Anti-seepage construction technology of center dividing zone

Abstract

The present invention belongs to the technical field of road construction and relates to a mid-dividing strip anti-seepage construction process, including the construction of a graded crushed stone layer, wherein the construction of the graded crushed stone layer comprises the following steps: 1) preparing a graded crushed stone mixture, M10 mortar, and anti-seepage cement slurry; 2) supporting a side form of the graded crushed stone layer on a lower bearing layer and applying a release agent to the inner surface of the side form; 3) applying an M10 mortar mortar to the side form of the graded crushed stone layer along the direction of the side form of the graded crushed stone layer; 4) paving the graded crushed stone layer with the graded crushed stone mixture, and spraying anti-seepage cement slurry near the mortar mortar during or after the paving process; 5) rolling and shaping the graded crushed stone layer; 6) removing the side form of the graded crushed stone layer 24 hours after the rolling is completed, thereby completing the mid-dividing strip anti-seepage construction. The present invention provides a mid-dividing strip anti-seepage construction process that has good anti-seepage effect and is easy to construct.

Description

Technical Field

[0001] The invention belongs to the technical field of road construction, and relates to an anti-seepage construction process for a central dividing strip, and in particular to an anti-seepage construction process suitable for a central dividing strip and a shoulder strip of an expressway. Background Art

[0002] Anti-seepage treatment of the central median of highways is one of the common problems in the field of civil engineering. During the construction process of the anti-seepage treatment of the central median, the common practice is to directly apply 2cm thick M10 cement mortar on the side of the base layer (cement-stabilized gravel layer (referred to as water-stabilized layer), graded gravel layer), and at the same time apply 2 layers of emulsified asphalt, and finally use anti-seepage geotextile for comprehensive treatment, that is, first form the base layer and then apply cement mortar on the side of the base layer. During the construction process, it is difficult to maintain a consistent thickness of the 2cm thick cement mortar, and the uneven thickness areas are prone to cracking. After being exposed to sunlight, the cement mortar is very easy to arch and damage; secondly, the construction of the central median anti-collision guardrail columns not only causes the brittle mortar layer to break into blocks, but also tears the anti-seepage geotextile into pieces, causing rainwater to penetrate into the roadbed, destroying the roadbed strength, and ultimately affecting the service life of the highway.

[0003] During the existing anti-seepage construction process for highway median strips, the anti-seepage layer is damaged by temperature fluctuations and puncture damage from pillars. No remedial measures have been found for the time being, and the damaged layer is directly filled with planting soil, leaving anti-seepage control essentially uncontrolled. To better address anti-seepage construction for median strips and pursue high-quality projects, it is necessary to address anti-seepage issues based on the construction characteristics of the structural layer and the requirements of each median strip process. Summary of the Invention

[0004] In order to solve the above technical problems existing in the background technology, the present invention provides a center-dividing zone anti-seepage construction process with good anti-seepage effect and easy construction.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A mid-strip anti-seepage construction process includes the construction of a graded crushed stone layer, which is characterized in that the construction of the graded crushed stone layer specifically includes the following steps:

[0007] 1) Prepare graded crushed stone mixture, M10 mortar and anti-seepage cement slurry;

[0008] 2) Support the side formwork of the graded crushed stone layer on the lower bearing layer and apply a release agent on the inner surface of the side formwork;

[0009] 3) Along the direction of the graded crushed stone layer side form, use M10 mortar as the base mortar in the graded crushed stone layer side form. The thickness of the base mortar is not less than 2 cm, and the length of the base mortar does not exceed 30 meters from the nearest paver to the working surface;

[0010] 4) Spreading the graded gravel layer using the graded gravel mixture prepared in step 1), and spraying anti-seepage cement slurry near the base during or after the paving process;

[0011] 5) rolling and shaping the graded crushed stone layer obtained in step 4);

[0012] 6) 24 hours after compaction is completed, remove the side formwork of the graded gravel layer and complete the anti-seepage construction of the center strip.

[0013] Preferably, the specific implementation method of step 4) adopted in the present invention is: the graded gravel mixture of step 1) is used to pave the graded gravel layer. After the paving is completed, anti-seepage cement slurry is sprayed on the upper surface of the paved graded gravel layer starting from the base slurry and 20-30 cm away from the base slurry in the direction extending toward the graded gravel.

