What is a roadbed. Sectional roadbed. Applications of the canvas

The invention relates to road construction. Roadbed, located on the ground, contains a base, drainage ditches along the base, a reinforcing device located on the base and an embankment over the reinforcing device. What is new is that the reinforcing device contains drainage slots, inside which there is a compacted sand and gravel mixture and which are made at the base of the soil across the roadway to a depth exceeding the height of the base and reaching the level of the soil, which has filtration properties and with a design pitch and width determined by the achievement of soil consolidation during the construction period, and also contains a reinforcing layer over the drainage slots, which provides fluid filtration in all directions without changing the properties of the reinforcing layer with increasing loads on the roadway, and a sand-gravel mixture compacted with vibratory rollers is also placed on the reinforcing layer. New in the method of erecting the roadway is that drainage slots are made for the reinforcing device across the roadway with a calculated pitch and width determined by the achievement of soil consolidation during the construction period, and a depth to the level of soil with filtration properties, the drainage slots are covered with a sand and gravel mixture , compact it, place a reinforcing layer over the drainage slots, fill the reinforcing layer with a sand-gravel mixture, which is compacted, and then fill the embankment in layers and each poured layer is compacted with vibration compaction. The technical result of the invention is to increase the bearing capacity of the roadway and accelerate the consolidation of base soils. 2 n. and 6 C.p. f-crystals, 4 ill.

The invention relates to road construction, and more specifically to a roadbed and a method for its construction mainly on soft soils.

The invention can be used for the construction of railways and highways in difficult engineering and geological conditions, especially in areas where waterlogged clay soils are spread, which make up a weak base and are rarely used for the construction of a roadbed.

Known roadbed, which can be used in the construction of highways on soft soils, including the base of the soil, an embankment with a reinforcing element in the form of discarded tires cut in the middle of the tread, connected by ropes. At the base of the sheet, the tires are laid with the cutting plane upwards with a decreasing diameter to the sides from the center of the sheet to the edges, and in the embankment slopes - with the cut plane downward with an increasing diameter from the sheet to the base of the embankment (patent RU No. 2200785, MKI E 01 C 5/00, 19.07 .2001).

There is a known method for the construction of this canvas, which consists in the fact that the strip set aside for the road is leveled, an embankment is erected, compaction layer by layer, tires are laid along the embankment and in the embankment slopes and the upper layer of the embankment with laid tires is compacted, pressing them into the upper layer of the embankment ( ibid).

There is a known method of road construction, which can be used in the construction of roads in conditions of soft soils in swamps and peat areas (patent RU No. 2043455, MKI E 01 C 5/00, 04.16.1992). The method of roadway construction includes the construction of an embankment, laying the utilized tires cut in half along the tread part and connected in mats to the base of the road over the bed, laid with a calculated step, filling the embankment with subsequent compaction, after which the embankment is erected. The embankment is backfilled with weakly decomposed peat or sand, followed by the laying of a geotextile layer.

There is a known method for the construction of earthworks in areas of the Far North with increased environmental requirements (patent RU No. 2221101, MKI E 01 C 1/00, 03/20/2002), in which the choice and creation of a geodetic road base is carried out through flooded areas - lakes, sites for construction and bushes - within the boundaries of these lakes, and filling or reclamation of earthen structures is carried out on their thawed base. During construction, use is made of frozen soil.

There is a known method of building a road on soft soils (SU No. 1174513 A, MKI E 01 C 9/08, 07/15/1983), in which volumetric elements of polyethylene material are used, filled with a local silty mixture, which are laid out on the subgrade, an intermediate layer between sections made of double polyethylene material, and the upper one is additionally screened with a layer of polyethylene sheet, and then the entire structure is subjected to the final embankment.

There is a known method of road construction (patent RU No. 2040626, MKI E 01 C 9/00, 01/15/1993), in which artificial structures are performed: ditches and drainage devices, prepare the subgrade by forming longitudinal and transverse road profiles with the construction of embankments and recesses , make an underlayment of sand and arrange a covering. At the same time, the underlying layer in the flooded areas is made of sand 50-60 cm high from the maximum level of groundwater and flood waters. The coating is made of clay or loam, on top of which an additional layer of sand is placed, after which it is watered and rolled to form a coherent skeletal structure.

The proposed invention is based on the task of intensifying road construction, reducing their cost and improving the performance of the roadway in conditions of soft soils.

The technical result is to increase the bearing capacity and accelerate the consolidation of base soils.

The problem is solved by the fact that the roadbed located on the ground and containing a base, drainage ditches along the base, a reinforcing device located on the base and an embankment on top of the reinforcing device has a reinforcing device that contains drainage slots, inside which a compacted sand and gravel mixture and which are made at the base of the soil across the roadway to a depth exceeding the height of the base and reaching the level of the soil, which has filtration properties and sufficient bearing capacity, and with a calculated step and width, determined by the achievement of soil consolidation during the construction period, and also contains on drainage slots a reinforcing layer that provides simultaneous filtration of the liquid in all directions without changing the properties of the reinforcing layer with increasing loads on the roadway, and a sand and gravel mixture is also placed on the reinforcing layer.

