RU2747300C1 - Road surface - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the construction of highways, airfield strips, railway foundations, cargo areas for various purposes and large-tonnage carrying capacity on soft soils. The road surface is made of rectangular reinforced concrete slabs of length (L) and width (H), laid in rows along the roadway on a road base made of reinforced concrete elements. Reinforced concrete base elements are slabs of the same shape and size as pavement slabs. Base slabs 2 are laid in parallel rows along the roadway, and their total width determines the width of the road base. Slabs 1 of the road surface are laid on top of the road base with an offset relative to the slabs 2 of the road base by half the length (L) and width (H) of these slabs 2 of the road base. In the middle of the lateral sides of the road base plates and the road surface, there are connecting elements 3 designed to ensure the connection of both adjacent road base plates and the road surface, and the road base plates and the road surface with each other.

EFFECT: reduced load per unit of base area.

7 cl, 9 dwg

Description

The technical field to which the invention relates

The invention relates to the construction of highways, airfield strips, railway foundations, cargo platforms for various purposes and foundations of large-tonnage carrying capacity on soft soils.

State of the art

It is known from the prior art that the problem of strengthening the bearing capacity and long-term preservation of high performance of pavements of newly built roads is solved, for example, by adding compactors - asphalt, cement, lime, etc. -85 "(APPROVED BY THE DECREE OF THE GOSSTROY OF THE USSR OF 17.12.85 N233) (Rev. dated 08.06.95). However, practice testifies to the insufficient rigidity of such coatings and their bases, which is manifested in the reduction of the overhaul life of roads as a result of the onset of premature damage.

Uneven loading is one of the significant causes of wear and tear on the road surface. The load under the tires of the wheels causes decompaction of the material of all (including compacted) layers of the coating and base, followed by wave formation, extrusion of the soil to the sides, subsidence, etc. (Gremyshev N.V., Technology and organization of road construction. M. Transport, 1992, p. 36, Pozdnyakov M.K. About track education on highways, http: mikekp.livejournal.com).

Known for strengthening the rigid type of road bed with monolithic and prefabricated reinforced concrete coatings. Despite the advantages in terms of durability of roads made of concrete slabs (30-40 years), they have technological and economic disadvantages.

The well-known monolithic concrete and reinforced concrete pavements work like slabs on elastic foundations. Simultaneous dynamic effects of loads of two or more transport axles cause multidirectional stresses in the slabs and, as a result, damage in the form of cracks, edge chips, destruction of corners and ruptures of fastening welded reinforcement, distortions, etc. With insufficient bearing capacity of the base, destructive processes are accelerated. All of these types of coatings have restrictions on the construction season, harden for a long time (about a month - monolithic concrete) and, most importantly, require high initial and repair costs.

Road pavements made of reinforced concrete slabs RU No. 2522567, EO1C 5/00, 2014; RU No. 2521683, EO1C 5/00, 2014; RU No. 2522547, EO1C 5/06, 2012; RU No. 2474639, EO1C 5/06, 2013; RU No. 2515654, EO1C 5/06, 2014, proposed to increase traffic safety and reduce costs, do not solve the problem of increasing the bearing capacity of the road bed for the passage of large-capacity vehicles on soft soils. There is a known solution for joining road slabs into a single prefabricated pavement using tensioning reinforcement inside the plates SU No. 1813823, E01C 5/10, No. 2371536, E01C 5/10, 2009; No. 2379406, E01C 5/08, 2010, or a geo-rope network, into the cells, which are inserted plates RU No. 2403334, E01C 5/08, 2010 in order to increase the carrying capacity, reliability and durability of the road surface.

The disadvantages of these technical solutions can be attributed to the fact that the slabs connected in packages operate on elastic foundations and dynamic sign-changing loads of large-capacity transport lead to damaging deformations of the road bed. The structural and technological complexity of the execution and ensuring the safety of anti-corrosion protection of rods increases the cost and prevents the widespread use of these solutions in the practice of road construction.

Close in technical essence is the invention described in patent RU No. 2407847 E01C 11/04, 2010, to strengthen the bearing capacity of the subgrade and reduce the cost of construction. The technical solution consists in the use of road slabs, the dimensions of which depend on the dimensions between the tracks (width) and axles (length) of medium-duty vehicles. The shortened track plates solve the problem of reducing the transport load on the base and saving initial costs due to the use of plates of lesser thickness and ordinary soil for the base.

