CN117026720A - Pavement subbase layer construction method based on precast beam field concrete panel - Google Patents

Abstract

The application provides a pavement subbase layer construction method based on a precast beam field concrete panel, which comprises the following steps: s1, paving a gravel cushion layer on a road base layer in a beam field construction stage, pouring a concrete panel on the gravel cushion layer, and setting a fracture joint and an expansion joint; s2, after prefabrication of the small box girder is completed, breaking the pedestal and the track pedestal, and reserving a concrete panel; s3, checking the concrete panel, further cleaning the broken joint and the expansion joint on the concrete panel, removing scraps in the cut, filling the water stop strip in the broken joint, embedding the filling material in the expansion joint, and finishing waterproof treatment; s4, paving a water-stable subbase layer on the concrete panel. The application can save materials and manpower in the road construction process, reduce construction noise and dust, improve the bearing capacity and the service life of the road surface structure, and reduce the later maintenance cost.

Description

A construction method of pavement subbase cushion based on prefabricated beam field concrete panels

Technical field

The invention relates to the technical field of highway construction, and in particular to a pavement subbase cushion construction method based on prefabricated beam field concrete panels.

Background technique

The highway pavement structure is generally divided from top to bottom into asphalt concrete surface layer, water stable base layer and road base layer. Among them, the water-stabilized subbase is an important component connecting the roadbed and asphalt concrete surface layer, playing the role of water isolation and load transmission. The water-stabilized base layer generally uses cement-stabilized gravel, asphalt-stabilized gravel and other materials. Its construction quality directly affects the bearing capacity and service life of the pavement.

During highway construction, it is usually necessary to build a precast beam field at a predetermined location for the production of bridge components such as prestressed concrete box girders. Prefabricated beam fields generally adopt concrete hardening treatment to form a strong and flat concrete panel to withstand the weight of components such as box beams and the load of transportation vehicles. After the precast beam field is used, the concrete panels need to be removed and processed to restore the original roadbed structure. This traditional construction technology not only increases the difficulty and cost of construction, but also causes waste and pollution of concrete materials.

Therefore, how to effectively utilize the concrete panels that are not broken in the precast beam field and improve their reuse rate and resource conservation is a technical problem that technicians in the field urgently need to solve.

Contents of the invention

In view of this, the present invention provides a pavement subbase cushion construction method based on precast beam field concrete panels to at least solve the problems of high construction difficulty and serious waste in the prior art.

In order to achieve the above objects, the present invention adopts the following technical solutions:

A pavement subbase cushion construction method based on precast beam field concrete panels includes the following steps:

S1. In the construction stage of the beam yard, a gravel cushion is laid on the roadbed, a concrete panel is poured on the gravel cushion, and fracture joints and expansion joints are set;

S2. After the prefabrication of the small box beams is completed, remove the pedestal and track pedestal, and retain the concrete panel;

S3. Inspect the concrete panel, and further clean the broken joints and expansion joints on the concrete panel, remove debris in the cuts, fill waterstops in the broken joints, and fill the expansion joints with Embed filling material and complete waterproofing treatment;

S4. Spread a water-stabilized base layer on the concrete panel.

Preferably, the thickness of the gravel cushion is 5 cm, and the thickness of the concrete panel is 25 cm.

Preferably, in S1, the top elevation of the concrete panel is controlled according to the finishing top elevation. For the fill section, a pre-lift value is set for the elevation based on the weight of the beam plate and the weight of the heavy truck when used in the beam yard.

Preferably, in S1, during the process of pouring the concrete panel, steel bars are pre-embedded between the base and the concrete panel to be poured.

Preferably, in S1, when the pedestal is poured, steel bars are arranged within the two end areas of the pedestal during the overall hardening process.

Preferably, during the early stage of track expansion foundation construction, the top elevation is set lower than the top elevation of the concrete panel.

Preferably, the locations and sizes of fracture joints and expansion joints are divided into blocks according to the length and width of the concrete panel.

Preferably, the inspection items for inspecting the concrete panel in S3 include deflection, bottom plate hollowing, cracks, hollows, honeycombs, elevation and flatness. When defects or deviations are found, they are repaired or replaced.

