Underbridge two-way four-lane pavement structure with limited clearance

Abstract

The clearance-limited underbridge two-way four-lane pavement structure comprises a broken stone hardcore, a cement stabilized broken stone lower base layer, an assembly type prestressed concrete upper base layer and an asphalt surface layer which are sequentially arranged in underbridge undisturbed soil from bottom to top, and is characterized in that brick piles driven into the underbridge undisturbed soil are uniformly arranged below the broken stone hardcore; each brick pile is composed of a plurality of solid clay brick layers which are staggered up and down; macadam blind ditches for discharging water in undisturbed soil under the bridge between the brick piles are formed in the two sides of the macadam hardcore. According to the clearance-limited under-bridge two-way four-lane pavement structure, the brick piles are adopted as the pile foundations, the height of a layer of solid clay bricks driven in each time is high, required machinery is light and convenient, vibration force is small, the influence on the pile foundations of existing bridges is small, and the clearance-limited under-bridge two-way four-lane pavement structure is not limited by the clear height of the bridges; and a pavement structure which is stable in structure and high in bearing capacity can be built below the existing bridge with the limited clearance.

Description

Technical Field

[0001] The utility model relates to a road surface structure, and more specifically, to a two-way four-lane road surface structure under a bridge with limited clearance. Background Art

[0002] With the development of urbanization in China, the supporting road traffic network has also expanded and developed synchronously, and then there has emerged the situation that newly built roads pass under existing railways or existing highways. Affected by the limited clearance height under the existing road, if a conventional roadbed is adopted, it is necessary to excavate the original soil under the bridge deeper. The deeper excavation of the original soil under the bridge will inevitably affect the pile foundation of the existing road, and the stability of the pile foundation will be adversely affected.

[0003] It is better not to excavate the original soil and adopt a pile foundation. If precast piles or cast-in-place piles are adopted, it is necessary to use large-sized machinery for pile driving operations. It is very difficult for the limited clearance of the existing road to accommodate the pile driving operations. Even if the pile driving operations can be accommodated, a large vibration will inevitably be generated during the pile driving process, which will also have an adverse impact on the bearing capacity and stability of the pile foundation of the existing road. Therefore, the utility model provides a two-way four-lane road surface structure under a bridge that is not restricted by the net height of the existing bridge and has little impact on the pile foundation of the existing bridge. Summary of the Invention

[0004] The utility model overcomes the above technical problems and provides a two-way four-lane road surface structure under a bridge with limited clearance.

[0005] The two-way four-lane road surface structure under a bridge with limited clearance of the utility model includes a crushed stone cushion layer, a cement stabilized crushed stone lower base layer, an assembled prestressed concrete upper base layer and an asphalt surface layer which are sequentially arranged from bottom to top in the original soil under the bridge. The assembled prestressed concrete upper base layer is laid by road-use pretensioned slabs; its characteristics are: brick piles are uniformly arranged below the crushed stone cushion layer and are driven into the original soil under the bridge. The brick piles are composed of several solid clay brick layers placed in a staggered manner up and down; crushed stone blind ditches for draining the moisture in the original soil between the brick piles are arranged on both sides of the crushed stone cushion layer.

[0006] In the two-way four-lane road surface structure under a bridge with limited clearance of the utility model, the solid clay brick layer is composed of four solid clay bricks placed vertically, and the solid clay bricks in the upper and lower adjacent solid clay brick layers form a 90° angle.

[0007] In the two-way four-lane road surface structure under a bridge with limited clearance of the utility model, the cross-section of the brick pile is a square with a side length of 240mm * 240mm, the height of the brick pile is 3.5m to 4.0m, and the pile spacing of the brick piles in the longitudinal and transverse directions is 0.5m to 0.8m.

[0008] The pavement structure of a two-way four-lane under a bridge with limited clearance of the present utility model, the cross-section of the gravel blind drain is a square with a size of 240mm * 240mm, the inner side of the gravel blind drain is connected to the gravel cushion layer, and a drainage facility connected thereto is arranged on the outer side.

