拟方法，分析了滑床岩体结构特征对抗滑桩嵌固段受力特征和变形规律的影响，提出了考虑嵌固段岩体结构特征的抗滑效果评价方法；基于抗滑桩与滑坡体相互作用过程模型，建立了基于抗滑桩与滑坡体相互作用过程的桩间距计算模型，提出了合理桩间距确定方法和滑坡三维空间形态的抗滑桩平面布设方法。研究成果不仅可为三峡库区地质灾害防治工程优化设计提供依据，也可为水库滑坡防治设计工作提供科学依据。