Q-slope

Q-slope utilizes similar parameters to the Q-system[4] which has been used for over 40 years in the design of ground support for tunnels and underground excavations.

However, the frictional resistance pair Jr and Ja can apply, when needed, to individual sides of a potentially unstable wedges.

The Q-system term Jw is replaced with Jwice, and takes into account a wider range of environmental conditions appropriate to rock slopes, which are exposed to the environment indefinitely.

The conditions include the extremes of erosive intense rainfall, ice wedging, as may seasonally occur at opposite ends of the rock-type and regional spectrum.

A simple formula for the steepest slope angle (β), in degrees, not requiring reinforcement or support is given by:

[1][2][3][5] Q-slope has also been applied in slopes with interbedded strata,[6] in faulted rocks and fault zones,[7] and in alpine and Arctic environments, which are susceptible to freeze-thaw and ice wedging.

[8] Rock slope design techniques have been derived using Q-slope and geophysical survey data, primarily based on Vp (P-wave velocity).

[10] Q-slope is not intended as a substitute for conventional and more detailed slope stability analyses, where these are warranted.

Q-slope has been correlated with other rock mass classifications including BQ,[11] RHRS,[12] and SMR.