This paper focuses on the relationship between water erosion and environmental protection of mountain roads, and deeply analyzes and expounds the importance of environmental protection of mountain roads. Combined with the optimized engineering design, the environment is developed and utilized, and the quality of highway environmental protection is improved and improved as much as possible, so as to finally achieve the harmony and unity between highway and surrounding environment.
1 overview of highway development in mountainous areas
Highway is an important infrastructure of modern economy and society, an objective reflection of economic development on traffic demand, and an important foundation for traffic modernization. Yunnan, located in the southwest border, is a plateau mountainous province. The mountainous area accounts for about 90% of Yunnan's land area. The terrain is high and deep, and the water is fast. It is also the area where the famous three rivers (Jinsha River, Lancang River and Nujiang River) are located, and the terrain is very complicated. By the end of 2005, the mileage of highways and expressways in our province had reached184,000 kilometers, which is of great significance for realizing the strategy of developing the western region, promoting Yunnan's economic cooperation and integrating into the ASEAN Free Trade Area.
2 the importance of highway environmental protection
Environmental protection is a basic national policy of our country, and the environmental protection and landscape coordination of highway construction projects are the main components of this basic national policy. In the past, the bottleneck of China's highway traffic development was mainly economic factors, and the design guiding ideology of "economic priority" was not conducive to the sustained and rapid development of highway traffic, which would lead to the relatively backward development of complete sets of highway construction technologies. With the gradual improvement of road design standards and the more complicated topographic and geological conditions, due to the lack of understanding of environmental hazards, the guiding ideology of construction still maintains the inertia of "economic thinking" and cannot be adjusted in time with the changes of construction conditions. In 1980s, the area of soil erosion in China reached 3.67 million square kilometers, accounting for 38% of the total land area. In 1980s, the area of soil erosion in China increased by 6.5438+500,000 km2 annually. Although the law enforcement of soil and water conservation was strengthened in 1990s, the area of soil and water loss still increased by 654.38+500,000 km2 every year. At present, soil erosion in quite a few areas of our country is intensifying. It is very common that treatment and destruction are carried out at the same time, first treatment and then destruction, on the one hand, treatment and destruction in many ways. In the state of local control and overall aggravation, soil erosion and erosion have become the number one environmental problem in China.
In addition, from the ecological point of view, mountain highway construction has caused at least three negative effects. First, the loss of natural features directly leads to the loss of wildlife, wildlife habitat, geological exposure zone or a certain landform feature. Second, with the change of hydrological conditions, the quantity and quantity of above-ground and underground water flow change, which in turn affects animals and plants along the highway foundation and even nearby areas, resulting in water pollution and changes in groundwater level. Third, it has other effects on wildlife. For mammals, reptiles and flightless animals, the expressway has always formed an obstacle area, blocking a lot of communication between them. In short, the natural conditions such as mountain hydrology and the limitations of its own technical indicators will inevitably occupy and separate the land passing through the area, and a large number of excavations and fills in the construction may also cause soil movement, deformation and destruction, resulting in vegetation destruction and soil erosion.
The environmental damage caused by highway construction can generally be divided into the following aspects: first, ecological damage, mainly manifested in soil erosion, vegetation destruction and reduction, occupation of cultivated land, destruction and occupation of animal and plant habitats. Second, air pollution, mainly dust pollution, mechanical exhaust pollution and nitrogen compound pollution; The third is noise pollution, which is mainly manifested in the pollution of construction noise and traffic noise; Fourth, water pollution, road runoff pollution and various harmful substances brought and discharged by vehicles pollute the water near the highway; Fifth, solid waste pollution refers to all kinds of domestic waste pollution abandoned near the expressway, especially plastic domestic waste, which is difficult to degrade and corrode, and will cause land hardening and have a particularly serious impact on the environment. Because highway environmental protection is a complex system engineering, it involves various professions of highway engineering. The harmonious development of highway environmental protection and highway construction can create the best and highest social benefits, economic benefits and humanistic harmony. Therefore, highway environmental protection should implement the principles of protection first, prevention first, combination of prevention and control, and comprehensive treatment, and combine the optimized engineering design to develop and utilize the environment, improve and improve the quality of highway environmental protection as much as possible, and finally realize the harmony and unity between highway and surrounding environment.
3 Treatment measures for highway protective scour
Because the highway is a linear project, there are many kinds of disturbances to the ground during the construction, such as digging at the height of the mountain, cutting slopes and repairing tunnels, filling high at the lower part, bridging at the ditch and river, and diverting some rivers. So its interference with the original natural environment is quite great. The road construction front is long, and the amount of waste soil, stone and slag is huge. Serious soil erosion in rainy season will bring great pollution to the natural environment around the road. Therefore, highway construction should prevent soil erosion, maintain the improvement and rational utilization of water and soil resources in mountainous areas, and maintain and improve land productivity in order to give full play to the economic and social benefits of water and soil resources and establish a good ecological environment around the highway. Therefore, the anti-scour measures for mountain roads should be carried out from four main aspects: highway drainage engineering, greening protection engineering, subgrade retaining engineering and bridge and culvert engineering, so as to build our built roads into real humanistic and environmental protection ecological roads.
