[Disaster Knowledge] Landslides and mudslides are coming. What should you do?

landslide

Landslide refers to the phenomenon that the slope or slope of the soil layer or rock layer slides down the slope under the influence of river erosion, rainfall, earthquake, artificial cut slope and other factors. Landslides are also called slippery, and there are popular names such as “walking mountains”, “mountain mountains” or “mountains peeling”.

Debris flow

Debris flow refers to a special torrent of solid material such as muddy sand, rocks, etc. that is generated on the valleys or slopes under the action of surface water flowing from precipitation, dam breaks, or melting of ice and snow. Commonly known as "walking 蛟 、 “ “ 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出 出.

Landslide and debris flow identification

Landslide identification basis

1. Terrain and geomorphology basis: When a slope-like chair-shaped horseshoe-shaped terrain or an irregular sill is developed on a slope, its shape is obviously inconsistent with the surrounding slopes; there is a depression in the upper part of the slope, and the lower slope foot extends more than the two sides. Into the riverbed; the origins of the two valleys turned and merged in the upper part of the slope; the above-mentioned geomorphological phenomena indicate that landslides may have occurred in these areas. There are obvious cracks on the slope, and the cracks have been extended and widened in the near future; the houses on the slope have cracked and tilted; the soil on the slope foot has been squeezed out and collapsed frequently; the above-mentioned landform phenomenon may be the basis for the formation of landslides.

2. Stratigraphic basis: In the section where landslides have occurred, the types and occurrences of rock layers or soils are often significantly different from the surrounding non-sliding slopes. Compared with the non-sliding slopes, the sliding rock or soil is usually disorderly in sequence and structurally loose.

3 , groundwater based on: landslides will destroy the integrity of the original slope aquifer, resulting in changes in groundwater flow paths, excretion sites. When it is found that the distribution of spring water points and seepage zones on local slopes and entire slopes are inconsistent, and many springs or original springs suddenly dry up in a short period of time, other evidence may be used to determine whether landslides are forming.

4. Vegetation basis: The trees on the surface of the slope are rampant. Generally, the slope has undergone a sharp slide. The trunk of the slope surface is bent down the slope and the upper trunk maintains a vertical growth, which is generally the result of a long-term slow sliding of the slope.

Debris flow gully identification basis

1. According to sources: The formation of debris flows must involve a certain amount of loose soil and stones. Therefore, there are many broken mountains and evacuated materials on both sides of the valley, and there are obvious landslides and collapses on both sides of the valley. Vegetation is not developed, and valleys with strong soil erosion and slope erosion are prone to mudslides.

2. Based on topography and geomorphology: Valleys that can collect large amounts of water and maintain high water flow speeds can accommodate and handle large amounts of soil and stone. The upper reaches of the valley are surrounded on three sides by mountains and steep slopes. The planform of the ditch is funnel-shaped, spoon-shaped, and leaf-shaped. The middle valley is narrow and the downstream valley is open. The elevation difference between the upper and lower reaches of the valley is more than 300 meters , and the slope on both sides of the valley is greater than 25. The terrain conditions are conducive to the formation of mudslides.

3. Water source: Water provides the dynamic conditions for the formation of debris flow. Local heavy rain-prone areas, reservoirs with dangerous dams, downstream of the dam, seasonal melting of ice and snow, and conditions for generating large amounts of flowing water in a short period of time are conducive to the formation of debris flows. Among them, in areas with frequent local heavy rainstorms, the highest frequency of mudslides occurred.

If a ditch is conducive to the formation of debris flow in terms of source, terrain, and water source, this ditch must be a debris flow ditch. However, the frequency, size and viscosity of mudslides will change with the above factors. There have been landslides and mudslides, and there is still danger of mudslides in the future.

Landslides and mud flows come and how to prevent them

(i) Avoiding landslides focuses on identifying precursors. The precursory features of the collapse mainly include the following aspects: the collapsed front edge falls off and falls, and small collapses and small collapses occur; the collapsed feet have new cracking trails that can smell abnormal odors; and can hear rock tears from time to time. , friction, cracked sound; there is anomalies such as heat, helium, gas, groundwater, and water; abnormal phenomena occur in animals and plants. If such signs are found, people living near landslides or walking on landslides will have to shift their evacuation early. If we find that the uplift of the soil on the front edge of the hill slope and the abnormal cracking and widening of the mountain cracks are serious, we must take measures such as shifting as soon as possible.

(b) The mudslide will run towards the sides of the hill when it breaks out. Debris flows often occur in specific mudslide valleys. Therefore, mastering the techniques for judging mudslides and moving them away from them is necessary for self-help. The debris flow valley upstream like funnels, rice scoops, leaves, the middle reaches of the deep and narrow, the downstream is more open, the upper and lower valleys relative elevation is generally more than 300 meters . If there are Shantang reservoirs in the upper reaches of the gully, or there is abundant groundwater in the gullies, they will be more prone to mudslides when they encounter continuous heavy rainfall. It should be particularly vigilant that mudslides often erupt, and therefore the chances of escape are small. Therefore, when you hear a roar in the ravine, or see the flood of the main river rise, and the normal flow of water suddenly stops, you should immediately realize that the mudslide is coming and take immediate measures to escape. In the escape, it is necessary to pay attention to choosing the correct direction: Do not run upstream or downstream in the direction of the ditch. You should run toward the slope on both sides of the ditch, but be careful not to stay on the slope.

The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network.