Anti-geological disaster handwritten newspaper

Geological disasters refer to natural disasters mainly caused by geological dynamic activities or abnormal changes in geological environment. Under the action of internal power, external power or artificial geological power, abnormal energy release, material movement, deformation and displacement of rock and soil and abnormal environmental changes occur on the earth, endangering human life and property, life and economic activities or destroying resources and environment on which human beings depend for survival and development. Adverse geological phenomena are usually called geological disasters, which refer to geological events caused by natural geological processes and human activities that worsen the geological environment, reduce environmental quality, directly or indirectly endanger human safety and cause losses to social and economic construction. Geological disasters refer to geological phenomena caused by natural or man-made factors, which cause damage and loss to human life, property and environment? [2]? . Such as collapse, landslide, debris flow, ground fissure, ground subsidence, ground collapse, rockburst, tunnel water inrush, mud outburst, gas outburst, spontaneous combustion of coal seam, loess collapsibility, geotechnical expansion, sand liquefaction, land freezing and thawing, soil erosion, land desertification and swamp, soil salinization, earthquakes, volcanoes and geothermal disasters.

Basic connotation

Editor? broadcast

Prevention and control of geological disasters refers to changing the process of these geological disasters by effective geological engineering means, such as mountain collapse, landslide, debris flow, ground collapse, ground fissure and ground subsidence caused by natural or man-made factors, so as to achieve the purpose of disaster reduction or prevention. The prevention and control of geological disasters shall be based on the principle of combining prevention with avoidance and treatment, and shall be carried out in accordance with the principle of combining prevention with prevention, overall planning and comprehensive treatment. ? [3]?

cause

Editor? broadcast

Geological disasters all occur under certain dynamic induction (destruction). Some are natural and some are man-made. Accordingly, geological disasters can also be divided into natural geological disasters and man-made geological disasters according to their dynamic causes. The location, scale and frequency of natural geological disasters are controlled by natural geological conditions, not by the development of human history; Man-made geological disasters are restricted by human engineering development activities and often increase with the development of social economy.

The main factors inducing geological disasters are:

1, the mining of mineral resources is not standardized, and there are few reserved pillars, resulting in goaf collapse, mountain cracking and landslide.

2. Slope excavation: refers to the artificial high and steep slopes and landslides formed during the construction of roads and houses built by mountains.

3. The leakage of reservoirs and canals in mountainous areas increases infiltration softening, leading to landslides and mudslides.

4. Other activities that damage the soil environment, such as quarrying, blasting, filling and chopping, are also the disaster-causing effects of geological disasters.

trait

Editor? broadcast

(1) showed a long-term high incidence trend.

The specific geological environment conditions in China determine that geological disasters are in a long-term high-risk situation. China's topography is undulating and its geological structure is complex, which has the environmental basis for geological disasters. It is predicted that under the background of global climate change at the beginning of this century, the frequency, intensity and regional distribution of extreme weather and climate events in China will become more complicated. The uncertainty of rainstorm caused by small and medium-scale weather system increases, local extreme weather events such as sudden heavy rainfall and typhoon increase, earthquakes become more active, the probability of geological disasters caused by heavy rainfall and earthquakes increases, and the overall situation of geological disasters may be more severe. In the next few years, geological disasters will remain a high-incidence period.

(2) There is an upward trend.

With the rapid development of economy and society in mountainous and hilly areas, unreasonable human engineering activities interfere with and destroy the geological environment, which will inevitably lead to or aggravate geological disasters and make them on the rise. The geological environment in the central and western regions is fragile, and large-scale infrastructure construction has a serious impact on the geological environment. Geological disasters such as landslides, collapses and mudslides caused by human activities such as clearing roads, building houses by cutting slopes and building reservoirs will continue to increase. With the acceleration of urbanization in the eastern region, a modern metropolitan area has gradually formed, and the contradiction between supply and demand of water resources has intensified. Land subsidence and ground fissure disasters caused by over-exploitation of groundwater and oil and gas will still show an upward trend. There are many hidden dangers of geological disasters caused by mining and excavation all over the country, and land subsidence and ground fissure disasters caused by mining activities are common in mining areas and mining cities.

