Integrated structure and construction method of converting existing roadbed block stone retaining wall from white to black pavement

Abstract

The invention discloses an integrated structure and construction method for converting a white-to-black road surface of an existing roadbed block stone retaining wall. The structure comprises a retaining wall, a drainage pipe, a fill and an original cement concrete road surface of an original roadbed. The original cement concrete road surface is mainly subjected to resonance crushing to form a base layer, and a steel mesh and a surface layer are laid on the base layer in sequence. A steel mesh fixed by anchoring steel bars is provided on the outer side and the top of the retaining wall. The steel mesh is interconnected with the steel mesh on the base layer and cement concrete is sprayed to form an integrated structure. Therefore, the invention has the advantages of simple structure, economic applicability, safety and reliability, energy saving and emission reduction, and dynamic self-stress balance. It can better save energy and protect resources, and embodies the concept of green and energy-saving road engineering construction. Combined with corresponding construction methods, it also has high economic benefits, energy-saving and emission reduction benefits, and social benefits.

Description

Technical Field

[0001] The invention relates to the field of energy-saving road construction, and in particular to an integrated structure and construction method for converting an existing roadbed block stone retaining wall from white to black pavement. Background Art

[0002] In order to effectively improve the sense of happiness and gain of people in mountainous areas, build four-good rural roads, beautify rural ecological tourism roads, develop rich tourism resources in mountainous areas, and improve road capacity and service levels, it is necessary to transform the damaged cement concrete pavement built in the early days into asphalt concrete pavement, that is, "white to black", and reinforce and transform the roadbed retaining wall.

[0003] At present, the retaining wall is often reinforced by pouring cement concrete on the outside of the original retaining wall to increase the cross section of the retaining wall or adding reinforcement bars in the roadbed. At the same time, a wire mesh is set between the new asphalt concrete pavement and the resonant gravel base of the original cement concrete pavement to transform the white to black. This old road reconstruction method transforms the pavement and the retaining wall as independent parts, ignoring the mutual connection between the pavement and the retaining wall, resulting in poor overall structural stress and economic benefits. The overall coordinated stress effect of each part of the engineering structure is better than the individual stress of each part. Therefore, the method of integrating the steel mesh at the bottom of the white-to-black asphalt concrete pavement and the reinforcement of the original retaining wall is obviously conducive to the coordinated stress of the pavement and the retaining wall, and exerting greater economic and energy-saving benefits. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide an integrated structure and construction method for converting the existing roadbed block stone retaining wall from white to black pavement, which is simple in structure, economical and applicable, safe and reliable, energy-saving and emission-reducing, and has dynamic self-stress balance.

[0005] The technical problem of the present invention is achieved through the following technical solutions:

[0006] An integrated structure of a white-to-black road surface of an existing roadbed block stone retaining wall comprises an existing roadbed retaining wall, a drainage pipe, a fill and an original cement concrete road surface. The original cement concrete road surface is resonantly crushed to form a base layer, on which a steel mesh and a surface layer are laid in sequence; the outer side and top of the retaining wall are provided with a steel mesh fixed by anchoring steel bars, the steel mesh is interconnected with the steel mesh on the base layer and sprayed with cement concrete to form an integrated structure.

[0007] The surface layer produces a deflection disk under the action of the vehicle load. xoy The plane deflection curve is simulated by the logistic equation, that is, the Logistic curve. The equation of the Logistic deflection curve is: , deflection curve equation Around xoy flat y The axis rotates one circle to form a concave deflection basin. Ignoring the compression deformation of the surface layer itself, the deformation curve of the wire mesh sinks synchronously with the surface layer and also forms a Logistic deflection curve of the same shape. According to the Winkler foundation hypothesis, the strength of the reaction force on the settlement of the wire mesh is , so the following calculation formula is obtained:

[0008] Formula 1:

[0009] Wire Mesh Bending Plate Center O , where the wire mesh contacts the surface layer at the top of the retaining wall A The midpoint between the two tire groups of the standard axle load of the vehicle B The sedimentation is ,by O The origin xoy The unknown parameters of the in-plane Logistic deflection curve equation and the related calculation formula are:

[0010]

[0011] In the formula

[0012]

[0013] From this, the unknown parameters of the Logistic deflection curve are obtained ;

[0014]

[0015] Formula 2:

[0016] In the case of a single car driving, due to the principle of force balance, the contact point between the wire mesh of unit width and the steel mesh at the top of the retaining wall A The tension and maximum deflection between O The tensions at

[0017]

[0018] In the formula

[0019]

[0020] When multiple cars are acting on a road surface section at the same time, the contact point between the wire mesh of unit width and the steel mesh at the top of the retaining wall A and maximum deflection O The tension at is calculated according to the superposition principle:

[0021] Formula 3:

[0022]

[0023] The steel mesh at the bottom of the surface layer and the steel mesh of the reinforced retaining wall are connected to each other at the top of the retaining wall. When a vehicle travels on the surface layer, the steel mesh at the bottom of the surface layer settles and stretches, generating a pulling force on the top of the retaining wall. This pulling force is dynamic and disappears as the vehicle leaves, and increases as the weight and number of vehicles increase, and is opposite to the horizontal active earth pressure of the retaining wall.

