How does vegetation help stabilize slopes quizlet?
By absorbing the water from a rainstorm, vegetation decreases water saturation of a slope’s material that would otherwise lead to a loss of shear strength. Vegetations root system also helps stabilize a slope by binding soil particles together and holding the soil to bedrock.
What factors do engineering geologists look at when studying slope stability quizlet?
Key characteristics that influence slope stability include the slope’s materials, its steepness, its water content, and its vegetation cover.
How does the addition of water onto a steep slope affect its stability?
Adding water increases slope instability. It lubricates rock fragments so that they slide down slope more easily. Mass wasting occurs more readily in rainy seasons for this reason. It turns out that a small amount of water in the soil can aid slope stability because of increased surface tension.
What two ways does water contribute to mass wasting events quizlet?
Water can saturate sediment, reducing the integrity of the slope and allowing it to move. b. Water can infiltrate sediment, partially filling the pore spaces between grains and reducing slope cohesion.
What makes a slope stable?
Slope stability is ultimately determined by two factors: the angle of the slope and the strength of the materials on it. In Figure 15.2 a block of rock situated on a rock slope is being pulled toward Earth’s centre (vertically down) by gravity.
Which of the following forces keeps materials from moving down slope?
The forces resisting movement down the slope are grouped under the term shear strength which includes frictional resistance and cohesion among the particles that make up the object.
What is the main force involved in the stability of slopes?
Slope Stability. The main force responsible for mass movement is gravity.
What factors increase slope stability?
Slope stability is ultimately determined by two factors: the angle of the slope and the strength of the materials on it.
What force causes mass movement?
Gravity is the main force responsible for mass movements. Gravity is a force that acts everywhere on the Earth’s surface, pulling everything in a direction toward the center of the Earth. On a flat surface, parallel to the Earth’s surface, the force of gravity acts downward.
What are the two forces that act on slope stability?
What factors control slope stability?
What are two opposing forces in controlling slope stability?
Definition of Factor of Safety Slope stability is controlled by 2 main factors: the driving and the resisting forces.
What causes slope stability?
Simply put, slope stability is based on the interaction of two forces: driving forces and resisting forces. Slope failures occur when driving forces overcome resisting forces. The driving force is typically gravity, and the resisting force is the slope material’s shear strength.
What are three factors affecting slope stability?
Terms in this set (3)
- adds weight.
- change angle of repose (stable angle for slope-usually stable between 35-45o)- when saturated with water reduced in eliminating grain to grain frictional contact.
- adsorption: electronially polar water molecules attach to the surface of the minerals.
- dissolve mineral cement.
What provides the forces that can cause rocks to move downhill?
Gravity can cause erosion and deposition. Gravity makes water and ice move. It also causes rock, soil, snow, or other material to move downhill in a process called mass movement.
When driving forces are greater than resisting forces slopes?
When the resisting forces are greater than the driving force (tangential component of gravity), the slope is steady and the boulder stays in place. When lubricating components reduce the resisting forces so much that the driving forces are greater than the resisting forces, slope failure occurs.
What is slope stability?
Slope stability is the process of calculating and assessing how much stress a particular slope can manage before failing. Examples of common slopes include roads for commercial use, dams, excavated slopes, and soft rock trails in reservoirs, forests, and parks.
How do you determine the stability of a slope?
Stability is determined by the balance of shear stress and shear strength. If the forces available to resist movement are greater than the forces driving movement, the slope is considered stable. A factor of safety is calculated by dividing the forces resisting movement by the forces driving movement.
Slope stability is ultimately determined by two factors: the angle of the slope and the strength of the materials on it. In Figure 15.2 a block of rock situated on a rock slope is being pulled toward Earth’s centre (vertically down) by gravity.
What is the most important factor that affects slope strength?
Apart from the type of material on a slope, the amount of water that the material contains is the most important factor controlling its strength. This is especially true for unconsolidated materials, like those shown in Figure 15.4, but it also applies to bodies of rock.
What is the strength of the materials on slopes?
The strength of the materials on slopes can vary widely. Solid rocks tend to be strong, but there is a very wide range of rock strength.
Why are the foliation and Sills parallel to the steep slope?
The foliation and the sills are parallel to the steep slope. The schist is relatively weak to begin with, and the feldspar in the sills, which has been altered to clay, makes it even weaker.