Introduction of rural roads?
rural highway
There are different opinions about the concept of rural roads, and the relevant state departments have the following definitions: rural roads generally refer to roads connecting townships (towns) and administrative villages. Tongxiang (town) highway refers to the highway from county to township (town) and between townships (towns). The highway to the administrative village refers to the highway from the township (town) to the administrative village. Some departments also believe that "in terms of China's current situation, rural roads refer to county and township roads and village roads." There are also some provinces and cities that give different definitions of rural roads according to the current situation of local rural roads. In many areas, Tongcun Highway within the jurisdiction of sub-district offices is also classified as rural highway.
abstract
Rural highway is an important part of highway network and one of the most important infrastructures to ensure rural social and economic development. Rural roads include county roads, township roads and village roads.
County road refers to the road which is of political and economic significance in the county (flag, county-level city), connecting the county and the main townships (towns) and major commodity production distribution centers in the county, as well as the road between counties that do not belong to national or provincial roads.
Township roads refer to roads that mainly serve the economy, culture and administration of townships (towns) and villages, as well as roads between townships (towns) and townships (towns) and between townships (towns) and the outside world.
Rural roads are mainly used by motor vehicles and meet certain technical standards. County roads generally adopt three or four highway standards; Township roads shall adopt Class IV highways or other external road standards. According to the requirements of the Highway Law, newly-built highways should meet the requirements of ministerial standards, and other highways that do not meet the minimum technical grade requirements should take measures to gradually transform them into highways that meet the technical grade requirements. In view of the small traffic of rural road vehicles connecting townships (towns) and administrative villages, and administrative villages in some poor mountainous areas, and the vehicles driving on the roads are mostly tractors, agricultural vehicles and other vehicles with relatively small volume and load, the requirements on the pavement width, longitudinal slope and curve radius of these roads can also be relaxed, and the contour roads can be temporarily adopted.
The following are some data, from which we can see that the Ministry of Communications attaches great importance to rural road construction and rural roads.
According to the statistical bulletin of the development of highway and waterway transportation in 20 12, the investment in highway construction in 20 12 was12713.95 million yuan, an increase of 0.9% over the previous year. Among them, the investment in rural highway construction is 2145.02 million yuan, up by 6.7%, and the newly rebuilt rural highway is195,000 kilometers. The investment in highway construction in poverty-stricken counties in concentrated contiguous poverty-stricken areas is 268.08 billion yuan.
By 20 12, the mileage of rural roads (including county roads, township roads and village roads) will reach 3,678,400 kilometers, an increase of 1 1.44 million kilometers over the end of last year. 99.97% of townships (towns) in China have access to highways, and 99.55% of established villages have access to highways. Among them, townships (towns) with hardened roads accounted for 97.43% of the total number of townships (towns) in China, and established villages with hardened roads accounted for 86.46% of the total number of established villages in China, up 0.25 and 2.42 percentage points respectively from the end of last year.
In June of 20 13, the investment in fixed assets in highway construction nationwide was RMB 0,000,000, an increase of 45.53% compared with RMB 27.424 billion in the same period of 20 12. The cumulative year-on-year growth rate of fixed assets investment in highway construction has increased for seven consecutive months, showing an accelerated recovery trend. By region, the fixed assets investment in highway construction in June was13.756 billion yuan, 72 1 0 and18.944 billion yuan respectively, with year-on-year growth rates of 70.09% and 5./kloc-0 respectively.
Building standard
Expose the draft
Highway department of Ministry of communications
February 2004
catalogue
1 general rules
2 control elements
Three routes
4 Subgrade pavement
5 bridges and culverts
6 tunnel
7 Traffic engineering and facilities along the line
8 villages and towns
general rule
In order to strengthen the technical guidance of rural highway construction, ensure the construction quality and improve the investment benefit, according to the technical standards of highway engineering and combined with the actual situation of rural highway construction, the Guiding Opinions on Rural Highway Construction Standards (hereinafter referred to as the Guiding Opinions) is formulated.