(3) There are many disasters.

There are many geological disasters in China, which seriously threaten people's lives and property, major national projects and urban security, and the task of prevention and control is very heavy. About 230,000 geological disasters have been discovered in China, which are distributed in the Three Gorges Project, the South-to-North Water Diversion Project, the West-to-East Power Transmission Project, the mountainous railway trunk line and the national trunk line project area, more than 400 towns, 100 large factories, hundreds of large mines and tens of thousands of villages, seriously threatening the lives and property of local people and the safety of major national projects. Among them, there are 280,000 landslides and mudslides that need to be treated, including more than 800 hidden danger points of extra-large geological disasters/kloc-0.

(4) Many problems need to be solved.

① The prevention and control of geological disasters still lacks comprehensive and systematic basic survey data, and the survey data cannot be updated in time.

② The monitoring system of geological disasters is weak. Only some areas have carried out the pilot construction of monitoring, forecasting and early warning system, and most areas are still mainly limited to low-level group monitoring and prevention.

(3) For a long time, China's geological disaster prevention and control funds are seriously insufficient, and there are many historical debts. Many hidden dangers of major geological disasters need engineering measures to control.

④ The public's knowledge and awareness of disaster prevention and mitigation need to be further popularized and improved, and the number and level of geological disaster prevention and management teams can't meet the actual needs.

⑤ The informatization level of geological disaster prevention is low, and all kinds of disaster prevention information are not fully utilized.

⑥ Economic and social development puts forward higher requirements for disaster prevention and mitigation. ? [4]?

Preventive and control measures

Editor? broadcast

Landslide, collapse and debris flow are the most frequent and serious geological disasters. In order to effectively reduce their threat to human life and property and minimize disaster losses, engineering measures are often taken to prevent and control these three types of geological disasters. The main engineering measures are as follows:

(1) Engineering Measures for Collapse Prevention and Control

1 block. For small and medium-sized collapses, shelter buildings or interception buildings can be built. Interception buildings include rockfall platforms, rockfall troughs, rockfall dikes or rockfall walls, and shelter buildings include openings and shed holes.

② Support and slope protection. Support refers to the use of piers, columns, walls or their combinations to support and strengthen dangerous rocks hanging above and likely to break or fall, such as cantilever or arch bridge, in order to achieve the purpose of controlling dangerous rocks. For the dangerous rock areas with contiguous distribution of dangerous rock blocks and weak interlayer or weak structural plane, firstly, some loose blocks are removed, and a stone retaining wall is built to protect the slope.

③ Anchoring. Slab, columnar and inverted cone-shaped dangerous rocks are easy to collapse, so prestressed anchor rods (cables) can be used to strengthen them to prevent collapse. Anchoring measures can reduce the crack width of rock mass near the free surface and improve the integrity of rock mass.

④ Grouting reinforcement. Consolidation grouting can enhance the integrity and strength of rocks. Generally, anchorage is carried out first, and then grouting reinforcement is carried out in sections.

⑤ Drainage bank slope and drainage seepage control. Through the construction of surface drainage system, the runoff generated by rainfall is intercepted and collected, and the drainage ditch is used to discharge the slope. For groundwater in landslide, drainage holes can be used to discharge groundwater, thus reducing pore water pressure and softening effect of groundwater on landslide rock and soil.

⑥ Cut and remove the slope. Slope cutting and load reduction refers to cutting off the upper part of dangerous rock or landslide to reduce the upper load and increase the stability of dangerous rock and landslide. The dangerous rock mass with small scale and high degree of danger can be removed by blasting or manual method, so as to completely eliminate the hidden danger of collapse and prevent harm.

