Composite reinforced roadbed structure suitable for railway road-bridge transition section

Abstract

The utility model belongs to the technical field of railway engineering, and discloses a composite reinforced roadbed structure suitable for a railway road-bridge transition section, which comprises a soil-rock mixed filler roadbed and a bridge abutment, and the composite reinforced roadbed structure is arranged between the soil-rock mixed filler roadbed and the bridge abutment. The composite reinforced roadbed comprises a reinforced earth-rock mixed filler secondary transition section roadbed and a reinforced gravel primary transition section roadbed, and geogrid cloth with high tensile strength is laid on the reinforced gravel primary transition section roadbed, so that the geogrid cloth is connected with the earth-rock mixed filler reinforced secondary transition section roadbed; the horizontal displacement of the roadbed is well limited through interface friction force generated between the geogrid cloth and the roadbed filler, meanwhile, when the net structure of the geogrid cloth is subjected to external force, the tension membrane effect can be generated, the stress in the roadbed can be effectively dispersed and transmitted, and the roadbed is prevented from being damaged. Therefore, local stress concentration is reduced, and roadbed settlement is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to railway engineering technical field, concretely relates to a kind of composite reinforced subgrade structure suitable for railway bridge transition section. BACKGROUND

[0002] In railway engineering, the differential settlement of bridge transition section is the key factor affecting the stability and safety of driving. This problem is mainly due to the large difference in elastic modulus between the soil and stone mixed filling subgrade and the concrete bridge, and the difference in the influence of the two structures on the foundation. Therefore, a transition section is set at the junction of the subgrade and the bridge in high-speed railway to reduce the settlement difference. The current commonly used transition section is an inverted trapezoidal bridge transition section formed by graded gravel filled in layers with cement. However, there is still a large difference in elastic modulus between the graded gravel transition section and the soil and stone mixed subgrade, and there is no connecting method between the two. The lack of integrity still has settlement difference after comprehensive analysis. This uneven settlement not only leads to the deterioration of track geometry, affecting the stability of train operation, but also may exacerbate the wear of track structure, shortening its service life. Therefore, a composite reinforced subgrade structure suitable for railway bridge transition section is proposed to solve the above problems. SUMMARY

[0003] The utility model aims at providing a composite reinforced subgrade structure suitable for railway bridge transition section to solve the problems raised in the background.

[0004] To achieve the above-mentioned purpose, the utility model provides the following technical scheme: a composite reinforced subgrade structure suitable for railway bridge transition section, comprising a soil and stone mixed filler subgrade and an abutment. A composite reinforced subgrade structure is provided between the soil and stone mixed filler subgrade and the abutment. The composite reinforced subgrade includes a reinforced soil and stone mixed filler secondary transition section subgrade and a reinforced gravel primary transition section subgrade.

[0005] The reinforced soil and stone mixed filler secondary transition section subgrade includes soil and stone mixed filler. The reinforced gravel primary transition section subgrade includes cement graded gravel. The interior of the cement graded gravel and the interior of the soil and stone mixed filler are provided with multiple layers of geogrid cloth. A plurality of waste tires are provided above each layer of geogrid cloth in the interior of the soil and stone mixed filler. Rubber particles and soil and stone mixed filler are pre-filled at the tire bead of the waste tire. The upper surface of the nylon strapping between the two adjacent waste tires is paved with a cement graded gravel base surface layer. A graded gravel cushion layer is provided at the bottom of the reinforced soil and stone mixed filler secondary transition section subgrade.

[0006] The geogrid cloth of each layer of the reinforced gravel primary transition section roadbed is wrapped to the filling of the upper layer at the position close to the abutment side, and the upper surface of the reinforced gravel primary transition section roadbed is paved with a cement graded gravel base surface layer, and the bottom of the reinforced gravel primary transition section roadbed is paved with a graded gravel cushion layer.

[0007] Preferably, the soil-rock mixed filling of the reinforced soil-rock mixed filling secondary transition section roadbed comprises angular gravel soil, round gravel soil, gravel soil, pebble soil, the maximum particle size is ≤60mm, and the fine particle soil content is <15%.

[0008] Preferably, in the reinforced gravel primary transition section roadbed, the cement mixing amount of the cement graded gravel is 3%, the particle size is ≤50mm, and the fine particle content is ≤10%.

[0009] Preferably, the compaction coefficient of the rubber particles and the soil-rock mixed filling should be ≥0.92, and the mixing amount of the rubber particles is 2%-5%.

[0010] Preferably, the geogrid cloth is a two-way warp-knitted polyester geogrid cloth, and the longitudinal / lateral tensile strength of the geogrid cloth is ≥100kN / m, the longitudinal / lateral tensile strength at 2% elongation F is ≥35kN / m, and the longitudinal / lateral tensile strength at 5% elongation is ≥70kN / m.