The "Guiding Opinions" are applicable to rural highway construction and reconstruction projects below the township level (including township level). Special sections of county and township highways in the west can be implemented with reference.
Rural highway construction should adhere to the basic principle of "planning first, adapting to local conditions, implementing step by step according to one's ability", take the road of sustainable development, rationally utilize land resources, pay attention to environmental protection, and improve rural traffic and production and living environment in combination with comprehensive improvement of villages and towns.
Rural highway construction standards should, in principle, implement highway engineering technical standards.
Due to economic, topographical, geological and other natural conditions, it is difficult to implement the road section (hereinafter referred to as the restricted road section), which can be implemented with reference to this guidance after technical and economic demonstration and approval. However, when conditions permit, it should be rebuilt as soon as possible to meet the standards of graded highways.
Rural highway sections that do not meet the grading standards stipulated in the technical standards for highway engineering shall not be included in the statistics of graded highways.
The design traffic volume forecast of rural roads should comply with the relevant provisions of Technical Standards for Highway Engineering, and it is suggested that the design traffic volume of Grade IV roads should be predicted according to 10 year.
Control element
Passenger cars are used as standard models for the conversion of traffic volume in rural highway design.
Except for restricted sections, the design speed of rural roads should be implemented in accordance with the relevant provisions of highway engineering technical standards, and it is suggested that the design speed of restricted sections should be controlled at not less than10 km/h. ..
When the traffic volume of different sections changes greatly, different standards can be adopted to implement it in sections. Transition sections should be set between sections with different design speeds, and the change points should be selected where the driver can clearly judge the change of road conditions, and warning signs should be set up.
A route should adopt the same clear height, generally not less than 4.50m, which can be appropriately reduced after technical and economic argumentation, but it should meet the transportation needs of local rural roads.
Village and town parts
general clause
In accordance with the principle of overall planning, comprehensive improvement and local conditions, we advocate the combination of rural highway construction and comprehensive management of towns and administrative villages with relatively concentrated population, and strengthen the standardization construction of rural highway sections.
The pavement type with good water stability and long service life is recommended for rural sections. The width should not be less than that of ordinary road sections, which can be appropriately widened according to the local economic bearing capacity and development needs, and the shoulder should be hardened in an appropriate form.
standard
Combined with the local actual situation, set up comprehensive drainage facilities, and the size and section type of drainage ditch should meet the functional requirements. Dry masonry (pebble) stone, mortar masonry (pebble) stone, reinforced concrete precast trough (block) and other types are recommended. Through the section of larger market towns, the culvert can be used in combination with the construction of small towns. Sidewalks and houses should be separated in an appropriate way, and hedges, flowers and plants should be encouraged to be green and beautified. The main crossings should be hardened with materials with good water stability, and corridors and culverts (pipes) should be set reasonably to ensure smooth drainage. Towns and towns connected by passenger buses can set fixed passenger bus stops and signs according to actual needs to ensure traffic safety.
routine
general clause
1 Route design should combine the topography, landforms, geology and hydrological conditions along the route, make route scheme selection and technical and economic demonstration according to factors such as project cost and social environment, rationally use technical indicators, and comprehensively consider the horizontal, vertical and horizontal factors to ensure the continuity and balance of alignment and the safety of driving.
2. Implement the principle of protecting cultivated land and saving land; Less demolition of houses and less relocation of public utility pipelines; Make full use of the old roads, safely use the original bridges and tunnels, avoid major modification or filling and excavation, and prevent the induction of new geological diseases; Convenient for farmers (herdsmen) to travel and serve urbanization; Pay attention to the coordination with the topography, landforms, environment and landscape along the line, and protect the natural ecological environment and cultural relics.
3 Try to avoid crossing areas with poor geology such as landslide, debris flow, soft soil and swamp, and special areas such as desert and frozen soil. When crossing is necessary, the crossing scope should be reduced and necessary engineering and technical treatment measures should be taken.