Preferably, the waterproofing treatment in S3 includes embedding filling material in the expansion joint and applying waterproof material; wherein the filling material includes polyurethane foam strips; and the waterproofing material includes sealant.

Preferably, the specific contents of S4 include:

Determine the paving thickness and set the paving thickness control points;

Spread the water-stabilizing material evenly on the concrete panel, and adjust the paving width and slope;

Compact the water-stabilized material and check whether its compactness meets the specification requirements.

It can be seen from the above technical solutions that compared with the existing technology, the present invention provides a pavement subbase cushion construction method based on prefabricated beam field concrete panels, which has the following beneficial effects:

(1) Use the concrete panels that cannot be broken in the prefabricated beam field as the pavement base layer, avoiding the dismantling and processing of the concrete panels, saving materials and manpower, and reducing construction noise and dust;

(2) Concrete panels have the advantages of high strength, good durability, and strong waterproofness, which can effectively improve the bearing capacity and service life of the pavement structure and reduce subsequent maintenance costs;

(3) The concrete panel adopts modular construction and sets reasonable fracture joints and expansion joints to prevent cracks and deformation caused by thermal expansion and contraction, and ensure the smoothness and stability of the road surface;

(4) This method simplifies the construction process of the pavement subbase, shortens the construction period, and improves construction efficiency.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic flow chart of a pavement subbase cushion construction method based on precast beam field concrete panels provided by the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

The invention provides a pavement subbase cushion construction method based on prefabricated beam field concrete panels. As shown in Figure 1, it includes the following steps:

S1. In the construction stage of the beam yard, a gravel cushion is laid on the roadbed, a concrete panel is poured on the gravel cushion, and fracture joints and expansion joints are set;

S2. After the prefabrication of the small box beams is completed, remove the pedestal and track pedestal and retain the concrete panel;

S3. Inspect the concrete panel, and further clean the fractures and expansion joints on the concrete panel, remove debris in the cuts, fill the fractures with waterstops, embed filling materials in the expansion joints, and complete the waterproofing treatment ;

S4. Pave the water-stabilized base layer on the concrete panel.

In this embodiment, the beam field is 587m long, 31m wide, and has a total area of 18,197 square meters. The pedestal and track pedestal are demolished by blasting. When blasting, attention should be paid to controlling the blasting volume and blasting direction to prevent damage to the concrete panel.

It should be noted that the setting of fracture joints and expansion joints is to prevent cracks and deformation of the concrete panel due to temperature changes, which will affect the stability and smoothness of the pavement structure.

In order to further implement the above technical solution, the thickness of the gravel cushion is 5cm and the thickness of the concrete panel is 25cm.

It should be noted:

The thickness of the road bed on the highway is 30cm, the gravel cushion is 5cm, and the concrete panel is 25cm, which can improve the load-bearing capacity of the panel and adjust the uneven settlement of the foundation.

In order to further implement the above technical solution, in S1, the top elevation of the concrete panel is controlled according to the finishing top elevation. For the fill section, the pre-lift value is set for the elevation according to the weight of the beam plate and the weight of the heavy truck when used in the beam field.

In actual application, the elevation of the finishing top surface is controlled: the elevation is the design value, which can be controlled according to the cross-sectional measurement method stipulated in the bridge regulations; the weight of the beam plate and the weight of the heavy vehicle travel set a pre-lift value for the elevation: it is obtained from construction experience and is only used when When setting up the beam field in the fill area, the pre-lift value should be taken into consideration. For every 1m of filling height, the pre-lift value needs to be increased by 0.006m. If the beam field is set up in the excavation area, since the foundation is very stable, settlement will basically not occur, so the pre-lift value is not considered.

In order to further implement the above technical solution, in S1, during the process of pouring the concrete panel, steel bars are pre-embedded between the base and the concrete panel to be poured.

It should be noted that considering that the integrity of the concrete panel will not be affected when the pedestal and track pedestal are removed in the later stage, concrete is poured as a whole during site hardening in the early stage, and steel bars are pre-embedded between the pedestal and the concrete panel to enhance the connection strength.