[0024] The symbols in Formula 1, Formula 2 and Formula 3 are defined as:

[0025] ——are the fitting parameters of the Logistic deflection curve, , dimensionless, ;

[0026] ——Single circle radius of standard axle load of automobile, ;

[0027] ——The distance from the center of the single circle of standard axle load of the car close to the retaining wall to the top of the retaining wall A The distance between the center and the center of the standard axle load of the vehicle O From the midpoint between the two tire groups of the standard axle load of the vehicle B The distance between ;

[0028] ——The surface layer produces a deflection plate under the action of vehicle load. xoy The plane deflection curve is simulated by the logistic equation, i.e., the logistic curve. The deflection curve equation is: , bend the basin to Curve around xoy flat y The axis rotates one circle to form a concave bending sink;

[0029] ——respectively, they are the single-circle uniformly distributed load strength of the standard axle load of the automobile, the deadweight strength of the surface material, and the reaction strength of the settlement of the wire mesh under the single-circle uniformly distributed load of the standard axle load of the automobile. ;

[0030] ——respectively the friction coefficient between the wire mesh and the surface layer and the base layer, and the foundation reaction coefficient, Obtained from reference materials or actual measurements, dimensionless, ;

[0031] ——Unit width wire mesh and top of retaining wall A Tensile force at the center of the single circle of the standard axle load of the automobileO The tensile force at the place, the allowable tensile force of the wire mesh, ;

[0032] ——respectively any position and x The angle of the axis, near the top of the retaining wall A Department and x The angle of the shaft, the center of the single circle of the standard axle load of the automobile O Department and x The angle between the axles and the midpoint between the two tire groups of the standard axle load of the vehicle B Department and x The angle of the axis, ;

[0033] ——Friction stress between the wire mesh and the surface layer and base layer, ;

[0034] ——Based on the center of the single circular bending sinker with standard axle load of automobile O The origin of coordinates x axis, y axis, ;

[0035] --coefficient, .

[0036] The steel mesh is connected to the wire mesh on the base and sprayed with cement concrete to form a protective layer. The sprayed cement concrete protective layer is C30, the thickness of the protective layer is 8cm to 20cm, the thickness of the steel mesh protective layer is not less than 3cm, and the protective layer on the top of the retaining wall can also be made of cast-in-place C30 cement concrete.

[0037] The steel mesh is a steel mesh sheet welded from hot-rolled steel bars; the steel mesh and wire mesh on the top of the retaining wall are welded together to form an integrated structure with the protective layer and the surface layer to bear force together.

[0038] The anchoring steel bars are hot-rolled steel bars; the steel mesh is fixed to the outer side and top of the retaining wall via anchoring steel bars, which are inserted into the gaps between the blocks of the retaining wall or drilled into the blocks of the retaining wall and arranged in a plum blossom shape.

[0039] The steel wire mesh is made of anti-corrosion treated steel wires woven into a hexagonal double-twisted metal mesh, the longitudinal overlap width of the steel wire mesh is 20cm-30cm, and the transverse overlap width is 15cm-20cm; a plurality of distributed steel bars are woven into the steel wire mesh at a certain interval along the longitudinal direction of the base layer, and at the same time, one distributed steel bar is woven into each of the two side edges of the base layer along the longitudinal direction; the steel wire mesh is fixed to the base layer through anchoring steel nails, and the anchoring point spacing of the anchoring steel nails is 90cm-100cm or 50cm-60cm in the longitudinal direction and 70cm-80cm or 40cm-50cm in the transverse direction, arranged in a plum blossom shape.

[0040] The distribution steel bars are common hot-rolled round steel bars, and the spacing along the longitudinal direction of the base layer is the distance of 1 or 2 hexagonal mesh holes. The distribution steel bars woven into the edges of both sides of the base layer along the longitudinal direction are disconnected every 2m to 3m to release the stress.

[0041] The retaining wall is a block stone masonry protective structure of the mountain road subgrade to be renovated and upgraded; the surface layer is the black asphalt concrete pavement after renovation.

[0042] The base layer is formed by crushing the original cement concrete pavement by a resonance crusher, and the upper half of the base layer is composed of dense granular fragments less than 10 cm, and the lower half of the base layer is composed of interlocking granular fragments of 10 cm to 20 cm.

[0043] A construction method for a white-to-black road surface integrated structure of an existing roadbed block stone retaining wall comprises the following steps:

[0044] Step 1: Integrated structural design of white-to-black road surface for retaining wall

[0045] ① Investigate and analyze the current status and bearing capacity of the old roadbed retaining wall, detect the deflection of the original road surface, formulate the thickness of the sprayed cement concrete of the existing roadbed block stone retaining wall, and select the specifications and layout methods of the steel mesh and wire mesh;

[0046] ② Determine the technical indicators of the materials used through experiments;

[0047] ③ Calculate the technical parameters of the integrated structure of the white-to-black road surface of the retaining wall by using Formula 1, Formula 2 and Formula 3, and carry out construction drawing design and propose a construction plan;

[0048] Step 2: Retaining wall reinforcement

[0049] ①Measure and lay out according to the design drawings;

[0050] ② Remove the top 20cm to 30cm of the existing roadbed stone retaining wall and clean up the severely weathered layer on the stone retaining wall surface;

[0051] ③ Make or purchase steel mesh and test it to be qualified, lay the steel mesh on the outside and top of the retaining wall, and fix it with anchor steel bars on the outside of the retaining wall and on the top after removing 20cm to 30cm;

[0052] ④ Prepare shotcrete mixture and pass the test;

[0053] ⑤ When spraying cement concrete protective layer on the retaining wall, first spray the gaps between the blocks of the retaining wall, use hand tools to tamp the sprayed cement concrete in the gaps to fill them densely, and then spray the entire wall surface, leaving the top of the retaining wall for spraying cement concrete or pouring cement concrete after the steel mesh and wire mesh are welded;

[0054] Step 3: Construction of the base after the original cement concrete pavement is resonantly crushed

[0055] ① First, replace the original cement concrete slabs that are severely cracked and damaged. When the strength of the replaced cement concrete slabs reaches more than 75% of the design strength, resonant crushing is carried out. The original cement concrete slabs that need to be replaced and those that do not need to be replaced are subjected to resonant gravel treatment together. The cement concrete pavement after resonant crushing is used as the base layer of the surface layer.

