Construction method of twisted road for testing fatigue durability of vehicle

Abstract

The construction method of the twisted road for testing the fatigue durability of the vehicle comprises the following steps: preparing data; processing a template; measuring and setting out; arranging a reinforcing mesh; mounting a template; concrete construction; construction joints are arranged; and preserving. According to the construction method, the construction progress is accelerated, the construction period is shortened, the qualified rate of various control indexes of the twisted road is increased, the formed twisted road is smooth in curve and free of break points, the automobile test requirement is met, and abrasion of the road surface twisted blocks is reduced.

Description

Technical Field

[0001] The present invention relates to the field of road construction, and more particularly to a construction method for a twisted road for testing vehicle fatigue durability. Background Art

[0002] An automotive test track is a place where various road conditions and usage conditions encountered during vehicle use are reproduced for full-vehicle road tests of automobiles. To meet the test requirements of automobiles, the main test facilities of an automotive test track are various test roads constructed centrally, including high-speed circular runways, high-speed straight runways, enhanced test sections, durability test runways, climbing test roads, and special test sections such as noise test sections, Belgian sections, washboard roads, corrugated roads, twisted roads, off-road roads, and wading roads.

[0003] Among them, a twisted road is a road surface formed by alternatingly changing in a sine or triangular form on one side, mainly testing the amount of torsional deformation of an automobile when driving on an unbalanced twisted road. The construction of a twisted road is difficult, and various design indicators have relatively high requirements. Currently, the mainstream construction method for the twisted road of test track fatigue durability is to use concrete to make precast twisted blocks and install the precast twisted blocks on the road surface to simulate the twisted road. The road surface formed by this method has too many inflection points, poor surface smoothness, excessive wear of the twisted blocks; and there are large errors in the elevation of the raised wave peaks of the road surface and large errors in wavelength control, which cannot accurately simulate the driving of an automobile on a twisted road and the test data is inaccurate. Therefore, there is an urgent need for a construction method for a twisted road for testing vehicle fatigue durability to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a construction method for a twisted road for testing vehicle fatigue durability, aiming at the problems of too many inflection points on the road surface curve of the twisted road in an automotive test track, poor surface smoothness, excessive wear of the twisted blocks, large errors in the elevation of the raised wave peaks of the road surface, large errors in wavelength control, inability to accurately simulate the driving of an automobile on a twisted road, and inaccurate test data.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A construction method for a twisted road for testing vehicle fatigue durability, the method comprising the following steps:

[0007] Step 1, data preparation;

[0008] Step 2, template processing;

[0009] Step 3, measurement and layout;

[0010] Step 4, laying of steel bar meshes;

[0011] Step 5, formwork installation;

[0012] Step 6, concrete construction;

[0013] Step 7, construction joint layout;

[0014] Step 8, curing.

[0015] The construction method of the twisted road for testing vehicle fatigue durability as described above, wherein step 1 data preparation includes the following steps:

[0016] The twisted road is divided into two forms: general twisted road and strong twisted road. The cross-section forms of the left and right sides of the general twisted road are sine functions; the cross-section forms of the left and right sides of the strong twisted road are regular trigonometric functions.

[0017] Select an appropriate function form as the cross-section form of the left and right road surface segments of the twisted road according to the design requirements; compile a data sheet for side form processing based on the road spectrum data.

[0018] The construction method of the twisted road for testing vehicle fatigue durability as described above, wherein step 2 formwork processing includes the following steps:

[0019] Step 2.1, draw an electronic formwork drawing according to the calculated formwork processing data sheet, process the formwork according to the drawing, number and divide each processed formwork according to the road spectrum data sheet to avoid formwork installation errors during installation. The length error and peak height error of each processed formwork meet the requirements.

[0020] Step 2.2, check and verify the processed formwork against the road spectrum data, and reprocess the formwork that does not meet the design dimensions or exceeds the error range.

[0021] The construction method of the twisted road for testing vehicle fatigue durability as described above, wherein step 3 measurement and layout includes the following steps:

[0022] Lay out the starting and ending points of the side form on the top of the curbstone that has been built according to the design drawing; then release the form position according to the convex perimeter designed in the road spectrum, and mark the form number on the top of the curbstone according to the form size designed in the road spectrum.

