Although catastrophic debris flow-slides from anthropogenic fill slopes are common, their failure mechanisms during both earthquakes and extreme rainfall events remains under-studied. We have used a suite of tests using a dynamic back-pressured shear box on fill materials with varying grain size characteristics and stress histories to explore their potential failure mechanisms in response to seismic loading and elevated pore water pressures. Our experiments demonstrate that whilst looser coarse-grained fills display a ductile style of deformation in response to elevated pore water pressures, denser fine-grained fills display a brittle style of deformation and require higher levels of pore water pressure to initiate failure. Dynamic loading of these fills did not generate significant excess pore water pressures or liquefaction but instead resulted in densification and seismic compression. This process of densification made these fills more prone to brittle failure in response to subsequent elevation of pore water pressures. Our results show that grain size characteristics and stress history (density) significantly impact fill slope failure mechanisms and indicate that, although in some instances, fill slopes may be strengthened by earthquake shaking, seismic compression often results in significant deformation, resulting in tension crack formation, severing of services and the development of new pore fluid pathways. This may allow high pore water pressure to develop in the slope in future rainstorms, which would increase their vulnerability to rapid debris flow-slides. The results provide new insights into the styles of failure that may be anticipated from different fill slopes and the hazards they may pose. These findings may help to inform future long-term management practices for engineered fill slopes in dynamic environments.

尽管来自人为填土斜坡的灾难性泥石流滑移很常见，但在地震和极端降雨事件中它们的破坏机理仍未得到充分研究。我们对动态变化的背压剪切箱进行了一系列测试，这些动箱对具有不同晶粒尺寸特征和应力历史的填充材料进行了研究，以探讨其潜在的破坏机制，以应对地震载荷和孔隙水压力升高的情况。我们的实验表明，虽然较松的粗粒填充物表现出对孔隙水压力升高的韧性变形，而较密实的细粒填充物表现出脆性的变形形式，并且需要较高水平的孔隙水压力才能引发破坏。这些填充物的动态加载不会产生明显的孔隙水压力或液化现象，而是会导致致密化和地震压缩。这种致密化过程使这些填充物更容易发生脆性破坏，以响应随后孔隙水压力的升高。我们的结果表明，晶粒尺寸特征和应力历程（密度）显着影响填充边坡破坏机理，并表明，尽管在某些情况下，填充边坡可能会因地震震动而加强，但地震压缩通常会导致明显的变形，从而导致张裂裂缝的形成。 ，切断服务和开发新的孔隙流体途径。在未来的暴风雨中，这可能会在斜坡上形成高孔隙水压力，这将增加他们对快速泥石流滑道的脆弱性。结果为从不同的填充坡度及其可能带来的危害中可以预期的破坏方式提供了新的见解。这些发现可能有助于为动态环境中工程填充坡度的未来长期管理实践提供信息。