[0056] ② Before construction, the resonance operation path is laid out and adjacent crushing paths are closely connected;

[0057] ③ Resonance crushing is carried out in a path parallel to the road direction, without tilting the crushing, missing vibration, repeated crushing, or overlapping crushing, and a test section is arranged for resonance testing to obtain relevant data;

[0058] ④ According to the process parameters determined in the test section and combined with the differences in road conditions in the construction section, the construction process parameters are reasonably fine-tuned to ensure that the crushing effect meets the quality requirements of the crushed stone layer;

[0059] ⑤ Sprinkle water and roll the resonant crushed gravel layer, with a watering rate of 1kg / m 2 ~3kg / m 2 The rolling of the gravel layer is carried out in three stages: initial rolling, secondary rolling and final rolling. The rolling equipment is steel wheel roller, steel wheel vibratory roller or tire roller. The rolling is carried out in the order of "roadside to the middle" and "from low to high". During rolling, the adjacent rolling belts overlap by no less than 1 / 3 of the rolling wheel width. The technical indicators of flatness and compaction are tested to be qualified;

[0060] ⑥ The gravel layer after resonance crushing shall be continuously subjected to subsequent construction, the exposure time of the gravel layer shall not exceed 3 days, and the gravel layer shall not be open to traffic;

[0061] Step 4: Laying the wire mesh

[0062] ①After the wire mesh is delivered to the site, it should be mechanically hoisted and placed gently, and the wire mesh should be well protected to prevent damage to the wire mesh surface caused by manual throwing or vehicle rolling;

[0063] ② The wire mesh is fully unfolded, manually adjusted to the correct position, and each piece is overlapped according to regulations;

[0064] ③After the wire mesh is laid and before it is fixed, use a rubber-wheel roller to roll it 1 to 2 times; after the synchronous crushed stone seal layer is paved, use a rubber-wheel roller to roll it 1 to 2 times again;

[0065] ④ The mesh surface of the wire mesh uses M8 compression screws as anchor nails and is fixed with a small impact drill. The density of the anchor nails is not less than 1 / m 2 The fixed end of the mesh surface, sharp bends, and the wheel track of the paver should be appropriately increased to ensure close contact with the road surface;

[0066] ⑤ After the steel mesh is laid and accepted, the gravel lower sealing layer is constructed synchronously;

[0067] ⑥SBS modified asphalt for synchronous crushed stone seal, asphalt dosage 1.8g / m 2 ~2.0kg / m 2 Aggregate spreading amount: 13kg / m 2 ~15kg / m 2 , the maximum particle size of graded aggregate for synchronous crushed stone seal layer shall not exceed 19mm;

[0068] Step 5: Asphalt concrete construction

[0069] ① The materials of the asphalt mixture meet the design requirements. Sampling inspection is carried out during the mixing operation to verify that the composition and proportion of the asphalt mixture tested meets the design requirements;

[0070] ② The synchronous gravel seal layer is cleaned by a road sweeper and a powerful blower to keep the surface clean, dry and flat;

[0071] ③ The hot asphalt mixture shall be spread and rolled along the direction of the overlapping upper mesh covering the lower mesh, and the construction technology and quality shall be ensured to meet the relevant standards and design requirements.

[0072] Compared with the prior art, the present invention mainly provides an integrated structure and construction method for converting the white-to-black road surface of an existing roadbed block stone retaining wall, which includes the retaining wall of the original roadbed, drainage pipes, fill and the base layer of the original cement concrete pavement after resonance crushing, and the wire mesh and surface layer laid thereon in sequence. At the same time, the outer side and top of the retaining wall are provided with a steel mesh fixed by anchoring steel bars, and the steel mesh is interconnected with the steel mesh on the base layer and sprayed with cement concrete to form an integrated structure. The invention has the following advantages: first, by adopting the resonance crushing base and laying wire mesh technology, the original cement concrete road panel is crushed into the base and fully utilized on site, thus saving materials, saving energy and reducing emissions; second, the wire mesh at the bottom of the surface layer of the asphalt concrete after the white-to-black transformation and the steel mesh of the reinforced retaining wall are connected to each other at the top of the retaining wall. When a vehicle travels on the surface layer, the wire mesh at the bottom of the surface layer settles and stretches, generating dynamic tension on the top of the retaining wall, which disappears as the vehicle leaves, and increases as the weight and number of vehicles increase, and is opposite to the horizontal active earth pressure of the retaining wall, playing a dynamic self-stress balancing role, enhancing the stability of the retaining wall structure, and effectively reducing the cross-sectional area and engineering quantity of the retaining wall; third, the provided calculation method has clear principles, is scientific and reasonable, practical and easy to implement, and can guide the design and construction of the white-to-black road surface integrated structure of the existing roadbed block stone retaining wall, so as to save costs and improve safety and quality performance. Therefore, the present invention is an integrated structure for converting the existing roadbed block stone retaining wall into a black pavement with simple structure, economy, applicability, safety, reliability, energy conservation and emission reduction, and dynamic self-stress balance. It can better save energy and protect resources, and embodies the concept of green and energy-saving road engineering construction. Combined with the corresponding construction method, it also has high economic benefits, energy conservation and emission reduction benefits, and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 It is a schematic diagram of the structural elevation of the present invention.

[0074] Figure 2 for Figure 1 Top view of wire mesh and steel mesh arrangement.