⑦ Soft foundation reinforcement. Protecting and strengthening soft foundation is a very important link to prevent collapse. For the exposed mudstone basement under steep cliffs, precipices and dangerous rocks, shotcreting in a certain range can prevent further weathering and increase the strength of soft foundation. If the soft soil foundation has formed weathering trough, it should be reinforced by burying or supporting according to its depth.

⑧ Line bypass. In areas where large-scale collapse may occur, even if strong buildings are used, they cannot withstand the damage of large-scale collapse, so railways or highways must be avoided as much as possible. According to the local conditions, either bypass the valley to face the rocks and stay away from the collapse body, or move to a stable mountain to pass through the tunnel.

Pet-name ruby reinforcement hillside and cutting slope. Above the adjacent road subgrade, if there are hanging dangerous rocks or huge dangerous rocks that threaten traffic safety, supporting buildings such as supporting and supporting should be built to adapt to the terrain, or reinforced by anchoring; Deep concave slopes should be embedded and dangerous cracks should be grouted.

(2) Engineering measures for landslide disaster prevention and control

① Eliminate surface water and groundwater. Landslide sliding is mostly related to surface water or groundwater activities. Therefore, in landslide prevention and control, it is often necessary to try to eliminate surface water and groundwater, avoid surface water from infiltrating into landslides, reduce the erosion of surface water on landslide rock and soil and the floating support of groundwater on landslides, and improve the shear strength of sliding soil and the overall stability of landslides.

② Weight reduction and loading. The purpose of landslide control can also be achieved by changing the mechanical equilibrium conditions of the sliding body through cutting, load reduction or filling. However, this measure can only be effective if it is loaded in the anti-sliding section of the landslide and the weight is reduced in the main sliding section or traction section.

If the sliding mode of landslide is push type, and the sliding surface is steep and gentle, the control method of weight reduction of main sliding section and rear traction section can play a role in controlling landslide. In order to reduce the weight, it is necessary to calculate the thrust of landslide and find the thrust along each sliding surface, so as to judge the stability of each sliding body. Improper weight loss can not only stabilize the landslide, but also aggravate its development.

Loading, that is, filling in front of the landslide or near the landslide shear outlet, to increase the anti-sliding ability of the anti-sliding section of the landslide. The premise of taking this measure is that there must be an anti-sliding section at the front of the landslide. Like weight reduction, the front load of landslide must be accurately calculated to achieve the goal of stabilizing landslide.

③ Anti-sliding retaining wall. Anti-slide retaining wall engineering is an effective measure commonly used in landslide control because of its small balance of mountain damage and quick effect of stabilizing landslide. Small and medium-sized landslides can be used alone, and anti-slide retaining walls can be used as part of comprehensive measures for large and complex landslides. When setting anti-slide retaining wall, it is necessary to find out the sliding range of landslide, the number and position of sliding surfaces, the direction and magnitude of thrust, etc. , and find out the situation of the retaining wall base, otherwise it will cause the deformation of the retaining wall, and even the retaining wall will slide with the landslide, resulting in the failure of the project.

④ Anchor cable. Anchor cable is a kind of prestressed steel strand, which is fixed at the outer end of the slope, and the other end is anchored in the stable rock mass in the sliding surface, passing through the sliding surface of the slope, directly generating anti-sliding resistance on the sliding surface, increasing the anti-sliding friction resistance, making the structural surface in a tight state, thus improving the integrity of the slope rock mass, fundamentally improving the mechanical properties of the rock mass, effectively controlling the displacement of the rock mass, improving its stability, and achieving the purpose of controlling bedding, landslides and dangerous rocks.

⑤ Anti-slide pile. Anti-slide pile is a kind of engineering to resist landslide sliding. Anti-slide pile, also called anchor pile, is to drive a number of large-size anchor piles between the sliding body and the sliding bed to make them a whole, thus playing an anti-slide role. The materials of piles include wooden stakes, steel sheet piles and reinforced concrete piles. In recent years, anti-slide piles have become the key engineering measures for landslide control and achieved good results.

