Road dam type roadbed structure with graded water drainage and storage function

Abstract

The utility model discloses a highway dam type roadbed structure with a graded water drainage and storage function, and aims to overcome the defects of low water storage efficiency and blockage of a drainage system in the prior art. The structure comprises a roadbed body, and a roadbed cushion layer is laid at the bottom of the roadbed body; the upstream face of the roadbed body is of a slope-shaped structure and is provided with slope protection measures; a drainage square culvert and a water control gate are arranged in the roadbed body. Through the innovative dam type roadbed structure design, the graded water drainage and storage system, the low-cost construction and maintenance scheme, the eco-friendly design and the optimized construction process, the functionality, stability and ecological benefits of the highway dam type roadbed in the loess gully area are remarkably improved, and meanwhile the construction and maintenance cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of road construction technology, specifically to a highway dam-type roadbed structure with graded drainage and water storage functions. Background Technology

[0002] The Loess Plateau is one of the regions in China most severely affected by soil erosion, with a fragile ecosystem and a prominent water shortage problem. Soil erosion covers an area of ​​430,000 square kilometers, not only damaging the local ecosystem but also causing large amounts of sediment to enter the lower reaches of the Yellow River, increasing the risk of flooding. Furthermore, due to insufficient water supply, especially in Gansu, Ningxia, and Shaanxi provinces where rainwater is the primary water source, uneven rainfall distribution and alternating droughts and floods are significant challenges. Therefore, rainwater collection and utilization are of paramount importance.

[0003] Against this backdrop, the construction of dam-type roadbeds demonstrates significant comprehensive benefits. Dam-type roadbeds integrate the functions of road transportation and water conservancy engineering, not only improving transportation conditions but also alleviating water scarcity through water storage; by controlling surface runoff, they reduce the intensity of direct rainwater erosion, effectively reducing soil erosion; they regulate the regional microclimate, promoting vegetation growth, and by reducing sediment inflow into downstream rivers, they help maintain the stability of downstream ecosystems; in areas with concentrated rainfall, dam-type roadbeds can effectively intercept and store rainwater, alleviating water shortages and providing a stable water source for surrounding residents and agriculture. Furthermore, this design is particularly suitable for the gully-ridden terrain of the Loess Plateau, especially in areas with dense ridges and gullies, fully leveraging its topographical advantages. It can simultaneously contribute to ecological protection and resource utilization while constructing high-grade highways.

[0004] An investigation of existing dam-type roadbeds in the Loess gully region reveals that, compared to traditional high roadbeds, dam-type roadbeds need to balance water storage and traffic functions, resulting in complex designs and greater construction difficulties. During long-term operation, frequent maintenance is required due to siltation, blockage of the water storage system, or structural damage, increasing later-stage operating costs. The water storage capacity of dam-type roadbeds is limited by terrain and engineering design; in dry years or during prolonged droughts, their regulation capacity may be insufficient. However, based on the current water storage situation of existing dam-type roadbeds, those with higher culvert design elevations have largely failed due to drainage system blockage caused by siltation. Furthermore, in dam-type roadbeds with higher culvert design elevations, the water level is far below the culvert bottom elevation, resulting in significant construction waste.

[0005] In summary, while dam-type roadbeds have potential for soil and water conservation and water resource regulation, their practical application suffers from problems such as unreasonable design, improper construction, and untimely maintenance, resulting in the failure to fully realize their water storage capacity and economic benefits. Therefore, it is necessary to optimize the design scheme based on local topographical conditions, precipitation patterns, and sediment flow characteristics to improve their efficiency in actual operation.

[0006] Therefore, in light of the above situation, there is an urgent need to develop a design for a dam-type roadbed structure and its associated drainage facilities suitable for loess gully regions. This design should, while ensuring roadbed stability, focus on reducing the construction cost of the dam-type roadbed and dynamically control the water storage height through tiered drainage and storage to minimize unnecessary resource waste. Simultaneously, the design should significantly reduce subsequent operation and maintenance costs, thereby addressing the construction waste caused by overly conservative existing designs. More importantly, the proposed dam-type roadbed structure and its associated drainage facilities design exhibit significant eco-friendliness. Through rational planning and optimized design, this scheme can effectively alleviate local soil erosion problems and promote the sustainable use of water and soil resources. This not only meets the requirements of ecological civilization construction but also provides a practical solution for the green engineering goals of loess gully regions. Utility Model Content

[0007] The purpose of this utility model is to provide a highway dam-type roadbed structure with graded water storage and drainage functions, so as to overcome the shortcomings of low water storage efficiency and drainage system blockage in the existing technology.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A highway dam-type roadbed structure with graded drainage and water storage functions includes a roadbed body, the bottom of which is covered with a roadbed cushion layer; the water-facing side of the roadbed body is a sloping structure and is equipped with slope protection measures; and a drainage square culvert and a water control gate are installed inside the roadbed body.

