Bridge widening anti-collision guardrail anchor steel bar structure and construction method

Abstract

The present invention discloses an anchored steel bar structure for widening a bridge anti-collision guardrail and a construction method. The structure comprises an edge T-beam, an upper flange plate, a beam rib, an anchor block and a new guardrail. The new guardrail is formed by a steel skeleton, a plurality of anchored steel bars for mainly resisting loads and cast cement concrete. The lower part of each anchored steel bar is implanted in the upper flange plate and fixed by an anchoring system, and the anchoring system is mainly composed of a spring, a grouting pipe, a closing block, a bellows, a vent pipe, a grouting template, a grouting body, an anchor plate, a screw and a nut. The anchored steel bar structure for widening a bridge anti-collision guardrail can not only improve the safety and durability of the new guardrail, but also can safely and economically widen the bridge deck and improve the quality of the project. The calculation method provided therein has clear principles, is practical and easy to implement, and also improves the safety and quality performance. It has the advantages of simple structure, convenient construction, low cost, safety and reliability, strong durability, high quality, and significant economic and social benefits.

Description

Technical Field

[0001] The invention relates to the field of bridge widening quality engineering construction, and specifically refers to a bridge widening anti-collision guardrail anchoring steel bar structure and a construction method. Background Art

[0002] Widening and expanding existing roads to improve the traffic capacity of existing roads and bridges and save engineering investment has important practical significance. In the process of bridge widening, implanting steel bars in the existing engineering structure to connect the widened part is one of the commonly used methods. However, when the implanted reinforcement collides with the important structure of the existing bridge, such as the prestressed steel bar system, that is, when there is a spatial conflict, the existing method of implanting reinforcement is difficult to implement. A new method of implanting reinforcement must be studied to ensure that the widened part meets the use requirements and saves engineering costs while preserving the safety of the existing bridge structure without damage. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a bridge widening anti-collision guardrail anchor steel bar structure and construction method which has simple structure, convenient construction, low cost, safety and reliability, strong durability and high quality.

[0004] The technical problem of the present invention is achieved through the following technical solutions:

[0005] A bridge widening anti-collision guardrail anchoring steel bar structure, including a side T-beam retained due to bridge widening and expansion, an upper flange plate retained on the outside of the side T-beam after the original guardrail is removed, a beam rib at the bottom of the side T-beam, and an anchor block arranged between the bottom of the upper flange plate and the middle of the beam rib and anchoring the bridge deck at the top of the side T-beam; the upper flange plate is connected to a frame template for constructing a new reinforced concrete guardrail, and the new guardrail is formed by a steel skeleton, a plurality of anchor steel bars in the steel skeleton that mainly resist loads, and cement concrete casting, the plurality of anchor steel bars are arranged at equal intervals, and the lower part of each anchor steel bar is implanted in the upper flange plate and fixed by an anchor system; the anchor system includes a spring, a grouting pipe, a closing block, a bellows, a vent pipe, a grouting template, a grouting body, an anchor plate, a screw and a nut; the closing block The top surface is placed on the top of the vertical part of each anchor steel bar, and the bottom surface of the closing block is a corrugated tube that is inserted into the anchor steel bar, and the bottom of the corrugated tube is flush with the bottom of the new guardrail and the bottom of the upper flange plate; the spring is inserted into the anchor steel bar and placed in the corrugated tube; the anchor plate is inserted into the lower end of the anchor steel bar from bottom to top through the reserved hole and is fastened by screws and nuts, and the top of the anchor plate is flush with the bottom of the new guardrail and the bottom of the upper flange plate; the grouting template is placed between the bottom of the new guardrail and the bottom of the upper flange plate, and a distance is reserved between the grouting template and the screws and nuts, and a space for the grouting body is formed with the gap in the corrugated tube, the anchor steel bar and the spring; one end of the ventilation pipe is horizontally inserted from the top of the corrugated tube, and the other end of the ventilation pipe extends to the outside of the template of the new guardrail; the grouting pipe is reserved in the grouting template and is externally connected to a grouting machine.

[0006] Each anchoring steel bar is reserved together with the spring, grouting pipe, closing block, bellows and vent pipe constituting the anchoring system when the new guardrail concrete is cast in situ. The gap between each anchoring steel bar and the spring, closing block and bellows is injected with grouting material under high pressure and finally solidified to form a grouting body, which is fastened by the anchor plate, screw and nut. The anchoring steel bar applies preliminary pressure to the spring before grouting. The grouting body reserves tensile energy to compensate for the shrinkage effect of the grouting body during its use. According to the bridge design standard, the design tensile force of a single anchor steel bar in the new guardrail that mainly resists the load is The anchorage length of the anchor steel bar is , the spring length is After the concrete pouring of the new guardrail is completed and reaches the specified strength, the anchor plate and nut are installed before the anchor steel bar is grouted, and the nut is twisted to apply initial pressure to the spring. Make the spring Length compressed to length, and then continue to twist the nut to apply final pressure to the spring And tighten, according to the elasticity theory and force balance principle, the following calculation formula is obtained:

[0007] Formula 1:

[0008] The anchor system for fixing the anchor steel bar is to twist the nut to apply initial pressure to the spring. Make the spring Length compressed to After the high-strength grouting fluid injected under high pressure solidifies, when the grouting body shrinks during the use stage, the spring has the function of preventing the grouting body from shrinking. The shrinkage rate of the grouting body reaches 2‰~5‰, so the spring compression rate is controlled at 3‰~5‰ as compensation for the shrinkage of the grouting body, and the initial pressure applied to the spring , which is the initial tension of the anchor steel bar ,but

[0009]

[0010] Formula 2:

[0011] The anchor system for fixing the anchor steel bar is to twist the nut to apply initial pressure to the spring. Make the spring Length compressed to length, and then continue to twist the nut to apply final pressure to the spring And tighten, at this time the spring pressure is still the initial pressure After the grouting liquid of the anchor steel bar is finally solidified, the sum of the friction between the grouting body and the corrugated pipe and the anchoring force of the screw or nut should be greater than the tensile force of the anchor steel bar under the load. The anchor steel bar size and related parameters are

[0012]

[0013] The symbols in Formula 1 and Formula 2 are defined as:

[0014] ——Design tensile force of a single anchor steel bar in a new guardrail to resist loads, ;

[0015] ——The initial tension of the screw before grouting the anchor steel bars, ;

[0016] ——The pressure on the spring before grouting the anchor steel bars, ;