[0075] Figure 3 This is the road vehicle load deflection diagram.

[0076] Figure 4 This is the wire mesh force calculation diagram. DETAILED DESCRIPTION

[0077] The embodiments of the present invention will be described in detail below with reference to the above-mentioned drawings.

[0078] like Figure 1~Figure 4As shown, 1. retaining wall, 11. drainage pipe, 2. fill, 3. base layer, 4. surface layer, 41. deflection curve, 5. wire mesh, 51. distributed steel bars, 52. wire mesh deformation curve, 6. steel mesh, 61. anchor steel bars, 7. protective layer.

[0079] The invention discloses an integrated structure and construction method for converting the existing roadbed block stone retaining wall from white to black pavement, comprising a retaining wall 1, a drainage pipe 11, a fill 2 and an original cement concrete pavement of the original roadbed. The original cement concrete pavement is resonantly crushed to form a base layer 3, and a wire mesh 5 and a surface layer 4 are laid in sequence on the base layer.

[0080] The outer side and top of the retaining wall 1 are provided with a steel mesh 6 fixed by anchoring steel bars 61. The steel mesh is connected to the steel mesh 5 on the base layer 3 and cement concrete is sprayed to form an integrated structure.

[0081] The retaining wall 1 is a block stone masonry protective structure of a mountain roadbed to be renovated and upgraded. After years of use, it generally meets the use function, but the exposed surface of the retaining wall 1 has weathering damage, so it needs to be reinforced with a steel mesh 6 and sprayed cement concrete.

[0082] The drainage pipe 11 is the original roadbed drainage facility, which generally meets the use function. When the retaining wall 1 is reinforced with steel mesh 6 and sprayed cement concrete, it needs to be extended to drain the accumulated water. The fill 2 is the fill of the original roadbed, which generally meets the use function.

[0083] The base layer 3 is formed by crushing the original cement concrete pavement by a resonance crusher. Since the original cement concrete pavement has many defects, the high-frequency and low-amplitude vibration energy is transmitted to the cement slabs by the crushing hammer of the resonance crusher for crushing. The upper part of the slab is in the form of granular fragments less than 10 cm, which changes from a relatively loose state to a dense state; the lower part of the slab is in the form of granular fragments of 10 cm to 20 cm, which are in an interlocking and biting state, thereby reducing or avoiding the occurrence of reflective cracks in the asphalt concrete surface layer during the white-to-black transformation. The crushing operation of the resonance crusher must not cause damage to the base layer 3, the roadbed and the surrounding structural facilities.

[0084] The surface layer 4 is asphalt concrete, that is, the original white cement concrete road surface is transformed into a black asphalt concrete road surface.

[0085] The wire mesh is made of anti-corrosion treated steel wires woven into a hexagonal double-twisted metal mesh. The longitudinal overlap width of the wire mesh is 20cm to 30cm, the transverse overlap width is 15cm to 20cm, and it is fixed to the base layer by anchoring steel nails. The anchoring steel nails use M8 pressure-explosive threaded nails, and the anchoring point spacing of the anchoring steel nails is 90cm to 100cm longitudinally and 70cm to 80cm transversely, arranged in a plum blossom shape; in unfavorable sections such as bends and steep slopes, the anchoring points of the wire mesh 5 are encrypted to a spacing of 50cm to 60cm longitudinally and 40cm to 50cm transversely. Before the wire mesh 5 is anchored, it needs to be flattened by a roller, and the wire mesh 5 should be tightened and flattened.

[0086] The steel mesh 5 is woven with a plurality of distribution steel bars 51 at a certain interval along the longitudinal direction of the base layer. At the same time, one distribution steel bar 51 is woven into each of the two side edges of the base layer along the longitudinal direction, which is beneficial to the integrity and crack resistance of the surface layer 4. The distribution steel bars 51 are ordinary hot-rolled round steel bars. The spacing along the longitudinal direction of the base layer is the distance of one or two hexagonal mesh holes. The diameter of the distribution steel bars 51 is larger than the diameter of the steel wire. The one distribution steel bar woven into each of the two side edges of the base layer along the longitudinal direction is disconnected every 2m to 3m to release the stress.

[0087] The steel mesh 6 is a steel mesh made of hot-rolled steel bars welded together, which is used to protect the exposed surface of the retaining wall 1 from weathering diseases and to enhance the integrity of the block stone retaining wall 1. It can be used together with shotcrete to reinforce the retaining wall. At the same time, the steel mesh 6 is welded to the wire mesh 5 at the top of the retaining wall 1, so that the road surface and the retaining wall 1 form a whole and bear the force together, and the steel mesh 6 can also use the wire mesh 5 according to actual conditions.

[0088] The anchoring steel bars 61 are hot-rolled steel bars, which are mainly used to fix the steel mesh 6 to the outer side and top of the retaining wall 1. The anchoring steel bars 61 are inserted into the gap between two blocks of the retaining wall 1 or drilled into the blocks of the outer side and top of the retaining wall 1 and arranged in a plum blossom shape.

[0089] The steel mesh 6 is connected to the steel wire mesh 5 on the base layer 3 and sprayed with cement concrete to form a protective layer 7, which can be used to protect the exposed surface of the retaining wall 1 from weathering diseases and enhance the integrity of the block stone retaining wall. The sprayed cement concrete protective layer is C30 with a thickness of 8cm to 20cm. The thickness of the protective layer of the steel mesh is not less than 3cm. The protective layer on the top of the retaining wall can also be made of cast-in-place C30 cement concrete.