[0011] Preferably, the length of the nylon strip is 80cm-150cm, and the width is 1cm-2cm.

[0012] Preferably, the vertical arrangement spacing of the multiple layers of the geogrid cloth is 300mm-600mm.

[0013] Preferably, the geogrid cloth on the reinforced gravel primary transition section roadbed is provided with a U-shaped nail for fixing itself.

[0014] Preferably, the U-shaped nail is made of a steel bar with a diameter of 10mm, and the length of the U-shaped nail is ≥15cm.

[0015] Preferably, the section width of the waste and old tire 6 is ≥225mm.

[0016] Compared with the prior art, the utility model has the beneficial effects that:

[0017] (1) The utility model discloses a high tensile strength geogrid cloth is laid on the reinforced gravel primary transition section subgrade, and the geogrid cloth is connected with the geogrid reinforced secondary transition section subgrade of earth-rock mixed filling, and the integrity of both is increased, the interface friction between the geogrid cloth and the subgrade filling is generated, and the horizontal displacement of the subgrade is well limited, and when the net structure of the geogrid cloth is subjected to external force, the tensile film effect can be generated, the geogrid can effectively disperse and transfer the internal stress of the subgrade through the effect, and then the local stress concentration phenomenon is reduced, and the subgrade settlement is reduced.

[0018] (2) For the main settlement area of the reinforced earth-rock mixed filling secondary transition section subgrade, the composite reinforced structure is formed by binding the waste tire above the geogrid cloth on the basis of the geogrid cloth reinforcement, compared with the two-dimensional reinforced structure of the single geogrid cloth reinforcement, the composite reinforced structure has three-dimensional, and the three-dimensional annular structure of the waste tire can significantly enhance the embedded force between the subgrade filling, and through the good elasticity of the waste tire, the subgrade seismic performance and toughness are increased, and the vertical settlement and permanent plastic deformation of the subgrade can be effectively reduced.

[0019] (3) Before the reinforced earth-rock mixed filling secondary transition section subgrade reinforced layer is filled, a small amount of rubber particles and earth-rock filling mixture are pre-filled into the tire bead of the waste tire, the problem that the tire bead is difficult to fill in the filling under the mechanical compaction is effectively prevented, so that the overall compaction degree of the subgrade can be fully ensured, and the small amount of rubber particles can also enhance the toughness of the subgrade.

[0020] (4) The utility model uses the waste tire as part of the subgrade reinforcement, which can be applied to the subgrade reinforcement engineering without treatment, thereby realizing efficient resource utilization, and reducing the engineering cost. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is the structure schematic diagram of the utility model;

[0022] Figure 2 It is Figure 1 It is the right view of A-A in the middle;

[0023] Figure 3 It is Figure 1 It is the right view of B-B in the middle;

[0024] Figure 4 It is the three-dimensional view of the geogrid connecting the waste tire of the utility model;

[0025] In the figure: 1, abutment; 2, earth-rock mixed filler roadbed; 3, geogrid cloth; 4, earth-rock mixed filler; 5, main settlement area; 6, waste tire; 7, nylon strap; 8, cement graded gravel base surface layer; 9, graded gravel cushion layer; 10, cement graded gravel; 11, U-shaped nail; 12, rubber particles and earth-rock mixed filler. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0027] Please refer to Figures 1-4 The technical solutions provided by the present application are as follows:

[0028] A composite reinforced roadbed structure suitable for a railway bridge transition section, the composite reinforced roadbed is arranged between an abutment 1 and an earth-rock mixed filler roadbed 2, and includes a reinforced earth-rock mixed filler secondary transition section roadbed and a reinforced gravel primary transition section roadbed.

[0029] The reinforced earth-rock mixed filler secondary transition section roadbed includes multiple layers of geogrid cloth 3 arranged in the earth-rock mixed filler 4, and waste tires 6 are used to fix each layer of geogrid cloth 3 in the main settlement area 5. Nylon straps 7 are arranged between adjacent two waste tires 6. The fixing method is to use nylon straps 7 to bind and fix the adjacent waste tires 6 and the geogrid cloth 3 together. A cement graded gravel base surface layer 8 is arranged on the upper surface of the roadbed, and a graded gravel cushion layer 9 is arranged at the bottom of the reinforced earth-rock mixed filler secondary transition section roadbed.

[0030] The reinforced gravel primary transition section roadbed includes multiple layers of geogrid cloth 3 arranged in the cement graded gravel 10. Each layer of geogrid cloth 3 is wrapped to the upper layer of cement graded gravel 10 at the abutment 1, and is fixed by using U-shaped nails 11. A cement graded gravel base surface layer 8 is arranged on the upper surface of the reinforced gravel primary transition section roadbed, and a graded gravel cushion layer 9 is arranged at the bottom of the reinforced gravel primary transition section roadbed. The reinforced gravel primary transition section roadbed is a multi-step inverted trapezoid and is engaged and overlapped with the multi-step right trapezoidal reinforced earth-rock mixed filler secondary transition section roadbed. The slope rate should not be steeper than 1:2. By arranging the secondary transition section, the settlement difference between different structures is smaller, and the transition is more stable.