Width of subgrade
(including the width of driveway and shoulder) shall strictly implement the provisions of Technical Standards for Highway Engineering, in which the width of two-lane pavement in restricted sections shall not be less than 5m, and that of single-lane pavement shall not be less than 3m. If single-lane pavement is adopted, the width of one-sided shoulder should not be less than 0.75m..
One-way streets should be set with wrong lanes within a proper distance. The wrong lane should be located in a favorable position where the driver can see the vehicles between two adjacent wrong lanes. The width of subgrade should not be less than 6.5m, and the effective length should not be less than 20m.
In the continuous long downhill section, safety lanes should be set up in places that endanger driving safety.
The maximum longitudinal slope in general areas of restricted sections should not be greater than 10%, and the maximum longitudinal slope in areas above 2000m above sea level or in areas with frozen snow should not be greater than 8%. When the maximum longitudinal slope is adopted, its maximum slope length should not be greater than the provisions of the Technical Standard for Highway Engineering.
There is an ultra-high curve in the restricted section, and its comprehensive slope value shall not exceed 1 1% (except for areas above 2000m above sea level or snow-covered areas).
Parking sight distance, overtaking sight distance, minimum circular curve radius, minimum slope length, maximum slope length of different longitudinal slopes, minimum vertical curve radius and other technical indicators. It can be appropriately reduced through technical and economic argumentation. But there should be no combination of unfavorable factors, and traffic safety facilities should be set up to ensure traffic safety.
When using turning curve in restricted sections, we should refer to the relevant provisions of Technical Standard for Highway Engineering (JTJ-97), reasonably determine its technical indicators through technical and economic argumentation, and set up traffic safety facilities and necessary speed limit signs.
Subgrade pavement
general clause
1 The design of subgrade and pavement should be comprehensively considered according to the use function, technical level, traffic volume, topography, geology, materials, construction methods and other factors, especially the design of drainage and protection facilities, which should have sufficient strength and stability and be economical and reasonable.
2 Due to natural and economic constraints, pavement works that cannot be completed at one time should be paved first and then paved in accordance with the principle of overall design and phased implementation, so that the preliminary works can be fully utilized in the later stage.
3 The sections crossing special geological and hydrological conditions should be investigated and studied, and personalized design should be carried out in combination with local actual experience.
standard
The subgrade should be filled with materials with good water stability, and the edge of the shoulder of the general road section should be more than 0.5m higher than the groundwater on both sides of the subgrade to ensure the minimum filling height of the subgrade. The elevation of subgrade along the river and flooded sections should be higher than the calculated water level plus backwater height, wave attack height and safety height of 0.5m The design flood frequency of Grade IV highway is determined by local governments according to the actual situation.
Take effective measures to control subgrade compaction. When the pavement adopts interlocking blocks such as bricks, rubble and cement concrete precast blocks, the compactness of subgrade can be reduced appropriately. If the strength and stability of subgrade can't meet the requirements, or the degree of compaction is insufficient due to the lack of compaction machinery and non-layered rolling, pavement works should be suspended or simple pavement transition should be adopted, and new pavement should be paved after the natural settlement of subgrade is stable.
Roadbed protection should be combined with local hydrological, geological and real estate data, and comprehensive protection measures such as revetment, retaining wall, stone slope protection, gabion, riprap and plant protection should be taken for key subgrade parts such as high slopes that are easy to collapse, unstable high embankments and sections along the river that are seriously washed, so as to prevent subgrade diseases and ensure subgrade stability.
On the premise of meeting the requirements of motor vehicle traffic, the original subgrade and protection can be kept in a stable state, and necessary traffic safety facilities should be set up in the reconstructed road section with particularly steep terrain and huge workload.
The standard axle load of pavement design is 100KN, with one axle and two wheels.
Pavement types should be reasonably selected according to traffic volume, natural and social environment, real estate materials and construction funds.
