In the early morning of May 1 1, a 1 landslide occurred on the back slope of Liang Shuo Street in Liangshuo Town, Tiandong County, Baise City, and two landslides occurred on the back hill of Liuguotun in Liangshuo Village, Liangshuo Town, with geographical coordinates of 107 18' 0.9 "respectively. East longitude 107 18' 23.7 ",north latitude 23 47' 54.2". The collapse body is arc-shaped, with a width of about 25m, a length of 7 ~ 15m, an average thickness of about 4m, a volume of about 1000m3, a maximum height of about 3m and a slope of about 70. The collapse caused the back wall of residents' houses to be destroyed.
Figure 1 Folding Panorama
The Liuguotun landslide is divided into two parts: 1 is located in the south of Liuguotun, with a width of 60m, a length of 30m, a thickness of 3 ~ 7m, a volume of 9000m3, and a main sliding direction of 305, which damages the back walls of eight villagers' houses. No.2 landslide is located in the northeast of Liuguotun, with a width of about 40m, a length of about 15m, a thickness of 3 ~ 5m, a volume of about 2400m3 and a main slip direction of 255. The back wall of three villagers' houses was destroyed and the 1 floor was buried. Due to the accurate release of early warning information, timely start of emergency plan and proper risk avoidance measures, 20 households and 30 people in the dangerous area were evacuated in advance, and no casualties were caused.
Liangshuo Town is an eroded hilly landform with an altitude of 330 ~ 5 14m, a slope of about 30, gentle peaks and undulating ridge lines. The collapse and landslide area covers the Quaternary slope eluvial layer, which is yellow, brownish yellow and grayish yellow silty clay with gravel, loosely ~ slightly densely stacked, with a thickness of 4 ~ 8m；; The underlying yellow and brownish yellow strongly weathered medium-thin mudstone mixed with sandstone. Rock mass is weathered and broken, and cracks are developed. The rock occurrences are 75 ∠ 20 and 75 ∠ 70 respectively. The vegetation in the disaster area is generally developed, some of which are cultivated land, mainly sugarcane, chestnut trees, weeds and shrubs. Because villagers cut slopes to build houses, an artificial slope with a height of 3 ~ 15m and a slope of 60 ~ 70 is formed, and there is no supporting measures and reasonable drainage system. From May 1 1 to May 12, heavy rainfall occurred, resulting in slope sliding.
Fig. 2 Liuguotun 1
2 Monitoring and emergency hedging
2. 1 monitoring and early warning
On the afternoon of May 1 1, Baise Geological Environment Monitoring Station and Meteorological Bureau issued yellow warning of geological disasters and rainstorm red warning signal in Tiandong County respectively. The leaders of Tiandong county, township and land departments immediately rushed to the jurisdiction to organize monitoring personnel to conduct inspections and investigate hidden dangers, and urged to strengthen monitoring. During the inspection that night, it was found that the back slopes of the houses of 5 villagers in Longyu Street of Liang Shuo Street and 5 villagers in South and Northeast Liu Guotun 15 were high and steep, with the front edge uplifted and the rear edge cracked, which directly threatened the life and property safety of 20 households with 30 people. Inspectors report to their superiors immediately.
2.2 Emergency hedging
After discovering the danger, the local government and the staff of the National Land Institute immediately organized the threatened people to evacuate, and at the same time pulled up the red warning line and took corresponding defensive measures. In the early morning of May 12, landslides occurred one after another. Due to timely monitoring and early warning, emergency hedging work was quickly put in place, causing no casualties.
2.3 Subsequent disposal
After the disaster, city and county leaders rushed to the disaster site, organized staff to conduct detailed disaster investigation and monitoring, issued emergency cards to affected households, and arranged construction units to strengthen houses and build retaining walls.
Fig.3 Liu Zhengdong, secretary of Baise Municipal Party Committee, inspected the landslide site.
3 Experience and Enlightenment
Governments at all levels and land departments attach importance to inspection and investigation. After receiving the meteorological warning, the Tiandong County Party Committee and the county government immediately organized monitoring personnel to inspect the prone areas and hidden dangers, and the township leaders and the director of the National Land Institute conducted inspections on all hidden dangers within their jurisdiction to find hidden dangers in time, which is the prerequisite for the success of this emergency avoidance.
Timely warning and rapid evacuation. For the disasters and dangers found, timely warning, rapid evacuation of threatened people, to ensure the safety of people's lives and property.
Technical training and popularization of disaster prevention knowledge. The effective avoidance of two geological disasters in Tiandong County is inseparable from the annual training of monitoring personnel and the popularization of public knowledge of geological disaster prevention and control.
Suggestion: The geological environment in Baise City is harsh, with many disasters, small scale, scattered distribution and strong suddenness. We must rely on the group monitoring and prevention system to avoid effective disasters. In addition, residential buildings are mostly built on cutting slopes, which increases the difficulty of early warning and forecasting of geological disasters. It is necessary to establish and improve the system of monitoring and prevention of geological disasters and expand the coverage as much as possible.
(This part of the basic information is provided by the Department of Land and Resources of Guangxi Zhuang Autonomous Region. Editor Zhang Nan)