To prepare the relationship between rainfall intensity and erosion using landslide physical model.
EQUIPMENTS REQUIRED Landslide flume, soil, water, sprinkler, stopwatch, rain gauge.
THEORY:
A landslide is the movement of rock, earth, or debris down a sloped section of land. Landslides are caused by rain, earthquakes, volcanoes, or other factors that make the slope unstable.
Landslides have three major causes: geology, morphology, and human activity.
Geology refers to characteristics of the material itself. The earth or rock might be weak or fractured, or different layers may have different strengths and stiffness.
Morphology refers to the structure of the land. For example, slopes that lose their vegetation to fire or drought are more vulnerable to landslides. Vegetation holds soil in place, and without the root systems of trees, bushes, and other plants, the land is more likely to slide away.
Human activity, such as agriculture and construction, can increase the risk of a landslide. Irrigation, deforestation, excavation, and water leakage are some of the common activities that can help destabilize, or weaken, a slope.
EROSION: Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth’s crust, and then transports it to another location (not to be confused with weathering which involves no movement). Water is one of the best eroding agents. Water break the bonds between material particles and carry then away. More flow of water through material will cause more erosion. Hence, more rainfall intensity will cause more erosion in the material. Therefore, the relationship between rainfall intensity and erosion will be direct. Due to more erosion, landslide will occur earlier.
PROCEDURE:
- Prepare the apparatus by providing slope to provide gravity by placing it with some angle by the help of following expression.
We have given the length and height of box by using trigonometric ratios we can easily find the angle.
Say length = l and height = h.
tan 𝛼 =ℎ / l
Or =𝛼 = tan inverse 1 (h/l)
- Add soil in the apparatus.
- Make slope at suitable angle.
- Compact soil if necessary.
- Cut the soil portion from bottom to some suitable distance.
- Start the sprinkler with the start of sprinker start the stopwatch to note the time.
- Note down the times when cracks appear on the soil.
Measure the quantity of water through the rain gauge.