[0090] The surface layer produces a deflection disk under the action of the vehicle load. xoy The plane deflection curve is simulated by the logistic equation, that is, the Logistic curve. The equation of the Logistic deflection curve is: , deflection curve equation Around xoy flat yThe axis rotates one circle to form a concave deflection basin. Ignoring the compression deformation of the surface layer itself, the deformation curve of the wire mesh sinks synchronously with the surface layer and also forms a Logistic deflection curve of the same shape. According to the Winkler foundation hypothesis, the strength of the reaction force on the settlement of the wire mesh is , so the following calculation formula is obtained:

[0091] Formula 1:

[0092] Wire Mesh Bending Plate Center O , where the wire mesh contacts the surface layer at the top of the retaining wall A The midpoint between the two tire groups of the standard axle load of the vehicle B The sedimentation is ,by O The origin xoy The unknown parameters of the in-plane Logistic deflection curve equation and the related calculation formula are:

[0093]

[0094] In the formula

[0095]

[0096] From this, the unknown parameters of the Logistic deflection curve are obtained ;

[0097]

[0098] Formula 2:

[0099] In the case of a single car driving, due to the principle of force balance, the contact point between the wire mesh 5 of unit width and the steel mesh 6 at the top of the retaining wall 1 A The tension and maximum deflection between O The tensions at

[0100]

[0101] In the formula

[0102]

[0103] When multiple cars are driving on a road surface layer 4, the contact between the wire mesh 5 of unit width and the steel mesh 6 on the top of the retaining wall 1 A and maximum deflection O The tension at is calculated according to the superposition principle:

[0104] Formula 3:

[0105]

[0106] The steel mesh 5 at the bottom of the surface layer 4 and the steel mesh 6 for reinforcing the retaining wall are connected to each other at the top of the retaining wall. When a vehicle travels on the surface layer, the steel mesh 5 at the bottom of the surface layer 4 settles and stretches, generating a pulling force on the top of the retaining wall 1. This pulling force is dynamic and disappears as the vehicle leaves, and increases as the weight and number of vehicles increase, and is opposite to the horizontal active earth pressure of the retaining wall 1.

[0107] The symbols in Formula 1, Formula 2 and Formula 3 are defined as:

[0108] ——are the fitting parameters of the Logistic deflection curve, , dimensionless, ;

[0109] ——Single circle radius of standard axle load of automobile, ;

[0110] ——The distance from the center of the single circle of standard axle load of the car on the side close to retaining wall 1 to the top of the retaining wall A The distance between the center and the center of the standard axle load of the vehicle O From the midpoint between the two tire groups of the standard axle load of the vehicle B The distance between ;

[0111] ——The surface layer 4 produces a deflection disk under the action of the vehicle load. xoy The plane deflection curve 41 is simulated by the logistic equation, i.e., the logistic curve. The deflection curve 41 equation is: , bend the basin to Curve around xoy flat y The axis rotates one circle to form a concave bending sink;

[0112] ——respectively, they are the single-circle uniformly distributed load strength of the standard axle load of the automobile, the deadweight strength of the surface material, and the reaction strength of the settlement of the wire mesh 5 under the single-circle uniformly distributed load of the standard axle load of the automobile, ;

[0113] ——respectively the friction coefficient between the wire mesh 5 and the surface layer 4 and the base layer 3, and the foundation reaction coefficient, Obtained from reference materials or actual measurements, dimensionless, ;

[0114] ——Unit width steel wire mesh 5 and top of retaining wall 1 ATensile force at the center of the single circle of the standard axle load of the automobile O The tensile force at the point, the allowable tensile force of the wire mesh 5, ;

[0115] ——respectively any position and x The angle of the axis, near the top of the retaining wall A Department and x The angle of the shaft, the center of the single circle of the standard axle load of the automobile O Department and x The angle between the axles and the midpoint between the two tire groups of the standard axle load of the vehicle B Department and x The angle of the axis, ;

[0116] ——Friction stress between the wire mesh 5 and the surface layer 4 and the base layer 3, ;

[0117] ——Based on the center of the single circular bending sinker with standard axle load of automobile O The origin of coordinates x axis, y axis, ;

[0118] --coefficient, .

[0119] In addition, a construction method for converting an existing roadbed block stone retaining wall into a black road surface integrated structure mainly includes the following steps:

[0120] Step 1: Integrated structural design of white-to-black road surface for retaining wall

[0121] ① Investigate and analyze the current status and bearing capacity of the old roadbed retaining wall, detect the deflection of the original road surface, formulate the thickness of the sprayed cement concrete of the existing roadbed block stone retaining wall, and select the specifications and layout methods of steel mesh 6 and wire mesh 5;

[0122] ② Determine the technical indicators of the materials used through experiments;

[0123] ③ Calculate the technical parameters of the integrated structure of the white-to-black road surface of retaining wall 1 by using formula 1, formula 2 and formula 3, and carry out construction drawing design and propose a construction plan;

[0124] Step 2: Retaining wall reinforcement

[0125] ①Measure and lay out according to the design drawings;

[0126] ② Remove the top 20cm to 30cm of the existing roadbed stone retaining wall and clean up the severely weathered layer on the stone retaining wall surface;

[0127] ③ Make or purchase steel mesh and test it to be qualified, lay steel mesh 6 on the outside and top of the retaining wall, and fix it on the outside of the retaining wall 1 and the top after removing 20cm to 30cm with anchor steel bars 61;

[0128] ④ Prepare shotcrete mixture and pass the test;

[0129] ⑤ When spraying the cement concrete protective layer on the retaining wall, first spray the gaps between the blocks of the retaining wall 1, and use a hand tool to tamp the sprayed cement concrete in the gaps to fill them densely, and then spray the entire wall surface, where the top of the retaining wall is left for spraying cement concrete or pouring cement concrete after the steel mesh 6 and the wire mesh 5 are welded;