[0009] The pavement structure of a two-way four-lane under a bridge with limited clearance of the present utility model, the precast prestressed concrete upper base is divided into a right side of the upper base and a left side of the upper base, adjacent pretensioned slabs in the longitudinal direction are connected by a transverse self-stress joint; between two adjacent pretensioned slabs in the right side of the upper base in the transverse direction, and between two adjacent pretensioned slabs in the left side of the upper base in the transverse direction are connected by a longitudinal self-stress joint; a temperature joint is arranged between the leftmost pretensioned slab in the right side of the upper base and the rightmost pretensioned slab in the left side of the upper base.

[0010] The pavement structure of a two-way four-lane under a bridge with limited clearance of the present utility model, the thickness of the gravel cushion layer is 20cm - 30cm.

[0011] The pavement structure of a two-way four-lane under a bridge with limited clearance of the present utility model, the thickness of the cement stabilized macadam lower base is 15cm - 18cm, and the 7-day compressive strength after the cement stabilized macadam lower base is poured is 2.5MPa - 4.0MPa.

[0012] The pavement structure of a two-way four-lane under a bridge with limited clearance of the present utility model, the thickness of the asphalt surface layer is 7cm - 15cm.

[0013] The beneficial effects of the present utility model are: for the pavement structure of a two-way four-lane under a bridge with limited clearance of the present utility model, brick piles, gravel cushion layer, cement stabilized macadam lower base, precast prestressed concrete upper base and asphalt surface layer are sequentially arranged from bottom to top in the original soil under the bridge. The pile foundation supporting the road structure uses brick piles. Each time, the height of a layer of solid clay bricks is driven in. The required machinery is relatively light, the vibration force is small, the influence on the pile foundation of the existing bridge is small, and the driving process of the brick piles is not restricted by the bridge net height, which is beneficial to constructing a pavement structure with stable structure and high bearing capacity under the existing bridge with limited clearance.

[0014] At the same time, gravel blind drains are arranged on both sides of the gravel cushion layer, which is beneficial to the drainage of the moisture in the original soil under the bridge between the brick piles, thereby improving the bearing capacity of the overall foundation of the road; the upper base uses a precast prestressed concrete base, which has a higher overall bearing capacity than other bases. There are basically no cracks during the use of the precast prestressed concrete base, so there are no base reflection cracks in the asphalt surface layer. Therefore, the service life of the asphalt surface layer is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the pavement structure of a two-way four-lane under a bridge with limited clearance of the present utility model;

[0016] Figure 2 It is the top view of the assembled prestressed concrete upper base in the present utility model;

[0017] Figure 3 It is the three-dimensional structure schematic diagram of the brick pile in the present utility model.

[0018] In the figure: 1 existing bridge, 2 asphalt surface course, 3 assembled prestressed concrete upper base, 4 cement stabilized macadam lower base, 5 gravel cushion, 6 gravel blind ditch, 7 brick pile, 8 bridge pile foundation, 9 pretensioned slab, 10 longitudinal self-stress joint, 11 transverse self-stress joint, 12 temperature joint, 13 right side of the upper base, 14 left side of the upper base, 15 original soil under the bridge, 16 solid clay brick layer. Specific implementation manners

[0019] The present utility model will be further described below in conjunction with the drawings and embodiments.

[0020] As Figure 1 shown, the structure schematic diagram of the two-way four-lane pavement structure under the bridge with limited clearance in the present utility model is given. It is composed of a brick pile 7, a gravel cushion 5, a cement stabilized macadam lower base 4, an assembled prestressed concrete upper base 3 and an asphalt surface course 2 which are sequentially arranged from bottom to top in the original soil 15 under the existing bridge 1. The gravel cushion 5 is formed by laying gravel after excavating the original soil 15 under the bridge. The brick piles 7 are evenly distributed in the original soil 15 under the gravel cushion 5. As Figure 3 shown, the three-dimensional structure schematic diagram of the brick pile in the present utility model is given. Each brick pile 7 is composed of a number of solid clay brick layers 16 stacked together. The solid clay bricks in the upper and lower adjacent solid clay brick layers 16 form a 90° angle. The cement stabilized macadam lower base 4 is laid above the gravel cushion 5. In this way, the brick piles 7 and the gravel cushion 5 jointly realize the stable support for the cement stabilized macadam lower base 4.

