Low- to high-velocity frictional properties of the clay-rich gouges from the slipping zone of the 1963 Vaiont slide, northern Italy
Low- to high-velocity frictional properties of the clay-rich gouges from the slipping zone of the 1963 Vaiont slide, northern Italy
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DOI：
10.1029/2011jb008338
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发表时间：
2011-09
影响因子：
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通讯作者：
F. Ferri;G. Toro;T. Hirose;R. Han;H. Noda;T. Shimamoto;M. Quaresimin;N. D. Rossi
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文献类型：
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作者：
F. Ferri;G. Toro;T. Hirose;R. Han;H. Noda;T. Shimamoto;M. Quaresimin;N. D. Rossi
在1963年Vaiont滑坡（意大利）以约30 m/s的速度最终滑动约450 m之前，有>3年的蠕变阶段，该阶段位于厘米厚的粘土富集层（60-70%蒙脱石，20-30%方解石和石英）中。在这里，我们研究了富含粘土层在类似于滑坡期间的变形条件下的摩擦特性：1-5 MPa的正应力，2 × 10^（-7）至1.31 m/s的滑动速率和高达34 m的位移。实验在室内湿度和潮湿条件下进行双轴，扭转和旋转剪切装置。在室内湿度和潮湿条件下，富含粘土的断层泥与速度无关，而与速度减弱无关。在室内湿度实验中，摩擦系数从0.47在v 0.70米/秒：充分润滑的结果，从形成连续的水膜在凿井。Vaiont滑坡发生在湿饱和条件下。滑坡的不稳定行为是由Vaiont粘土丰富的泥的速度弱化行为解释。在滑动区形成连续的液态水膜使摩擦系数降低到几乎为零，即使没有引起热加压的激活。这就解释了在最后的坍缩过程中，滑动所达到的极高速度。
The final slip of about 450 m at about 30 m/s of the 1963 Vaiont landslide (Italy) was preceded by >3 year long creeping phase which was localized in centimeter-thick clay-rich layers (60–70% smectites, 20–30% calcite and quartz). Here we investigate the frictional properties of the clay-rich layers under similar deformation conditions as during the landslide: 1–5 MPa normal stress, 2 × 10^(−7) to 1.31 m/s slip rate and displacements up to 34 m. Experiments were performed at room humidity and wet conditions with biaxial, torsion and rotary shear apparatus. The clay-rich gouge was velocity-independent to velocity-weakening in both room humidity and wet conditions. In room humidity experiments, the coefficient of friction decreased from 0.47 at v 0.70 m/s: full lubrication results from the formation of a continuous water film in the gouge. The Vaiont landslide occurred under wet to saturated conditions. The unstable behavior of the landslide is explained by the velocity-weakening behavior of the Vaiont clay-rich gouges. The formation of a continuous film of liquid water in the slipping zone reduced the coefficient of friction to almost zero, even without invoking the activation of thermal pressurization. This explains the extraordinary high velocity achieved by the slide during the final collapse.