土石混合体的宏细观动力特性及其边坡的地震失稳渐进破坏研究

Soil-rock-mixture slopes are widely existed in southwest China, where the earthquakes are frequently and intensively occurred. The soil-rock-mixture slope failures triggered by the earthquakes are significant potential safety hazard. However, the dynamic characteristics of soil-rock-mixture and the seismic progressive failure of its slope remain to be investigated. This project consider soil-rock-mixture with different rock block content as the research object. First, the dynamic triaxial tests will be conducted to study the quantitative relationship between dynamic properties of soil-rock-mixture (e.g., dynamic shear modulus, damping ratio and dynamic strength, etc.) and rock block content. After that, discrete element method for fine numerical assemblies will be modelled based on particle scanning, and numerical tests will then be carried out. The relationship between macro-dynamic properties and micro-structure characteristics will be explored, aiming at reveal the microscopic mechanism that how rock block content influences dynamic properties. Lastly, shaking table model tests will be performed, and the particle image velocimetry (PIV) measuring technique will be employed to clarify the seismic progressive failure process of soil-rock-mixture slopes. Furthermore, numerical simulations will be accomplished to reveal the microscopic failure mechanism of slope failure. The expected research findings of this project will not only lay a foundation for geomechanics theory that could apply to the soil-rock-mixture, but also provide a scientific basis for reasonable evaluation of the seismic stability and landslide prediction of soil-rock-mixture slopes in practical engineering.

土石混合体边坡在我国西南地区分布广泛，该地区地震频繁且强度较大，地震诱发土石混合体边坡破坏是重大的安全隐患。目前对土石混合体的动力特性及其边坡的地震失稳渐进破坏过程和破坏机理有待探明。本项目拟以不同含石量的土石混合体为研究对象，首先基于室内动三轴试验建立土石混合体的动剪切模量、阻尼比和动强度等动力特性指标与含石量间的定量关系；其次通过颗粒扫描构建精细化土石混合体的离散元数值模型，采用数值试验探究土石混合体动力特性指标与细观结构特征间的联系，揭示含石量影响动力特性的细观机理；最后通过振动台模型试验，采用PIV(particle image velocimetry)测量技术阐明土石混合体边坡的地震失稳渐进破坏过程，结合数值模拟揭示边坡破坏的细观机制。预期研究成果不仅为建立适用于土石混合体的岩土力学理论奠定基础，而且在实际工程中为合理评估土石混合体边坡在地震作用下的稳定性和滑坡预测提供科学依据。

地震触发的土石混合体边坡导致的重大灾难事件在我国西南山区时常发生。目前对土石混合体的动力特性及其边坡的地震失稳渐进破坏过程有待探明。针对该问题，本项目首先对不同含石量土石混合体进行动三轴试验，探明了不同含石量土石混合体的动力特性。其次基于颗粒扫描，提出了颗粒形状指标的量化标准。然后采用扫描颗粒构建了精细化离散元数值模型，研究了颗粒形状和含石量对土石混合体的宏观力学特性和相应细观机理。最后通过振动台模型试验，采用PIV(particle image velocimetry)测量技术阐明土石混合体边坡的地震失稳渐进破坏过程。研究成果为建立适用于土石混合体的岩土力学理论奠定基础，且为实际工程中为合理评估土石混合体边坡在地震作用下的稳定性和滑坡预测提供科学依据。