[0130] Step 3: Construction of the base after the original cement concrete pavement is resonantly crushed

[0131] ① First, the original cement concrete slabs with serious cracks and damage are replaced, and when the strength of the replaced cement concrete slab reaches more than 75% of the design strength, resonance crushing is performed; the original cement concrete slabs that need to be replaced and those that do not need to be replaced are subjected to resonance rubble treatment together, and the cement concrete pavement after resonance crushing is used as the base layer 3 of the surface layer 4;

[0132] ② Before construction, the resonance operation path is laid out and adjacent crushing paths are closely connected;

[0133] ③ Resonance crushing is carried out in a path parallel to the road direction, without tilting the crushing, missing vibration, repeated crushing, or overlapping crushing, and a test section is arranged for resonance testing to obtain relevant data;

[0134] ④ According to the process parameters determined in the test section and combined with the differences in road conditions in the construction section, the construction process parameters are reasonably fine-tuned to ensure that the crushing effect meets the quality requirements of the crushed stone layer;

[0135] ⑤ Sprinkle water and roll the resonant crushed gravel layer, with a watering rate of 1kg / m 2 ~3kg / m 2 The rolling of the gravel layer is carried out in three stages: initial rolling, secondary rolling and final rolling. The rolling equipment is steel wheel roller, steel wheel vibratory roller or tire roller. The rolling is carried out in the order of "roadside to middle" and "from low to high". During rolling, the adjacent rolling belts overlap by no less than 1 / 3 of the rolling wheel width. The technical indicators such as flatness and compaction are tested to be qualified;

[0136] ⑥ The gravel layer after resonance crushing shall be continuously subjected to subsequent construction, the exposure time of the gravel layer shall not exceed 3 days, and the gravel layer shall not be open to traffic;

[0137] Step 4: Laying the wire mesh

[0138] ① After the wire mesh 5 is delivered to the site, it is mechanically hoisted and placed gently, and the wire mesh is well protected to prevent damage to the mesh surface due to manual throwing or vehicle rolling;

[0139] ② The mesh surface of the wire mesh 5 is fully unfolded, manually adjusted to the correct position, and each piece is overlapped according to regulations;

[0140] ③ After the wire mesh 5 is laid and before it is fixed, use a rubber-wheel roller to roll it 1 to 2 times; after the synchronous crushed stone seal layer is paved, use a rubber-wheel roller to roll it 1 to 2 times again;

[0141] ④ The mesh surface of the wire mesh 5 uses M8 pressure-explosive threaded nails as anchoring steel nails, and is fixed using small impact drills and other equipment. The density of the anchoring steel nails is not less than 1 / m 2 The fixed end of the mesh surface, sharp bends, and the wheel track of the paver should be appropriately increased to ensure close contact with the road surface;

[0142] ⑤ After the steel mesh 6 is laid and accepted, the gravel lower sealing layer is constructed synchronously;

[0143] ⑥SBS modified asphalt for synchronous crushed stone seal, asphalt dosage 1.8g / m 2 ~2.0kg / m 2 Aggregate spreading amount: 13kg / m 2 ~15kg / m 2 , the maximum particle size of graded aggregate for synchronous crushed stone seal layer shall not exceed 19mm;

[0144] Step 5: Asphalt concrete construction

[0145] ① The materials of the asphalt mixture meet the design requirements. Sampling inspection is carried out during the mixing operation to verify that the composition and proportion of the asphalt mixture tested meets the design requirements;

[0146] ② The synchronous gravel seal layer is cleaned by road sweepers, powerful hair dryers and other equipment to keep the surface clean, dry and flat;

[0147] ③ The hot asphalt mixture shall be spread and rolled along the direction of the overlapping upper mesh covering the lower mesh, and the construction technology and quality shall be ensured to meet the relevant standards and design requirements.

[0148] The embodiments of the present invention are only used to illustrate the present invention and are not used to limit the scope of the present invention. It should also be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the present application.