[0010] The bottom layer of the roadbed is filled with rubble, above which is a stone slag cushion layer, and above the stone slag cushion layer is a non-woven permeable geotextile.

[0011] The slope protection measures include a concrete seepage prevention zone from below the design flood level +0.5m to the original ground surface, a vegetation slope protection zone from above the design flood level +0.5m to the road surface, and a cement concrete foundation for the intermediate slope platform.

[0012] The concrete seepage prevention zone consists of a cement-soil cushion layer, a composite geomembrane, and cement concrete laid sequentially from the bottom of the slope upwards; the vegetation slope protection zone is a cement concrete arched framework combined with vegetation protection.

[0013] Composite geomembranes consist of a middle layer of non-woven geotextile and two upper and lower layers of polyethylene membrane.

[0014] The thickness of the cement-soil cushion layer is 60cm.

[0015] The net thickness of the cement concrete in the concrete seepage prevention zone is 3cm, with a 15cm*15cm steel mesh installed inside.

[0016] The drainage square culverts are laid in the area at or below the design flood level +0.5m. The bottom of the uppermost drainage square culvert is level with the design flood level +0.5m. A drainage square culvert is laid in the middle of the middle slope platform, and a drainage square culvert is laid in the middle of the two side slope platforms.

[0017] The drainage culvert has a square cross-section with an inner diameter of 1m and a single-sided wall thickness of 200mm. A water control gate is provided at the water-facing end of the drainage culvert, and grooves are left on the left, right and below where the drainage culvert contacts the water control gate.

[0018] The water control gate is made of stainless steel. It is 102cm long, 150cm high, and 5cm thick. The top of the water control gate has a U-shaped handle with a handle height of 10cm.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] This invention proposes a dam-type roadbed structure with tiered drainage and storage functions. Addressing the challenges of water scarcity, it utilizes a dam-type roadbed approach to transportation construction, combining the functions of a dam and a highway. In the Loess Plateau gully region, it achieves multi-functional synergistic optimization of transportation, water conservancy, and ecology, providing a replicable engineering paradigm for regional soil and water conservation and sustainable water resource utilization. Traditional dam-type roadbeds, with their fixed culvert elevations, result in a water storage capacity utilization rate of less than 30%, and siltation easily clogs the drainage system. This technology, through tiered drainage and storage design combined with dynamic control of water storage height, effectively avoids drainage system blockage caused by siltation, thereby ensuring the effective storage and utilization of water resources.

[0021] Existing dam-type roadways have complex structures and redundant materials. By using standardized prefabricated components, construction and maintenance costs are reduced. This invention optimizes the dam structure while ensuring roadbed stability, reducing construction difficulty and unnecessary resource waste. Simultaneously, the optimized drainage system design significantly reduces the frequency of later maintenance. Addressing alternating droughts and floods and extreme weather events, this invention not only improves water retention capacity during droughts but also ensures flood discharge safety during heavy rains, increasing peak runoff reduction by 25% and lowering downstream flood risk.

[0022] The highway dam-type roadbed structure of this utility model has strong adaptability and can be applied under various terrain conditions. It fully considers the complex terrain conditions of the Loess Plateau region, especially in areas with dense ridges and gullies, where it can better leverage its terrain advantages, achieve the organic integration of soil and water conservation and transportation functions, and further enhance the multifunctionality of the roadbed. Attached Figure Description

[0023] Figure 1This is a schematic diagram of a highway dam-type roadbed structure with graded drainage and water storage functions in an embodiment of this utility model.

[0024] Figure 2 This is a top view of a highway dam-type roadbed structure with graded drainage and water storage function in an embodiment of this utility model.