[0017] - the ultimate anchoring force of the screw or nut, ;

[0018] ——The safety factor of the anchor steel bars in the new guardrail against loads shall be determined according to relevant standards and specifications or taken as 1.3 to 1.5;

[0019] ——respectively the outer diameter of the spring, the middle diameter of the spring, and the diameter of the spring wire material, ;

[0020] ——The effective number of coils of the spring;

[0021] ——The spring is deformed under pressure, ;

[0022] ——Shear deformation modulus of the spring, ;

[0023] ——The wrapped length of the anchor steel bar and the grouting body in the corrugated pipe, which is also the length of the spring after compression. ;

[0024] ——Average inner diameter of the bellows, ;

[0025] - the length of the threaded engagement portion of the screw or nut, ;

[0026] - the average diameter of the threaded part of the screw or nut, ;

[0027] ——Effective diameter of anchor steel bar, ;

[0028] ——shear design value of grouting body, ;

[0029] ——the shear design value of the screw or nut, ;

[0030] - tensile design value of the screw or nut, .

[0031] The spring is a compression spring formed by cold bending of high-strength steel wire around a round tube or round bar. The outer diameter of the spring is 0.5cm to 1cm smaller than the inner diameter of the bellows, and the inner diameter of the spring is 1cm to 3cm larger than the outer diameter of the anchor steel bar. The top of the spring is welded to the bottom of the closing block and the length is Before the spring is compressed, a hole is opened at the contact point between the new guardrail bottom template and the spring to expose the spring to the new guardrail bottom. length, and the spring is compressed After the length is reached, the bottom is flush with the bottom of the new guardrail and the bottom of the upper flange plate.

[0032] The grouting pipe is a hard plastic pipe pressed into the grouting body, which is inserted into the grouting template from the reserved hole on the grouting template, and the outer wall of the grouting pipe is sealed with the reserved hole of the grouting template, and the outer end of the grouting pipe is connected to the grouting machine.

[0033] The closing block is a circular steel plate or a square steel plate placed on the top of the corrugated pipe and is firmly welded to the steel frame of the new guardrail. The cross-sectional size of the closing block is 2cm to 3cm larger than the maximum outer diameter of the corrugated pipe and the thickness is 1cm to 1.2cm. The bottom of the closing block and the top of the corrugated pipe are bonded and sealed with a strong adhesive, and there is no air leakage or slurry leakage when pouring concrete for the new guardrail.

[0034] The bellows is a steel corrugated round tube with a length of The inner diameter matches the anchor steel bars, springs and the corresponding reserved gaps. The outer diameter of the corrugated pipe is one-quarter to one-third of the distance between the two anchor steel bars. The top of the corrugated pipe and the bottom of the closing block are bonded and sealed with a strong adhesive. The bottom of the corrugated pipe is sealed with the new guardrail formwork, and the cement slurry when pouring the new guardrail concrete does not leak into the corrugated pipe.

[0035] The vent pipe is arranged at the top of the corrugated pipe and extends outside the new guardrail template to exhaust air during grouting. The connection between the outer wall of the vent pipe and the corrugated pipe is closed, and cement slurry does not leak into the vent pipe when pouring new guardrail concrete.

[0036] The anchor plate is a wedge-shaped steel plate with a circular or square plane. The top plane of the anchor plate has the same inclination as the bottom of the new guardrail and the bottom of the upper flange plate. The bottom plane of the anchor plate is a horizontal plane. The cross-sectional size is 3cm to 5cm larger than the maximum outer diameter of the corrugated pipe and the thickness is 1.5cm to 2.0cm. A reserved hole is vertically reserved in the center of the anchor plate for inserting the anchor steel bar. A cross-shaped semicircular groove is horizontally symmetrically arranged in the center of the top of the anchor plate as a grouting channel. The radius of the cross-shaped semicircular groove is not greater than one-third of the thickness of the anchor plate.

[0037] The grouting body is formed by grouting and solidifying high-strength grouting material with water and an appropriate amount of micro-expansion agent; the screw and nut are made of steel, the screw is the threaded part at the lower end of the anchor steel bar, and the engagement length of the screw thread and the nut thread is determined by calculation.

[0038] A construction method for anchoring a steel bar structure for widening a bridge anti-collision guardrail comprises the following steps:

[0039] Step 1: Develop a bridge widening design

[0040] ①Measure the dimensions of the side T beams and original guardrails of the bridge and collect basic data on load standards;

[0041] ② Prepare a preliminary design plan for bridge widening and select raw materials and construction plans;

[0042] ③ Calculate the design tensile force of a single anchor steel bar that mainly resists the load in the steel frame of the new guardrail according to formula 1 and formula 2. Apply initial pressure to the spring before grouting the anchor reinforcement , and determine the main design parameters;

[0043] ④ Determine the materials used and the technical requirements for construction technology;

[0044] Step 2: Purchase the main engineering materials and process the components

[0045] ① Select high-performance and high-strength grouting materials and micro-expansion agents as the raw materials for the grouting body, and determine the design mix ratio and other technical parameters through experiments;

[0046] ② Select the raw materials of spring steel wire to make springs; select the raw materials of anchor steel bars, the length and technical parameters of screws and nuts;

[0047] ③ Make other anchoring system components, and the quality shall meet the design requirements;

[0048] ④ Select qualified grouting machinery, the grouting pressure is 0.2MPa~0.5MPa, check the operation of grouting equipment and pipelines, and set grouting parameters such as gel time, grouting pressure and grouting amount;

[0049] ⑤ Make the steel frame and formwork of the new guardrail, and the quality shall meet the design requirements; test the concrete mix ratio and pavement material mix ratio;

[0050] Step 3: Remove the original guardrail and part of the pavement and road surface

[0051] ①Measure and mark the demolition scope of the original guardrail, road surface and pavement according to the design drawings;

[0052] ② Select appropriate cutting machinery according to the concrete strength and volume of the demolished components:

[0053] ③When cutting and removing some components, pay attention to protecting the retained components, and ensure the safety of the bridge deck after removing some components;

[0054] Step 4: New guardrail construction

[0055] ①Measure and locate the exact position of the new guardrail and make a mark;

[0056] ② Lifting the new guardrail steel frame requires accurate positioning;

[0057] ③ Make and set up new guardrail steel formwork, requiring accurate positioning;