3. 1 Drainage Works
Water is the main natural factor that harms the highway, and the erosion, subsidence and collapse of the highway are related to the erosion and erosion of soil, surface water and groundwater to varying degrees. Stable subgrade is of great significance to ensure the service performance and service life of highway, so we should attach great importance to the importance of drainage engineering in highway design and construction.
The design and construction of highway drainage engineering include surface drainage and underground drainage. In the design and construction, comprehensive consideration and arrangement should be made according to the highway grade and combined with the terrain, geology, hydrology, meteorology and other conditions along the line, and all drainage facilities should be connected and coordinated with each other to make water discharge from the highway quickly. Surface drainage facilities mainly include side ditches, intercepting ditches, drainage ditches, falling water rapids, evaporation pools, oil-water separation pools, drainage pumping stations, etc. , should be combined with the terrain and natural water system layout, import and export positions should be selected and handled well. Prevent blockage, overflow, leakage, siltation, scouring and freezing. , which mainly discharges surface runoff, surface water, slope rainwater and surface water affecting subgrade stability in adjacent areas. Underground drainage facilities mainly include underground ditches, seepage ditches, seepage tunnels, seepage wells, inclined drainage holes, inspection wells and dredging wells. The type, location and size of facilities should be determined according to engineering geological and hydrological conditions, and coordinated with ground drainage facilities to discharge groundwater flowing to subgrade or reduce groundwater level.
3.2 Greening Protection Project
The greening around the expressway generally adopts three basic forms: planting grass, spreading turf and planting trees. In order to improve the landscape ecological environment on both sides of the highway and prevent soil erosion, greening and beautification works should be carried out for cutting slopes, embankment slopes, isolation belts, central separation belts, earth shoulders, crushing platforms, back-pressure lanes, isolation belts, interchange areas, tunnel entrances and exits, toll stations, living service areas, borrow and spoil areas, etc. No matter what greening protection measures are taken, the ultimate goal is to beautify the surrounding environment of the highway and reduce soil erosion.
3.3 subgrade retaining engineering
Highway subgrade retaining engineering is an important facility to ensure subgrade stability, prevent soil erosion, improve environmental landscape and protect ecological balance. In mountainous highway along the river, the subgrade generally adopts the forms of plant protection, mortar or concrete protection, riprap, gabion, geomembrane bag, groin, dam, sandbar and submerged dike. In highway retaining engineering, retaining wall is also one of the commonly used protective measures, including gravity retaining wall, reinforced retaining wall, buttress retaining wall, anchor retaining wall, anchor plate retaining wall and reinforced retaining wall. The subgrade retaining engineering should be designed and constructed according to the actual terrain, hydrology, geology and other conditions, which can not only protect the stability of subgrade, but also play a icing on the cake role in the surrounding environment of highway.
3.4 Bridges and Culverts Engineering
Yunnan is a mountainous province on the plateau, with many rivers, high mountains and deep valleys, river fluctuation and riverbed siltation and erosion, which are closely related to people's production and life. Building roads in mountainous areas requires crossing rivers and ditches, so bridges and culverts need to be built. Here, we must consider the problems of river erosion and environmental protection. For bridges, especially large bridges and extra-large bridges, the construction of bridges cannot be separated from the environment. The construction of the bridge is closely related to topography, landforms, landforms, geology and hydrology. During the construction of the bridge, the natural environment should be fully protected to avoid the destruction of ecological vegetation and the imbalance of the natural environment caused by the construction of the bridge, especially in the rainy season, which will wash away a lot of sediment and cause serious pollution of river water sources. Bridges are generally divided into beam bridges, arch bridges, cable-stayed bridges and suspension bridges according to bridge types. The selection of bridge types in mountainous areas must be adapted to local conditions, and the feasibility of construction and the convenience of transportation should be fully considered, so that the selected bridge types can fully conform to the principles of "safe structure, comfortable use, good economy, convenient construction and maintenance, beautiful appearance and harmony with the natural environment", and the completed bridge is an ecological bridge full of humanistic colors.
4 conclusion
After systematically analyzing and expounding the characteristics of highway water erosion in mountainous areas and the importance of environmental protection, combining with the actual requirements of environmental protection, this paper puts forward many ideal and feasible measures for controlling highway water erosion in mountainous areas, and lists many meaningful examples. I hope this idea can provide reference for mountain highway construction in the area where the Yangtze River environmental protection project belongs.
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