[0023] The construction method of the twisted road for testing vehicle fatigue durability as described above, wherein step 4 steel mesh layout includes the following steps:

[0024] Step 4.1, accurately pop the grid on the concrete base according to the reinforcement drawing of the twisted road on site; mark the spacing points for steel bar layout. All steel bars are tied with double wires and tied firmly. The remaining length of the tied wire heads should extend into the inner side of the steel bars and shall not extend into the net cover layer. The steel bar spacing and the thickness of the steel bar cover layer meet the design requirements.

[0025] Step 4.2: Spacingly arrange dowel bars in the longitudinal steel bar mesh, and smooth round steel bars are used for the dowel bars.

[0026] After tying the first layer of steel bars, place lower cushion blocks below; after the steel bars are tied, the steel bar spacing shall be rechecked, and those not meeting the design and specification requirements shall be adjusted.

[0027] Check whether the thickness of the steel bar protection layer at the bottom of the steel bars and at the side formwork meets the design requirements, and adjust the non-compliant parts in a timely manner.

[0028] The construction method of the twisted road for testing the fatigue durability of a vehicle as described above, wherein Step 5 formwork installation includes the following steps:

[0029] Step 5.1: Fix the prefabricated steel formwork inside the curb according to the road spectrum dimensions, and the inner wall of the steel formwork and the inside of the curb are in the same vertical plane; the starting position of the steel formwork is installed according to the requirements of the road spectrum.

[0030] After the formwork is placed, it shall be reinforced stably. The verticality of the formwork is 90°, and the elevation error and the installation deviation of the formwork plane position shall be controlled.

[0031] The construction method of the twisted road for testing the fatigue durability of a vehicle as described above, wherein Step 6 concrete construction includes the following steps:

[0032] Step 6.1: Concrete pouring:

[0033] Step 6.1.1: Pour the concrete into the formwork without concentrated pouring and impacting the steel bar skeleton. When the pouring height is greater than 2m, a tremie pipe or a chute shall be used for discharging the material, and the free fall height from the discharging pipe orifice to the pouring layer shall not be greater than 1.5m.

[0034] Step 6.1.2: The concrete slab is poured continuously. After the pouring is completed, add a stop plank, and the reserved hole is located in the middle of the wooden formwork; insert the dowel bar steel bar into the stop plank, and the inserted length is half of the designed value of the dowel bar length.

[0035] Step 6.1.3: Pouring each concrete slab shall be carried out continuously. If it is necessary to have an interval, the interval time shall be shortened as much as possible, and it shall be before the initial setting of the previous section of concrete; when touching the surface of the poured concrete and it is not sticky to the hand, carry out surface texturing treatment on the concrete surface.

[0036] When pouring the concrete, often observe whether the formwork, steel bars, and reserved holes are displaced, deformed, or blocked. If any problem is found, it shall be dealt with immediately, and it shall be repaired well before the initial setting of the already poured concrete.

[0037] Step 6.2: Concrete vibration:

[0038] Vibration shall follow the principle of fast insertion and slow extraction. The insertion points of the vibrator shall be arranged evenly in a plum blossom shape, moving point by point in sequence without omission to achieve uniform compaction. The vibration moving spacing shall not be greater than 1.5 times the vibration action radius, generally controlled at 30 - 40 cm. The vibration duration shall be such that the concrete surface generates floating slurry, has no bubbles, and does not sink. After the concrete pouring is completed, use a screed to shape it. When shaping, the screed takes the top linear shape of the left and right side forms as the track and smoothly levels the top surface of the concrete. The screed shall be closely attached to the top of the left and right forms.

[0039] The construction method of the twisted road for testing the fatigue durability of a vehicle as described above, wherein step 7 of the construction joint layout includes the following steps:

[0040] Construction joint layout: When the pouring ends every day or the paving interruption time exceeds 60 minutes, a transverse construction joint shall be set. Its position shall preferably coincide with the expansion joint or contraction joint. When it is really difficult to coincide, the construction joint shall adopt the form of a tongue-and-groove joint with threaded dowel bars. The cutting of the joint can be carried out after the concrete has finally set. The joint width is 5 - 10 mm and the depth is greater than 70 mm.