[0058] ④ Check the sealing of the bellows and the vent pipe, use an air compressor to press air into the vent pipe, and check whether there is any leakage in the bellows, vent pipe, closing block itself and the joints. If there is leakage, take sealing measures again until there is no leakage;

[0059] ⑤ Use a pump truck to pour cement concrete for the new guardrail, vibrate it with an inserted vibrator to make it dense, and cover it with geotextile for maintenance after the cement concrete has finally set;

[0060] ⑥ Generally, the side formwork will be removed after 12 hours, and the geotextile will be covered and watered for curing; when the concrete strength reaches 75%, the bottom formwork will be removed and cured to the specified strength;

[0061] Step 5: Compress the spring and grout the anchor steel bars

[0062] ①Clean the concrete residue at the contact point between the bottom of the new guardrail and the anchor block and grind it flat. Insert the anchor plate and nut from the bottom of the anchor steel bar in sequence. Screw in the nut to press the anchor plate and spring into the new guardrail until they are flush with the bottom. Continue to screw in the nut until the design torque is reached. For standard nuts, the final torque of tightening the nut with a wrench is determined by the specifications of the nut and the corresponding torque from the relevant standards. For non-standard nuts, the final torque of tightening the nut with a wrench is determined by the structure of the screw or nut and the final anchoring force. Calculated;

[0063] ② Before grouting, a baffle is set up at the vent opening, leaving a gap between the baffle and the vent opening, and the observer observes the grouting situation at a safe distance;

[0064] ③Install the grouting template, and seal the contact points between the grouting template and the bottom of the new guardrail, the side of the beam rib of the side T beam and the grouting pipe to prevent air leakage and grout leakage;

[0065] ④ Prepare high-performance grouting liquid with the selected grouting material. Grouting is performed by professional and skilled personnel. First, grouting is performed with low pressure and small flow rate. If a small amount of slurry emerges from the vent pipe, gradually increase the grouting pressure and flow rate. When the pressure is relatively stable and the grouting amount is determined, continue grouting for 10s to 20s to complete the grouting of each hole.

[0066] ⑤ After the grouting body is finally set, the grouting formwork is removed, the exposed grouting body at the original grouting formwork is wrapped with geotextile and cured to the specified strength, and the exposed grouting body is polished with a grinding wheel. The exposed grouting body is required to be neat and beautiful;

[0067] Step 6: Post-surface construction

[0068] ① After cleaning, fill in the surface layer. The surface is required to be rough, and the surface layer should be filled in accordance with the designed mix ratio;

[0069] ② Use a small roller to compact the surface layer.

[0070] Compared with the prior art, the present invention mainly provides a steel bar anchoring structure for bridge widening anti-collision guardrail, and has the following advantages: First, due to the presence of multiple simply supported and then continuously prestressed steel bars and anchor blocks on the side T-beam bridge deck, the lower part of the conventional embedded steel bars cannot be smoothly implanted. If the conventional embedded steel bars are forcibly implanted, the bridge deck's simply supported and then continuously prestressed system may be damaged, thereby causing serious safety hazards. Therefore, adjusting the conventional embedded steel bars to anchor steel bars can effectively avoid the original multiple simply supported and then continuously prestressed steel bars and anchor blocks on the side T-beam bridge deck, which can safely and economically widen the bridge deck and improve the engineering quality of bridge widening. Quality; secondly, the micro-expansion agent in the high-performance grouting body of the anchoring steel bar anchoring system has short-term anti-shrinkage performance, which complements the long-term anti-shrinkage performance of the spring, and the new guardrail after the bridge deck is widened has long-term safety and durability; thirdly, the exposed anchor plates, screws, and nuts of the anchoring steel bar anchoring system are sealed with grouting bodies to protect the anchor plates, screws, and nuts from corrosion, thereby improving the safety and durability of the new guardrail; fourthly, the provided calculation method has clear principles, is practical and easy to use, and can be used as a design and construction guide for the anchoring steel bar structure of the bridge widening anti-collision guardrail, thereby improving the safety and quality performance. Therefore, the present invention is a bridge widening anti-collision guardrail anchoring steel bar structure with simple structure, convenient construction, low cost, safety and reliability, strong durability and high quality, which, combined with the corresponding construction method, has high economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 It is a schematic diagram of the structural elevation of the present invention.

[0072] Figure 2 for Figure 1 Enlarged view of point A.

[0073] Figure 3 This is the force calculation diagram for anchor steel bars before grouting.

[0074] Figure 4 This is the force calculation diagram for anchor steel bars after grouting. DETAILED DESCRIPTION

[0075] The embodiments of the present invention will be described in detail below with reference to the above-mentioned drawings.

[0076] like Figure 1~Figure 4 As shown, 1. side T-beam, 11. anchor block, 12. cutting line, 2. original guardrail, 3. pavement layer, 4. surface layer, 41. supplementary surface layer, 5. new guardrail, 6. steel skeleton, 61. anchor steel bar, 62. conventional embedded steel bar, 7. spring, 8. grouting pipe, 81. closing block, 82. corrugated pipe, 83. ventilation pipe, 84. grouting formwork, 85. grouting body, 9. anchor plate, 91. grouting channel, 92. screw, 93. nut.

[0077] Bridge widening anti-collision guardrail anchor steel structure and construction method, such as Figure 1 , Figure 2 As shown, it relates to the field of bridge widening quality engineering construction, and its structure includes a side T-beam 1 that is retained due to bridge widening and expansion, the original guardrail 2 that is removed, the upper flange plate retained on the outside of the side T-beam after the original guardrail is removed, the beam rib at the bottom of the side T-beam, and an anchor block 11 that is arranged between the bottom of the upper flange plate and the middle of the beam rib and anchors the top bridge deck of the side T-beam 1.

[0078] The two side T-beams 1 are combined with the multiple middle T-beams on the top to form each bridge deck, and before the bridge deck is widened, the original guardrail 2 is arranged on the upper part of the outer end of each side T-beam 1. The bridge deck composed of multiple middle T-beams and two side T-beams 1 is first simply supported and then continuous, and multiple continuous prestressed steel bars of the bridge deck need to be arranged, and the multiple continuous prestressed steel bars of the bridge deck are anchored and fixed by anchor blocks 11.