It is advisable that the calculated spacing of the drainage slots would be from 4 to 6 meters.

It is advisable that the width of the drainage slots is between 1 and 1.4 m.

It is also advisable that the depth of the drainage slots is up to 3.5 ... 4 m.

It is very advisable that the reinforcing layer be made of geotextile.

The problem is also solved by the fact that in the method of erecting a roadbed, mainly on soft soils, which consists in the fact that the base is in the ground, drainage ditches along the base and a reinforcing device and an embankment are placed on the base over the reinforcing device, drainage slots are made for the reinforcing device across the roadway with a design pitch and width, determined by the achievement of soil consolidation during the construction period, and a depth to the level of the soil, which has filtration properties and sufficient bearing capacity, fill the drainage slots with a sand-gravel mixture, place a reinforcing layer on the drainage slots, providing simultaneous filtration of the liquid in all directions without changing the properties of the reinforcing layer with increasing loads on the roadway, the reinforcing layer is filled with a sand-gravel mixture, which is compacted, and then the embankment is filled in layers and each filled layer is compacted with a vibration compaction niy.

It is advisable that during vibration compaction, the process load would be corrected to select the optimal mode of the sealing load and the design safety factor.

It is also advisable that the thickness of the backfill layer is between 0.4 and 0.6 m.

In the future, the invention is illustrated by drawings, in which: figure 1 shows a horizontal section of the roadway according to the invention, figure 2 - the same roadway, section A-A (transverse profile), figure 3 - the same roadway , section В-В (transverse profile), in Fig. 4 - graphs of changes in the fluidity index along the depth of the roadway in natural bedding (1) and during the construction of the roadway (2), according to the invention.

The roadbed (figure 1) contains a base 1, drainage ditches 2, made along the base 1 of the roadway, a reinforcing device located on the base.

The reinforcing device, according to the invention, contains drainage slots 3, inside which is placed a compacted sand-gravel mixture, reinforcing layer 5 located on drainage slots 3 and providing simultaneous filtration of the liquid in all directions without changing the properties of the reinforcing layer with increasing loads on the roadway. The reinforcing layer 5 also contains a sand-gravel mixture 6.

Drainage slots 3 are made in the base 1 across the roadway to a depth H (Fig. 2) exceeding the depth h of the base 1 (Fig. 3), and reach the level of the soil 4, which has filtration properties and sufficient bearing capacity. Drainage slots 3 are made in the base 1 with a calculated step t and a width of 1, determined by the achievement of soil consolidation during the construction period.

The roadbed also contains an embankment 7 over the reinforcing device. The embankment 7 and the sand-gravel mixture 6 of the reinforcing device are compacted.

Drainage slots 3, according to the invention, can be located with a step t - from 4 to 6 m, have a width of 1 - from 1.0 to 1.4 m and a depth H - 3.5 ... 4 m.

As a reinforcing layer 5, to reduce stress in the soil and increase its strength, a material is used that provides mobility and drainage (filtration in all directions without changing properties with increasing loads) properties in all directions - a synthetic material, for example, the well-known geotextile. For backfill 6, a sand-gravel mixture is used.

The system of compacted drainage slots and reinforcing pavement with compacted backfill, according to the invention, form a single device at the base of the roadway with simultaneous reinforcing and filtration wringing, which increases the bearing capacity of the roadway on a weak base and accelerates the consolidation of the base soils.

The roadbed is erected as follows.

The soil and vegetation layer is cut out to a depth of 0.5-1 m and to the width of the roadway and the resulting cut is filled with a sand and gravel mixture to obtain a base 1. The soil is cut out under drainage ditches 2 in the form of a depression in the soil on both sides along the roadbed with a depth of up to 4 m, 1.5-2 m wide, depending on the filtration characteristics of the soils, and the resulting cut is filled with a sand-gravel mixture.

Then, drainage slots 3 are cut, according to the invention, across the roadway with a step of 4 to 6 m in the form of a depression in the soil to a depth to the level of the soil, which has filtration properties and sufficient bearing capacity, a depth of, for example, 4 m, a width of 1.0 up to 1.4 m. Cutting of drainage slots is carried out with an excavator while filling them with sand and gravel mixture, carried out by a front loader working in a single link with an excavator, while the gap between them should not exceed 5-10 meters. At the level of the earth's surface, a reinforcing layer 5 of geotextiles is laid at the base of the embankment, while the width of the laying should ensure the overlap of the longitudinal drainage ditches. The rolls of geotextiles are rolled manually with an overlap of the canvases by 22-24 cm and fastening every 1.5 m. Then they begin to fill the sand and gravel mixture over the geotextile. Backfilling of geotextiles is done "from the head", the layer thickness is 0.6 m (according to the safety condition of a weak base, for which the safety factor is greater than 1), leveling is carried out by a bulldozer or motor grader from the middle to the edges. The filled up sand and gravel layer 6 is compacted with rollers without vibration. Then the embankment is poured with 7 layers of 8 from the soil. Each poured layer 8 is compacted with vibration compaction. For vibration compaction, rollers 9 are used, which move across the dumped layer 8. The movement of the rollers is shown by a dotted line.