In order to further implement the above technical solution, in S1, when the pedestal is poured, steel bars are arranged within the two end areas of the pedestal during the overall hardening process.

It should be noted that when pouring the pedestal, considering the subsequent tensioning process, the arching of the beam body will cause greater pressure on both ends of the pedestal. In order to improve the load-bearing capacity of both ends of the pedestal, steel bars are arranged within the area at both ends of the pedestal.

In order to further implement the above technical solution, during the initial construction of the track expansion foundation, the top elevation was set lower than the top elevation of the concrete panel.

It should be noted that the track expansion foundation is the beam yard gantry crane track expansion foundation, which is arranged longitudinally along the length of the beam yard and is constructed at the same time as the concrete pouring of the beam yard panel; the gantry crane track expansion foundation is a key process for the gantry crane layout and is the key to the production of the beam yard. Necessary conditions for beam operation.

Setting the top elevation lower than the top elevation of the concrete panel is to consider that the expanded foundation roof will not be higher than the finishing top elevation when the track pedestal is subsequently broken.

In order to further implement the above technical solution, the positions and sizes of fracture joints and expansion joints are divided into blocks according to the length and width of the concrete panel.

During the general implementation process, the longitudinal fracture positions are divided according to the beam field area. The beam field area includes the hydraulic formwork placement area at the edge of the beam field, the beam field prefabricated pedestal placement area, and the beam field prefabricated pedestal placement area. The horizontal expansion joints are divided according to the beam field area. Arrangement of drainage ditches in the site; in this embodiment, the concrete panel is longitudinally divided into 2.5+10.5+4+10.5+2.5m, where 2.5m refers to the area where the hydraulic formwork is placed at the edge of the beam field, and the actual distance from the edge of the beam field 2.5m; 10.5m refers to the area where the prefabricated pedestal is placed in the beam yard, and is actually 13m away from the sideline of the beam yard; 4m refers to the middle lane area of the beam yard, which is actually 17m away from the sideline of the beam yard; it is disconnected laterally at the horizontal ditch position, and the disconnection distance is 40m . The width of the break joint and the expansion joint are both 2cm and the depth is 10cm.

In order to further implement the above technical solution, the inspection items of concrete panels in S3 include deflection, bottom plate hollowing, cracks, hollows, honeycombs, elevation and flatness. When defects or deviations are found, they will be repaired or replaced.

In this embodiment, according to the acceptance index requirements of Hunan Provincial Transportation Planning, Survey and Design Institute Co., Ltd., the deflection requirements of the concrete panels in the precast yard in the K7+890~K8+477 section are: ≤45 (0.01mm). Elevation requirements: ±5cm. Concrete panels 5cm higher than the design elevation of the top of the road bed shall be milled. Road sections lower than the design elevation of the top of the road bed shall be leveled with water-stabilizing materials to the elevation of the top of the road bed (in the water level of the road surface). Leveling should be carried out during construction to stabilize the base layer).

In order to further implement the above technical solution, the waterproofing treatment in S3 includes embedding filling material in the expansion joint and applying waterproof material; the filling material includes polyurethane foam strips; the waterproofing material includes sealant.

In this embodiment, the width of the break seam and the expansion joint are both 2cm and the depth is 10cm. The waterstop is a rubber waterstop, the polyurethane foam strip is a flexible foam strip, and the sealant is polyurethane sealant. When filling, the uniformity and tightness of the filling material should be ensured to prevent water seepage and looseness.

In order to further implement the above technical solutions, the specific contents of S4 include:

Determine the paving thickness and set the paving thickness control points;

Spread the water-stabilizing material evenly on the concrete panel, and adjust the paving width and slope;

Compact the water-stabilized material and check whether its compactness meets the specification requirements.

During the specific implementation process, the thickness of the water-stabilized base was set to 20cm, including 4% cement-stabilized gravel, with a compressive strength of 3-5Mpa;

The water-stabilized material is paved using a special paver, and sensors are used to automatically control the paving thickness and cross slope. The paving speed should be kept constant and controlled between 1.0 and 3.0m/min.

