Snowpack

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Fracture Characteristics

Fracture Character

Progressive Compression


Resistant Planer


Sudden Planar


Sudden Collapse


Non-Planar Break

Code

PC


RP


SP


SC


R

Fracture Characteristic

Fracture usually crosses column with one loading step, followed by gradual compression of the layer with subsequent loading steps.

Planar or mostly planar fracture that requires more than one loading step to cross column and/or black does not slide easily* on weak layer.

Planar fracture suddenly crosses column with one loading step and the block slides easily* on weak layers.

Fracture suddenly crosses column with one loading step and causes noticeable slope normal displacement.

Irregular fracture surface.

Concern?

No


No


Yes


Yes


No

* Block slides off column on steep slopes. On low angles slopes, hold sides of block and note resistance to sliding by gently pulling.

Additional Resources

• Fracture Characteristics in Compression Tests by Alec van Herwijnen and Bruce Jamieson
• Interpreting Fracture Character in Stability Tests by Alec van Herwijnen and Bruce Jamieson

• VIDEO: Fracture Character in Compression Tests by Bruce Jamieson

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Persistent Weak Layers

• A Winter of Learning: Blog post from February 5, 2014