[0014] Preferably, the specific implementation method of step 4) adopted in the present invention is: the graded gravel mixture of step 1) is used to pave the graded gravel layer. During the paving process, starting from the base slurry and 20-30 cm away from the base slurry in the direction extending to the graded gravel, anti-seepage cement slurry is sprayed on the upper surface of the paved graded gravel layer. The spraying height is about 2 / 3 of the structural layer. Then, the sprayed anti-seepage cement slurry is lifted by rolling with a rubber wheel to form a slurry film.

[0015] Preferably, the anti-seepage cement slurry used in the present invention is a mixture of cement and water, the ratio of cement to water in the anti-seepage cement slurry is a; the ratio of cement to water in the graded crushed stone mixture is b; a is slightly higher than b, the difference between a and b is c, and c = 0.5%-1%.

[0016] Preferably, in step 5) adopted in the present invention, the specific implementation method of rolling is: in the construction order, from front to back, static pressing is performed once by double steel wheels, vibration pressing is performed once by a 22-ton single steel wheel, rolling is performed twice by rubber wheels, vibration pressing is performed twice by a 26-ton single steel wheel, kneading is performed once by a rubber wheel, and finishing is performed by double steel wheels.

[0017] Preferably, the center-dividing zone anti-seepage construction process adopted in the present invention also includes the construction of a water-stable layer, and the construction process of the water-stable layer is exactly the same as the construction process of the graded crushed stone layer.

[0018] Preferably, the center-dividing zone anti-seepage construction process adopted in the present invention further comprises the step of applying an asphalt coating on the upper surface and sides of the water-stabilizing layer after the water-stabilizing layer is constructed.

[0019] Preferably, the asphalt coating used in the present invention is applied twice.

[0020] Preferably, the median strip anti-seepage construction process adopted by the present invention also includes the construction of central dividing strip anti-collision guardrail columns between the construction of the water-stable layer and the construction of the asphalt coating. During the construction of the central dividing strip anti-collision guardrail columns, a pile driver is first used to hit the water-stable layer and drive in the anti-collision guardrail columns. Then, anti-seepage mortar is used to clean and grout the damaged water-stable layer, and finally the asphalt coating is applied.

[0021] The advantages of the present invention are:

[0022] The present invention provides a middle-dividing zone anti-seepage construction process, including the step of constructing a water-stable layer, and the water-stable layer construction specifically includes the following steps: 1) preparing a graded crushed stone mixture, M10 mortar and anti-seepage cement slurry; 2) supporting a side form of the graded crushed stone layer on a lower bearing layer and applying a release agent on the inner surface of the side form; 3) using M10 mortar as a base mortar in the side form of the graded crushed stone layer along the direction of the side form of the graded crushed stone layer, wherein the thickness of the base mortar is not less than 2 cm, and the length of the base mortar does not exceed 30 meters of the paver closest to the working surface; 4) using the graded crushed stone mixture obtained in step 1) to pave the graded crushed stone layer, and during or after the paving, spraying the anti-seepage cement slurry to a position close to the base mortar; 5) rolling and shaping the graded crushed stone layer obtained in step 4); 6) removing the side form of the graded crushed stone layer 24 hours after the rolling is completed, and completing the middle-dividing zone anti-seepage construction. The present invention adopts M10 mortar mixed with graded crushed stone mixture and rolled to form a stable and dense whole with the structural layer. It will not arch or crack after being affected by temperature, and plays a waterproof role in the center dividing zone. Compared with the prior art method of first constructing the base structural layer and then applying 2cmM10 cement mortar on the side of the base structural layer, it avoids the side from collapsing easily after demoulding on the second day, and overcomes the phenomenon of excessive "shaqima" gaps on the side of the structural layer; after using M10 mortar to slurry on the side mold in advance and spraying anti-seepage cement slurry within 20cm outside the spiral spreader of the paver during the mixture spreading process, after the whole is rolled, the problems faced by the prior art can be fully solved, and the side of the structural layer and the exposed upper surface are smooth and flat, without missing edges and corners, and have good anti-seepage effect. During the subsequent construction of the anti-collision guardrail columns of the center dividing zone, the anti-seepage geotextile was penetrated by the columns and the periphery of the hole was torn, resulting in poor anti-seepage effect, and there are no better remedial measures. After adopting the new construction process, the perimeter of the columns is unaffected, and the column openings are sealed with anti-seepage mortar, which is easy to construct and meets anti-seepage requirements. This can greatly reduce the use of anti-seepage geotextiles, saving costs. The edges of the road surface are affected by space and generally have a relatively low degree of compaction. The surface of the water-stabilizing layer near the central dividing strip is less dense than the middle of the road. After the cement slurry is sprinkled and rubbed with rubber wheels, a slurry film is formed on the surface of the water-stabilizing layer, which has good integrity and better anti-seepage effect. This invention is simple to construct, easy to operate, low-cost, and highly applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1This is a flow chart of the anti-seepage construction process of the center-dividing zone provided by the present invention;

