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The "7" landslide disaster in Narenguole, Jinghe County, Xinjiang Uygur Autonomous Region

1 Introduction

20 14 at 3: 30am on July 4th, a landslide occurred in Gele, Na Ren, the lower pasture of No.3 Animal Husbandry Team of Bajiahu Farm in Jinghe County, Bortala Mongolian Autonomous Prefecture, with a linear distance of 55km and a highway mileage of 80km. Six people were killed, 1500 sheep and 78 cows (horses) were buried, four houses and some livestock sheds were destroyed, resulting in family property losses of more than 3.3 million yuan and grassland losses of more than 600 mu.

The landslide disaster is located in the middle mountain area of the northern slope of Boluokuno Mountain, with geographical coordinates of 82 52 ′ 34 ″ east longitude and 44 06 ′ 32 ″ north latitude. The length of landslide accumulation is about1300m, the width is about100 ~ 250m, the maximum thickness is about 30m, and the estimated accumulation volume is about 5 million cubic meters.

2 Geological hazard characteristics

2. 1 Regional geological environment conditions

The landslide disaster is located in the south branch of Narenguolegou, Zhongshan District, south of Jinghe County, with an altitude of 2,800 meters ... The overall terrain is high in the south and low in the north. The slope of the landslide is 40 ~ 50, and the river valley is about 2.5km long. Can't find running water.

The lithology of landslide disaster area is mainly granite and limestone. The loose accumulation layer on the hillside slope is 3 ~ 30m thick, mainly composed of eluvial deposits, mainly composed of granite and limestone, and the gravel size is 0.3~5.0m, which is angular or subangular.

The area where the landslide is located is rich in precipitation, and it is a spruce forest belt and a mountain grassland belt, which is a good summer grassland.

2.2 Geological hazard characteristics

The landslide is a loose accumulation layer landslide, the sliding bed is the contact surface between loose accumulation layer and bedrock, and the landslide body is gravel soil. Generally, the diameter of gravel particles is 0.3~5.0m, and the maximum can reach 15m. It can be seen that there are a large number of aggregates with ice as cement, and the aggregate diameter is generally 5 ~ 10m. A large number of pine and shrub residues can be seen on the surface of landslide accumulation. The width of the landslide back wall is about 150m, and there are many cracks. The rear edge of landslide is 2860m above sea level, and the front edge of accumulation is 2340m above sea level, with an overall drop of 520m. The length and width of landslide accumulation are about 1300m, and the maximum thickness is 30m. It is estimated that the accumulation amount is about 5 million m3. According to the scale of landslide, it is a large landslide.

Photo 1 panorama of landslide accumulation body

Fig. 2 steep wall at the rear edge of landslide

2.3 Disasters and dangers

The landslide disaster is located in the Zhongshan area on the northern slope of Polokonu Mountain. It is estimated that the length of landslide accumulation is about1300m, the width is about100 ~ 250m, and the maximum thickness is about 30m. It is estimated that the volume of accumulation body is about 5 million m3, which is relatively large. The landslide disaster caused 6 deaths, 1500 sheep and 78 cattle (horses) were buried, 4 houses and some livestock sheds were destroyed, resulting in family property losses of more than 3.3 million yuan and grassland losses of more than 600 mu. The disaster is moderate.

After the disaster, the slope of the rear edge of the landslide exceeds 50, cracks appear in the rear wall, and gravel soil has separated from the rear edge. Due to the melting of colloidal ice exposure, gravel clods continue to slide down the slope of the back wall.

3 Cause analysis and trend judgment

3. 1 formation conditions

The slope of landslide is 40 ~ 50, which provides favorable terrain conditions for landslide. The thickness of loose deposits on slopes is relatively thick, and the maximum thickness can reach 30m, which provides material conditions for landslide disasters. The landslide is located at an altitude of 2800m, and the loose deposits on the slope are seasonal frozen soil, which is currently in the melting period.

The direct cause of landslide is the recent sharp rise in temperature, the rapid melting of seasonal frozen soil, and the sharp decline in landslide resistance under the action of water, resulting in landslide disasters.

This landslide disaster is not within the range of hidden danger points of geological disasters listed in Investigation and Zoning of Geological Disasters in Jinghe County (completed in 2005), and belongs to sudden geological disasters.

3.2 Trend analysis

According to the field investigation and analysis, at present, the landslide accumulation body is in a basically stable state, and the trailing edge of the landslide is in an extremely unstable state, and the landslide phenomenon continues to appear.

Landslides will be unstable for a certain period of time and pose a threat to the surrounding animal husbandry activities.

4. Emergency prevention and control of geological disasters

4. 1 emergency response investigation

Jinghe County Bureau of Land and Resources immediately reported to the Bureau of Land and Resources of Bortala Mongolian Autonomous Prefecture after receiving the disaster report at 7: 50 am on July 4, and immediately rushed to the scene. After receiving the report, the Bureau of Land and Resources of Bortala Mongolian Autonomous Prefecture immediately reported to the geological disaster emergency management office and the geological disaster emergency center of the autonomous region and rushed to the scene.

According to the report of the Bureau of Land and Resources of Bortala Mongolian Autonomous Prefecture, the Department of Land and Resources of the Autonomous Region immediately reported to the Geological Disaster Emergency Management Office of the Ministry of Land and Resources, and urgently dispatched a geological disaster emergency investigation team composed of the Department of Land and Resources, the Autonomous Region Geological Disaster Emergency Center and the Geological Disaster Emergency Investigation and Disposal Office to the disaster site, completed the geological disaster emergency investigation on the 5th, and guided the geological disaster rescue on the spot, and put forward relevant preventive measures and requirements for geological disasters.

4.2 Emergency measures

On July 4th, after the landslide disaster in Jinghe County, Bortala Mongolian Autonomous Prefecture immediately launched a Class III emergency plan. Party committees, governments and relevant departments of Bortala Mongolian Autonomous Prefecture and Jinghe County rushed to the scene at the first time to carry out emergency rescue work and evacuate people in dangerous areas, and found the bodies of all six victims around 15 on the afternoon of the 5th.

Photo 3 Landslide rescue site

5 Experience and Enlightenment

(1) Evacuate the surrounding herdsmen and livestock, and set warning signs around the landslide to prevent the landslide disaster from causing casualties and property losses again.

(2) Investigate the surrounding herdsmen's activity areas, especially the areas at the same altitude as the landslide, to prevent similar accidents from happening again.

(3) It is suggested that Jinghe County should be investigated in detail to improve the basic data base of geological disaster prevention and control.