Climatological influences of deep seated translational landslides in residual clay shale bedrock

缓慢移动的山体滑坡对公路和铁路等高价值基础设施构成巨大的经济风险。两个具体的例子包括加拿大西部的战略运输走廊，如萨斯喀彻温省的耶洛黑德高速公路和不列颠哥伦比亚省（BC）的汤普森河谷铁路走廊。这些地点正在进行的移动造成了维护费用增加的风险，以及与斜坡移动后基础设施关闭有关的经济损失。这项拟议的研究将探讨与这些滑坡相关的两个关键故障机制的相互作用：预剪切基岩的行为和气象效应对延迟故障的影响，导致渐进软化。 在半干旱气候下，孔隙压力动态变化幅度很大，向深层地下水系统的净渗透率出现季节性或年际波动。这些孔隙压力动力学的破坏面的发展的影响还没有很好地了解大型，深层次的平移滑坡。这些气候驱动的孔隙压力动态往往是复杂的水位波动深切的河谷沿着的交通基础设施建设。这些循环孔隙水压力可导致应变软化，导致边坡的渐进位移。尽管当水位升高时，边坡附近的河流水位可以提供稳定的超载力，但它也会导致边坡内的孔隙压力增加，其消散速度比洪峰事件后河流水位的后续下降更慢。拟议的研究将结合现场测试和监测，实验室测试和数值模拟，旨在表征萨斯喀彻温省中部和不列颠哥伦比亚省中部非常缓慢移动的山体滑坡的地面运动。当局会在斜坡内安装仪器，以补充现有的监察工作。概念（定性）和数值（定量）建模将用于演示孔隙压力动态和河流侵蚀之间的联系，应变的演变和滑坡体的稳定性变化。

Slow-moving landslides present large economic risks to high-value infrastructure such as roadways and railways. Two specific examples include strategic Western Canadian transportation corridors such as the Yellowhead Highway in Saskatchewan and the Thompson River Valley rail corridor in British Columbia (BC). Ongoing movements at these locations are creating risks in terms of increased maintenance costs, and economic losses associated with infrastructure closure following slope movement. This proposed research will explore the interactions of two key failure mechanisms associated with these landslides: the behaviour of pre-sheared bedrock and the influence of meteorological effects on delayed failure resulting from progressive softening. Semi-arid climates are subject to wide swings in pore-pressure dynamics and produce seasonal or inter-annual pulses in the rates of net percolation into deeper groundwater systems. The impact of these pore-pressure dynamics on the development of failure surfaces is not well understood for large, deep-seated translational landslides. These climate-driven pore-pressure dynamics are often compounded by fluctuations of the water levels in deeply incised river valleys along which transportation infrastructure is constructed. These cyclic pore-water pressures can result in strain softening, leading to progressive displacement of the slope. Although the river level adjacent to the slope can provide a stabilizing surcharge force when the water level is elevated, it can also result in pore pressure build up within the slope, which dissipates more slowly than the subsequent drop in river levels following peak flood events. The proposed research will incorporate a combination of field testing and monitoring, laboratory testing, and numerical modelling designed to characterize the ground movement of very slow-moving landslides in central Saskatchewan and central BC. Instrumentation will be installed within the slopes to supplement existing monitoring. Conceptual (qualitative) and numerical (quantitative) modelling will be used to demonstrate the linkages between pore-pressure dynamics and river erosion on the evolution of strain and changes in the stability of the slide mass.