[0024] Figure 2 This is a schematic diagram of the central divider;

[0025] Figure 3 This is a side view of a structural layer without waterproof mortar in the prior art;

[0026] Figure 4 This is a construction site diagram of high-speed laying of anti-seepage geotextile in existing technology;

[0027] Figure 5 This is a construction site diagram of the side formwork support and the application of the release agent for the structural layer provided by the present invention;

[0028] Figure 6 This is a construction site diagram of the center-dividing zone anti-seepage construction process provided by the present invention when M10 slurry is used;

[0029] Figure 7 This is a construction site diagram of spraying anti-seepage cement slurry provided by the present invention;

[0030] Figure 8 This is a construction site diagram of the road paving process using the median strip anti-seepage construction process provided by the present invention;

[0031] Figure 9 This is a construction site diagram of the rolling and forming of the center-dividing belt anti-seepage construction process provided by the present invention;

[0032] Figure 10 This is a construction site diagram of the center-dividing strip anti-seepage construction process provided by the present invention during the covering and sprinkling curing process;

[0033] Figure 11 This is a cross-sectional view of a middle dividing strip after the middle dividing strip anti-seepage construction process provided by the present invention is completed;

[0034] Figure 12 This is a diagram of the construction results in Example 1. DETAILED DESCRIPTION

[0035] The principle of the present invention is: in terms of the principle of anti-seepage and the control of heat arching of the thin mortar layer, the essence of the anti-seepage treatment on the side of the central dividing strip is to use the mixed and rolled mortar with the structural layer to dissolve into one, so as to play a role of comprehensive prevention and control. During the construction of the anti-seepage layer of the central dividing strip, under the influence of internal factors (mortar initial setting time + water-stabilizing layer setting time + slurry spraying amount + admixture dosage + water content of water-stabilizing layer mixture) and external factors (temperature change + rolling time and method), it is necessary to accurately control according to the actual situation of the project, adjust the dosage in time according to the construction situation of the rolling section, and do a good job of preventive control in the process. The exposed part of the upper structural layer is waterproofed by spraying anti-seepage cement slurry within 20 cm outside the spiral spreader of the paver. The spraying height is about 2 / 3 of the structural layer, and the spraying needs to be uniform. The adsorption force during the rolling of the rubber wheel is used to lift the cement slurry sprinkled at 2 / 3 of the height of the structural layer to form a slurry film, which plays the role of an upper waterproof layer. Finally, two layers of asphalt are applied to the exposed upper part and sides of the structural layer to add an anti-seepage barrier, thus providing double protection.

[0036] The present invention aims to establish a complete central median anti-seepage system, primarily consisting of a flat surface formed by rolling cement slurry and a base mixture, dense side anti-seepage formed by rolling M10 cement mortar and the base mixture, and multi-layer anti-seepage by applying an asphalt coating to the flat surface and sides. The relative stability and rigidity of the water-stable layer are utilized to protect the anti-seepage function of the mortar layer, and the combination with the asphalt coating achieves an effective anti-seepage effect. When the base and mortar are mixed, the water content of the mixture must not exceed the optimal water content, and the initial setting time of the mixture and mortar must be roughly the same (i.e., the cement material must be the same type), so that the two mixtures are mixed and rolled together to form an overall anti-seepage system.

[0037] During the construction of the structural layer within the central dividing strip, workers shall spread cement slurry (mixed with anti-seepage agent, but not directly on the surface of the water-stabilizing layer). The amount used shall be based on the standard of single steel wheel non-stick wheel, and the slurry can be raised after being rolled by rubber wheel. Figure 7 shown.