[0025] Figure 3 This is a schematic diagram of the installation of the drainage square culvert and the water control gate in an embodiment of this utility model.

[0026] Figure 4 This is a schematic diagram of the installation cross-section of the drainage square culvert and the water control gate in an embodiment of this utility model. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] Next, combine Figures 1 to 4 A specific embodiment of this utility model will be described below. (Refer to...) Figure 1 and Figure 2As shown, this is a highway dam-type roadbed structure with graded drainage and water storage function in this specific embodiment, including a roadbed body, the bottom of which is paved with a roadbed cushion layer; the water-facing surface of the roadbed body is a sloping structure and is provided with slope protection measures; a drainage square culvert and a water control gate are provided in the roadbed body.

[0031] The bottom of the roadbed is filled with rubble, and stone chips are filled on top of the rubble layer to form a stone chip cushion layer. Non-woven permeable geotextile is then laid on top of the stone chip cushion layer.

[0032] Slope protection measures include a concrete seepage-proof zone from 0.5m below the design flood level to the original ground level, a vegetation protection zone from 0.5m above the design flood level to the road surface, and a C25 cast-in-place concrete foundation for the intermediate slope platform. The concrete seepage-proof zone consists of a cement-soil cushion layer at the bottom of the slope, a composite geomembrane on top of the cement-soil cushion layer, and C25 cement concrete cast-in-place on top of the geomembrane. The vegetation protection zone uses a C25 cast-in-place concrete arched framework combined with vegetation protection.

[0033] The thickness of the cement-soil cushion layer is 60cm. The cement-soil can be made by mixing cement and clay in a general ratio of 8% to 10%, or by using local soil and selecting an appropriate cement content.

[0034] The composite geomembrane adopts a two-layer structure with a non-woven geotextile in the middle and polyethylene material on the top and bottom layers.

[0035] In the C25 cast-in-place concrete layer, a 15cm*15cm steel mesh is arranged with steel bars of 8mm in diameter, and the net thickness of the concrete cover is 3cm.

[0036] The concrete arch frame has a clear spacing of 3.0m, a main frame thickness of 0.6m, an arch frame thickness of 0.4m, and a foundation depth of 0.5m.

[0037] The C25 cast-in-place concrete foundation has a depth of 3m.

[0038] The drainage culverts are installed in the area at or below the design flood level +0.5m. The bottom of the uppermost drainage culvert is level with the design flood level +0.5m. One drainage culvert is installed in the middle of the middle slope platform, and one drainage culvert is installed in the middle of each of the two side slope platforms. The longitudinal distance between two adjacent drainage culverts is 1m.

[0039] Reference Figure 3 and Figure 4As shown, the drainage culvert has a square cross-section with an inner diameter of 1m and a single-sided wall thickness of 200mm. A water control gate is installed at the water-facing end of the culvert. Grooves, 1m long, 5cm wide, and 1cm high, are provided on the left, right, and bottom of the contact point between the culvert and the water control gate. An opening, 1m long and 5cm wide, is provided at the top, allowing the water control gate to move up and down. The drainage culvert is constructed of C40 concrete. Main reinforcement bars, 12mm in diameter and spaced 200mm apart, are placed at the four corners of the culvert. Stirrups, 6mm in diameter and spaced 150mm apart, are placed along the length of the culvert.

[0040] The water control gate is made of stainless steel. It is 102cm long, 150cm high, and 5cm thick. The top of the water control gate has a U-shaped handle with a handle height of 10cm.

[0041] To make the present invention easier to understand, a specific embodiment of the present invention will be explained below in conjunction with the construction method. The construction process of this specific embodiment mainly includes the filling of the highway dam-type roadbed, slope protection construction, and drainage facility construction.

[0042] The implementation process for the roadbed filling of the dam-type highway begins with clearing the silt from the bottom of the ditch to ensure the base is clean. Afterward, a 50 cm thick layer of rubble is filled in, followed by another 50 cm thick layer of rubble on top. Next, an 80 cm thick layer of crushed stone is laid, and the top is covered with non-woven permeable geotextile to prevent the roadbed fill from blocking drainage channels. The fill material uses strongly weathered sandstone and strongly weathered argillaceous sandstone, etc., and is filled in layers and compacted layer by layer to ensure that the compaction quality of each layer meets the design requirements. After each layer is filled, it is tested, and if it passes the test, construction continues to the next layer until the design elevation is reached.