After paving, the water-stabilized material is rolled. The rolling sequence is: first use a static pressure roller for 2 passes, then use a vibratory roller for 4 passes, and finally use a rubber wheel or double steel wheel roller for 2 passes. The rolling speed is appropriately adjusted according to different types of road rollers and different stages of rolling, generally between 1.5 and 2.5km/h. When rolling, check the compactness and flatness while rolling, and deal with unqualified parts in time.

After the construction of water stabilizing materials is completed, health care and protection should be carried out in time. Health protection should start after the cement is finally set, and traffic should be closed for no less than 7 days. During the curing period, the surface should be kept moist, and methods such as sprinkling water or covering with geotextile should be used for curing. Heavy vehicle traffic is strictly prohibited during the health care period.

The above embodiments are only used to illustrate the technical solutions of the present application, but are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments. Modifications are made to the recorded technical solutions, or equivalent substitutions are made to some of the technical features; these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and shall be included in this application. within the scope of protection.

Claims (10)

1. The pavement subbase layer construction method based on the precast beam field concrete panel is characterized by comprising the following steps of:

s1, paving a gravel cushion layer on a road base layer in a beam field construction stage, pouring a concrete panel on the gravel cushion layer, and setting a fracture joint and an expansion joint;

s2, after prefabrication of the small box girder is completed, breaking the pedestal and the track pedestal, and reserving the concrete panel;

s3, checking the concrete panel, further cleaning a broken joint and an expansion joint on the concrete panel, removing scraps in the cut, filling a water stop strip in the broken joint, embedding a filling material in the expansion joint, and finishing waterproof treatment;

s4, paving a water-stable subbase layer on the concrete panel.

2. The method for constructing the pavement subbase layer based on the precast beam field concrete panel according to claim 1, wherein the thickness of the crushed stone subbase layer is 5cm, and the thickness of the concrete panel is 25cm.

3. The construction method of the pavement subbase layer based on the precast beam field concrete panel according to claim 1, wherein in S1, the elevation of the top surface of the concrete panel is controlled according to the elevation of the finish top surface, and for the filling section, a pre-lifting value is set according to the weight of the beam slab and the walking weight of the heavy truck when the beam field is used.

4. The construction method of the pavement subbase layer based on the precast beam field concrete panel according to claim 1, wherein in the step S1, steel bars are pre-buried between the pedestal and the concrete panel to be poured in the process of pouring the concrete panel.

5. The method for constructing a pavement underlayment layer based on precast beam field concrete panels according to claim 1, wherein in S1, steel bars are arranged in the range of the two end regions of the pedestal in the process of integral hardening when the pedestal is poured.

6. The method for constructing a pavement subbase layer based on a precast beam field concrete panel according to claim 1, wherein the top surface elevation is set to be lower than the top surface elevation of the concrete panel in the preliminary track expansion foundation construction.

7. The method for constructing a pavement subbase layer based on a precast beam field concrete panel according to claim 1, wherein the positions and the sizes of the break joints and the expansion joints are divided into blocks according to the length and the width of the concrete panel.

8. The method for constructing a pavement underlayment layer based on precast beam farm concrete panels according to claim 1, wherein the inspection items for inspecting the concrete panels in S3 include deflection, floor run-out, cracks, hollows, honeycomb, elevation and flatness, and repair or replacement is performed when defects or deviations are found.

9. The construction method of a pavement subbase layer based on a precast beam field concrete panel according to claim 1, wherein the waterproofing treatment in S3 comprises embedding a filler material in an expansion joint and brushing a waterproofing material; wherein the filler material comprises polyurethane foam strips; the waterproof material comprises a sealant.

10. The pavement subbase layer construction method based on the precast beam field concrete panel according to claim 1, wherein the specific content of S4 comprises:

determining a paving thickness, and setting a paving thickness control point;

uniformly spreading the water stabilizing material on the concrete panel, and adjusting spreading width and gradient;

compacting the water stable material and detecting whether the compactness meets the specification requirement.