[0041] Contraction joint layout: One contraction joint shall be set every 5 m for the cement concrete roadbed. The contraction joint is provided with a dowel bar of φ25, 70 cm long, and the spacing is 60 cm. One end of the dowel bar is coated with asphalt and wrapped with polyethylene film. The cutting of the joint can be carried out after the concrete has finally set. The joint width is 5 - 10 mm and the depth is 70 mm.

[0042] Expansion joint layout: One expansion joint shall be set every 100 m. The expansion joint adopts a 2 cm extruded polystyrene board as the joint filler board. The arrangement of the dowel bars is the same as that of the contraction joint, and the joint filling depth is 30 - 40 mm.

[0043] The construction method of the twisted road for testing the fatigue durability of a vehicle as described above, wherein step 8 of curing includes the following steps:

[0044] The concrete after pouring shall be covered with geotextile and watered for curing. The sprinkler truck shall travel along the side of the road surface, and a plastic hose shall be used to connect the sprinkler truck to sprinkle water on the concrete surface without leakage. The number of watering times depends on the temperature of the day, and the surface shall always be kept moist. The curing time shall not be less than 7 days.

[0045] The beneficial effects of the present invention are as follows:

[0046] 1. The construction progress is improved and the construction period is shortened. The construction method of the present invention adopts the formwork shaping method, replacing the construction process of elevation control piles. The construction method is simple, fast, conducive to the organization of construction production, and effectively shortens the construction period.

[0047] 2. The shaping quality is high. The construction method of the present invention adopts the formwork shaping method, and through accurate shaping by the formwork, the qualification rate of various control indicators of the twisted road is improved.

[0048] 3. Good appearance quality: After the construction of the present invention using the template shaping method, the surface of the raised part of the twisted road is polished smooth with a scraping bar, the curve is smooth and there is no inflection point. The twisted road formed by the technical solution of the present invention can meet the vehicle test requirements to the greatest extent. Since the twisted blocks are formed by one-time pouring with the road surface, the wear of the road surface and the twisted blocks can be reduced after the connection. Detailed implementation mode

[0049] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further introduced in detail below.

[0050] A construction method of a twisted road for testing vehicle fatigue durability, the method includes the following steps:

[0051] Step 1. Data preparation:

[0052] The twisted road is divided into two forms: general twisted road and strong twisted road. The cross-section forms of the left and right sides of the general twisted road are sine functions, the maximum value of the wave crest is 0.127m, the maximum wavelength is 8.2m, and the minimum wavelength is 1.95m. The cross-section forms of the left and right sides of the strong twisted road are regular trigonometric functions, the maximum value of the wave crest is 0.3m, the maximum wavelength is 11m, and the minimum wavelength is 4.8m.

[0053] Select an appropriate function form as the cross-section form of the left and right sides of the twisted road according to the design requirements; compile a data sheet for side mold processing according to the road spectrum data.

[0054] Step 2. Template processing:

[0055] Step 2.1. Draw a 1:1 CAD electronic template drawing according to the calculated template processing data sheet, use a machine tool to process the template according to the drawing, number and divide the processed templates according to the road spectrum data sheet. The left side of the general twisted road is numbered with YZ1, YZ2, YZ3,..., YZn, and the right side is numbered with YY1, YY2, YY3,..., YYn; the left side of the strong twisted road is numbered with QZ1, QZ2, QZ3,..., QZn, and the right side is numbered with QY1, QY2, QY3,..., QYn to avoid incorrect template installation during installation. The length error of each processed template is required to be ±1mm, and the wave crest height error is required to be ±2mm.

[0056] Step 2.2. Compare and review the processed templates with the road spectrum data, and reprocess the templates that do not meet the design dimensions or exceed the error range.

[0057] Step 3. Measurement and layout:

[0058] Use a total station to set out the starting and ending points of the side formwork on the top of the curbstone that has been built according to the design drawings; then use a steel tape measure to release the formwork position according to the raised perimeter of the road spectrum design, and mark the formwork number on the top of the curbstone according to the formwork size of the road spectrum design.