[0079] The upper flange plate connection frame formwork is used to construct a new reinforced concrete guardrail. The new guardrail 5 is composed of a steel frame 6, a plurality of anchor steel bars 61 in the steel frame that mainly resist the load, and cement concrete. The lower part of the anchor steel bar 61 is usually implanted in the upper flange plate. Due to the presence of multiple simply supported and then continuously prestressed steel bars and anchor blocks on the bridge deck, the lower part of conventional embedded bars cannot be implanted smoothly. If conventional embedded bars are forcibly implanted, the bridge deck's simply supported and then continuously prestressed system may be damaged, resulting in serious safety hazards. Therefore, it is necessary to adjust the conventional embedded bars to anchor steel bars. The multiple anchor steel bars 61 are arranged at equal intervals, and the lower part of each anchor steel bar 61 is implanted in the upper flange plate and fixed by the anchor system. In this way, the original multiple simply supported and then continuously prestressed steel bars and anchor blocks of the side T-beam bridge deck can be effectively avoided, thereby safely and economically widening the bridge deck and improving the engineering quality of the bridge widening.

[0080] The steel skeleton 6 is the structural reinforcement of the new guardrail. According to the external dimensions and stress conditions of the new guardrail 5, various types of steel bars are welded or tied to form an integral skeleton that can be mechanically hoisted. The steel skeleton 6 is manufactured in sections to facilitate hoisting and installation, removal of concrete formwork and pouring of concrete.

[0081] The anchor steel bar 61 is the main load-resisting steel bar in the new guardrail 5. Its steel bar model, quantity and diameter are all determined by calculation. The anchor steel bar 61 is arranged on the inner side of the new guardrail steel bar skeleton 6. The upper part is inclined along the shape of the inner side of the new guardrail 5, and the lower part is vertical. The threaded screw 92 at the bottom is engaged and anchored with the nut 93.

[0082] The anchoring system of each anchoring steel bar 61 in the new guardrail 5 is composed of a spring 7, a grouting pipe 8, a closing block 81, a bellows 82, a vent pipe 83, a grouting template 84, a grouting body 85, an anchoring plate 9, a grouting channel 91, a screw 92, a nut 93 and other components, and their relative positions and connections are as follows: the top surface of the closing block 81 is placed on the top of the vertical part of each anchoring steel bar 61, and the bottom surface of the closing block 81 is a bellows 82 inserted into the anchoring steel bar 61, and the bottom of the bellows is flush with the bottom of the new guardrail 5 and the bottom of the upper flange plate; the spring 7 is inserted into the anchoring steel bar 61 and placed in the bellows 82; the anchoring plate 9 is reserved The hole is inserted into the lower end of the anchor steel bar 61 from bottom to top and fastened by the nut 93. The top of the anchor plate 9 is flush with the bottom of the new guardrail 5 and the bottom of the upper flange plate; the grouting template 84 is placed between the bottom of the new guardrail 5 and the bottom of the upper flange plate, and a distance is reserved between the grouting template 84 and the screw 92 and the nut 93, and a space for the grouting body 85 is formed with the gap in the corrugated pipe 82, the anchor steel bar 61 and the spring 7; one end of the vent pipe 83 is horizontally inserted from the top of the corrugated pipe 82, and the other end of the vent pipe 83 extends to the outside of the template of the new guardrail 5; the grouting pipe 8 is reserved in the grouting template 84 and is externally connected to a grouting machine.

[0083] The spring 7 is a compression spring formed by cold bending a high-strength steel wire around a round tube or a round bar of a certain diameter. The outer diameter of the spring is 0.5 cm to 1 cm smaller than the inner diameter of the bellows, and the inner diameter of the spring is 1 cm to 3 cm larger than the outer diameter of the anchor steel bar. The top of the spring 7 is welded to the bottom of the closing block 81 and the length is Before the spring is compressed, a hole is opened at the contact point between the new guardrail bottom template and the spring 7 to allow the spring to be exposed at the bottom of the new guardrail 5. Length, spring compression After the length is reached, the bottom is flush with the bottom of the new guardrail and the bottom of the upper flange plate.

[0084] The grouting pipe 8 is a hard plastic pipe pressed into the grouting body 85, which is inserted into the grouting template from the reserved hole of the grouting template 84. The outer wall of the grouting pipe 8 is sealed with the reserved hole of the grouting template 84, and the outer end is connected to the grouting machine.

[0085] The closing block 81 is a circular steel plate or a square steel plate placed on the top of the corrugated pipe 82. It is firmly welded to the steel skeleton 6 of the new guardrail 5 with auxiliary steel bars. The cross-sectional size is 2cm to 3cm larger than the maximum outer diameter of the corrugated pipe 82 and the thickness is 1cm to 1.2cm. The bottom of the closing block 81 and the top of the corrugated pipe 82 are bonded and sealed with a strong adhesive, so that there is no air leakage or slurry leakage when pouring the new guardrail concrete.

[0086] The bellows 82 is a steel corrugated circular tube with a length of The inner diameter matches the anchor steel bar 61, the spring 7 and the corresponding reserved gap, and the outer diameter is one-fourth to one-third of the distance between the two anchor steel bars 61. The top of the corrugated pipe and the bottom of the closing block are bonded and sealed with a strong adhesive, and the bottom of the corrugated pipe is sealed with the new guardrail template. The cement slurry when pouring the new guardrail concrete does not leak into the corrugated pipe.

[0087] The vent pipe 83 is arranged on the top of the corrugated pipe 82 and extends to the outside of the new guardrail formwork, which is used to exhaust air during grouting. The junction between the outer wall of the vent pipe 83 and the corrugated pipe 82 is sealed, so that cement slurry does not leak into the vent pipe 83 when pouring the new guardrail concrete.

[0088] The grouting template 84 is placed between the bottom of the new guardrail 5 and the bottom of the upper flange plate and is separated from the screw 92 and the nut 93 by a certain distance. The gap between the grouting template 84 and the inside of the corrugated pipe 82, the anchor steel bar 61 and the spring 7 is the space for the grouting body 85. The anchor plate 9, the screw 92 and the nut 93 are sealed with the grouting body 85 to protect the anchor plate 9, the screw 92 and the nut 93 from corrosion, thereby improving the safety and durability of the new guardrail 5.

[0089] The grouting body 85 is formed by grouting and solidifying high-strength grouting material with water and an appropriate amount of micro-expansion agent. The micro-expansion agent has short-term anti-shrinkage performance, which complements the long-term anti-shrinkage performance of the spring 7. The new guardrail 5 has long-term safety and durability.