[0038] After the horizontal and side anti-seepage construction is completed (the formwork is removed every 24 hours), clean the scum on the surface of the water-stabilizing layer, apply two coats of asphalt coating (which can also play a role in water retention and health care), and the joints must be completely painted.

[0039] During the construction of the central median anti-collision guardrail columns, if the water-stabilizing layer is damaged in some areas due to the impact of the pile driver, anti-seepage mortar is directly used to clean the joints and grout, and finally an asphalt layer is applied.

[0040] The technical solution provided by the present invention is described in detail below with reference to the accompanying drawings:

[0041] See also Figure 1 The anti-seepage construction process of the middle dividing zone provided by the present invention comprises the following steps:

[0042] 1) Construction Organization. Prepare coarse and fine aggregates and cement according to the structural layer construction, with a material reserve of no less than 3 days. Before construction, clean or compact the underlying layer, debug all types of transportation, paving, and compaction equipment, inspect steel formwork and corresponding auxiliary materials and tools, and equip mechanical equipment with wearing parts. Keep roads and access roads clear, perform traffic maintenance when necessary, and ensure safety and civilized work on site. Check weather conditions before construction; construction shall not be carried out when the temperature is below 5°C or on rainy days.

[0043] 2) Measure and lay out. According to the design drawings (such as Figure 2 (as shown) to carry out coordinate layout and measure the elevation of the steel bar pile.

[0044] 3) Formwork installation. Support the structure layer formwork along the measuring pile position, see Figure 5 , ensure the width of the road surface; the formwork must be firm, the joints must be smooth, and the height must be equal to or slightly lower than the compacted thickness of the structural layer by 1-2 cm.

[0045] 4) M10 mortar. After the base mix is ​​transported to the construction site, the M10 mortar that has been mixed and transported to the site is placed along the formwork. Figure 6 As shown, the mortar base thickness should be no less than 2cm, the height should be the same as the formwork height, and the mortar base length should not exceed 30 meters from the nearest paver to the working surface to prevent rapid evaporation of mortar moisture that affects the project quality. The mortar base must be continuous and uninterrupted during the mortar base application. The mortar base thickness at the formwork joints is slightly thicker than that of ordinary areas.

[0046] When there are fewer than three transport vehicles waiting to be paved on site and subsequent transport vehicles are blocked or the shift is nearing its end, the length of the mortar bed should be controlled to avoid mortar waste. During construction, mortar that exceeds the initial setting time or is not used in the day's construction should be transported back to the mixing station for centralized waste disposal.

[0047] 5) Spreading of mixture. Figure 8 Once the mixture arrives at the construction site, enter through the gap as indicated by the sign. Turn around 150 meters from the paver. Do not swerve while standing still when turning, and avoid colliding with the wire rope and steel formwork. The moisture content of the mixture must not exceed the optimum moisture content during mixing, and the initial setting time of the mixture to be paved must be no less than one hour. Otherwise, it will be transported back to the mixing station and disposed of as waste. The paver must be equipped with back-mixing blades to ensure that there is no severe segregation of the mixture at the edge of the pavement.

[0048] 6) Spray anti-seepage cement slurry. When paving the mixture, spray anti-seepage cement slurry within 20cm outside the spiral spreader of the paver. Figure 7As shown, the spray height is approximately 2 / 3 of the way up the structural layer. Spray evenly, and areas of overspray require replacement. The spray volume should exceed the optimal mix content by 0.5%-1%. The adsorption force of the rubber tire during rolling lifts the cement slurry at 2 / 3 of the structural layer, forming a slurry film that acts as an upper waterproof layer.

[0049] 7) Rolling molding. Figure 9 The present invention performs rolling in the following order: the first pass is static compaction with double steel wheels, the second pass is vibration compaction with a 22-ton single steel wheel, the third pass is two passes with rubber wheels, the fourth pass is two passes with a 26-ton single steel wheel, the rubber wheel kneads the surface once more, and finally, the double steel wheels smooth the surface. After multiple compactions, the anti-seepage mortar layer forms a dense and smooth surface.