[0031] As Figure 1 , Figure 3 , Figure 4As shown in the figure, the reinforced earth-rock mixed filler secondary transition section subgrade is composed of multiple layers of composite reinforced layers of waste tires 6 and geogrid cloth 3, and earth-rock mixed filler 4 is laid on the upper and lower layers of each composite reinforced layer. The earth-rock mixed filler 4 contains angular gravel soil, round gravel soil, broken stone soil and pebble soil, the maximum particle size is not greater than 60 mm, and the fine particle content is less than 15%. Before filling the upper layer of the earth-rock mixed filler 4, the waste tire 6 is pre-filled with rubber particles and earth-rock mixed filler 12 at the tire bead, the compaction coefficient should be greater than or equal to 0.92, the rubber particle mixing amount is 2% to 5%, and the waste tire 6 is preferably a larger cross-section width tire, such as 225 mm or more, and the tire model should be uniform.

[0032] The geogrid cloth 3 used is a two-way warp-knitted polyester geogrid, and the technical requirements are: longitudinal / transverse tensile strength ≥100 kN / m, longitudinal / transverse tensile strength at 2% elongation F ≥35 kN / m, longitudinal / transverse tensile strength at 5% elongation ≥70 kN / m, the vertical reinforcement spacing of each layer of geogrid cloth 3 is 300 mm to 600 mm, and the geogrid 3 along the direction of the reinforced gravel primary transition section subgrade should be reserved for 1 m or more at the slope surface to lap with the geogrid 3 of the reinforced gravel primary transition section subgrade, so as to ensure the integrity of the two transition sections.

[0033] In addition, in the utility model, the length 7 of the nylon rolling belt for fixing the waste tire 6 and the geogrid cloth 3 is 80 to 150 cm, and the width is 1 to 2 cm. In order to save cost and increase utilization, the waste tire 6 is only arranged in the main settlement area 5, the main settlement area 5 is the load distribution width of the top of the subgrade calculated under the train load environment, and is projected downward to the range of the top of the graded gravel cushion 9, wherein the load distribution width should refer to the "Railway Subgrade Design Specification".

[0034] In addition, in the utility model, regarding the above-mentioned reinforced gravel primary transition section subgrade, as shown in the figure, Figure 1 、 Figure 2 The reinforced gravel primary transition section subgrade is composed of multiple layers of geogrid cloth 3 and reinforced cement graded gravel 10, wherein the cement mixing amount of the cement graded gravel 10 is 3%, the particle size is not greater than 50 mm, and the fine particle content should be not greater than 10%.

[0035] In addition, in the utility model, the geogrid cloth 3 used for the geogrid cloth 3 of the reinforced earth-rock mixed filler secondary transition section subgrade is of the same specification, and the spacing of the geogrid cloth 3 should be uniform with the laying spacing of the geogrid cloth 3 of the secondary transition section and should be lapped with each other, and the lap length should be greater than 1 m or more. The length of each layer of geogrid cloth 3 along the direction of the abutment 1 should be reserved for 1.6 m or more for backfilling to the upper layer of cement graded gravel 10 and lapping with the geogrid cloth 3 of the upper layer, and the lap is fixed by using a U-shaped nail 11.

[0036] And, in order to facilitate the connection of personnel, to provide specific paving steps, as follows:

[0037] For further explanation, the embodiment provides a specific construction step suitable for a composite reinforced subgrade structure suitable for a railway bridge transition section:

[0038] S1: First, the reinforced soil and stone filler secondary transition section subgrade is constructed, which is adjacent to the soil and stone filler subgrade 2 and the reinforced gravel transition section.

[0039] S2: After the foundation treatment is completed, the site is leveled, and then the graded gravel cushion 9 is laid, and a layer of geogrid cloth 3 is laid in the cushion.

[0040] S3: The soil and stone filler 4 is laid in zones on the graded gravel cushion 9, and after initial leveling with a bulldozer, it is compacted to the designed compaction degree with a roller, then the geogrid cloth 3 is laid on the soil and stone filler 4, and a length of the geogrid cloth 3 is reserved in the direction of the abutment 1, and the geogrid cloth 3 is overlapped with the geogrid cloth 3 of the reinforced gravel primary transition section subgrade constructed later, and then the two adjacent waste tires 6 and the geogrid cloth 3 in the main settlement area 5 are bound with a nylon strip 7, and before filling the next layer of soil and stone filler 4, the tire bead of each waste tire 6 is pre-filled with rubber particles and soil and stone filler 12, and then the next layer is filled. Repeat the above operation to fill layer by layer until the bottom of the cement graded gravel base surface layer 8, and finally fill the shape of a multi-step positive trapezoid.