[0090] The anchor plate 9 is a wedge-shaped steel plate with a circular or square plane. The top plane has the same inclination as the bottom of the new guardrail 5 and the bottom of the upper flange plate. The bottom plane is a horizontal plane. The cross-sectional size is larger than the maximum outer diameter of the corrugated pipe 82 by 3cm to 5cm and the thickness by 1.5cm to 2.0cm. A hole is vertically reserved in the center of the anchor plate 9 for inserting the anchor steel bar 61 as a reserved hole. A cross-shaped semicircular groove is horizontally symmetrically arranged in the center of the top of the anchor plate 9 as a grouting channel 91. The radius of the cross-shaped semicircular groove is not greater than one-third of the thickness of the anchor plate 9.

[0091] The screw 92 and nut 93 are made of steel. The screw 92 is the threaded portion of the lower end of the anchoring steel bar 61. The engagement length of the screw thread and the nut thread is determined by calculation. The thread of the nut 93 matches the thread of the screw 92, and a standard thread is preferably used.

[0092] Each anchoring steel bar 61 is reserved together with the spring 7, grouting pipe 8, closing block 81, bellows 82 and vent pipe 83 constituting the anchoring system when the new guardrail concrete is cast in situ. The gap between each anchoring steel bar 61 and the spring 7, closing block 81 and bellows 82 is injected with grouting material under high pressure and finally solidified to form a grouting body 85, which is fastened by the anchor plate 9, screw 92 and nut 93. The anchoring steel bar 61 applies preliminary pressure to the spring 7 before grouting. The grouting body 85 reserves tensile energy to compensate for the shrinkage effect of the grouting body during its use. According to the bridge design standard, the design tensile force of the single anchor steel bar 61 in the new guardrail 5 that mainly resists the load is , the anchorage length of the anchor steel bar 61 is , the length of spring 7 is After the concrete pouring of the new guardrail is completed and reaches the specified strength, the anchor plate 9 and the nut 93 are installed before the anchor steel bar 61 is grouted, and the nut is twisted to apply initial pressure to the spring 7. Make the spring Length compressed to length, and then continue to twist the nut 93 to apply the final pressure to the spring 7 And tighten, according to the elasticity theory and force balance principle, the following calculation formula is obtained:

[0093] Formula 1:

[0094] The anchor system of the anchor steel bar 61 is fixed by twisting the nut 93 to apply initial pressure to the spring 7. Make the spring Length compressed to Length, after the high-strength grouting liquid injected under high pressure solidifies, when the grouting body 85 contracts during the use stage, the spring 7 has the function of preventing the grouting body from contracting. The contraction rate of the grouting body 85 reaches 2‰~5‰, so the compression rate of the spring 7 is controlled at 3‰~5‰ as compensation for the contraction of the grouting body, and the initial pressure applied to the spring 7 , which is the initial tension of the anchor steel bar 61 ,but

[0095]

[0096] Formula 2:

[0097] The anchor system of the anchor steel bar 61 is fixed by twisting the nut 93 to apply initial pressure to the spring 7. Make the spring Length compressed to length, and then continue to twist the nut 93 to apply the final pressure to the spring 7 And tighten, at this time the pressure of spring 7 is still the initial pressure After the grouting liquid of the anchoring steel bar 61 is finally solidified, the sum of the frictional resistance between the periphery of the grouting body 85 and the corrugated tube 82 and the anchoring force of the screw 92 or the nut 93 should be greater than the tensile force of the anchoring steel bar 61. The dimensions and related parameters of anchor steel bar 61 are

[0098]

[0099] The symbols in Formula 1 and Formula 2 are defined as:

[0100] ——The design tensile force of the single anchor steel bar 61 in the new guardrail 5 to resist the load, ;

[0101] ——The initial tension of the screw 92 before grouting the anchor steel bar 61, ;

[0102] ——The pressure on the spring 7 before grouting the anchor steel bar 61, ;

[0103] ——the final anchoring force of the screw 92 or nut 93, ;

[0104] ——The safety factor of the anchor steel bar 61 in the new guardrail 5 against load shall be determined according to relevant standards and specifications or taken as 1.3 to 1.5;

[0105] ——respectively the outer diameter of spring 7, the middle diameter of spring, and the diameter of spring wire material, ;

[0106] ——The effective number of turns of spring 7;

[0107] ——Spring 7 is deformed under pressure, ;

[0108] ——Shear deformation modulus of spring 7, ;

[0109] ——The wrapped length of the anchor steel bar 61 and the grout 85 in the corrugated tube 82 is also the length of the spring 7 after compression, ;

[0110] ——average inner diameter of bellows 82, ;

[0111] - the length of the threaded engagement portion of the screw 92 or nut 93, ;

[0112] - the average diameter of the threaded engagement portion of the screw 92 or nut 93, ;

[0113] ——Effective diameter of anchor bar 61, ;

[0114] ——The shear design value of 85 grouting body, ;

[0115] ——The shear design value of the screw 92 or the nut 93, ;

[0116] ——The tensile design value of the screw 92 or the nut 93, .

[0117] The construction method of the bridge widening anti-collision guardrail anchoring steel bar structure mainly includes the following steps:

[0118] Step 1: Develop a bridge widening design

[0119] ①Measure the dimensions of the bridge's side T-beam 1 and original guardrail 2, and collect basic data on load standards;

[0120] ② Prepare a preliminary design plan for bridge widening and select raw materials and construction plans;

[0121] ③ Calculate the design tensile force of the single anchor steel bar 61 that mainly resists the load in the steel skeleton 6 of the new guardrail 5 according to formula 1 and formula 2 Apply initial pressure to spring 7 before grouting the anchor reinforcement , and determine the main design parameters;

[0122] ④ Determine the materials used and the technical requirements for construction technology;

[0123] Step 2: Purchase the main engineering materials and process the components

[0124] ① Select high-performance and high-strength grouting materials and micro-expansion agents as the raw materials for the grouting body, and determine the design mix ratio and other technical parameters through experiments;

[0125] ② Select the raw material of spring steel wire to make spring 7; select the raw material of anchor steel bar, the length and technical parameters of screw rod 92 and nut 93;

[0126] ③ Make other anchoring system components, and the quality shall meet the design requirements;

[0127] ④ Select qualified grouting machinery, the grouting pressure is 0.2MPa~0.5MPa, check the operation of grouting equipment and pipelines, and set grouting parameters, such as gel time, grouting pressure and grouting amount;

[0128] ⑤ Make the steel skeleton 6 and formwork of the new guardrail 5, the quality of which meets the design requirements; test the concrete mix ratio and the pavement material mix ratio;