[0043] It should be noted that during the implementation process, when treating the base, it is important to consider that the thickness of the silt layer at the bottom of the ditch varies greatly from year to year. Before the replacement construction, a test pit should be excavated every 50m from the upstream to the downstream slope of the gully, with a depth reaching the top surface of the strongly weathered sandstone layer, in order to accurately determine the longitudinal distribution of the silt thickness at the bottom of the gully. The thickness of the longitudinal rubble and gravel cushion layer at the bottom of the gully, i.e., the roadbed cushion layer, should be adjusted on site to ensure that the base sediment is completely removed. The roadbed cushion layer should form a longitudinal slope of 3% to 5% along the bottom of the gully.

[0044] Dynamic compaction was carried out on the subgrade base and within a 5m radius beyond the slope toe. The compaction points were arranged in a square pattern with a 5m spacing. The first pass was for primary compaction, the second for secondary compaction, interspersed between the primary points, and the third for full compaction. The hammer marks overlapped by one-quarter of each other during continuous compaction. The primary and secondary compaction points used a single-blow energy of 2000 kN·m, and the full compaction point used a single-blow energy of 1000 kN·m. The number of blows per compaction point, i.e., the optimal compaction energy, should be determined based on on-site test compaction. The principle should be to maximize the compression of the compaction pit and minimize the ground heave around the pit, with the average settlement of the last two or three blows not exceeding 50mm. The interval between primary, secondary, and full compaction points was controlled at 72 hours. The compaction sequence followed the principle of starting with the outer edge of the subgrade and gradually moving towards the center.

[0045] After the top of the gravel layer is leveled, a layer of non-woven permeable geotextile should be laid to prevent the embankment fill from blocking the drainage channels of the roadbed subgrade at the bottom of the ditch. The top surface of the gravel layer should be filled and leveled with unsorted crushed stone.

[0046] When constructing the foundation of a highway dam, the lower 15.0m of the embankment should be filled with strongly weathered sandstone or strongly weathered argillaceous sandstone, while the upper embankment can be filled with strongly weathered sandstone, strongly weathered argillaceous sandstone, loess sand, aeolian sand, or loess-like silt. It is required that the rubble and stone chips used must not be expansive rocks, easily soluble rocks, soluble rocks, or saline rocks. The uniaxial saturated compressive strength of the stone should not be less than 30MPa, and the particle size of the rubble should be 100~300mm; the maximum particle size of the stone chips should not exceed 150cm, and the content of particles smaller than 0.075mm should not exceed 5%.

[0047] Before compaction, the humus, weeds, trees, etc. within the dam foundation outline and soil site are removed and cleared to the fresh soil. Based on the location of the soil extraction point at the dam site, the properties of the soil, and the dam height, the earthwork for the dam body is carried out by extracting soil from both banks. After the foundation clearing and trench excavation are completed, the dam body filling begins.

[0048] Before filling, the width of the working face at the bottom of the ditch should be cleared to ensure the width of the working face for machinery at the bottom of the ditch. Construction access roads should be prepared. Then, layer filling and compaction should be carried out. When filling the roadbed, the loose colluvial soil layer and plant roots on the ditch wall should be cleared while filling the roadbed from the bottom of the ditch upwards. After filling to the first-level embankment slope platform, the earthwork should be excavated according to the requirements of the drawing and the over-excavated steps should be overlapped with the roadbed on the excavated side. The height of the last step is 70cm of the height of the upper embankment.

[0049] To reduce embankment settlement, strict control of compaction quality is required. It is necessary to ensure that the embankment is filled in layers from the bottom of the ditch and compacted layer by layer. The embankment compaction quality control standard should be improved, requiring the upper embankment to have a compaction degree of not less than 95% and the lower embankment to have a compaction degree of not less than 94%.

[0050] When constructing a steep slope embankment, loose sloping soil should be cleared first, followed by excavation of steps. Generally, the step width should be no less than 4.0m, with the last step no less than 8.0m wide. The height of the last step should be 0.7m above the embankment. To reduce uneven settlement of the embankment, five layers of geogrid should be laid from the first slope platform upwards. The geogrid at the first slope platform should extend to one side of the step, and the geogrid on both sides of the upper embankment should extend to one side of the step. The geogrid on the subgrade bottom surface should be laid transversely. When there is no transverse fill joint for a steep slope embankment, the geogrid on both the upper embankment and the subgrade bottom surface should be laid transversely. φ10 U-shaped steel nails should be used to fix the geogrid. The spacing of the steel nails at the transverse ends of the geogrid and the side walls of the steps should be 1.0m × 1.0m, and the spacing of the steel nails at other locations should be 2.0m × 2.0m.

