Defense structures in avalanche starting zones - SLF

4 > Overview of snow pressure effects 45
4 > Overview of snow pressure effects
4.1 General
This section provides only a general overview of the forces arising. Dimensioning of
the structures is covered in Section 5. In general, the snow pressure in a plane perpendicular
to the slope, is attributable to the pressure arising from local retardation of the
> creep movement (creep pressure) and, where present,
> glide movement (glide pressure).
4.2 Pressure component in the line of slope
The component of creep and glide pressure in the line of slope on a rigid supporting
surface lying normal to the slope and of infinite length in the contour line amounts to
2
H
S'N
= ρ ⋅ g⋅
⋅K
⋅N
[kN/m'] (11)
2
S'N snow pressure component in the line of slope per meter run of the supporting
surface along the contour line [kN/m']
ρ average density of the snow cover (dependent on altitude and slope exposure)
[t/m³]
g gravitational acceleration (=10 m/s²)
H vertical snow height [m]
K creep factor (dependent on the slope inclination ψ and the density ρ given in
Tab. 6)
N glide factor as given in Section 3.10.5
The values given in Tab. 6 multiplied by sin2ψ give the approximate K values at the
densities stated.
In general, S'N is assumed to be uniformly distributed over the height (simplification of
the complex pressure distribution present both in homogeneous and non-homogeneous
snow cover).
Tab. 6 > Creep factor K as a function of average snow density (ρ) and slope inclination (ψ).
ρ [t/m³] 0.2 0.30 0.40 0.50 0.60
K/sin2ψ 0.7 0.76 0.83 0.92 1.05