ERI: Identifying Seismically-induced Failure Mechanisms in Homogenous Rock Slopes

该工程研究启动奖(ERI)支持旨在解释均质岩坡在地震期间的基本行为的研究。在本研究中，均质指的是没有明确定义的预先存在的不连续面的岩体建模。该研究将探讨岩石边坡内部裂隙的萌生和扩展，以及地震和边坡特征对破坏机制的控制作用。识别导致破裂的动应力将增强我们对地震波如何与斜坡几何形状相互作用从而在岩体中诱发破裂的知识。这项工作将通过量化与不同破坏机制相关的触发阈值，使人们能够对地震期间导致岩石边坡破坏的因素有一个新的理解。这一认识将提高工程师在有岩质斜坡的地震危险区进行区域性危险分析的能力。区域灾害分析可以通过使设计者和政策制定者能够就与这一现象相关的灾害风险和缓解做出数据知情的决策，从而拯救生命并保护关键的基础设施经济投资，从而改善人口稠密地区危险岩坡的个人安全和福祉。这项研究的目的是确定导致均质岩质边坡起始和破坏的动应力状态特征，确定导致这些临界应力状态的地面运动特征、岩体特性和边坡几何形状的组合，并开发和测试预测同震岩质边坡性能的预测框架。岩石边坡的动态应力状态、裂缝的萌生、扩展和合并将使用称为粘结颗粒模型的离散元方法的子集来模拟。结合粒子模型的动态实现可以捕捉波在边界上的传输、反射和吸收。这项研究将通过校准软化键模型来扩展以前的动态结合粒子模型的能力，该模型捕获了用于动态模拟的广泛范围的脆性比。对导致完整岩体边坡破坏的动应力状态特征和随后的边坡性能进行系统研究，以开发预测框架。该框架预测真实世界同震岩坡性能的能力将通过与记录良好的岩坡破坏案例进行比较来评估。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This Engineering Research Initiation (ERI) award supports research aiming to explain the fundamental behavior of homogenous rock slopes during earthquakes. In this study, homogenous refers to modeling of the rock mass without explicitly defined pre-existing discontinuities. The study will investigate the initiation and growth of fractures within the rock slope and earthquake and slope characteristics controlling the failure mechanisms. Identifying the dynamic stresses that lead to failure initiation will enhance our knowledge of how seismic waves interact with slope geometries to induce rupture in the rock mass. This work will enable a new understanding of the factors contributing to rock slope failures during earthquakes by quantifying the triggering thresholds associated with different failure mechanisms. This understanding will enhance engineers' ability to perform regional-scale hazard analysis in seismic hazard areas with rock slopes. Regional hazard analysis can improve the safety and well-being of individuals in populated areas with hazardous rock slopes by enabling designers and policy-makers to make data-informed decisions about hazard risk and mitigation associated with this phenomenon, thus saving lives and preserving critical infrastructure economic investments. The research in this study will be complemented by developing outreach materials focused on engaging middle and high school students in civil engineering.The goals of this study are to identify the dynamic stress state characteristics leading to the initiation and failure of homogeneous rock slopes, identify the combinations of ground motion characteristics, rock mass properties, and slope geometries that lead to those critical stress states, and develop and test a predictive framework for predicting co-seismic rock slope performance. Rock slope dynamic stress states, fracture initiation, propagation, and coalescence will be modeled using a subset of the discrete element method called the bonded particle model. The dynamic implementation of the bonded particle model can capture wave transmission, reflection, and absorption at boundaries. The study will extend previous dynamic bonded particle model capabilities by calibrating the softening bond model, which captures a broad range of brittleness ratios for dynamic simulation. A systematic study of the dynamic stress state characteristics leading to initiation of failure of intact rock mass slopes and subsequent slope performance will be used to develop the predictive framework. The ability of the framework to predict real-world coseismic rock slope performance will be evaluated through comparison to well-documented case histories of rock slope failures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.