Highway landscape design is carried out on the basis of highway technical design, so the content of highway landscape design is also closely related to highway facilities, mainly including the following aspects:
1. Aesthetic requirements of highway alignment design
The beauty of highway alignment is the foundation of highway landscape. When choosing the route scheme, we will investigate the landform features along each route scheme through careful reconnaissance, and determine some scenic control targets (such as scenic spots and historical sites, dangerous peaks and rocks, beautiful coastal scenery, endless streams, etc.). ), and at the same time determine some characteristic targets that must be avoided, such as forest reserves and farmland protection areas. , and then repeatedly compare the location of the line, make full use of these scenic resources, diversify the landscape along the line, and skillfully integrate the expressway.
Highway plane alignment should take curve as the main body to better adapt to the terrain. In addition, long straight road sections are easy to distract drivers and cause traffic accidents. The vertical alignment should try to avoid high filling and deep excavation, otherwise it will seriously damage the natural environment. The final three-dimensional alignment should adapt to the terrain as much as possible, coordinate with the surrounding landscape, and the overall alignment should be continuous, smooth and predictable.
After the alignment design is completed, the highway environmental landscape is displayed and evaluated with the help of CAD system and geographic information, and further revised to obtain the best route design scheme.
2. Landscape modeling of the structure
Highway structures mainly include bridges, culverts, interchanges, overpass bridges and retaining structures. Structure is an important part of highway landscape. In the design, we should not only consider its technical and economic rationality, but also have a novel and beautiful appearance, and also cooperate with the modeling of other structures along the line to echo the natural landscape and customs of the region. If the highway structure in the scenic spot is too rigid, it will often destroy the scenery. Some successful bridges, such as Nanjing Yangtze River Bridge, Xiamen Haicang Bridge and Dongguan Humen Bridge, have become an extremely beautiful scenery with their special historical significance, majestic momentum and beautiful shape.
3. Roadbed and pavement landscape design
By reasonably adopting subgrade elevation and section modeling, and adopting separated subgrade in necessary sections, on the basis of good linear design, the highway structure can better adapt to natural topography, existing regional topography and greening.
For drivers and passengers, the road surface is an important landscape element that occupies the field of vision. In addition to ensuring the reasonable ratio between the main lane and the shoulder, the shoulder, carriageway and separation zone can be built by using pavement materials with different colors, which not only strengthens the decoration of the highway, but also provides good visual guidance.
4. Central median greening
The important purpose of greening the central separation zone is to shade and prevent glare and guide the line of sight; In order to facilitate the safe passage of vehicles, its height and width must meet the requirements of current specifications. The choice of anti-glare tree species is:
Low (about 1.5m), slow growth and strong resistance. The general principle of spacing is to calculate by the functional relationship between the light diffusion angle, human dynamic vision and driving speed, and the spacing in a single row is generally 2-3m.
The ground greening part is mainly composed of lawn and ground cover plants. By selecting ground cover plants with different leaf colors and flowering periods and setting them in sections, the color of the central separation zone can be changed and the beautification effect can be enhanced.
5. Greening of green belts on both sides
Setting green belts on both sides of the highway to form green corridors along the highway is an effective means to rebuild the landscape environment, prevent dust and sound insulation, and coordinate the relationship between the highway and the surrounding environment. If the green belt covers a wide area, multiple rows of trees, shrubs and colorful flowers and trees can be set up to form a spectacular green belt. But generally speaking, in the case of limited land for green belts, it is better to plant in a single row, with the distance between deciduous leaves and evergreen trees (5 ~ LOM), and the tree species should be determined according to the local climate conditions. In this way, sightseeing will not be affected by visual obstacles caused by too close spacing, and green can be seen all year round, and at the same time, a single tree species can be prevented from being susceptible to pests and diseases.
When setting up green belts on both sides, attention should be paid to ensuring the visibility conditions inside the curve and near the intersection to avoid traffic accidents.
6. Slope and vertical greening
Slope greening has a good slope protection function, which has a direct effect on stabilizing subgrade, preventing erosion and conserving water and soil. Slope greening requires high coverage and long green period. However, because the slope soil is subgrade fill or exposed soil after cutting excavation, the soil quality is not suitable for planting, and the irrigation conditions are poor, so it is difficult to maintain. Therefore, it is required to do a good job in grass seed selection, planting methods and early maintenance. According to the practice of highway slope greening, in terms of grass species selection, local wild grass species suitable for greening are more suitable, easy to survive and low in cost. Grass seeds with deep roots are better than those with shallow roots. In terms of planting methods, drilling is better than sowing, planting grass is better than planting grass, and autumn sowing is better than spring sowing. In addition, in recent years, the introduction of wet spray seeding and foreign soil spray seeding technology can effectively improve the construction efficiency and survival rate, adapt to the poor soil quality of highway slopes, and also complete the construction work of high and steep slopes. The vertical greening part mainly includes mud slope protection and retaining wall. Climbing plants such as Parthenocissus tricuspidata and Lingxiao can be planted under it, or hanging vines can be planted on top of it to cover the structure, reduce the oppressive and rough feeling of the structure and beautify the road capacity.
7. Landscape design of interchange, service area and toll station.
From the perspective of landscape architecture, interchange, service area and toll station are the largest and most plastic parts in landscape design, which can be considered as the climax of the whole expressway landscape design. The landscape design of these locations should be comprehensively planned from the aspects of architectural form, topographical features, local cultural features, garden layout, etc., which echoes the style of interchanges and service areas along the line. In recent years, many domestic expressways have many successful models in landscape design of these parts, with distinctive styles, different concepts and rich connotations. To sum up, there are mainly garden style, classical style and natural style.
The above is the related introduction of the content of highway environment by Construction Network.
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