[0059] Step 4. Steel mesh layout:

[0060] Step 4.1. On-site, use an engineering ink box to accurately pop out a 5m * 3.8m grid on the concrete base according to the distorted road reinforcement drawing; use a marker pen and a steel tape measure to mark the reinforcement layout spacing points. All steel bars must be tied with double wires and tied firmly. The remaining length of the tying wire head should extend into the inner side of the steel bar and shall not extend into the net cover layer. The steel bar spacing is 0.2m horizontally and 0.15m vertically, arranged in a single layer in both directions, and the steel bar cover thickness is 5cm.

[0061] Step 4.2. Place load transfer bars at intervals of 5m in the longitudinal steel mesh. The length of the load transfer bar is 0.7m, and the load transfer bar uses a smooth round steel bar with a diameter of Φ25.

[0062] Step 4.3. After tying the first layer of steel bars, place lower cushion blocks below; after the steel bar tying is completed, the steel bar spacing should be rechecked, and those that do not meet the design and specification requirements should be adjusted.

[0063] Step 4.4. Check whether the steel bar cover thickness at the bottom and side formwork parts meets the design requirements, and adjust the non-conforming parts in time; avoid corrosion of steel bars due to insufficient cover thickness.

[0064] Step 5. Formwork installation:

[0065] Step 5.1. Fix the prefabricated steel formwork inside the curbstone according to the road spectrum size, and the inner wall of the steel formwork is in the same vertical plane as the inside of the curbstone; the starting position of the steel formwork is installed according to the road spectrum requirements.

[0066] Step 5.2. After the formwork is placed, it should be strengthened. The strengthening should be stable. The verticality of the formwork is 90°, the elevation error is controlled within ±2mm, and the installation deviation of the formwork plane position is controlled within ±1mm.

[0067] Step 6. Concrete construction:

[0068] Step 6.1. Concrete pouring:

[0069] Step 6.1.1. When the concrete is put into the formwork, it shall not be poured concentratedly to impact the steel bar skeleton. When the pouring height is greater than 2m, a tremie pipe or a chute shall be used for discharging. The free fall height of the discharging pipe orifice to the pouring layer shall not be greater than 1.5m.

[0070] Step 6.1.2: The concrete type for the twisted road is HF-4.5. The concrete slab is poured continuously. After pouring, end plates are added. The reserved holes are located in the middle of the wooden formwork with a spacing of 60 cm. Insert the dowel bars into the end plates, and the inserted length is half of the designed value of the dowel bar length.

[0071] Step 6.1.3: Each concrete slab should be poured continuously. If there must be an interruption, the interruption time should be minimized and should be before the initial setting of the previous section of concrete. The maximum interruption time should be determined according to the type of cement used, the temperature, and the concrete setting conditions. Generally, if it exceeds 1 h, it should be treated as a construction joint. When the concrete setting time is less than 2 h, the initial setting time of the concrete should be followed. When the surface of the poured concrete does not stick to the hand, the surface of the concrete should be roughened.

[0072] During the concrete pouring, the formwork, steel bars, and reserved holes should be observed regularly for any movement, deformation, or blockage. If any problems are found, they should be dealt with immediately and should be repaired before the initial setting of the already poured concrete.

[0073] Step 6.2: Concrete vibration:

[0074] Vibration should follow the principle of quick insertion and slow extraction. The insertion points of the vibrator are arranged in a plum blossom shape evenly. Move point by point in sequence without omission to achieve uniform compaction. The vibration moving distance is not greater than 1.5 times the vibration action radius, generally controlled at 30 - 40 cm. The vibration duration should be such that the concrete surface produces floating slurry, no bubbles, and does not sink. After the concrete pouring is completed, use a screed to shape it. When shaping, the screed takes the top line of the left and right side forms as the track and smoothly levels the top surface of the concrete. The screed should be close to the top of the left and right forms.

