20 13 On May 3rd, a landslide occurred in Groups 5 and 6 of Jinkuang Village, Liubei Town, Yunxian County, Shiyan City, with a landslide volume of about 4× 104m3, belonging to a small soil landslide. The landslide deformation is strong, which poses a serious threat to the life and property safety of residents near the slope. As the local government and relevant departments take corresponding measures in time to rescue and provide disaster relief, 8 households with 48 people have successfully avoided risks, avoiding economic losses of 6.5438+0 million yuan, and achieved good disaster prevention effects.
2 General situation of geological disasters
2. 1 Geological environment conditions
Landslide belongs to low mountain and hilly terrain, and the terrain slope in the area is 25 ~ 35, with a local gradient of 40. The types of groundwater in landslide area are mainly loose rock pore water and bedrock fissure water. Pore water of loose rock occurs in the pores of gravelly silty clay on residual slope, which has strong water permeability, water content but insufficient water quantity, obvious seasonal variation and extremely uneven distribution, and is prone to seepage failure. The groundwater type is mainly phreatic water, with local upper stagnant water; It is mainly replenished by atmospheric precipitation and discharged to nearby low-lying places. Bedrock fissure water is mainly distributed in schist fissures of Wudang Group, which is controlled by the weathering degree of rock mass and structural development intensity. Generally, the amount of water is small and the richness of water is weak.
2.2 Basic characteristics
20 13 Landslide deformation occurred at around 9: 00 on May 3rd. At first, only a few east-west cracks with a length of 1 ~ 5m were found, and then the deformation became stronger. The longest staggered scarp joint was about 20m, accompanied by soil settlement, forming staggered scarps with a height of 20 ~ 40m. Landslide deformation is mainly manifested in surface tension settlement and small-scale collapse. Cracks are mainly distributed at the intersection of steep and gentle terrain, mainly in the east-west direction, and a small number of small-scale NE-oriented cracks can be seen on both sides. Landslides are mainly distributed in the front of landslide near the steep slope of artificial slope cutting and in the open areas near the valleys on both sides. It is a small soil landslide with poor stability (Figure 1 ~ Figure 4).
Figure 1 Arc cracks are developed at the rear edge of landslide.
Figure 2. Pulling down of landslide near goaf.
Figure 3. Pulling down of landslide near goaf.
Fig. 4 Arc cracks are developed at the trailing edge of landslide.
2.3 Cause analysis
Landslide belongs to low mountain and hilly terrain, and the surface schist is weathered and broken, and its structure is relatively loose, which is conducive to water infiltration. It provides favorable terrain conditions and location basis for the development of geological disasters, and belongs to the geological disaster-prone area. Artificial excavation and slope cutting form a high and steep slope, which destroys the original equilibrium state of the slope and provides free conditions for landslide deformation. A large amount of artificial waste slag is mainly dumped on the slope surface below the village-level highway, which increases the load on the upper part of the slope and changes the structure of the slope. On April 22nd, 29th and 30th of 20 13, there was a general rainstorm in Yunxian county, and a rare short-term rainstorm occurred in the landslide area, which had a certain impact on the occurrence of geological disasters.
3. Geological hazard inspection and monitoring
Yunxian county belongs to the area prone to geological disasters. Land and resources departments at all levels have established a relatively complete geological disaster monitoring system and emergency mechanism, and signed letters of responsibility at county, township (town) and village levels. Therefore, in the event of geological disasters, emergency measures can be taken in time. After the occurrence of disasters and dangerous situations, the land department promptly organized professional teams to conduct emergency investigations, strengthened deformation monitoring according to the requirements of the investigation conclusions, and conducted regular inspections before, during, after and outside the landslide. During the period when the danger has not been lifted, patrol 3 times a day in rainy days and 1 ~ 2 times a day in sunny days, so as to analyze the landslide deformation and development trend and take preventive measures in time. At the same time, according to the deformation characteristics and stability of the landslide, the dangerous areas are divided, and a warning line is set up along the 50m line around the landslide. Relocation and avoidance of residents threatened by geological disasters of landslides, life supervision of villagers in areas that may be affected by landslides, issuance of disaster prevention cards to all villagers threatened by geological disasters, formulation of emergency plans for safe evacuation, determination of responsible persons, early warning signals, evacuation routes and specific locations for temporary avoidance, and ensuring the safety of people's lives. If the landslide deformation intensifies, evacuate people in time.
4. Safe haven resettlement for geological disasters
In view of the serious danger, in order to ensure the life and property safety and long-term stability of residents near the landslide, the Yunxian People's Government decided to relocate the affected residents as a whole.
4. 1 Determine the relocation object
In line with the principle of "giving priority to severe disasters and gradually advancing", adhere to the principle of self-help by the masses, supplemented by government subsidies, implement the relocation and avoidance of geological disasters, determine the relocation targets, fully consider its necessity and feasibility, and respect the wishes of the masses. Villagers' groups put forward relocation applications in combination with their respective disaster situations, township research reports, on-the-spot evaluation and appraisal by experts organized by county land departments, and finally determined by county leaders.
4.2 Selection of relocation and resettlement sites
Choose relocation sites, fully consider whether it is beneficial to people's production, life and future development, do not occupy cultivated land, and cannot be far away from water, power and traffic trunk lines; Don't choose places with hidden dangers of geological disasters. Relocation and resettlement sites must be determined by the county land department to organize relevant geological experts to evaluate and identify them.
4.3 Strict planning and control
Adhere to the principle of land conservation, scientifically formulate plans for relocation and construction, and rationally arrange village roads, water supply, drainage, power supply and other infrastructure construction and mass housing land.
5 Experience and Enlightenment
(1) After the danger appeared, the local land and resources management department dealt with it decisively and reported it in time, which won the initiative for the timely lifting of the landslide danger. In addition, after the dangerous situation appeared, the land and resources departments and geological disaster prevention units responded quickly and the personnel were in place in time, which provided basic geological data for the next geological disaster prevention and control.
(2) After receiving the landslide danger report, governments at all levels should make decisive decisions and timely organize people in areas affected by landslides to quickly escape.