Road Section Design

Summary

This diploma project presents the project of the highway IV of the technical category Malinovka - Stupkino in the Ryazan region.

The explanatory note includes a brief description of the natural conditions of the design area, calculations of small culverts and versions of road clothing structures, of which one of the most economical option 3 was chosen, as well as a technical and economic comparison and selection of the highway route option.

During the routing, 2 versions of the highway were designed. For both options, abbreviated longitudinal profiles were compiled, excavation volumes were calculated, eras of the final accident rates were built, and traffic speeds were calculated.

Of the 2 options, one was chosen, the most economical, option 2. For which a longitudinal profile was drawn up, the design line of which was designed by the tangent method, transverse profiles of the roadbed were designed. Superelevation spurs on circular curves were also calculated and a linear planning schedule for the organization of construction work was built.

The explanatory note contains 87 pages. When issuing the note, 12 literary sources were used.

This diploma project includes, in addition to the explanatory note, 10 sheets of working drawings of A1 format.

Introduction.

The road is a complex of engineering structures designed to transport passengers and cargo by cars, and provide round-the-clock, uninterrupted, safe and convenient movement of cars with design speeds, trucks with design loads, traffic flow with an average annual optimal speed.

In conditions of high development of the national economy of the Russian Federation, great attention is paid to the development of road transport. The goals were set to increase the efficiency of its work, reduce costs and time for transportation, reduce accidents on roads. To achieve these objectives, efforts should be directed towards increasing the volume and quality of road construction.

In modern conditions, roads around the world are characterized by high rates of traffic intensity, significantly exceeding the growth rate of the road network. A study of the distribution of traffic intensity on the road network showed that 10% of the length of the road network accounts for 40% of the total traffic intensity, 10-30% of the road extension - 30% of the intensity. The length of sections of roads with low intensity is 40%, they account for 10% of traffic.

Great attention is paid to road safety. To improve traffic safety, the elimination of emergency road sections is of great importance, since road conditions are the basis for road accidents in 40-60% of cases. To improve the transport and operational qualities of roads, it is necessary to study in detail their condition, traffic modes, and regularly certify roads. Only on the basis of such detailed surveys can the required type of repair work and its sequence be correctly established.

The construction of any highway contributes to the development of the national economy of the regions through which it passes: new settlements, enterprises appear, economic activity is intensified and improved, the connection of the village with the city and between settlements, districts and regions is improved. This leads to an increase in traffic intensity and loads on the road, which accelerates its wear and tear.

The road should be, first of all, resistant to loads from cars, for which it is intended to pass. Automotive loads are dynamic. The effect of such loads is especially dangerous for road clothing during a period of severe humidification of its base and roadway. In this regard, in order to prevent the destruction of road clothing in the spring, the passage of heavy trucks is limited on lower categories of roads until the bottom of the road clothing is completely dried. Roads of categories I to III must provide travel at any time of the year.

When designing and operating roads, it is necessary to take into account the influence of weather and climatic conditions in such a way that the road as an engineering structure operates in extremely unfavorable conditions.

2. Designing Route Plan Variants

2.1. Routing by Map

The scale of the plan is 1:10 000, the cross section of the contours is 2.5 m. Design is carried out on the basis of technical requirements. The initial point of the highway is the village of Malinovka, the final - the village of Stupkino.

When routing a road route through a map in contours, keep in mind that the normalized alignment elements in the plan are the smallest curve radii, the smallest spiral parameters, and the length of the straight runs. The listed normalized elements should be used in connection with the landscape of the area with each other.

The length of straight sections of the route is assigned based on the conditions for preventing dulling of drivers' attention and their progressive fatigue when driving along long straight lines, especially in conditions of a monotonous landscape.

Therefore, it is recommended to limit straight sections of the route to a length of 4-6 km.

Very short straight inserts between curves should be avoided. The driver shall be able to evaluate the rounding, decide on the need to change the driving mode and make this change. Therefore, very short straight inserts between curves are not recommended.