[0075] Step 7: Construction joint layout:

[0076] Construction joint layout: When the pouring ends every day or the paving interruption time exceeds 60 min, a transverse construction joint should be set. Its position should preferably coincide with the expansion joint or the contraction joint. If it is really difficult to coincide, the construction joint should adopt the form of a tongue-and-groove joint with threaded dowel bars. The concrete can be cut after final setting, with a joint width of 5 - 10 mm and a depth greater than 70 mm.

[0077] Contraction joint layout: One contraction joint is set every 5 m for the cement concrete roadbed. The contraction joint is provided with φ25 dowel bars, 70 cm long, with a spacing of 60 cm. One end of the dowel bar is coated with asphalt and wrapped with polyethylene film. The concrete can be cut after final setting, with a joint width of 5 - 10 mm and a depth of 70 mm.

[0078] Expansion joint layout: One expansion joint is set every 100 m. The expansion joint uses a 2 cm extruded polystyrene filling board. The arrangement of the dowel bars is the same as that of the contraction joint, and the grouting depth is 30 - 40 mm.

[0079] Step 8: Curing:

[0080] The cast - in - place concrete shall be covered with geotextiles and watered for curing. The water truck shall travel along the side of the road surface, and a plastic hose shall be used to connect the water truck to sprinkle water on the concrete surface without omission. The number of water - sprinkling times shall depend on the temperature of the day, and the surface shall always be kept moist; the curing time shall not be less than 7 days.

[0081] The above is a detailed introduction to the solution provided by the embodiments of the present invention. For those skilled in the art, according to the idea of the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. The scope to be protected by the present invention is not limited to the technical solutions mentioned in this embodiment, and any technical solution inspired by the present invention falls within the protection scope of the present invention.

Claims

1. A method for constructing a twisted road for testing vehicle fatigue durability, the method comprising the following steps: Step 1: Data preparation; Step 2: Template processing; Step 3: Measurement and setting out; Step 4: laying out the steel mesh; Step 5: Template installation; Step 6: Concrete construction; Step 7: Construction joint layout; Step 8: Maintain health.

2. The method for constructing a twisted road for testing vehicle fatigue durability according to claim 1, characterized in that: Step 1 Data preparation includes the following steps: According to the design requirements, select the appropriate function form as the cross-sectional form of the pavement sections on the left and right sides of the twisted road; prepare the side mold processing data table based on the road spectrum data.

3. The method for constructing a twisted road for testing vehicle fatigue durability according to claim 2, characterized in that: Step 2 Template processing includes the following steps: Step 2.1, draw an electronic template drawing according to the calculated template processing data table, process the template according to the drawing, and number and divide each processed template according to the road spectrum data table to avoid template installation errors during installation; the length error and peak height error of each processed template meet the requirements; Step 2.2: Verify the processed templates against the road map data, and perform secondary processing on templates that do not meet the design dimensions or exceed the error range.

4. The method for constructing a twisted road for testing vehicle fatigue durability according to claim 3, characterized in that: Step 3: Measurement and setting out includes the following steps: According to the design drawings, mark the starting and ending points of the side formwork on the top of the completed curb; then lay out the template position according to the raised circumference designed in the road map, and mark the template number on the top of the curb based on the template size designed in the road map.

5. The method for constructing a twisted road for testing vehicle fatigue durability according to claim 4, characterized in that: Step 4: Steel mesh layout includes the following steps: Step 4.1: Accurately pop up the grid on the concrete base according to the twisted road reinforcement diagram on site; mark the spacing points for steel bar layout, tie all steel bars with double wires and twist them firmly, the excess wire heads should extend into the inner side of the steel bars and should not extend into the net protective layer, and the steel bar spacing and steel bar protective layer thickness should meet the design requirements; Step 4.2: Arrange the dowel bars at intervals along the longitudinal steel mesh, and use plain round steel bars for the dowel bars; Step 4.3: After tying the first layer of steel bars, place pads underneath; after tying the steel bars, check the spacing between them and make adjustments if they do not meet the design and specification requirements; Step 4.4: Check whether the thickness of the steel bar protection layer at the bottom of the steel bar and the side formwork meets the design requirements, and make timely adjustments to any unsatisfactory parts.