Claims

1. An integrated structure for converting an existing roadbed block stone retaining wall into a black road surface, comprising an existing roadbed retaining wall (1), a drainage pipe (11), a fill (2) and an original cement concrete road surface, characterized in that The original cement concrete pavement is resonantly crushed to form a base layer (3), on which a steel mesh (5) and a surface layer (4) are laid in sequence; the outer side and top of the retaining wall (1) are provided with a steel mesh (6) fixed by anchoring steel bars (61), the steel mesh and the steel mesh (5) on the base layer (3) are interconnected and sprayed with cement concrete to form an integrated structure; the surface layer (4) generates a deflection plate under the action of a vehicle load, and the deflection plate is xoy The plane deflection curve (41) is simulated by the logistic equation, i.e., the logistic curve. The equation of the logistic deflection curve is: , deflection curve equation Around xoy flat y The axis rotates one circle to form a concave deflection basin. Ignoring the compression deformation of the surface layer itself, the deformation curve (52) of the wire mesh sinks synchronously with the surface layer (4) to form a Logistic deflection curve of the same shape. According to the Winkler foundation hypothesis, the strength of the reaction force on the wire mesh settlement is , so the following calculation formula is obtained: Formula 1: Wire Mesh Bending Plate Center O , where the wire mesh contacts the surface layer at the top of the retaining wall A The midpoint between the two tire groups of the standard axle load of the vehicle B The sedimentation is ,by O The origin xoy The unknown parameters of the in-plane Logistic deflection curve equation and the related calculation formula are: In the formula From this, the unknown parameters of the Logistic deflection curve are obtained ; Formula 2: When a single car is moving, due to the principle of force balance, the contact point between the wire mesh (5) of unit width and the steel mesh (6) at the top of the retaining wall (1) is A The tension and maximum deflection between O The tensions at In the formula When a road surface layer (4) section is subjected to the impact of multiple vehicles at the same time, the contact point between the wire mesh (5) of unit width and the steel mesh (6) at the top of the retaining wall (1) A and maximum deflection O The tension at is calculated according to the superposition principle: Formula 3: The steel mesh (5) at the bottom of the surface layer (4) and the steel mesh (6) for reinforcing the retaining wall are connected to each other at the top of the retaining wall. When a vehicle travels on the surface layer, the steel mesh (5) at the bottom of the surface layer (4) settles and stretches, thereby generating a pulling force on the top of the retaining wall (1). This pulling force is dynamic and disappears as the vehicle leaves, and increases as the weight and number of vehicles increase, and is opposite to the direction of the horizontal active earth pressure of the retaining wall (1). The symbols in Formula 1, Formula 2 and Formula 3 are defined as: ——are the fitting parameters of the Logistic deflection curve, , dimensionless, ; ——Single circle radius of standard axle load of automobile, ; ——respectively from the center of the single circle of standard axle load of the car on the side close to the retaining wall (1) to the top of the retaining wall A The distance between the center and the center of the standard axle load of the vehicle O From the midpoint between the two tire groups of the standard axle load of the vehicle B The distance between ; ——The surface layer (4) produces a deflection disk under the action of the vehicle load. xoy The plane deflection curve (41) is simulated by the logistic equation, i.e., the logistic curve. The deflection curve equation (41) is: , bend the basin to Curve around xoy flat y The axis rotates one circle to form a concave bending sink; ——are respectively the single circular uniformly distributed load strength of the standard axle load of the automobile, the deadweight strength of the surface material, and the reaction strength of the settlement of the wire mesh (5) under the single circular uniformly distributed load of the standard axle load of the automobile, ; ——respectively the friction coefficient between the wire mesh (5) and the surface layer (4) and the base layer (3), and the foundation reaction coefficient, Obtained from reference materials or actual measurements, dimensionless, ; ——Unit width steel wire mesh (5) and top of retaining wall (1) A Tensile force per unit width of wire mesh (5) at the center of a single circle with standard axle load of the automobile O The tensile force at the point, the allowable tensile force of the wire mesh (5), ; ——respectively, any part of the wire mesh (5) after settlement and deformation x The angle of the axis, near the top of the retaining wall A Department and x The angle of the shaft, the center of the single circle of the standard axle load of the automobile O Department and x The angle between the axles and the midpoint between the two tire groups of the standard axle load of the vehicle B Department and x The angle of the axis, ; ——Frictional stress between the wire mesh (5) and the surface layer (4) and the base layer (3), ; ——Based on the center of the single circular bending sinker with standard axle load of automobile O The origin of coordinates x axis, y axis, ; --coefficient, .

2. The white-to-black road surface integrated structure of the existing roadbed block retaining wall according to claim 1 is characterized in that The steel mesh (6) and the steel wire mesh (5) on the base layer (3) are connected to each other and sprayed with cement concrete to form a protective layer (7). The sprayed cement concrete protective layer is C30, the thickness of the protective layer (7) is 8 cm to 20 cm, the thickness of the protective layer of the steel mesh (6) is not less than 3 cm, and the protective layer on the top of the retaining wall (1) is also made of cast-in-place C30 cement concrete.

3. The white-to-black road surface integrated structure of the existing roadbed block retaining wall according to claim 2 is characterized in that The steel mesh (6) is a steel mesh sheet formed by welding hot-rolled steel bars; the steel mesh (6) and the steel wire mesh (5) at the top of the retaining wall (1) are welded together, and the protective layer (7) and the surface layer (4) form an integrated structure to bear force together.

4. The integrated structure of converting the existing roadbed block retaining wall from white to black according to claim 1 is characterized in that The anchoring steel bars (61) are hot-rolled steel bars; the steel mesh (6) is fixed to the outer side and top of the retaining wall (1) via the anchoring steel bars (61); the anchoring steel bars are inserted into the gaps between the blocks of the retaining wall (1) or are drilled into the blocks of the retaining wall (1) and arranged in a plum blossom shape.

5. The integrated structure of converting the existing roadbed block retaining wall from white to black according to claim 1 is characterized in that The steel mesh (5) is a hexagonal double-twisted metal mesh made of anti-corrosion treated steel wires. The longitudinal overlap width of the steel mesh (5) is 20 cm to 30 cm, and the transverse overlap width is 15 cm to 20 cm. A plurality of distribution steel bars (51) are woven into the steel mesh (5) at a certain interval along the longitudinal direction of the base layer, and at the same time, one distribution steel bar (51) is woven into each of the two side edges of the base layer along the longitudinal direction. The steel mesh (5) is fixed to the base layer via anchoring steel nails. The anchoring point spacing of the anchoring steel nails is 90 cm to 100 cm or 50 cm to 60 cm in the longitudinal direction and 70 cm to 80 cm or 40 cm to 50 cm in the transverse direction, and is arranged in a plum blossom shape.

6. The white-to-black road surface integrated structure of the existing roadbed block retaining wall according to claim 5 is characterized in that The distribution steel bars (51) are common hot-rolled round steel bars, and the spacing along the longitudinal direction of the base layer is the distance of one or two hexagonal mesh holes. The distribution steel bars (51) woven into the edges of both sides of the base layer along the longitudinal direction are disconnected every 2m to 3m to release the stress.