[0129] Step 3: Remove the original guardrail and part of the pavement and road surface

[0130] ① Measure and mark the demolition scope of the original guardrail 2, road surface and pavement according to the design drawings;

[0131] ② Select appropriate cutting machinery according to the concrete strength and volume of the demolished components:

[0132] ③When cutting and removing some components, pay attention to protecting the retained components, and ensure the safety of the bridge deck after removing some components;

[0133] Step 4: New guardrail construction

[0134] ① Measure and locate the exact position of the new guardrail 5 and make a mark;

[0135] ② Hoist the new guardrail steel frame 6, requiring accurate position;

[0136] ③ Make and set up new guardrail steel formwork, requiring accurate positioning;

[0137] ④ Check the sealing of the bellows 82 and the vent pipe 83, use an air compressor to press air into the vent pipe, and check whether there is any leakage in the bellows, vent pipe, closing block itself and the joints. If there is leakage, take sealing measures again until there is no leakage;

[0138] ⑤ Use a pump truck to pour cement concrete for the new guardrail 5, vibrate it with an inserted vibrator to make it dense, and cover it with geotextile for maintenance after the cement concrete has finally set;

[0139] ⑥ Generally, the side formwork will be removed after 12 hours, and the geotextile will be covered and watered for curing; when the concrete strength reaches 75%, the bottom formwork will be removed and cured to the specified strength;

[0140] Step 5: Compress the spring and grout the anchor steel bars

[0141] ① Clean the concrete residue at the contact point between the bottom of the new guardrail and the anchor block 11 and grind it flat. Insert the anchor plate 9 and nut 93 in sequence from the bottom of the anchor steel bar 61, screw in the nut to press the anchor plate 9 and the spring 7 until they are flush with the bottom of the new guardrail; continue to screw in the nut 93 until the design torque is reached; for standard nuts, the final torque of tightening the nut with a wrench is determined by the specifications of the nut and the corresponding torque from the relevant standards; for non-standard nuts, the final torque of tightening the nut with a wrench is determined by the structure of the screw or nut and the final anchoring force Calculated;

[0142] ② Before grouting, a baffle is set up at the vent opening, leaving a gap between the baffle and the vent opening, and the observer observes the grouting situation at a safe distance;

[0143] ③Install the grouting template, and seal the contact between the grouting template and the bottom of the new guardrail, the side of the beam rib of the side T beam 1 and the grouting pipe 8 to prevent air leakage and grout leakage;

[0144] ④ Prepare high-performance grouting liquid with the selected grouting material. Grouting is performed by professional and skilled personnel. First, grouting is performed with low pressure and small flow rate. If a small amount of slurry emerges from the vent pipe, gradually increase the grouting pressure and flow rate. When the pressure is relatively stable and the grouting amount is determined, continue grouting for 10s to 20s to complete the grouting of each hole.

[0145] ⑤ After the grouting body 85 is finally set, the grouting template 84 is removed, the exposed grouting body at the original grouting template is wrapped with geotextile and cured to the specified strength, and the exposed grouting body is polished with a grinding wheel. The exposed grouting body is required to be neat and beautiful;

[0146] Step 6: Post-surface construction

[0147] ① After cleaning, fill the surface layer 41 part of the space, the surface is required to be rough, fill and fill the surface layer 41 according to the designed mix ratio;

[0148] ② Use a small roller to compact the backfill surface layer 41.

[0149] In addition, the construction method of the anchored steel structure of the anti-collision guardrail for widening the above-mentioned bridge also involves a cutting line 12, a pavement layer 3 and a supplementary surface layer 41, etc., wherein the cutting line 12 refers to the cutting and removal line of the side T-beam 1 that is retained due to the widening and expansion of the bridge, the dismantled original guardrail 2 and the corresponding bridge deck pavement layer 3 and surface layer 4, and it is required that the retained side T-beam 1, bridge deck pavement layer 3 and surface layer 4 structures are not damaged during mechanical cutting. The rough surface of the cutting line 12 is conducive to firm bonding with the new guardrail concrete, pavement layer 3 and supplementary surface layer 41; the pavement layer 3 is the connecting structural layer after the installation of multiple middle T-beams and two side T-beams 1 on each bridge deck, and is the base layer of the surface layer 4; the supplementary surface layer 41 is the partial surface layer that is restored with the original surface layer material to fill the vacant part after the original guardrail 2 is dismantled.

[0150] The above description is only a specific embodiment of the present invention. Those skilled in the art should understand that any structural design equivalent to this embodiment should be included in the protection scope of the present invention.

Claims

1. A bridge widening anti-collision guardrail anchoring steel bar structure, comprising a side T-beam (1) retained due to the widening and expansion of the bridge, an upper flange plate retained on the outer side of the side T-beam after the original guardrail (2) is removed, a beam rib at the bottom of the side T-beam (1), and an anchor block (11) arranged between the lower part of the upper flange plate and the middle part of the beam rib and anchoring the bridge deck at the top of the side T-beam; the upper flange plate is connected to a frame template to construct a new reinforced concrete guardrail (5), characterized in that The new guardrail (5) is formed by a steel frame (6), a plurality of anchoring steel bars (61) in the steel frame that mainly resist the load, and cement concrete. The plurality of anchoring steel bars (61) are arranged at equal intervals, and the lower part of each anchoring steel bar (61) is implanted in the upper flange plate and fixed by an anchoring system. The anchoring system comprises a spring (7), a grouting pipe (8), a closing block (81), a corrugated pipe (82), a vent pipe (83), a grouting template (84), a grouting body (85), an anchoring plate (9), a screw (92) and a nut (93). The top surface of the closure block (81) is provided with At the top of the vertical part of each anchoring steel bar (61), the bottom surface of the closing block (81) is a corrugated tube (82) inserted into the anchoring steel bar (61), and the bottom of the corrugated tube is flush with the bottom of the new guardrail (5) and the bottom of the upper flange plate; the spring (7) is inserted into the anchoring steel bar (61) and placed in the corrugated tube (82); the anchoring plate (9) is inserted into the lower end of the anchoring steel bar (61) from bottom to top through the reserved hole and is fastened by the screw rod (92) and the nut (93), and the top of the anchoring plate (9) is flush with the bottom of the new guardrail (5) and the bottom of the upper flange plate; the grouting template (84) is placed at the bottom of the new guardrail (5). A distance is reserved between the grouting template (84) and the screw rod (92) and the nut (93), and a space is formed between the grouting body (85) and the gap between the bellows (82) and the anchor steel bar (61) and the spring (7); one end of the vent pipe (83) passes horizontally through the top of the bellows (82), and the other end of the vent pipe (83) extends to the outside of the template of the new guardrail (5); the grouting pipe (8) is reserved in the grouting template (84) and is connected to a grouting machine; the grouting pipe (8) is a hard plastic pipe pressed into the grouting body (85), which is inserted from the grouting template The reserved hole on (84) is inserted into the grouting template, and the outer wall of the grouting pipe (8) is sealed with the reserved hole of the grouting template (84), and the outer end of the grouting pipe is connected to the grouting machine; the closing block (81) is a circular steel plate or a square steel plate placed on the top of the corrugated pipe (82), and is firmly welded to the steel frame (6) of the new guardrail (5). The cross-sectional size of the closing block (81) is larger than the maximum outer diameter of the corrugated pipe (82) by 2cm to 3cm and the thickness is 1cm to 1.2cm. The bottom of the closing block (81) and the top of the corrugated pipe (82) are bonded and sealed with a strong adhesive, and no air leakage or grout leakage occurs when pouring the new guardrail concrete.