⑥ Micro-piles. Micro-pile refers to an inserted pile or cast-in-place pile with a diameter less than 300mm and a slenderness ratio greater than 30. Its pile diameter is small, it can reach a great depth, it can pass through all kinds of rocks and obstacles, and it can even tilt at will. Because of its large amount of reinforcement, it can bear the bending stress of small displacement; During construction, the vibration, ground disturbance and noise are low, and it can be used above and below the groundwater level, and can also be installed under difficult conditions; It shows obvious advantages under the conditions of narrow space, difficult access and harsh environment and working conditions.

⑦ Slope protection works. Slope protection project mainly refers to the reinforcement of landslide slope, with the purpose of preventing surface water from scouring and infiltrating the slope. For loess and expansive soil landslides, slope reinforcement nursing is more effective. The concrete methods are concrete lattice slope protection and mortar rubble slope protection. Planting turf in the grid of concrete grid frame slope protection is both greening and erosion prevention.

8 avoid. Avoidance is a preventive measure, not a control measure. For the prevention and control of large-scale landslides or landslide groups, it is sometimes necessary to take avoidance measures to prevent landslide disasters because of the great difficulty, high cost and long construction period.

Pet-name ruby other measures. In view of the bad engineering properties of the sliding zone soil, the landslide is prevented by improving the strength of the sliding zone soil. The method includes drilling blasting, roasting, chemical reinforcement and electroosmosis drainage. These methods are feasible in theory, but they are rarely used in practice for technical and economic reasons.

(3) Engineering measures for debris flow disaster prevention and control

(1) Cross-project. Building bridges and culverts above the debris flow ditch can make the debris flow have a drainage channel and ensure the smooth road.

② Crossing project. Tunnels, open tunnels and aqueducts will be built under the debris flow, so that the debris flow can be discharged from above without affecting the traffic below. This is another major engineering form that passes through the debris flow area. The general principle of design and selection of tunnels, open tunnels and aqueducts is to adapt to local conditions.

(3) Protection works. Bridges, tunnels, roadbed and important engineering facilities in debris flow areas should be protected by slope protection, retaining walls, dams and groins, so as to resist the erosion, impact, lateral erosion and siltation of debris flow.

④ Drainage works. Construction of diversion dikes, rapids, beam dikes and other drainage projects will improve the potential of debris flow and increase the discharge capacity of bridges and other buildings.

(5) retaining engineering. Construction of sand dams, fixed bed dams, silt dams, water retaining projects, flood retaining projects and other water retaining projects, to control the solid matter and rainwater runoff of debris flow, weaken the flow, flow and energy of debris flow, and slow down the erosion, impact, siltation and other hazards of debris flow.

For engineering measures to prevent and control debris flow, it is often necessary to take a combination of various measures. The most common retaining and discharging projects are the combination of ballast dam and rapids, the retaining and discharging projects of diversion dike, sand dam and rapids, and the open-cut tunnel (or aqueduct) projects of sand dam, rapids and aqueducts. Protection works are usually used in combination with other projects. The combination of various engineering measures is more effective and economical than adopting only one engineering measure.

To prevent and control geological disasters, in addition to the above-mentioned engineering measures, we must also strengthen disaster monitoring, effectively predict disasters, minimize disaster losses, rationally protect and manage the geological and natural environment in various regions, and weaken the basic conditions for disaster activities. Its basic practice is to scientifically carry out resource development and engineering construction activities according to regional conditions, paying special attention to rational use of resources and avoiding over-development. Afforestation should be widely carried out in mountainous areas to control mountains and water. Appropriate agriculture means agriculture, appropriate grazing means grazing, and appropriate forest means forest, so as to preserve soil and water and prevent soil erosion. In towns and coastal areas, we should also pay attention to the rational development and utilization of water resources and maintain the dynamic balance of groundwater. Only in this way can we fundamentally eliminate geological disasters, ensure the safety of people's lives and property, ensure the rational utilization of resources and maintain the sustainable development of the national economy.