[0050] 8) 24h demoulding. The completed water-stable layer needs to be demoulded after 24 hours to ensure that the anti-seepage mortar does not fall off, so as not to affect the overall anti-seepage effect. During the demoulding process, it is strictly forbidden to use a crowbar to insert the interface between the base and the template to remove the mold to prevent damage to the anti-seepage layer. The demoulded template should be handled with care and it is forbidden to place it obliquely on the side of the water-stable layer. After demoulding, it is still necessary to Figure 10 The mutual maintenance process shown is a conventional technical means and will not be described in detail here.

[0051] 9) Clean the loose layer. After the entire width of the pavement water-stabilizing layer is completed, the scattered debris on the surface of the water-stabilizing layer and the residue on the edges shall be cleaned and piled up, and removed uniformly from the center strip for disposal.

[0052] 10) Asphalt coating: After the structural layer is completed, apply asphalt coating. Apply the asphalt coating to the corners first, then apply it twice to the entire surface.

[0053] 11) Quality Control. The quality of the center-dividing strip anti-seepage construction process provided by this invention is strictly implemented in accordance with the "Technical Specifications for Highway Pavement Base Construction" (JTG / T F20-2015), the "Design Code for Masonry Mortar Mix Ratio" (JGJ98-2000), the "Technical Specifications for Highway Engineering Construction Safety" (JTG F90-2015), and the "Highway Engineering Quality Inspection and Assessment Standard" (JTG F80 / 1-2017).

[0054] 12) Process quality standards

[0055] Table process quality standards

[0056]

[0057]

[0058] After the construction of the present invention, the problem of the mortar layer being easily arched and cracked due to heat and the problem of the anti-seepage geotextile being broken due to column construction are solved, the risk of rainwater seeping into the roadbed is solved, the roadbed strength is improved, and the service life of the highway is extended. After the anti-seepage mortar of the center dividing zone is set, the construction process of the anti-seepage geotextile of the center dividing zone can be omitted (such as Figure 4 As shown in the figure, in the past, after laying anti-seepage geotextiles on highways, pillars were installed, resulting in two holes every four meters; and there was a gap at the interface between the top surface of the geotextile and the curbstone, and the waterproofing of the center strip was in name only. After practical verification, after adopting this invention as a technical guarantee, the construction period of the center strip can be saved by 3 days per kilometer, and 1900m of anti-seepage geotextile can be saved. 2 .

[0059] K2+330-K3+057 of this project is located in the middle of the contract section of the embankment. The integral roadbed is 26m wide and adopts the highway I load standard. The design speed is 100 kilometers per hour, the maximum fill height is 7.795m, the minimum fill height is 1.524m, and the center strip is coated with hot asphalt + anti-seepage composite geomembrane for prevention and treatment. According to the actual situation of the project, the original design plan was changed. The characteristics of the structural layer and the damage to the composite geomembrane in the subsequent process were used to mix M10 cement mortar with the water-stable layer. After being compacted by a roller, it was pressed into a whole with the water-stable layer to solve the problem that the single layer of the mortar layer is prone to arching, cracking and damage due to heat. During the paving process, cement slurry is sprinkled to the middle and upper part of the structural layer. After the rubber wheel is rolled, the tire absorbs the slurry to form a layer of slurry film on the surface of the base layer, which can prevent rainwater from seeping in and solve the problem of water seepage on the surface of the water-stable layer "Shaqima" (the structure of "Shaqima" is as shown in the figure). Figure 3 As shown, Figure 3 The side of the structural layer without waterproof mortar: the side of the graded crushed stone base is loose; the side of the water-stable base has large pores and is in the shape of sand. After the expressway is built, the structural layer as a whole has no waterproof effect). After the above treatment, the use of anti-seepage geotextile can be greatly reduced, the construction cost is reduced, the roadbed strength is improved, and the service life of the expressway is extended, providing a reference for the construction of expressways with similar situations in the future.