The disadvantage of the technical solution is the limited bearing capacity of the prefabricated coating, which can withstand the track load of only medium-duty vehicles, which limits the passage of large-tonnage shipments.

The closest analogue is the "Method of paving pavement on pads", described in patent RU 2648122 C1, E01C 5/06, publ. 03/22/2018, preventing deformation of joints and seams in the road surface. A method for constructing a reinforced concrete pavement on pads includes preparing an embankment of sand or sand and gravel mixture (ASM), arranged on a subsoil (bedrock) or a compacted embankment. At the same time, at the joints and in the places of the envisaged expansion joints, and also possibly in the intervals between them, prefabricated or monolithic reinforced concrete linings are placed (arranged) on the ground base, playing the role of a damper, filling the gap between them with sand or ASG flush with surfaces of these linings with the subsequent arrangement of a prefabricated or monolithic reinforced concrete pavement along them.

The disadvantages of this road surface should be attributed to the short service life with the intensive passage of heavy vehicles on soft soils.

Disclosure of invention

The objective of the present invention is to increase the bearing capacity of the roadbed by reducing and evenly distributing the load over a large area of the base in order to avoid material loosening, the formation of subsidence and rutting, and to extend the service life during intensive passage of heavy vehicles on soft soils.

This problem can be solved using the features set forth in the independent claim. The subject of the dependent claims is optimized road surface designs.

According to the invention, the road surface is made of rectangular reinforced concrete slabs of length (L) and width (H), laid in rows along the roadway on a road base made of reinforced concrete elements. Reinforced concrete base elements are slabs of the same shape and size as pavement slabs, while:

- base slabs are laid in parallel rows along the roadway, and their total width determines the width of the road base;

- the pavement slabs are laid on top of the road base with an offset relative to the road base slabs by half the length (L) and width (H) of the said road base slabs;

- on the middle of the lateral sides of the road base slabs and the road surface, there are connecting elements designed to ensure the connection of both adjacent road base plates and the road surface, and the road base plates and the road surface with each other.

The parameters of reinforced concrete slabs should be selected depending on the distances between the wheels of the axles and the distances between the axles in order to ensure that one wheel or wheels of only one chassis of a large-capacity vehicle touch and move on a single slab at any time.

It is advisable to make the road surface collapsible. The connection of adjacent pavement slabs and adjacent pavement slabs, as well as the pavement slabs and the pavement with each other, is not rigid, allowing mutual displacement and / or rotation of the connected slabs relative to each other. The connecting elements of the slabs are interconnected with staples and / or chains.

The turn of the roadway can be performed by means of radial reinforced concrete slabs of the road base and road surface, equipped with docking elements designed to provide a non-rigid connection of both adjacent radial slabs of the road base and road surface, and radial plates of the road base and road surface with each other, and / or with pavement and pavement slabs.

A layer of asphalt can be applied to the road surface.

The technical result of using the road surface according to the invention is to reduce the load and evenly distribute it over a large area of the base to eliminate local stresses - the reasons for the formation of subsidence, ruts during intensive passage of heavy vehicles on soft soils.

The present invention includes the principle of calculating a reinforced concrete road slab, the parameters of which always ensure that only one wheel or wheels of only one chassis of heavy vehicles touches and moves on the slab.

Brief Description of Drawings

The invention is described in detail with reference to the drawings.

FIG. 1 - scheme of laying pavement slabs;

fig. 2 - rectangular plate with connecting elements;

fig. 3 - assembly and butt joint of the slabs (connection of the upper layer slab with the lower layer slab through a bracket and fastening of adjacent slabs of one layer using a chain);

fig. 4 is a diagram of the installation of radial connecting elements of the lower layer of slabs when turning the roadway;

fig. 5 is a diagram of the installation of radial connecting elements of the upper layer of slabs when turning the roadway;

fig. 6 and 7 - diagram of the Road Train-Sortimentovoz MAZ-642205-020, MAZ-998640 with indication of wheel loads and the corresponding load distribution over the base plates of the road surface;

fig. 8 and 9 - a diagram of a trailed road train with an indication of wheel loads and the corresponding load distribution over the base plates of the road surface.