2. The bridge widening anti-collision guardrail anchoring steel bar structure according to claim 1 is characterized in that Each anchoring steel bar (61) is reserved together with the spring (7), grouting pipe (8), closing block (81), bellows (82) and vent pipe (83) constituting the anchoring system when the new guardrail concrete is cast in situ. Grouting material is injected into the gap between each anchoring steel bar (61) and the spring (7), closing block (81) and bellows (82) under high pressure and finally solidified to form a grouting body (85). The grouting body is fastened by an anchoring plate (9), a screw rod (92) and a nut (93). The anchoring steel bar (61) applies preliminary pressure to the spring (7) before grouting. The grouting body (85) reserves tensile energy to compensate for the shrinkage effect of the grouting body during its use. According to the bridge design standard, the design tensile force of the single anchor steel bar (61) in the new guardrail (5) that mainly resists the load is , the anchorage length of the anchor steel bar (61) is , the length of spring (7) is After the concrete pouring of the new guardrail is completed and reaches the specified strength, the anchor plate (9) and the nut (93) are installed before the anchor steel bar (61) is grouted, and the nut is twisted to apply initial pressure to the spring (7). Make the spring Length compressed to length, and then continue to twist the nut (93) to apply final pressure to the spring (7). And tighten, according to the elasticity theory and force balance principle, the following calculation formula is obtained: Formula 1: The anchor system for fixing the anchor bar (61) is twisted by the nut (93) to apply initial pressure to the spring (7). Make the spring Length compressed to After the high-strength grouting liquid injected under high pressure solidifies, when the grouting body contracts during the use stage, the spring (7) has the function of preventing the grouting body (85) from contracting. The contraction rate of the grouting body reaches 2‰ to 5‰, so the compression rate of the spring (7) is controlled at 3‰ to 5‰ as compensation for the contraction of the grouting body (85). The initial pressure applied to the spring (7) , which is the initial tension of the anchor steel bar (61) ,but Formula 2: The anchor system for fixing the anchor bar (61) is twisted by the nut (93) to apply initial pressure to the spring (7). Make the spring Length compressed to length, and then continue to twist the nut (93) to apply final pressure to the spring (7). And tighten, at this time the pressure of the spring (7) is still the initial pressure After the grouting liquid of the anchoring steel bar (61) is finally solidified, the sum of the frictional resistance between the periphery of the grouting body (85) and the corrugated pipe and the anchoring force of the screw (92) or the nut (93) should be greater than the tensile force of the anchoring steel bar (61) under the load. The anchoring force pressure of the screw (92) or the nut (93) The dimensions and related parameters of the anchor reinforcement (61) are The symbols in Formula 1 and Formula 2 are defined as: ——The design tensile force of a single anchor steel bar (61) in the new guardrail (5) to resist the load, ; ——The initial tension of the screw (92) before grouting the anchor bar (61), ; ——The pressure on the spring (7) before grouting the anchor steel bar (61), ; - the final anchoring force of the screw (92) or nut (93), ; - the safety factor of the anchor steel bars (61) in the new guardrail (5) against loads shall be determined in accordance with relevant standards and specifications or shall be 1.3 to 1.5; ——respectively the outer diameter of the spring (7), the middle diameter of the spring, and the diameter of the spring wire material, ; - effective number of turns of the spring (7); ——The spring (7) is deformed under pressure, ; —— shear deformation modulus of spring (7), ; ——The wrapped length of the anchor steel bar (61) and the grout (85) in the corrugated tube (82), which is also the length of the spring (7) after compression. ; - average inner diameter of the bellows (82), ; - length of the threaded engagement portion of the screw (92) or nut (93), ; - the average diameter of the threaded portion of the screw (92) or nut (93), ; ——Effective diameter of anchor bar (61), ; —— shear design value of grouting body (85), ; - shear design value of the screw (92) or nut (93), ; - tensile design value of the screw (92) or nut (93), .

3. The bridge widening anti-collision guardrail anchoring steel bar structure according to claim 1 is characterized in that The spring (7) is a compression spring formed by cold bending a high-strength steel wire around a round tube or a round bar. The outer diameter of the spring (7) is 0.5 cm to 1 cm smaller than the inner diameter of the bellows (82). The inner diameter of the spring (7) is 1 cm to 3 cm larger than the outer diameter of the anchoring steel bar (61). The top of the spring (7) is welded to the bottom of the closing block (81) and the length is Before the spring (7) is compressed, a hole is opened at the contact point between the new guardrail bottom template and the spring so that the spring is exposed at the bottom of the new guardrail (5). length, and the spring is compressed After the length is reached, the bottom is flush with the bottom of the new guardrail (5) and the bottom of the upper flange plate.

4. The bridge widening anti-collision guardrail anchoring steel bar structure according to claim 1 is characterized in that The bellows (82) is a steel corrugated circular tube with a length of The inner diameter is matched with the anchor steel bar (61), the spring (7) and the corresponding reserved gap. The outer diameter of the bellows (82) is one-fourth to one-third of the distance between the two anchor steel bars (61). The top of the bellows (82) and the bottom of the closing block (81) are bonded and sealed with a strong adhesive. The bottom of the bellows (82) is sealed with the new guardrail template, and the cement slurry when pouring the new guardrail concrete does not leak into the bellows (82).