1 Asphalt concrete pavement and cement concrete pavement are advocated in areas where conditions permit.
Asphalt infiltration, asphalt macadam, asphalt surface treatment, stones, concrete blocks, bricks and other types of pavements can be used in general areas.
3. Staged construction projects can use various pavements such as sand and gravel and lean concrete macadam.
The water-crossing pavement can be built on seasonal wide and shallow rivers and mudslides.
The pavement with steep mountain, sharp bend and steep slope should be paved with pavement with high friction coefficient, and the wet and excessively wet pavement should not be paved with bricks.
In the snow-covered and frozen areas, asphalt pavement and cement pavement should not be used in the sections with lower highway grades, and gravel pavement should be built.
Rural roads with special functions, such as digging roads with more heavy vehicles, should be specially designed in combination with the actual traffic volume and traffic composition.
Subgrade and pavement drainage should be combined with natural conditions such as meteorology, topography, geology and hydrology along the line, and necessary surface drainage and underground drainage facilities should be set up, and combined with drainage and irrigation systems of bridges and culverts along the line to form a good drainage system. Trapezoidal soil ditches should be set up in general sections, and hardened ditches should be set up in severely eroded mountain sections, with the width and depth of the ditch bottom not less than 0.4m The ditches in rural sections should be implemented according to the relevant provisions of this guidance.
Bridges and culverts
general clause
1 factors such as local conditions, convenient construction, local materials and maintenance should be considered for the bridge. According to the functional requirements, nature and expected development needs of the highway, the design should follow the principle of "safety, practicality, economy, aesthetics and environmental protection".
New bridges and culverts are recommended to adopt bridge (culvert) type with standard span, mature technology, easy construction, economy and practicality. Generally, simply supported beam bridges should be built, arch bridges can be built when the foundation bearing capacity meets the requirements, flood control bridges can be built on seasonal wide and shallow rivers, and light abutments are recommended for bridges with small span and suitable hydrogeological conditions. The utilization scheme of the original bridge should be determined according to the hydrogeological conditions, traffic composition, the use of the original bridge and other factors.
3 Bridges and culverts should consider the needs of farmland irrigation and drainage, bridges close to villages, towns, railways and water conservancy facilities should be fully utilized, and diversion structures or protective structures should be built when necessary.
standard
The vehicle load grade of the new bridge and culvert design should adopt the highway secondary standard or above (including the public secondary standard). The original large and medium-sized bridges and newly-built four-level highway bridges and culverts with few heavy vehicles can be designed according to the load effect of highway-secondary lane and the load effect of vehicles by 0.8 times.
Generally, the bridge deck width should not be less than 6m, and the bridge deck width of single-lane road section should not be less than 4.5m When the bridge width is less than the subgrade width, the approach road at the bridgehead should be provided with gradual change sections, and the length of unilateral gradual change should not be less than 20m.
Bridges in densely populated areas of villages and towns should be provided with sidewalks with a width of not less than 0.75m m.
Anti-collision walls (or guardrails) should be set for bridges and medium bridges over 50 m (including 50 m), and safety belts (or low guardrails) should be set for other small and medium-sized bridges.
We should make rational use of the original bridge on the principle of economy and safety.
1 The large and medium-sized bridges should be professionally appraised. Can not reach the load level, can be reinforced, partially utilized, limited load or demolition. The small bridge should demonstrate its driving safety and decide whether to use it.
2 The widening of the old bridge should adopt the same (or similar) structural type and span as the original bridge, and the new bridge and the old bridge should bear the force together. It is advocated that bridge widening and reinforcement should be carried out simultaneously and meet the requirements of load grade. Bridges that are in good use and cannot be widened or reinforced due to economic, technical and other factors should be set with narrow bridges or load limit signs.