Implementation of the invention

As shown in FIG. 1, the road surface is made of rectangular reinforced concrete slabs of length (L) and width (H), laid in rows along the roadway on a road base made of reinforced concrete elements. Reinforced concrete base elements are slabs of the same shape and size as pavement slabs.

Base slabs 2 (bottom layer slabs) are laid in parallel rows along the roadway, and their total width determines the width of the road base. The pavement slabs 1 (top layer slabs) are laid on top of the road base with an offset relative to the road base slabs by half the length (L) and width (H) of said road base slabs 2. In the middle of the lateral sides of the road base plates 2 and road surface plates 1, connecting elements 3 are made, designed to ensure the connection of both adjacent road base plates 2 and road surface plates 1, and road base plates 2 and road surface plates 1 with each other.

According to the invention, the pavement structure distributes the local traffic load from each tire spot of one axle wheel or tire spots of one running gear of the transport across the area of the pavement slab evenly over the area of 4 pavement slabs (Fig. 1). This solution fundamentally changes the nature of the work of the road base slabs, which is aimed at distributing and repeatedly reducing the load from each wheel on a large base area and damping the stresses that weaken the soil.

Another feature of the proposed design is a non-rigid connection of precast reinforced concrete slabs, which makes it possible to distribute the transport load separately from each slab over a large base area. And at the same time, non-rigid fasteners through assembly and docking joints (brackets, chains) provide sufficient dynamic stability of the plates, both along the vertical axis and along the horizontal axes, and allow thermal compression and expansion (Fig. 3). The second important characteristic of the structure is the calculated correspondence of the overall dimensions of the slabs to the track (width), axial (length) dimensions and the carrying capacity of the transported vehicle. This condition ensures that only one wheel or wheels of only one chassis of large-tonnage vehicles touches the plate and moves along the plate.

In this case, to calculate the overall dimensions of the plates, the parameters of modern large-capacity trucks, widely used on the roads of all countries, were used. It is known that the track width of MAZ, MAN, RAF, etc. is more than 2 meters, and the distance between the axles is not less than 3.6 m.

For example, MAZ-642205-020 has a track width of front and rear wheels - 2.032 m. Therefore, to divide the axle load into two plates, the width of each plate must be less than the track width of the transport, i.e. less than 2.032 m. The length of the slab should not exceed the distance between the axes - 3.6 m. Preferably, the parameters of a rectangular slab are selected: 1.75 m wide, 3.0 m long and 0.17 m thick, with a carrying capacity of 30 tons. The most suitable, for the case under consideration, is a serial prestressed reinforced concrete slab 1P30-18-30 GOST 21924.0-84 area - 5.25 m ² with ribbed surfaces, weight - 2.2 tons. Concrete - 88 m ² . It is possible to use reinforced concrete paving slabs with reinforcement strained in the longitudinal direction, and in the transverse direction with unstressed reinforcement [GOST - 25912.1-91].

FIG. 2 shows the dimensions of the slab. FIG. 3 shows the assembly-butt joint of the slabs (the connection of the pavement slab to the base slab through a bracket and fastening of adjacent slabs of one layer using a chain) The assembled units are insulated with construction foam.

Under this condition, the distribution of the local load from each spot of the tire is ensured evenly over the area of an individual road slab. The paving slab distributes the resulting load to the area of 4 slabs (5.25 m ² × 4 = 21 m ² ) of the base, and the axial load to 8 slabs (5.25 m ² × 8 = 42 m ² ). The load, which is many times reduced and distributed over the entire area of 8 base plates, is transferred to the base, which does not cause decompaction of the base material, the formation of subsidence, rutting, but compacts (consolidates) it, extending the service life of the roadway. As an example, the performance characteristics of the proposed design are presented under the action of static wheel loads of tracks having different center-to-center dimensions.