[0021] The assembled prestressed concrete upper base 3 is laid on the cement stabilized macadam lower base 4. It is composed of evenly laid road pretensioned slabs 9. After prefabrication, the pretensioned slabs 9 have compressive stress in the longitudinal direction, enabling them to withstand the tensile stress formed on the road during vehicle driving. The asphalt surface course 2 is laid above the assembled prestressed concrete upper base 3.

[0022] As Figure 3 shown, since the brick pile 7 is composed of multiple layers of solid clay brick layers 16 stacked together, and each solid clay brick layer 16 is formed by 4 solid clay bricks arranged side by side and placed vertically, in this way, a mechanical device with a smaller volume can be used to press the solid clay bricks layer by layer to form the brick pile 7. The pressing of the brick pile 7 can be successfully completed under the existing bridge 1 with limited clearance. Since the required pressing mechanical device is relatively light and has a small vibration force, the influence on the pile foundation of the existing bridge 1 is small.

[0023] It can be seen that by adopting the method of pressing solid clay brick layers 16 one by one, the problem that the stability of the existing bridge 1 subgrade is affected due to the deep excavation of the original soil 15 under the bridge by the conventional subgrade is avoided, and the problem that precast piles or cast-in-place piles cannot be constructed due to the limited net height of the existing bridge 1 and the adverse impact on the stability of the existing bridge 1 is also avoided. At the same time, the solid clay brick can also adsorb the water in the original soil 15 under the bridge, further improving the bearing capacity of the original soil 15 between the brick piles 7.

[0024] Both sides of the shown gravel cushion layer 5 are provided with gravel blind ditches 6. The inner side of the gravel blind ditches 6 is connected to the gravel cushion layer 5, and a drainage facility connected thereto is arranged on the outer side of the gravel blind ditches 6. In this way, the gravel blind ditches 6 can drain the moisture in the original soil under the bridge between the brick piles 7, thereby improving the bearing capacity of the overall road foundation.

[0025] As Figure 2 shown, the top view of the precast prestressed concrete upper base in the present utility model is given. The precast prestressed concrete upper base 3 is composed of pre-tensioned slabs 9 laid evenly. For a pavement structure forming a two-way four-lane road, 4 pre-tensioned slabs 9 need to be laid in the transverse direction of the road. The two columns of pre-tensioned slabs 9 on the right form the right side of the upper base 13, and the two columns of pre-tensioned slabs on the left form the left side of the upper base 14.

[0026] In the precast prestressed concrete upper base 3, two adjacent pre-tensioned slabs 9 in the longitudinal direction are connected by a transverse self-stress joint 11. In the transverse direction, two adjacent pre-tensioned slabs 9 in the right side of the upper base 13 are connected by a longitudinal self-stress joint 10. Similarly, two adjacent pre-tensioned slabs 9 in the left side of the upper base 14 in the transverse direction are also connected by a self-stress joint 10; high-expansion concrete is poured into the longitudinal self-stress joint 10 and the transverse self-stress joint 11 to form a compressive stress on the ends of the pre-tensioned slabs 9, so as to improve the strength of the ends of the pre-tensioned slabs 9. A temperature joint 12 is arranged between the left pre-tensioned slab 9 in the right side of the upper base 13 and the right pre-tensioned slab 9 in the left side of the upper base 14 to adapt to the expansion and contraction of the pre-tensioned slabs 9 caused by temperature changes.