[0041] S4: Perform the cement graded gravel base surface layer 8 construction at the secondary transition section, spread the cement graded gravel 10 on the top of the base layer, and after initial leveling with a bulldozer, compact it to the designed compaction degree with a roller.

[0042] S5: Complete the reinforced soil and stone filler secondary transition section subgrade construction, and construct the reinforced gravel primary transition section subgrade, which is adjacent to the abutment 1 and the reinforced soil and stone filler secondary transition section subgrade.

[0043] S6: After the foundation treatment is completed, the site is leveled, and then the cement graded gravel 10 is filled layer by layer, and a layer of geogrid cloth 3 is laid after each layer of filling is completed, and a length of the geogrid cloth 3 is reserved in the direction of the abutment 1 for backfilling, and the spacing of the geogrid cloth 3 should be the same as that of the geogrid cloth 3 in the secondary transition section and should be overlapped with each other, and the overlapping is fixed with U-shaped nails 11. Then start the next layer of filling, and the length of the geogrid in the direction of the abutment 1 is backfilled to the layer, and is overlapped with the geogrid cloth 3 in the layer, and the overlapping is fixed with U-shaped nails 11, and then the above operation is repeated until the bottom of the cement graded gravel base surface layer 8.

[0044] S7: Perform the initial transition section cement graded gravel base surface layer 8 construction, paving cement graded gravel 10 on the top of the base layer, and use the bulldozer to perform the initial flat, and then use the roller to compact multiple times to the design compaction degree.

[0045] S8: Complete the entire composite reinforced transition section subgrade construction.

[0046] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A composite reinforced subgrade structure suitable for railway-bridge transition sections, characterized in that: It includes a soil-rock mixed fill roadbed (2) and a bridge abutment (1), and a composite reinforced roadbed structure is provided between the soil-rock mixed fill roadbed (2) and the bridge abutment (1). The composite reinforced roadbed includes a reinforced soil-rock mixed fill secondary transition section roadbed and a reinforced crushed stone primary transition section roadbed. The reinforced soil-rock mixture secondary transition section subgrade includes soil-rock mixture (4), and the reinforced crushed stone primary transition section subgrade includes cement-graded crushed stone (10). Multiple layers of geogrid cloth (3) are provided inside the cement-graded crushed stone (10) and inside the soil-rock mixture (4). Multiple waste tires (6) are provided above each layer of geogrid cloth (3) inside the soil-rock mixture (4). Nylon cable ties (7) are provided between two adjacent waste tires (6). The upper surface of the reinforced soil-rock mixture secondary transition section subgrade is covered with a cement-graded crushed stone subgrade surface layer (8), and the bottom of the reinforced soil-rock mixture secondary transition section subgrade is covered with a graded crushed stone cushion layer (9). It also includes that each layer of geogrid cloth (3) at the position of the reinforced crushed stone primary transition section subgrade near the bridge abutment (1) is wrapped back to the upper layer of fill material, and the upper surface of the reinforced crushed stone primary transition section subgrade is covered with a cement-graded crushed stone subgrade surface layer (8), and the bottom of the reinforced crushed stone primary transition section subgrade is covered with a graded crushed stone cushion layer (9).

2. The composite reinforced subgrade structure suitable for railway-bridge transition sections according to claim 1, characterized in that: The geogrid (3) is a biaxial warp-knitted polyester geogrid, and the longitudinal / transverse tensile strength of the geogrid (3) is ≥100kN / m, the longitudinal / transverse tensile strength at 2% elongation F is ≥35kN / m, and the longitudinal / transverse tensile strength at 5% elongation is ≥70kN / m.

3. A composite reinforced subgrade structure suitable for railway-bridge transition sections according to claim 1, characterized in that: The nylon cable ties (7) are 80cm to 150cm long and 1cm to 2cm wide.

4. A composite reinforced subgrade structure suitable for railway-bridge transition sections according to claim 1, characterized in that: The vertical spacing of the multi-layer geogrid fabric (3) is 300mm to 600mm.

5. A composite reinforced subgrade structure suitable for railway-bridge transition sections according to claim 1, characterized in that: The geogrid fabric (3) on the primary transition section of the reinforced crushed stone roadbed is provided with U-shaped nails (11) for fixing itself.

6. A composite reinforced subgrade structure suitable for railway-bridge transition sections according to claim 5, characterized in that: The U-shaped nail (11) is made of a steel bar with a diameter of 10mm and the length of the U-shaped nail (11) is ≥15cm.

7. A composite reinforced subgrade structure suitable for railway-bridge transition sections according to claim 1, characterized in that: The cross-sectional width of the waste tire (6) is ≥225mm.

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