5. The bridge widening anti-collision guardrail anchoring steel bar structure according to claim 1 is characterized in that The vent pipe (83) is arranged at the top of the corrugated pipe (82) and extends outside the new guardrail formwork to exhaust air during grouting. The junction between the outer wall of the vent pipe (83) and the corrugated pipe (82) is sealed, and cement slurry during pouring of the new guardrail concrete does not leak into the vent pipe (83).

6. The bridge widening anti-collision guardrail anchoring steel bar structure according to claim 1 is characterized in that The anchor plate (9) is a wedge-shaped steel plate with a circular or square plane. The top plane of the anchor plate (9) has the same inclination as the bottom of the new guardrail (5) and the bottom of the upper flange plate. The bottom plane of the anchor plate (9) is a horizontal plane. The cross-sectional dimensions are 3 cm to 5 cm larger than the maximum outer diameter of the corrugated pipe (82) and 1.5 cm to 2.0 cm thick. A reserved hole is vertically reserved at the center of the anchor plate (9) for inserting the anchor steel bar (61). A cross-shaped semicircular groove is horizontally symmetrically provided at the center of the top of the anchor plate (9) as a grouting channel (91). The radius of the cross-shaped semicircular groove is not greater than one-third of the thickness of the anchor plate (9).

7. The bridge widening anti-collision guardrail anchoring steel bar structure according to claim 1 is characterized in that The grouting body (85) is formed by adding water and an appropriate amount of micro-expansion agent to a high-strength grouting material and then grouting and solidifying. The screw (92) and nut (93) are made of steel. The screw (92) is a threaded portion at the lower end of the anchoring steel bar. The engagement length between the screw thread and the nut thread is determined by calculation.

8. A construction method for anchoring a steel bar structure for widening a bridge anti-collision guardrail according to claim 2, characterized in that The construction method comprises the following steps: Step 1: Develop a bridge widening design ① Measure the dimensions of the bridge's side T-beam (1) and the original guardrail (2), and collect basic data on the load standard; ② Prepare a preliminary design plan for bridge widening and select raw materials and construction plans; ③ Calculate the design tensile force of the single anchor steel bar (61) that mainly resists the load in the steel frame (6) of the new guardrail according to Formula 1 and Formula 2: Apply initial pressure to the spring (7) before grouting the anchor reinforcement , and determine the main design parameters; ④ Determine the materials used and the technical requirements for construction technology; Step 2: Purchase the main engineering materials and process the components ① Select high-performance and high-strength grouting material and micro-expansion agent as the raw materials of the grouting body (85), and determine the design mix ratio and other technical parameters through experiments; ② Selecting raw materials of spring steel wire to make spring (7); selecting raw materials of anchor steel bars, lengths and technical parameters of screw rod (92) and nut (93); ③ Make other anchoring system components, and the quality shall meet the design requirements; ④ Select qualified grouting machinery, the grouting pressure is 0.2MPa~0.5MPa, check the operation of grouting equipment and pipelines, and set grouting parameters such as gel time, grouting pressure and grouting amount; ⑤ Make the steel frame (6) and formwork of the new guardrail (5), the quality of which meets the design requirements; Test concrete mix proportions and pavement material mix proportions; Step 3: Remove the original guardrail and part of the pavement and road surface ① Measure and mark the demolition range of the original guardrail (2), road surface and pavement (3) according to the design drawings; ② Select appropriate cutting machinery according to the concrete strength and volume of the demolished components: ③When cutting and removing some components, pay attention to protecting the retained components, and ensure the safety of the bridge deck after removing some components; Step 4: New guardrail construction ① Measure and locate the exact position of the new guardrail (5) and mark it; ② Install the new guardrail steel frame (6) in an accurate position; ③ Make and set up new guardrail steel formwork, requiring accurate positioning; ④ Check the sealing of the bellows (82) and the vent pipe (83). Use an air compressor to pressurize air into the vent pipe and check whether there is any leakage in the bellows, vent pipe, sealing block (81) and the joints. If there is any leakage, take sealing measures again until there is no leakage. ⑤ Use a pump truck to pour cement concrete for the new guardrail (5), vibrate it with an inserted vibrator to make it dense, and cover it with geotextile for curing after the cement concrete has finally set; ⑥ Generally, the side formwork will be removed after 12 hours, and the geotextile will be covered and watered for curing; when the concrete strength reaches 75%, the bottom formwork will be removed and cured to the specified strength; Step 5: Compress the spring and grout the anchor steel bars ① Clean the concrete residue at the contact point between the bottom of the new guardrail and the anchor block (11) and grind it flat. Insert the anchor plate (9) and the nut (93) in sequence from the bottom of the anchor steel bar (61). Screw in the nut to press the anchor plate (9) and the spring (7) until they are flush with the bottom of the new guardrail. Continue to screw in the nut (93) until the design torque is reached. For standard nuts, the final torque of tightening the nut with a wrench is determined by looking up the corresponding torque from the relevant standards according to the specifications of the nut. For non-standard nuts, the final torque of tightening the nut with a wrench is determined by the structure of the screw or nut and the final anchoring force. Calculated; ② Before grouting, a baffle is set up at the vent opening, leaving a gap between the baffle and the vent opening, and the observer observes the grouting situation at a safe distance; ③ Install the grouting template (84), and seal the contact points between the grouting template and the bottom of the new guardrail (5), the side of the beam rib of the side T beam (1) and the grouting pipe (8) to prevent air leakage and grout leakage; ④ Prepare high-performance grouting liquid with the selected grouting material. Grouting is performed by professional and skilled personnel. First, grouting is performed with low pressure and small flow rate. If a small amount of slurry emerges from the vent pipe, gradually increase the grouting pressure and flow rate. When the pressure is relatively stable and the grouting amount is determined, continue grouting for 10s to 20s to complete the grouting of each hole. ⑤ After the grouting body (85) is finally set, the grouting template (84) is removed, the exposed grouting body at the original grouting template is wrapped with geotextile and cured to the specified strength, and the exposed grouting body is polished with a grinding wheel. The exposed grouting body is required to be neat and beautiful; Step 6: Post-surface construction ① After cleaning, fill the surface layer (41) part of the space. The surface is required to be rough and fill the surface layer according to the designed mix ratio; ② Use a small roller to compact the backfill surface layer (41).

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