[0051] For high embankments crossing gullies, five layers of geogrid are to be laid as required to reduce uneven settlement after construction. The geogrid is laid continuously, covering the gully wall steps, and uses GSGS100-100 steel-plastic geogrid with a longitudinal and transverse ultimate tensile strength ≥100KN / m, elongation at the longitudinal and transverse ultimate tensile strength ≤3%, and ultimate separation force at the connection point ≥500N. When the geogrid is overlapped, the overlap width should not be less than 20cm. The overlap is connected in a zigzag pattern using nylon ropes with low elongation. The geogrid is fixed with φ10U-shaped steel nails. The spacing of the steel nails at the longitudinal ends of the geogrid and the side walls of the steps is 1.0m×1.0m, and the spacing at other locations is 2.0m×2.0m. At the embankment slope, the two ends of the geogrid are folded back and wrapped, with a folding length not less than 1.5m. The maximum particle size of the subgrade fill material within 10cm of the geogrid should not exceed 10cm.

[0052] When using impact compaction to enhance compaction of dam-type embankments, a triangular impact roller with a power of at least 25KJ is required. One layer of compaction is applied every 1.5m, with 15 passes. For sections where the minimum working length of impact compaction is not met (100m), a 50t drag vibratory roller is used for enhanced compaction, with 15 passes. Dam-type embankments are then reinforced with dynamic compaction. One layer of dynamic compaction is applied every 4m from the base to the first-level slope platform (including the first-level slope platform). During construction, compaction is performed from the outside of the slope towards the center of the roadbed. Note that a smaller compaction energy is used near the roadbed slope, and a 3m safety distance is reserved to prevent the already filled roadbed slope from being pushed and damaged.

[0053] The high embankment section contains culverts. The embankment below the culvert bottom is reinforced by dynamic compaction. The horizontal and vertical distances between the compaction point and the culvert are not less than 40m. In areas where dynamic compaction cannot be used, impact rolling (drag vibration) is required to enhance compaction, and it should meet the specific requirements for culvert construction.

[0054] If embankment construction is suspended for an extended period due to unforeseen circumstances, the compacted surface should be cambered with a cross slope of 2% to 4%, and the embankment slopes should be leveled and compacted. Upon resumption of work, the compaction degree should be tested, and construction can only continue if the requirements are met.

[0055] Slope protection construction begins with the preparation and spreading of cement-soil mixture. A 60 cm thick cement-soil cushion layer is formed on the slope below the design flood level, topped with a composite geomembrane to enhance seepage prevention. An 8# steel mesh (15 cm x 15 cm) is installed on top of the composite geomembrane, with a net protective layer thickness of 3 cm. C25 concrete is then poured in place to form the concrete seepage prevention zone. Above the design flood level, a C25 cast-in-place concrete arched framework combined with vegetation protection is used. The clear spacing between the arches is 3.0 m, the main framework thickness is 0.6 m, and the arch framework thickness is 0.4 m. A C25 cast-in-place concrete foundation is poured at the intermediate slope platform location, buried 3 m deep. Finally, grass is planted within the arched framework to enhance the ecological benefits of the slope.

[0056] It should be noted that when cleaning the subbase, the base layer on which the composite geomembrane is laid should be flat, with a local height difference of no more than 50 mm. Tree roots, grass roots and hard objects should be removed to avoid damaging the composite geomembrane.

[0057] Before laying the geomembrane, first check for any damage or breakage. The composite geomembrane must be laid in its primary stress direction, and should not be pulled too tight; allow for some expansion and contraction to accommodate substrate deformation. During laying, it should be manually tightened to ensure there are no wrinkles and it adheres tightly to the underlying layer. It should be secured immediately after laying to prevent it from being blown away by the wind. Construction should not be carried out when there is standing water or during rain. The bentonite mat laid on the same day must be covered with backfill soil. When laying the composite geomembrane, there must be a margin of at least 1000 mm at each end.

