Grain-size distribution and frictional behaviour of sediment cores from the Nice Slope

The upper shelf of the landslide-prone Ligurian Margin (Western Mediterranean Sea) off Nice well-known for the 1979 Airport Landslide is a natural laboratory to study preconditioning factors and trigger mechanisms for submarine landslides. For this study low-stress ring shear experiments have been carried out on a variety of sediments from >50 gravity cores to characterise the velocity-dependent frictional behaviour. Mean values of the peak coefficient of friction vary from 0.46 for clay-dominated samples (53 % clay, 46 % silt, 1 %) sand up to 0.76 for coarse-grained sediments (26 % clay, 57 % silt, 17 % sand). The majority of the sediments tested show velocity strengthening regardless of the grain size distribution. For clayey sediments the peak and residual cohesive strength increases with increasing normal stress, with values from 1.3 to 10.6 kPa and up to 25 % of all strength supported by cohesive forces in the shallowmost samples. […]

位于尼斯附近、以1979年机场滑坡事件而闻名的地中海西部（利古里亚边缘）的易发滑坡的上层区域，是一个研究海底滑坡预置因素和触发机制的自然实验室。为了进行此项研究，对来自超过50个重力柱状样品的各种沉积物进行了低应力环剪实验，以表征其速度依赖性摩擦行为。峰值摩擦系数的平均值从以粘土为主的样品的0.46（粘土53%，粉砂46%，砂1%）上升至粗颗粒沉积物的0.76（粘土26%，粉砂57%，砂17%）。大多数测试的沉积物无论其颗粒大小分布如何，均表现出速度强化现象。对于粘土质沉积物，峰值和残余的粘聚力随着法向应力的增加而增加，数值从1.3至10.6千帕，并在最浅层样品中高达全部强度支持的25%。