[0060] Application Examples

[0061] The invention for anti-seepage construction based on the center-divider strip was first applied to the first contract section of the Wuhan-Hong'an Expressway. The project is located in Miersi Town, Hong'an County, Hubei Province. The area has a subtropical climate with an average annual precipitation of 1116.2 mm, with summer rainfall accounting for half of the total annual rainfall. The relative humidity is 77%. According to the climate zoning of the "Technical Specifications for Highway Asphalt Pavement Construction," this project area is characterized by hot summers and cold, humid winters. The main line pavement structure within the contract section consists of an 18cm graded crushed stone layer, a 20cm water-stable base layer, a 20cm water-stable upper base layer, and an 18cm asphalt layer. The center-divider strip waterproofing project involves applying a 1cm thick mortar to the longitudinal blind ditch, followed by a layer of hot asphalt, and finally laying an anti-seepage geotextile throughout the center-divider strip.

[0062] The present invention is mainly used for the median strip formed during the construction of the road surface engineering of section K2+330-K3+057. The gradation and the side of the water-stable structural layer are mixed with the waterproof mortar and the structural layer mixture. After being rolled by a heavy roller, an overall dense surface layer is formed. After construction, there is no arching or cracking phenomenon, and it has a good waterproof effect. Figure 11 as well as Figure 12 Among them, Figure 12 In the middle, after the graded crushed stone subbase and the water-stable base are completed, the mortar, graded crushed stone and water-stable layer form a whole, and the side surface is smooth and dense.

Claims

1. A mid-zone anti-seepage construction process, including the construction of a graded crushed stone layer, characterized by: The construction of the graded crushed stone layer specifically comprises the following steps: 1) Prepare graded crushed stone mixture, M10 mortar and anti-seepage cement slurry; 2) Support the side formwork of the graded crushed stone layer on the lower bearing layer and apply a release agent on the inner surface of the side formwork; 3) Along the direction of the graded crushed stone layer side form, use M10 mortar as a base mortar in the graded crushed stone layer side form. The thickness of the base mortar shall not be less than 2 cm and the height shall be the same as the height of the graded crushed stone layer side form. The length of the base mortar shall not exceed 30 meters from the nearest paver to the working surface. 4) using the graded crushed stone mixture described in step 1) to pave the graded crushed stone layer, and during the paving process, spraying anti-seepage cement slurry near the base slurry, specifically implementing the following method: using the graded crushed stone mixture described in step 1) to pave the graded crushed stone layer, and during the paving process, starting from the base slurry and 20-30 cm away from the base slurry in the direction extending toward the graded crushed stone, and within 20 cm outside the spiral spreader of the paver, spraying anti-seepage cement slurry on the upper surface of the paved graded crushed stone layer, and the spraying height is 2 / 3 of the graded crushed stone layer; The anti-seepage cement slurry is a mixture of cement and water, the ratio of cement to water in the anti-seepage cement slurry is a; the ratio of cement to water in the graded crushed stone mixture is b; a is slightly higher than b, the difference between a and b is c, and c = 0.5%-1%; 5) rolling the graded crushed stone layer obtained in step 4) into shape; the rolling is specifically implemented by, in order of construction, performing static pressing once with a double steel wheel, vibrating pressing once with a 22-ton single steel wheel, rolling twice with a rubber wheel, vibrating pressing twice with a 26-ton single steel wheel, kneading once with a rubber wheel, and finishing with double steel wheel rolling; wherein, the adsorption force of the rubber wheel during rolling is utilized to lift the anti-seepage cement slurry sprayed on 2 / 3 of the height of the structural layer in step 4), forming a slurry film, which serves as an upper waterproof layer; 6) 24 hours after compaction is completed, remove the side formwork of the graded crushed stone layer and complete the anti-seepage construction of the center zone; The method also includes the construction of a water-stabilizing layer, the construction process of which is exactly the same as that of the graded crushed stone layer. After the construction of the water-stabilizing layer, the method also includes the step of applying an asphalt coating on the upper surface and sides of the water-stabilizing layer.

2. The anti-seepage construction process for the center-dividing zone according to claim 1 is characterized in that: The asphalt coating is applied twice.

3. The anti-seepage construction process for the center-dividing zone according to claim 1 is characterized in that: The center strip anti-seepage construction process also includes the construction of the central dividing strip anti-collision guardrail columns between the construction of the water-stabilizing layer and the application of the asphalt coating. During the construction of the central dividing strip anti-collision guardrail columns, a pile driver is first used to hammer the water-stabilizing layer, and then the damaged water-stabilizing layer is cleaned and grouted with anti-seepage mortar, and finally the asphalt coating is applied.

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