Highway Construction Technology and Equipments

First, construction preparation

1. Organization preparation

Mainly is to establish and improve the construction team and management organization, clear construction tasks, formulate the necessary rules and regulations, establish the construction should achieve the goal.

2. Technical preparation

Before subgrade starts, the construction unit shall, on the basis of being fully familiar with the design documents and design disclosure, carry out on-site verification and construction investigation, verify the number of works according to the information collected on the site, and prepare the construction organization design for implementation according to the requirements of the construction period, the degree of construction difficulty and the preparation of personnel, equipment and materials. Report to site supervision engineer or owner for approval and timely submit commencement report.

3. Material preparation

Mainly is a variety of materials and machinery equipment purchase, collection, processing, adjustment and storage, as well as life logistics supply.

4. Construction measurement

Before the subgrade is started, the construction measurement should be done well, including retest of traverse, center line and level point, cross-section inspection and retest, additional level point, etc.

5. Review and test before construction

Before subgrade construction, the construction personnel should conduct a detailed survey of the geological and hydrological conditions within the subgrade engineering scope, determine its nature and scope through sampling and testing, and understand the existing buildings nearby and the treatment method of special soil.

6. Site cleaning

Before construction, highway land lofting shall be carried out according to the design requirements, and land requisition procedures shall be handled by the owner.

7. Test section

Expressway, first-class highway and roadbed construction in special areas or with new technology, new technology, new materials, different construction schemes should be used as test sections, from which the best scheme of roadbed construction guide the whole line construction.

Two, basic work

The basic work of roadbed construction mainly includes embankment base treatment, selection of filler, determination of filling mode, bridge and culvert structure filling, cutting excavation forming, soil transport, embankment compaction, roadbed quality inspection, etc.

Highway subgrade construction machinery and equipment

The main mechanical equipment of high – grade highway subgrade construction often includes shovel transport, excavation, rolling machinery.

1. In earthmoving construction, the commonly used shovel transport machinery includes bulldozer, scraper, grader, etc.

2, with the excavation and loading of soil, stone, gravel and loose material construction machinery has excavators and loaders.

3. In subgrade construction, the transportation of a large number of earth, gravel, bulk building materials, mechanical and electrical equipment, engineering machinery and other materials mainly depends on the wheeled engineering transport vehicles, including truck and various trailers and semi-trailers towed by wheeled tractor.

4, compaction machinery; The principle of pressing strength is divided into three types: static rolling machinery, vibration rolling machinery and tamping machinery.

According to the walking mode is divided into tow type and self-propelled type.

According to the shape of the roller, it is divided into three kinds: light wheel, half castor wheel and inflatable tire wheel.

Three, highway subgrade drainage requirements

1. The catchment area of the highway pavement is large, especially in the bend section. When it rains, there is more water near the central divider.

2, do a good job of interchange area and underpass bridge drainage. Overpass area and underpass are easy to collect water in rainy season, which has great influence on the strength and stability of roadbed.

3. The highway, close to the hard shoulder part, to set the water curb, in the appropriate length of the dustpan with the jet trough to drain the road surface water outside the roadbed.

4. At the foot of the filling subgrade of the expressway, the drainage ditch at the foot of the embankment is set up to prevent rainwater from penetrating into the subgrade.

Four, highway subgrade construction requirements in wind-blown sand area

Subgrade construction in wind-blown sand areas should be concentrated in sections in the season of low wind, low wind speed or rain, and completed before the wind. Before construction, adequate protective materials should be prepared to protect the original vegetation and surface hard shell on both sides of the road.

The location of the pit should be selected according to the local wind direction. In the area with a single wind direction, the soil pit should be located on the downwind side of the embankment, at least 5m away from the foot of the embankment. In the area with alternating reverse wind, the soil pit can be located on both sides of the embankment. After the construction, the slope will be built into a gentle slope, making its section into a shallow trough.

For subgrade compaction, compaction machinery and compaction method should be determined according to the natural conditions of the site, sand characteristics and water source distribution, and mechanical vibration compaction should be adopted as the main method, combined with water storage, fast forming, fast protection construction method. When using sand filling embankment, it should be layered compaction.

For the sand roadbed with water shortage, soil shortage and compaction difficulties, geosynthetic materials can be used, such as woven bags and woven cloth to reinforce the roadbed. In the area of wind-sand flow with open terrain, obstacles such as small beaches, abandoned mounds and mounds that may cause sand accumulation within 20 ~ 50m on both sides of the subgrade should be removed. The main control pile, guard pile, level point, roadbed side pile, etc. of the route should be set up obvious signs, and properly protected to prevent sand buried.

Five, highway greening project

From the comprehensive requirements of “practical, solid, economic and beautiful”, highway aesthetics has become an important aspect of design. Therefore, the highway lines and structures should pay attention to the coordination with the surrounding beautiful landscape and ecological environment, through the harmonious restoration and greening to reduce the construction traces, so that the highway and natural landscape integration as one, to create comfort and beauty for drivers.Trees, shrubs, flowers and sod shall be planted on both sides of the highway, along the side slopes, dividing belts, abandoned mounds and open Spaces within the land boundaries according to local conditions according to the road grade. Highway green plane should be arranged according to the design regulations. Road trees should only be planted outside the side slope. No trees should be planted on the shoulder of the road. Only shrubs should be planted on the slope protection road. The tree species planted should be changed according to the road section. The service facilities of expressways and first-class highways shall be green according to the design requirements.

The selection of highway greening plant varieties should comply with the following principles:

1, with the ability to stabilize the highway slope;

2. Easy to reproduce, transplant and manage;

3. Suitable for local planting;

4, with good environmental and landscape effects.

6. Prevention and control of air pollution

The prevention and control measures of roadbed construction to air pollution include the following:

1. The storage yard and processing plant of materials shall be far away from residential areas and keep a prescribed distance to prevent dust and bad odor from material processing from polluting the air and producing noise, which may harm human health.

2. Prevent dust from polluting the environment and harmful to the health of construction personnel.

3. Take measures to reduce the pollution of waste oil, waste gas and smoke caused by mechanical construction to the surrounding environment.

7. Prevent water and soil pollution and erosion

The garbage and waste materials generated by highway construction, if not properly treated, are easy to damage the landscape and pollute the water, soil and environment. For waste soil and rock, it is easy to produce new debris flow, destroy farmland and pollute the environment. Therefore, the highway construction of the production of waste, should do a good job.

1. Clean up the surface humus produced by the site, which can be used for slope planting grass, planting nutritive soil or for field construction.

2, the eradication of thorns jungle, shrubs, etc., should be planned to burn or bury.

3. The abandoned earthwork and the remaining waste materials of the project should be processed according to the needs of the landscape and the project in a planned way. Prevent soil erosion and pollution of rivers.

4, cleaning machinery, construction equipment waste water and domestic sewage should be taken necessary purification measures, in order to discharge.

5, the use of industrial waste as road building materials, when the industrial waste contains soluble harmful substances, isolation measures should be taken to prevent the harmful soluble substances from melting, pollution of soil and water.