Water and Slope Stability
Adding more of this to a slope increases its load and stress, making the slope more unstable.
What is water?
This slow-moving type of mass wasting is most often caused by freeze-thaw cycles and is typically only noticeable on the surface.
What is creep?
This national park has experienced a significant increase in rockfall activity in the last few decades, with over 40 recorded incidents.
What is Yosemite National Park?
When assessing potential slope failure, past landslides can often be identified by this type of feature.
What is a landslide scarp?
This type of vegetation helps to stabilize slopes by binding the regolith and reducing erosion.
What is rooted vegetation?
This phenomenon occurs when water in cracks expands, forcing rocks apart and weakening them.
What is frost wedging?
In this type of mass wasting, material falls freely after undercutting or failure, often resulting in piles of rubble at the base.
What is a rockfall?
This area in Yosemite has had 20 structures hit by boulders since 1999.
What is Camp Curry?
A sign that a slope might be unstable, this phenomenon can involve cracks or bulging ground on the surface.
What is cracked or bulging ground?
Avoiding this common practice helps prevent slopes from becoming overly steep and prone to failure.
What is oversteepening slopes?
This term refers to the angle at which dry, loose, granular material is stable before it begins to fail.
What is the angle of repose?
This involves the rapid movement of a debris mass, often containing rocks and soil, down a defined surface.
What is a debris slide?
The 1996 Happy Isles Rock Fall occurred in Yosemite and saw rocks fall at speeds of up to 260 miles per hour.
What is Happy Isles?
These are the changes that could indicate instability, such as shifting ground features or changes in vegetation.
What are measurable changes in surveyed land features?
This engineering technique involves adding structures like walls or blocks to stabilize slopes and prevent movement.
What is a retaining wall?
Adding too much water to loose granular material results in this failure, in which grains lose contact with each other.
What is a flow or mass wasting failure?
These slides involve intact material moving downslope along a slip plane, with no rotation.
What is a rock slide?
This disaster in 1928 killed 431 people due to a landslide that occurred at the base of a dam.
What was the St. Francis Dam Failure?
This is the process of observing changes in the ground or materials that could indicate a slope's likelihood of failure.
What is geologic mapping?
This bio-engineering technique involves planting vegetation to help remove water and anchor soil, reducing the risk of mass wasting.
What is revegetation?
This condition, caused by the infiltration of water, decreases the cohesion of material and can lead to mass wasting events.
What is saturation?
This type of flow involves rapid movement of larger particles, including boulders, and occurs on steep slopes.
What is a debris flow?
This 1999 tragedy in Venezuela was caused by debris flows after 36 inches of rain, burying towns and causing massive destruction.
What is the Vargas Tragedy?
When assessing slope failure potential, one of the things to look for is these changes in the physical slope or material.
What are conditions of material?
This method involves limiting the water within a slope through systems like drainage to prevent saturation and reduce risk.
What is dewatering?