地震作用下反倾岩质边坡破坏全过程的机制研究

For the whole failure process of anti-dip rock slopes subjected to seismic loads, the problem of 'the failure modes and their criterion of anti-dip rock slopes subjected to seismic loads' and 'the dynamic collapse failure mechanism of anti-dip rock slopes' will be investigated in this fund by laboratory tests and numerical simulation. In the shaking table model test, the thresholding method and image processing technique will be introduced to capture the real-time displacement vector diagram of rock slopes, and the variation law of displacement and stress field is studied to reveal the deformation mechanism of the whole failure process of anti-dip rock slopes subjected to seismic loads. In addition, according to the variation law of displacement and stress fields of rock slopes, the failure modes of anti-dip rock slopes will be classified and the typical eigenvalues of the different failure modes will be determined. Moreover, the dynamic- large deformation- friction coupling numerical method will be proposed to simulate the whole failure process of anti-dip rock slopes subjected to seismic loads. Then, the effects of some factors including slope height, slope angle, strata inclination, thickness of stratum on the location of fracture plane and the stability of anti-dip rock slopes subjected to seismic loads will be investigated using the proposed numerical method. The nonlinear dynamic response and dynamic collapse failure mechanism of anti-dip rock slopes subjected to seismic loads will be revealed. The failure criterion of anti-dip rock slopes subjected to seismic loads will be proposed. In all, it can be expected that from this study a scientific guide would be provided for the seismic design and the reinforcement measure of anti-dip rock slopes.

本项目以地震作用下反倾岩质边坡破坏问题为工程背景，采用室内试验和数值模拟相结合的研究方法，围绕“地震作用下反倾岩质边坡破坏模式及其判据”和“反倾边坡岩体动力灾变失效机制”等问题开展研究。在振动台相似模型试验中采用阈值分割法和图像处理技术获得岩质边坡的实时位移矢量图，研究其位移场和应力场的变化规律，揭示地震作用下反倾岩质边坡的变形机制。此外，根据反倾岩质边坡位移场和应力场的变化特点，对地震作用下反倾岩质边坡的破坏模式进行类别划分，并确定不同破坏模式的典型特征值。提出模拟地震作用下反倾岩质边坡破坏全过程的动力-大变形-摩擦接触耦合数值分析方法，研究地震作用下坡高、坡角、岩层倾角和岩层厚度对破裂面位置和稳定性的影响，揭示地震作用下反倾岩质边坡的非线性动力响应规律和动力灾变失效机制，确定地震作用下反倾岩质边坡破坏模式的判据。该项目的研究成果将为反倾岩质边坡工程的抗震设计和加固措施提供理论支持。

本项目以地震作用下反倾岩质边坡破坏问题为工程背景，采用室内试验、理论推导和数值模拟相结合的研究方法，围绕“地震作用下反倾岩质边坡破坏模式及其判据”和“反倾边坡岩体动力灾变失效机制”等问题开展了研究。采用室内相似模型试验，基于阈值分割法和图像处理技术获得了岩质边坡的实时位移矢量图和位移云图，研究了位移场和应力场的变化规律，揭示了地震/外部荷载作用下反倾岩质边坡的变形机制；根据相似模型试验中反倾岩质边坡位移场和应力场的变化特点，对地震/外部荷载作用下反倾岩质边坡的破坏模式进行了类别划分，并确定了不同破坏模式的典型特征值；此外，以扩展有限单元法为基础，植入Newmark隐式时间积分方案处理时程较长的动力响应问题，基于罚函数法引入了修正的库伦摩擦模型作为裂隙表面的摩擦接触本构，在完全拉格朗日格式的框架下建立了动力-大变形-摩擦接触耦合的非线性数值方法，编制了计算机程序，能够很好地模拟地震/外部荷载作用下反倾岩质边坡的破坏全过程；最后，采用区域分解和区域匹配的方法，将整体研究区域分解成不同的子区域，分别构造平面SH波激励作用下，符合子区域应力和位移边界条件的波函数级数解。引入了适合边坡模型的分数阶贝塞尔函数的Graf加法准则，以实现局部坐标系到全局坐标系的波函数坐标转换。利用虚拟边界上的应力连续条件和位移连续条件，求解了子区域波场位移函数中的待定系数，得到了相应的子区域波场位移函数解。基于此项目的研究，揭示了地震作用下反倾岩质边坡的非线性动力响应规律和动力灾变失效机制，确定了地震作用下反倾岩质边坡破坏模式的判据。该项目的研究成果能够为反倾岩质边坡工程的抗震设计和加固措施提供理论支持。