7. The integrated structure of converting the existing roadbed block retaining wall from white to black according to claim 1 is characterized in that The retaining wall (1) is a block stone masonry protective structure of a mountain road foundation to be renovated and upgraded; the surface layer (4) is a black asphalt concrete pavement after renovation.

8. The white-to-black road surface integrated structure of the existing roadbed block retaining wall according to claim 1 is characterized in that The base layer (3) is formed by crushing the original cement concrete pavement by a resonance crusher, and the upper half of the base layer is in the form of dense granular fragments less than 10 cm, and the lower half of the base layer is in the form of interlocking granular fragments of 10 cm to 20 cm.

9. A construction method for converting the existing roadbed block stone retaining wall from white to black pavement integrated structure according to any one of claims 1 to 8, characterized in that The construction method comprises the following steps: Step 1: Integrated structural design of white-to-black road surface for retaining wall ① Investigate and analyze the current status and bearing capacity of the old roadbed retaining wall, detect the deflection of the original road surface, formulate the thickness of the sprayed cement concrete of the existing roadbed block stone retaining wall, and select the specifications and layout methods of the steel mesh and wire mesh; ② Determine the technical indicators of the materials used through experiments; ③ Calculate the technical parameters of the integrated structure of the white-to-black road surface of the retaining wall (1) by using Formula 1, Formula 2 and Formula 3, and make a construction drawing design and propose a construction plan; Step 2: Retaining wall reinforcement ①Measure and lay out according to the design drawings; ② Remove the top 20cm to 30cm of the existing roadbed stone retaining wall and clean up the severely weathered layer on the stone retaining wall surface; ③ Make or purchase steel mesh and inspect it to be qualified, lay the steel mesh (6) on the outside and top of the retaining wall, and fix it to the outside of the retaining wall (1) and the top after removing 20 cm to 30 cm with anchor steel bars (61); ④ Prepare shotcrete mixture and pass the test; ⑤ When spraying the cement concrete protective layer on the retaining wall, first spray the gaps between the blocks of the retaining wall, and use a hand tool to tamp the sprayed cement concrete in the gaps to fill them tightly, and then spray the entire wall surface, wherein the top of the retaining wall is left for welding the steel mesh (6) and the wire mesh (5) before spraying cement concrete or pouring cement concrete; Step 3: Base construction after resonance crushing of the original cement concrete pavement ① First, the original cement concrete slabs that are severely cracked and damaged are replaced, and when the strength of the replaced cement concrete slab reaches more than 75% of the design strength, resonance crushing is performed; the original cement concrete slabs that need to be replaced and those that do not need to be replaced are subjected to resonance rubble treatment together, and the cement concrete pavement after resonance crushing is used as the base layer (3) of the surface layer (4); ② Before construction, the resonance operation path is laid out and adjacent crushing paths are closely connected; ③ Resonance crushing is carried out in a path parallel to the road direction, without tilting the crushing, missing vibration, repeated crushing, or overlapping crushing, and a test section is arranged for resonance testing to obtain relevant data; ④ According to the process parameters determined in the test section and combined with the differences in road conditions in the construction section, the construction process parameters are reasonably fine-tuned to ensure that the crushing effect meets the quality requirements of the crushed stone layer; ⑤ Sprinkle water and roll the resonant crushed gravel layer, with a watering rate of 1kg / m 2 ~3kg / m 2 The rolling of the gravel layer is carried out in three stages: initial rolling, secondary rolling and final rolling. The rolling equipment is steel wheel roller, steel wheel vibratory roller or tire roller. The rolling is carried out in the order of "roadside to the middle" and "from low to high". During rolling, the overlapping of adjacent rolling belts is not less than 1 / 3 of the rolling wheel width. The technical indicators of flatness and compaction are tested to be qualified; ⑥ The gravel layer after resonance crushing shall be continuously subjected to subsequent construction, the exposure time of the gravel layer shall not exceed 3 days, and the gravel layer shall not be open to traffic; Step 4: Laying the wire mesh ① After the wire mesh (5) is transported to the site, it should be mechanically hoisted and placed with care, and the wire mesh should be well protected to prevent damage to the mesh surface due to manual throwing or vehicle rolling; ② The wire mesh (5) is fully unfolded and manually adjusted to the correct position, with each piece overlapped as required; ③ After the wire mesh (5) is laid and before it is fixed, use a rubber-wheeled roller to roll it once or twice; after the synchronous crushed stone seal layer is laid, use a rubber-wheeled roller to roll it once or twice again; ④ The mesh surface of the wire mesh (5) uses M8 compression screws as anchoring steel nails and is fixed with a small impact drill. The density of the anchoring steel nails is not less than 1 / m 2 The fixed end of the mesh surface, sharp bends, and the wheel track of the paver should be appropriately increased to ensure close contact with the road surface; ⑤ After the steel mesh is laid and accepted, the gravel lower sealing layer is constructed synchronously; ⑥SBS modified asphalt for synchronous crushed stone seal, asphalt dosage 1.8g / m 2 ~2.0kg / m 2 Aggregate spreading amount: 13kg / m 2 ~15kg / m 2 , the maximum particle size of graded aggregate for synchronous crushed stone seal layer shall not exceed 19mm; Step 5: Asphalt concrete construction ① The materials of the asphalt mixture meet the design requirements. Sampling inspection is carried out during the mixing operation to verify that the composition and proportion of the asphalt mixture tested meets the design requirements; ② The synchronous gravel seal layer is cleaned by a road sweeper and a powerful blower to keep the surface clean, dry and flat; ③ The hot asphalt mixture shall be spread and rolled along the direction of the overlapping upper mesh covering the lower mesh, and the construction technology and quality shall be ensured to meet the relevant standards and design requirements.

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