Example 1 (Fig. 6, 7)

FIG. 6. - Road train-Sortimentovoz MAZ-642205-020, MAZ-998640 with wheel loads. FIG. 7. - Distribution of the load on the base plates of the pavement 1 - the location of the wheels; 2 - slabs of the lower layer; 3 - slabs of the upper layer, 4 - initial axial load, 5 - load of slabs on the base, I-VI - rows of slabs of the lower layer. As seen in FIG. 7 the load from each wheel (41.47 kN) of the first axle, located on a separate plate of the upper layer (41.47 kN: 2 = 20.735 kN), is redistributed to an area of 21 m ^{2 of} 4 plates of the I-II row of the lower layer (20.735 : 21 = 0.98 kN).

The total load of the 2nd and 3rd axles (67.4 kN + 67.5 kN = 134.9 kN), placed on 2 separate plates of the upper layer (134.9 kN: 2 = 67.45 kN), redistributed from each slab of the upper layer to the area of 4 slabs II-III of the row of the lower layer 67.45 kN: 21 m ² = 3.21 kN.

As can be seen in the diagram, the bottom plates of row II are subject to a total load from the first + (second + third axis) 0.98 kN + 3.21 kN = 4.19 kN.

The load of the fourth axis (69.6 kN), placed on 2 separate slabs of the upper layer (69.6: 2 = 34.8 kN), is distributed from each slab of the upper layer to the area of 4 slabs IV, V row of the lower layer ( 34.8: 21 m ² = 0.66 kN).

The total load of the 5th and 6th axles (70.0 kN + 41.6 kN = 111.6 kN), located on 2 V, VI, rows of the lower layer 55.8 kN: 21 = 2.66 kN ... It can also be seen from the diagram that the lower plates of the V row are subject to additional load from the wheel of the 4th axle: 2.66 kN + 0.66 kN = 3.32 kN.

According to the presented performance characteristics, the proposed design provides an increased bearing capacity of the roadway for the passage of the MAZ Sortimentovoz road train. More than 20 times reduction of the transport load allows to operate the roads all year round, excluding winter-spring breaks. The special value of this structure for loggers is also in the fact that at the end of the work or changing the places of logging, the prefabricated structure can be disassembled without loss and moved to a new route. Disassembly and assembly of slabs (2.2 t) can be performed by timber trucks with forklifts (2.8 t), which is economically attractive.

Example 2 (Fig. 8, 9). The front axle load - 8 tons, located by the wheels on two plates of the upper layer of the structure (8 tons: 2 = 4 tons) is redistributed from each plate of the upper layer to the area of 4 plates of the lower layer (4000 kgf: 21 m ² = 190.48 kgf / m ² = 1.87 kN). The load of the second axle 10 tons, also placed by the wheels on two plates of the upper layer, (10 tons: 2 = 5 tons) is redistributed from each plate of the upper layer to the area of 4 plates of the lower layer (5000 kgf: 21 m ² = 238.09 kgf / m ² = 2.33 kN).

The second row of lower plates has a summed load from the first and second axes: 190.48 kgf / m ² +238.09 kgf / m ² = 428.52 kgf / m ² = 4.11 kN.

The load of the third, fourth and fifth axles is in total 24 tons, which is distributed by three wheels of one running gear to two plates of 24 tons: 2 = 12 tons. The load of each plate of the upper layer is distributed over an area of 6 plates (5.25 m ² × 6 = 35 , 1 m ² ) of the lower layer: 12000 kgf: 31.5 m ² = 380.95 kgf / m ² = 3.73 kN.

The analysis of the results established the universal ability of this design to provide an increased bearing capacity of the roadway for the passage of large-tonnage vehicles, regardless of the differences between the axle dimensions of different brands of road trains. The constructive reduction of the transport load, for example, - 24 tons of three axles to 380.95 kgf / m ² , allows you to minimize the design thickness of the compacted base layer from local soil.

The road surface, according to the invention, is able to strengthen the bearing capacity of cargo areas for various purposes, in particular, the runways of airfields, foundations.

Example No. 3. The use of a prefabricated pyramidal structure for the construction of airfield runways. The impact of the wheels of modern airplanes Airbus-320, Boeing 737, etc. on the coating plate during landing = 300-330 tons. The dimensions of the wheel track of the Airbus-320 = 5 m, and Boing-737 = 3.76 m, are decisive when choosing the dimensions of the construction slabs for the landing strips. For a prefabricated pyramidal structure of airfield strips, suitable parameters at the slab are PDP 60.20-100. AIV-а.F 200. This is a rectangular road slab, 6000 mm long, 2000 mm wide, (S = 12 m ² ) under a load of 100 kN, with tension steel reinforcement of class AIV and frost resistance of concrete of class F 200.