6. The method for constructing a twisted road for testing vehicle fatigue durability according to claim 5, characterized in that: Step 5 Template installation includes the following steps: Step 5.1, fix the prefabricated steel template on the inner side of the curb according to the road spectrum size, and the inner wall of the steel template and the inside of the curb are on the same vertical plane; the starting position of the steel template is installed according to the requirements of the road spectrum; Step 5.2: After the template is placed, reinforce it. The reinforcement must be stable, the verticality of the template must be 90°, and the elevation error and installation deviation of the template plane position must be controlled.

7. The method for constructing a twisted road for testing vehicle fatigue durability according to claim 6, characterized in that: Step 6 Concrete construction includes the following steps: Step 6.1, concrete pouring: Step 6.1.1: When pouring concrete into the mold, do not pour it in a concentrated manner to impact the steel frame. When the pouring height is greater than 2m, use a string tube or chute to discharge the material. The free height of the pouring from the discharge pipe to the pouring layer shall not be greater than 1.5m. Step 6.1.2: Continuous pouring is adopted for pouring of concrete slabs. After pouring, a plugging plate is added with the reserved hole located in the middle of the wooden formwork. The dowel rod reinforcement is inserted into the plugging plate with the insertion length being half of the design value of the dowel rod length. Step 6.1.3: Casting of each concrete slab should be carried out continuously. If it is necessary to pause, the pause time should be shortened as much as possible and should be done before the initial setting of the previous concrete. When the surface of the cast concrete is not sticky when touched by hand, the concrete surface should be roughened; Step 6.2: Concrete vibration: Vibration should follow the principle of fast insertion and slow withdrawal. The insertion points of the vibrating rods should be evenly arranged in a plum blossom shape, and moved point by point in sequence without omission to ensure uniform vibration. The vibration movement interval should not be greater than 1.5 times the vibration action radius, generally controlled at 30-40cm. The vibration duration should be sufficient to produce floating slurry on the surface of the concrete, without bubbles and without sinking. After the concrete is poured, a scraper is used to shape it. When shaping, the scraper uses the top line of the left and right side molds as the track to scrape the top surface of the concrete flat. The scraper should be close to the top of the left and right molds.

8. The method for constructing a twisted road for testing vehicle fatigue durability according to claim 7, characterized in that: Step 7 Construction joint layout includes the following steps: Construction joint layout: When pouring is completed or the paving interruption time exceeds 60 minutes every day, a transverse construction joint should be set, and its position should coincide with the expansion joint or contraction joint. If it is really difficult to coincide, the construction joint should adopt the tongue-and-groove joint with a threaded force transmission rod; the joint can be cut after the concrete is finally set, with a width of 5-10mm and a depth of more than 70mm; Contraction joint layout: A contraction joint is set every 5m in the cement concrete road trough. A φ25 dowel rod is set in the contraction joint, which is 70cm long and 60cm apart. One end of the dowel rod is coated with asphalt and wrapped with polyethylene film. The joint can be cut after the concrete is finally set. The joint width is 5-10mm and the depth is 70mm. Expansion joint layout: one expansion joint is set every 100m. The expansion joint is filled with 2cm extruded board. The force transfer rod is placed at the same time as the contraction joint, and the filling depth is 30-40mm.

9. The method for constructing a twisted road for testing vehicle fatigue durability according to claim 8, characterized in that: Step 8: Health preservation includes the following steps: The poured concrete should be covered with geotextile and sprinkled with water for curing. The sprinkler truck should run on the side of the road and be connected to the sprinkler truck with a plastic hose to sprinkle water on the concrete surface. No water should be missed. The number of watering times depends on the temperature of the day to keep the surface moist at all times. The curing time shall not be less than 7 days.

10. The method for constructing a twisted road for testing vehicle fatigue durability according to any one of claims 1 to 9, characterized in that: Distorted roads are divided into two types: general distortion roads and strong distortion roads: Generally, the cross-section of the road surface on the left and right sides of a twisted road is a sinusoidal function; The cross-section of the road surface on the left and right sides of the severely twisted road is a regular trigonometric function.