[0058] For laid composite geomembranes, the edges and seams should be kept clean, free of oil, moisture, dust, etc. Before welding, the overlap width of the two PE single-layer films at the seam should be adjusted to 6-8 cm, ensuring a smooth and wrinkle-free surface. During welding, a double-rail welding machine should be used, employing a hot welding method to heat and melt the surfaces of the PE films to fuse them together under pressure. Simultaneously, parameters such as weld overlap width, natural wrinkles, allowance for expansion and contraction, and excess material should be carefully controlled. Furthermore, attention should be paid to details such as the working temperature, travel speed, and welding method of the hot-melt welding. For damaged areas of the composite geomembrane, hot-melt repair can be performed using materials of the same cut specifications, or sealing and repair can be done using a special geomembrane adhesive.

[0059] Install the formwork according to the measured and marked positions, ensuring that the flatness, verticality, and stability of the formwork meet the requirements. During installation, pay attention to the treatment of the formwork joints to prevent grout leakage. At the same time, install concrete protective layer spacers on the inside of the formwork according to the design requirements to ensure that the protective layer thickness of the reinforcing mesh is 3cm.

[0060] When processing and installing reinforcing bars, first process 8mm diameter reinforcing bars into a 15cm x 15cm grid. During processing, pay attention to the straightness of the reinforcing bars and the regularity of the grid. Accurately install the processed reinforcing mesh inside the formwork according to the measured and marked positions, and fix it to the spacers by binding or welding to ensure the stability and positional accuracy of the reinforcing mesh. During installation, pay attention to the thickness of the protective layer of the reinforcing mesh, maintaining a distance of approximately 3cm between it and the inside of the formwork.

[0061] At the batching plant, materials are batched and mixed according to the C25 concrete mix proportion. The mixing time should be controlled within a reasonable range to ensure the uniformity and fluidity of the concrete. During the mixing process, the quality of raw materials and the accuracy of the mix proportion should be checked regularly, and adjustments made promptly. Concrete mixer trucks and other equipment are used to transport the mixed concrete to the construction site in a timely manner. During transportation, the uniformity and fluidity of the concrete should be maintained to avoid segregation and bleeding. The time from concrete mixing to pouring should be minimized to ensure the performance of the concrete.

[0062] When pouring concrete, remove debris from inside the formwork or on the subgrade. Moisten the dry foundation, subgrade, and formwork with water. When the ambient temperature exceeds 35℃, it is advisable to spray water on metal formwork to cool it down. No standing water should remain after spraying. Concrete should be poured in layers, with each layer controlled between 20-40cm in height. Use an immersion vibrator to thoroughly vibrate each layer to avoid voids and cracks. The upper layer of concrete should be poured before the lower layer has initially set. The concrete placement point should be close to the pouring location, and measures should be taken to reduce the impact of concrete pouring. When the pouring height of concrete inside column or wall formwork exceeds the specified limit, chutes, pipes, or other similar devices should be installed.

[0063] Next, the concrete should be vibrated. During vibration, the vibrator should be inserted quickly and withdrawn slowly, with the insertion points evenly spaced and moved point by point in sequence to ensure uniform compaction. The spacing between vibration points should not exceed 1.5 times the radius of action of the vibrator, generally 30-40cm. When vibrating the upper layer, the vibrator should be inserted 5-10cm into the lower layer to eliminate the joint between the two layers. During vibration, care should be taken to avoid collisions with the reinforcing bars and formwork to prevent displacement of the reinforcing bars and deformation of the formwork.

[0064] After concrete is poured, it should be moistened to allow it to fully harden and solidify, typically for 7-14 days. During this period, the concrete surface should be kept moist to prevent cracking due to dryness. Methods include watering, covering with plastic film, or using a curing solution. When watering, ensure the concrete surface has sufficient moisture to prevent excessive evaporation; when covering with plastic film, ensure the film is sealed tightly to prevent airflow and moisture loss.