[0027] As specific dimensional requirements, the cross-section of the brick pile 7 is a square with a size of 240mm * 240mm, the height of the brick pile 7 is 3.5m to 4.0m, and the pile spacing of the brick piles 7 in the longitudinal and transverse directions is 0.5m to 0.8m. The cross-section of the gravel blind ditch 6 is a square with a size of 240mm * 240mm; the thickness of the gravel cushion layer 5 is 20cm to 30cm, the thickness of the cement stabilized macadam lower base 4 is 15cm to 18cm, and the 7-day compressive strength of the cement stabilized macadam lower base 4 after pouring is 2.5MPa to 4.0MPa. The thickness of the asphalt surface layer 2 is 7cm to 15cm.

[0028] Among them, in order to achieve the adsorption effect of the solid clay brick on the moisture in the original soil 15 under the bridge, it is advisable to use solid clay bricks that are no more than 10 days away from the time of leaving the kiln. During the construction of the longitudinal self-stress joint 10 and the transverse self-stress joint 11, first pour the transverse self-stress joint 11, and then pour the longitudinal self-stress joint 10 after 7 days of water curing. After the longitudinal self-stress joint 10 is poured, water cure for 7 days.

Claims

1. A two-way four-lane pavement structure under a bridge with limited headroom, comprising a crushed stone cushion layer (5), a cement stabilized crushed stone lower base layer (4), a precast prestressed concrete upper base layer (3), and an asphalt surface layer (2) sequentially arranged from bottom to top in the original soil (15) under the bridge. The precast prestressed concrete upper base layer is laid by road-use pretensioned slabs (9); it is characterized in that: Below the gravel cushion layer, brick piles (7) driven into the original soil under the bridge are evenly arranged. The brick piles are composed of a number of solid clay brick layers (16) placed alternately up and down; on both sides of the gravel cushion layer, there are gravel blind ditches (6) for draining the moisture in the original soil under the bridge between the brick piles.

2. The under-bridge two-way four-lane pavement structure with limited clearance according to claim 1, characterized in that: The solid clay brick layer (16) is composed of four solid clay bricks placed vertically, and the solid clay bricks in the adjacent upper and lower solid clay brick layers form a 90° angle.

3. The under-bridge two-way four-lane pavement structure with limited clearance according to claim 1 or 2, characterized in that: The cross-section of the brick pile (7) is a square with a size of 240mm * 240mm, the height of the brick pile is 3.5m to 4.0m, and the pile spacing of the brick piles in the longitudinal and transverse directions is 0.5m to 0.8m.

4. The under-bridge two-way four-lane pavement structure with limited clearance according to claim 1 or 2, characterized in that: The cross-section of the gravel blind ditch (6) is a square with a size of 240mm * 240mm. The inner side of the gravel blind ditch is connected to the gravel cushion layer (5), and a drainage facility is provided on the outer side and is connected to it.

5. The under-bridge two-way four-lane pavement structure with limited clearance according to claim 1 or 2, characterized in that: The precast prestressed concrete upper base (3) is divided into the right upper base (13) and the left upper base (14). The adjacent pretensioned slabs (9) in the longitudinal direction are connected by a transverse self-stress joint (11); between two adjacent pretensioned slabs in the right upper base in the transverse direction, and between two adjacent pretensioned slabs in the left upper base in the transverse direction are connected by a longitudinal self-stress joint (10); a temperature joint (12) is provided between the leftmost pretensioned slab in the right upper base and the rightmost pretensioned slab in the left upper base.

6. The structure of the two-way four-lane road surface under the bridge with limited clearance according to claim 1 or 2, characterized in that: The thickness of the gravel cushion layer (5) is 20cm to 30cm.

7. The under-bridge two-way four-lane pavement structure with limited clearance according to claim 1 or 2, characterized in that: The thickness of the cement stabilized macadam lower base (4) is 15cm to 18cm, and the 7-day compressive strength after the cement stabilized macadam lower base is poured is 2.5MPa to 4.0MPa.

8. The structure of the two-way four-lane road surface under the bridge with limited clearance according to claim 1 or 2, characterized in that: The thickness of the asphalt surface layer (2) is 7cm to 15cm.

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