Slab avalanche measurements

1977 ◽  
Vol 14 (2) ◽  
pp. 206-213 ◽  
Author(s):  
R. Perla
Keyword(s):  
Shear Strength ◽  
Statistical Analysis ◽  
Failure Stress ◽  
In Situ Measurement ◽  
Failure Plane ◽  
Unresolved Problem ◽  
Shear Frame ◽  
Frame Device

From a study of 205 slab avalanches it is concluded that failure initiates where the slope is 25° or steeper, that slab failure stress is in the range 102–104 N/m2, and that the slab failure plane is most commonly at a temperature of −5 °C or warmer.The in situ measurement of shear strength is still an unresolved problem. A statistical analysis of a shear-frame device shows that the device is sensitive to the rate of pull and to the frame area. The larger the frame area, the smaller the measured shear strength. Approximately 10 measurements are required to sample a mean shear strength of a slab failure plane to within 15% accuracy at 90% confidence.

scholarly journals Experience with Shear Frames

1983 ◽  
Vol 29 (103) ◽  
pp. 485-491 ◽  
Author(s):  
R. Perla ◽  
T. M. H. Beck
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Normal Stress ◽  
Shear Failure ◽  
Statistical Data ◽  
Failure Plane ◽  
Shear Frame ◽  
Strength Distributions

AbstractThe shear frame is a simple in situ device for indexing the shear strength of thin weak layers. The index is sensitive to shear-frame geometry, rate-of-pull, and shear-frame mass. It is time-consuming to carefully align the device on the Gleitschicht (shear failure plane) in a slab avalanche zone. The ratio shear frame index/shear stress of the Gleitschicht has a high variance, and may not be a fundamental measure of slab avalanche stability. Corrections for the normal stress on the Gleitschicht reduce the variance only slightly. Despite these limitations, the shear frame is a useful tool for gathering statistical data on strength distributions and anisotropies of the Gleitschicht until a more fundamental technique is developed.

scholarly journals Experience with Shear Frames

1983 ◽  
Vol 29 (103) ◽  
pp. 485-491 ◽  
Author(s):  
R. Perla ◽  
T. M. H. Beck
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Normal Stress ◽  
Shear Failure ◽  
Statistical Data ◽  
Failure Plane ◽  
Shear Frame ◽  
Strength Distributions

AbstractThe shear frame is a simplein situdevice for indexing the shear strength of thin weak layers. The index is sensitive to shear-frame geometry, rate-of-pull, and shear-frame mass. It is time-consuming to carefully align the device on theGleitschicht(shear failure plane) in a slab avalanche zone. The ratioshear frame index/shear stressof theGleitschichthas a high variance, and may not be a fundamental measure of slab avalanche stability. Corrections for the normal stress on theGleitschichtreduce the variance only slightly. Despite these limitations, the shear frame is a useful tool for gathering statistical data on strength distributions and anisotropies of theGleitschichtuntil a more fundamental technique is developed.

scholarly journals Short Note on Slab-Avalanche Measurements

1978 ◽  
Vol 20 (82) ◽  
pp. 221-222
Author(s):  
R. Perla
Keyword(s):  
Shear Strength ◽  
Short Note ◽  
Failure Stress ◽  
Failure Plane

AbstractFrom a study of 205 slab avalanches it is concluded that failure initiates where the slope is 25° or steeper, that slab failure stress is in the range 102N m-2 to 104N m-2, and that the slab failure plane is most commonly at a temperature of -5°C or warmer. The study also indicates that the shear strength of weak layers varies approximately as the square of the density.

scholarly journals Short Note on Slab-Avalanche Measurements

1978 ◽  
Vol 20 (82) ◽  
pp. 221-222
Author(s):  
R. Perla
Keyword(s):  
Shear Strength ◽  
Short Note ◽  
Failure Stress ◽  
Failure Plane

Abstract From a study of 205 slab avalanches it is concluded that failure initiates where the slope is 25° or steeper, that slab failure stress is in the range 102N m-2 to 104N m-2, and that the slab failure plane is most commonly at a temperature of -5°C or warmer. The study also indicates that the shear strength of weak layers varies approximately as the square of the density.

Sign in / Sign up

Export Citation Format

Share Document