The impact load during landing by side wheels is transferred to two plates of the upper layer of the structure (330 t: 2 = 165 t). Further, through the slab of the upper layer, it is redistributed onto the area of 4 slabs (12 m ² × 4 = 48 m ² ) of the lower layer and onto the base. (165 tons: 48 m ² = 3.44 tons = 33.7 kN). As a result, the prefabricated pyramidal structure reduces the shock load of the aircraft from 300-330 tons to 3.44 tons.

It follows from the example that the proposed structure increases the bearing capacity of the platforms and at the same time reduces the load on the base. This confirms the validity of the use of a low strength category "C" of the base (bed coefficient of the base 25 <K _se ≤60 MN / m ³ ) for airfield landing strips

The proposed design is also capable of increasing the load-bearing capacity of supporting clothes, when arranging foundations for slabs without pile foundations of buildings, overpasses and structures. This is especially true for construction in areas of permafrost and swamps.

The turns of the track have features of mounting the radial connecting elements of the claimed design. The curvature, the number of turns of the roadbed are determined locally during the design and survey work of the track.

The installation diagrams of the road surface turning elements are shown in Fig. 4 and 5.

Р-1, Р-2, Р-3 - radial docking reinforced concrete elements 170 mm thick. The dimensions of the elements depend on the angle of rotation and are calculated by the designers in advance for production. After laying, the radial elements are not rigidly attached to the plates of the lower layer through the assembly-butt joints. The radius of curvature of the turn for tracks is not less than 12.5 m.

R-4, R-5, R-6, R-7 - radial docking reinforced concrete elements with a thickness of 170 mm. After laying, the elements are not rigidly attached to the plates of the upper layer through the assembly-butt joints.

The invention is an economical prefabricated reinforced concrete pavement structure with an increased load-bearing capacity due to a rigid support for the wheels and a multiple decrease in the load per unit area of the base, which does not cause decompaction of the base material, the formation of subsidence, rutting, but compacts (consolidates) it, with intensive passing large-tonnage vehicles and extends the service life of roads. To protect against weather factors and unevenness in the installation of slabs, the structure can be covered with a layer of asphalt 7-9 cm. The pavement slabs are easy to replace, and also disassembled for access to earthworks, laying communications or relocating the route.

Claims (10)

1. A road surface made of rectangular reinforced concrete slabs of length (L) and width (H), laid in rows along the roadway on a road base made of reinforced concrete elements, characterized in that the reinforced concrete base elements are slabs of the same shape and size as the slabs road surface, while: - base slabs are laid in parallel rows along the roadway, and their total width determines the width of the road base; - the pavement slabs are laid on top of the road base with an offset relative to the road base slabs by half the length (L) and width (H) of the said road base slabs; - on the middle of the lateral sides of the road base slabs and the road surface, there are connecting elements, by means of which both adjacent road base and road surface slabs and the road base and road surface slabs are connected to each other. 2. The road surface according to claim 1, characterized in that the parameters of reinforced concrete slabs are selected depending on the distance between the wheels of the axles and the distance between the axles from the condition of ensuring that one wheel or wheels of only one chassis of a large-tonnage vehicle touch and move on a single plate. any moment in time. 3. The road surface according to claim 1 or 2, characterized in that it is collapsible. 4. The road surface according to any one of paragraphs. 1-3, characterized in that the connection of adjacent slabs of the road base and adjacent slabs of the road surface, as well as the slabs of the road base and the road surface between each other is non-rigid, allowing mutual displacement and / or rotation of the connected slabs relative to each other. 5. The road surface according to any one of paragraphs. 1-4, characterized in that the connecting elements of the plates are interconnected by brackets and / or chains. 6. The road surface according to any one of paragraphs. 1-5, characterized in that it is equipped with radial reinforced concrete slabs of the road base and road surface, equipped with connecting elements, by means of which a non-rigid connection of the radial slabs of the road base and the road surface, both adjacent and between themselves and with the plates of the road base and road surface, is provided. 7. The road surface according to any one of paragraphs. 1-6, characterized in that a layer of asphalt is applied to it.

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