When vibration compaction is carried out to increase the strength, the process load is corrected to select the optimal sealing load mode and the design safety factor.

The filling of the embankment 7 is carried out with a thickness of the filled layer of 0.4 m ... 0.6 m. Each filled layer is vibrated during the estimated time determined from the condition of achieving the calculated degree of consolidation of the weak foundation. Vibration compaction is carried out under control (monitoring) by sampling the soils of embankment 7 and base 1 from a pre-drilled well, determining the characteristics of the samples and calculating the parameters: deformation modulus, settlement, pore pressure, calculate the safety and stability factor, compare with the calculated values \u200b\u200band according to them adjust the intensity of the technological load on the road bed being built, influencing the vibration compaction, vibration frequency, vibration amplitude and duration of vibration compaction. In practice, this can be done, for example, by changing the operating mode of the roller, the speed of its movement, as well as the thickness and number of layers of dumping, the type and thickness of the synthetic material. In the course of intensive vibration compaction, the pore pressure increases. The reinforcing layer, according to the invention, allows under vibration load to additionally squeeze and drain water from the soil layers under the roadbed under construction, reducing the water saturation of weak soils. This, in turn, makes it possible to increase the compaction load, increase the construction draft and the strength of the roadway. In general, the calculation of the control parameters is directly related to the assessment of the safety of the roadway being erected under a constantly increasing load.

The roadbed and the method for constructing the roadway according to the invention were applied on an experimental section of the roadway on the hikes to the bridge over the river. The mass of the rollers used was from 12 to 20 tons, the speed of movement was 4.5-5 km / h. In the first layer of dumping, vibration compaction was carried out with rollers across the drainage slots for 4 ... 5 days. The monitoring showed that the consolidation of the foundation soils was achieved during the construction period. Acceleration of soil consolidation was 75-80% compared to temporary surcharge with unchanged embankment design. The deformation modulus increased by 3.7-4.5 MPa, the strength characteristics increased: adhesion - by 25-35%, the angle of internal friction - by 30-40%. The density of the base soils increased by 4-6%, the moisture content of the base soils decreased by 4-6%.

Figure 4 shows the results of the change in the fluidity index along the depth of the roadbed in natural bedding (1) and during the construction of the roadway (2), according to the invention, which were obtained on the basis of the analysis of two groups of soil samples in depth taken from drilled wells in the experimental section ... As can be seen from the graphs, during the construction of the roadbed, the flow rate was improved and, therefore, the bearing capacity was increased and the consolidation of the base soil layers was accelerated.

1. A roadbed located on the ground and containing a base, drainage ditches made along the base, a reinforcing device located on the base and an embankment over the reinforcing device, characterized in that the reinforcing device contains drainage slots, inside which a compacted sand and gravel mixture is placed and which are made at the base of the soil across the roadway to a depth exceeding the height of the base and reaching the level of the soil with filtration properties, and with a calculated pitch and width determined by the achievement of soil consolidation during the construction period, and also contains a reinforcing layer over the drainage slots, which ensures filtration of the liquid in in all directions without changing the properties of the reinforcing layer with increasing loads on the roadway, and on the reinforcing layer there is also a sand-gravel mixture compacted with vibratory rollers.

2. The roadbed according to claim 1, characterized in that the calculated spacing of the drainage slots is from 4 to 6 m.

3. The roadbed according to claim 1, characterized in that the width of the drainage slots is from 1 to 1.4 m.

4. Roadbed according to claim 1, characterized in that the reinforcing layer is made of geotextile.

5. The roadbed according to claim 1, characterized in that the depth of the drainage slots is up to 3.5 ... 4 m.

6. A method of erecting a roadway according to claim 1, characterized in that drainage slots are made in the reinforcing device across the roadway with a calculated pitch and width determined by the achievement of soil consolidation during the construction period, and a depth to the level of soil with filtration properties, drainage the slots with a sand-gravel mixture, compact it, place a reinforcing layer over the drainage slots, which provides filtration of the liquid in all directions without changing the properties of the reinforcing layer with increasing loads on the roadway, fill the reinforcing layer with a sand-gravel mixture, which is compacted, and then fill in the layers and each dumped layer is compacted with vibration compaction.

A strip of land intended for driving.

(Terms of Russian architectural heritage. Pluzhnikov V.I., 1995)

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"Roadbed" in books

A road accident