When you design an alignment, you schedule the rotation angles for both route variants. Checks are used to check the correctness of the statement. The rotation angle statements and their checks are drawn up in tabular form. For the first version of the route in Table 2.1, for the second - in Table 2.2.

Both route plan options are shown on sheet # 1 of the working drawing of this project.

3. Calculation of roadway structures

Roadwear is the most expensive part of the road. The cost of their construction sometimes reaches 6070% of the estimated construction cost. Road transport productivity and cost of transportation depend on the state of road clothing.

According to the conditions of work under load, rigid and non-rigid road clothes are distinguished.

Paving design consists of its design and thickness calculation, as well as cross-sectional design.

The main task is to obtain a roadway structure that meets all the basic requirements.

3.1. Design and calculation of the first version of pavement

3.1.1. Construction of roadworks

Road clothing has the following basic requirements:

1) strength and deformability, expressed in the long-term ability of road clothes to resist operational effects without the occurrence of unacceptable deformations or damage;

2) surface flatness required to ensure the movement of cars at a given speed without the occurrence of excessive values ​ ​ of rolling resistance and vibrations of the car, which cause dynamic effects on its elements and affect the comfort of movement and safety of goods;

3) surface roughness ensuring safe movement of vehicles at specified speeds due to a sufficient value of the coefficient of adhesion of the wheel to the coating, allowing reliable braking under adverse weather and climatic conditions;

4) futility associated with the intensity of the coating wear processes;

5) reliability, which expresses the probability of maintaining operability for a given service life under certain operating conditions;

6) economy, expressing the expediency of investing money in the construction of road clothes.

Ensuring the requirements for roadwear also depends on the strength, density, stability and water-thermal conditions of the soils of the roadbed.

The design of road clothing and roadway represents a single process of designing and calculating the road structure for strength, frost resistance and drainage and feasibility of options.

The following principles shall be used in the design of road pavements:

1) the type of coating, the design of clothing as a whole must meet the transport and operational requirements for the road;

2) clothing structure should be selected as standard or re-developed for each section or a number of sections of the road characterized by similar natural conditions, the same design loads;

3) local low strength materials shall be widely used in the respective structural elements;

4) the design should be technological and provide the possibility of maximum mechanization and industrialization of road construction processes;

5) The regional experience in the construction and operation of roads in a given area should be taken into account when assigning a road structure.

The variety of conditions encountered in practice does not make it possible to exhaustively recommend the construction of a clothing track. However, some basic provisions should be cited:

1) Road lining structure and earthwork shall be designed together;

2) in order to ensure reliable drainage of all road clothing, it is advisable to arrange separate structural layers in order to gradually increase the filtration coefficient with depth;

3) in conditions where the main source of humidification is water vapors moving from warm to colder places, it is necessary to arrange a vapor insulating layer in the lower part of the road clothing to prevent migration of water from the bottom up, condensation of it on cold stone materials and overwetting of the soil base;

(4) The paving materials shall be arranged so that their strength is reduced from top to bottom;

5) for technological reasons, road clothing should be designed with a minimum number of structural layers;

6) to reduce the cost of road clothing, reduce transport work on the transportation of materials, it is necessary to use local materials as much as possible;

7) when selecting materials for structural layers, the requirements for these layers and the materials for them should be taken into account.

Basements for asphalt concrete pavements must be arranged without seams from materials that ensure the base continuity and operation during the design service life without the appearance of temperature cracks. To this end, asphalt concrete pavements reinforced with binding stone materials must be used in the upper layers of the base.

With improved lightweight coatings, crushed stone, gravel materials are used as bases; soils reinforced with inorganic and organic binders; slags.

With transition coatings, the bases are usually absent and their functions are performed by an additional layer of the base.

Local materials are used for additional base removal.

In the case of laying coarse-grained materials on clay and loamy soils, in order to prevent soil penetration into the material layer, an anti-silting interlayer should be provided, with a thickness of at least 5 cm from sand, sowing, and reinforced soil.