Culverts shall be set to meet the drainage requirements of subgrade, and the fill at the top of culvert shall meet the minimum thickness requirements. Culverts should be economical and practical, such as circular tube culverts.
tunnel
general clause
1 According to the requirements of highway function and development, follow the principles of safety, economy and environmental protection, and comprehensively consider the terrain, geology, construction and maintenance of the road section where the route is located. When the subgrade excavation depth is more than 25 m, technical and economic argumentation should be carried out to determine whether to build a tunnel.
It is not suitable to build medium-long tunnels on rural roads, but generally two-lane tunnels should be built. Single-track tunnels can be built under special circumstances, such as solving the problems of administrative villages connecting highways, annual average daily traffic volume less than 400 vehicles, and difficult construction. The original one-lane tunnel that does not have the reconstruction conditions can continue to be used by setting up signal lights or other effective traffic safety facilities.
standard
The width of the newly-built two-lane tunnel should not be less than 7.50 m, and the width of the newly-built one-lane tunnel should not be less than 4.00 m. Generally, sidewalks are not required, but car avoidance holes and corresponding warning and prohibition signs should be set up.
Attention should be paid to tunnel drainage and waterproof design. Full-face waterproof and drainage measures can be adopted for conditional tunnels. In general, comprehensive measures such as dredging in the tunnel and intercepting water outside the tunnel should be taken to ensure traffic safety and the normal use of tunnel structure and equipment.
Short tunnels may not be equipped with facilities and equipment such as ventilation, lighting, communication, alarm and fire fighting.
One-way tunnel should adopt straight tunnel, and the length should not exceed 250 m. When the width is less than the width of road subgrade or the width of subgrade is less than 6.5m, staggered lanes should be set at both ends outside the tunnel, with the width not less than 6.5m, the effective length not less than 30m and the wiring at both ends not less than 50 m.
In principle, the tunnel should be lined according to the surrounding rock conditions. There is little change in geological structure, no fracture (layer), monoclinic layered rock and undeveloped joints. After technical demonstration, the lining may not be carried out locally.
On the premise of ensuring safety, use the original tunnel. When deciding whether to use or rebuild, technical appraisal (including safety demonstration) and special design should be carried out. Comprehensive treatment measures, such as strengthening, increasing waterproof and drainage measures, improving entrance conditions and setting signs, are taken to ensure the strength, stability and durability of the main structure.
means of transportation
general clause
1 Traffic works and facilities along the line shall follow the principle of "ensuring safety, economy and applicability", and be set up according to the use function, grade and traffic volume of the highway, combined with the local natural conditions and the specific conditions of subgrade and pavement, so as to be eye-catching and firm.
2. Traffic safety facilities on restricted sections shall be completed simultaneously with the main highway project.
Rural highway traffic engineering and facilities along the line should reach Grade D or above.
Rural roads should be equipped with necessary traffic safety facilities.
standard
1 In dangerous sections such as high embankment, approach bridge, steep slope, sharp bend, near reservoir, along the river, along dangerous roads and cliffs, speed limit, warning signs and safety facilities such as bollards, stone piers and piles should be set up on the roadside, and steel guardrails can be set up if conditions permit; Warning signs should be set up on sections such as bridge approach road, overflow bridge and water-crossing pavement; Benchmarks should be set on overflow bridges and water-crossing roads.
2 In sharp bends with poor sight distance, linear guide signs, warning signs, deceleration signs, etc. Settings should be made as required; At intersections, crossing signs and other necessary signs shall be set up.
3. Continuous long downhill sections shall be provided with deceleration devices at appropriate positions.
4 Warning signs such as deceleration, load limit and height limit should be set at the starting and ending points of restricted sections.
Warning, prohibition signs and necessary indication signs should be set up on sharp bends, steep slopes, large structures, schools and other special sections.
Conditional rural roads can set milestones and draw marking lines.
It is advocated to combine protective works to green rural roads, improve the visual environment, enhance driving safety and meet the requirements of driving sight distance.
The above is the introduction of Zhong Da Consulting on the basic situation of rural roads.
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