高填方边坡地震失稳机制与稳定性研究

China is a mountainous and earthquake-prone country. A large number of high fill slopes emerge due to the infrastructure construction in mountainous area, and the frequent occurrence of strong earthquake brings a serious threat to the stability of high fill slopes and safety of infrastructures. The wave propagation of stress in slope and cyclic softening of soil induced by earthquake lead to local tension and shear failure of soil, which dynamically extends to form penetrated sliding surfaces, and trigger slope failure and landslide. Firstly, the cyclic softening law of soil and sliding surface under seismic load will be studied by laboratory test, and the rules for the production and extension of sliding surface will be proposed. the constitutive model of soil basing on continuous deformation and the constitutive model of sliding surface basing on discontinuous deformation will be consequently developed, respectively. On this basis, the dynamic finite element method with continuous and discontinuous deformation analysis, as well as the corresponding algorithm for solving dynamic response, will be put forward to simulate the production and extension process of sliding surfaces. And the numerical analysis platform for slope seismic response can then be setup. By numerical simulation and high gravity centrifuge test, the process of slope failure and landslide will be reemerged to reveal the seismic response dynamic characters and landslide modes of high fill slopes along with the corresponding trigger mechanism, and evaluate the effects of slope structure types, time and frequency domain properties of seismic wave on the seismic stability of slope. Finally, a new analysis method basing on continuous and discontinuous deformation analysis for factor of safety of slope seismic stability will be presented, which will provide technique support for seismic stability assessment of high fill slope.

我国是一个多山地、多地震国家，山区基础设施建设形成大量高填方边坡，不断发生的强烈地震严重威胁边坡稳定和基础设施安全。地震引起边坡应力波动传播、土体循环软化，导致边坡局部发生张拉和剪切破坏，并扩展为拉裂缝和剪切带并存的贯通滑裂面，触发边坡失稳滑坡。本项目首先试验研究地震作用下土与滑裂面的循环软化规律，确定滑裂面产生与扩展准则，建立基于连续变形的土体本构模型和基于非连续变形的滑裂面本构模型。在此基础上，提出模拟滑裂面产生和扩展过程的连续-非连续变形动力有限元分析理论及相应的求解算法，构建边坡地震响应数值分析平台。结合数值模拟和超重力离心模型试验，再现地震作用下边坡失稳滑坡过程，揭示高填方边坡地震响应动力特征、失稳模式及其触发机制，分析边坡结构形式、地震波时频特性等对地震稳定性的影响规律。最后，基于连续-非连续变形分析，提出边坡地震稳定安全系数分析方法，为高填方边坡地震稳定性评价提供技术支撑。

我国山区基础设施建设形成大量高填方边坡，不断发生的强烈地震严重威胁边坡稳定和基础设施安全。因此，开展地震作用下的高填方边坡稳定性研究，揭示地震边坡失稳模式、触发机制及其影响显得尤为必要。本项目首先试验研究静/动力荷载下土石料的劣化机制，确定裂面产生与扩展准则，建立滑裂面本构模型；其次，改进传统数值分析方法，提出能够模拟滑裂面产生及扩展的连续-非连续数值分析理论及相应的求解算法，构建边坡地震响应数值分析平台；开展不同地震动强度、水位、反压等工况下的土石料超重力离心机模型试验；最后，结合数值模拟和超重力力学模型试验，再现了地震引发的边坡失稳滑坡过程，加深地震边坡失稳破坏机理的认识。