[0065] Based on the control piles of the arch frame, the concrete foundation pit was excavated. Due to the shallowness and small size of the pit, manual excavation was used, and the dimensions were in accordance with the design drawings, without over-excavation. After passing inspection, the foundation concrete was poured. Due to the small size of individual foundations, 0.147 m³ per 100 meters was used, and the foundations in one section were poured in one go. The foundation concrete strength grade was C25. The concrete was centrally mixed at the mixing plant and transported to the construction site by truck. After the concrete was poured into the formwork, it was vibrated promptly using an immersion vibrator to ensure compaction. The vibration time was strictly controlled. Then, the top surface was smoothed, and the precast blocks for the foundation top were installed before the concrete initially set, ensuring accurate positioning.

[0066] The construction of drainage facilities involves precise positioning of the axial lines of the square drainage culverts through surveying and setting out, ensuring their tiered layout along the design flood level. Support structures are erected according to the dimensions of the square drainage culverts, ensuring their load-bearing capacity and stability. 12 mm diameter main reinforcement bars are placed at the four corners of the square drainage culvert, spaced 200 mm apart, and 6 mm diameter stirrups are placed along the length, spaced 150 mm apart. Steel formwork or bamboo plywood is installed as formwork, ensuring its strength, rigidity, and stability. C40 concrete is used to pour the square drainage culverts, and a vibrator is used for thorough compaction to ensure the concrete's density and uniformity. A stainless steel water control gate is installed at the water-facing end of the square drainage culvert. The gate is 102 cm long, 150 cm high, and 5 cm thick, with a U-shaped handle at the top. After installation, the opening and closing of the water control gate is checked for flexibility to ensure the normal operation of the drainage system.

[0067] It should be noted that during the surveying and setting out, based on the design drawings, a total station and other surveying instruments should be used to accurately locate the axis position of the drainage square culvert, including the culvert position at the middle slope platform and the position of the culvert in the middle of the two slope platforms, as well as the control point with a longitudinal spacing of 1m between adjacent culverts. The elevation point of +0.5m of the design flood level should be measured and marked to ensure that the bottom of the uppermost drainage square culvert is level with this elevation.

[0068] Next, the scaffolding is erected. Based on the dimensions of the square culvert and the weight of the concrete, a suitable scaffolding system is selected, such as a cup-lock scaffolding or a disc-lock scaffolding, to ensure the load-bearing capacity and stability of the scaffolding. The scaffolding is then assembled and installed according to the erection plan. The spacing between scaffolding uprights generally does not exceed 1.2m, and the horizontal bar spacing does not exceed 1.5m. Scissor bracing and ground bracing are also installed to enhance the overall stability of the scaffolding.

[0069] When laying the reinforcing bars, first place 12mm diameter main bars at the four corners of the square culvert, spaced 200mm apart. The main bars must be firmly connected to the foundation's embedded reinforcing bars to ensure the stability of the reinforcing cage. Next, place 6mm diameter stirrups along the length of the square culvert, spaced 150mm apart. The stirrups must be tightly tied to the main bars to form a stable reinforcing mesh. At the end of the square culvert facing upstream where a water control gate is located, the reinforcing bars must be pre-reserved and adjusted according to the dimensions of the grooves and openings to ensure that the reinforcing bars do not obstruct the formation of the grooves and openings while meeting the structural stress requirements.

[0070] Steel formwork or bamboo plywood should be selected as the formwork for the square culvert. The formwork must have sufficient strength, rigidity, and stability, with a smooth and flat surface, tight joints, and close fit with the reinforcing steel frame to prevent grout leakage. At the water-facing end of the square culvert, corresponding notches should be reserved according to the dimensions of the grooves and openings, and sealed with materials such as foam boards to ensure no grout leakage during concrete pouring.

[0071] Concrete pouring involves transporting C40 concrete to the construction site using concrete mixer trucks, and then pumping it into the square culvert formwork using concrete pump trucks or cranes. A vibrator is used for thorough compaction to remove air bubbles and ensure the concrete's density and uniformity. During pouring, the deformation of the formwork and reinforcing steel should be carefully observed, and any problems should be addressed promptly. If segmented pouring is required, construction joints must be installed according to specifications, and waterstops or water-stop steel plates must be pre-embedded at the construction joints to ensure their waterproofing performance.

[0072] After the concrete of the square culvert reaches the design strength, the water control gate is installed. The stainless steel water control gate is hoisted into the groove at the water-facing end of the square culvert, with the U-shaped handle facing upwards. The length, height, and thickness of the gate must conform to the design dimensions. Expansion bolts or chemical anchors are used to fix the water control gate into the groove of the square culvert, ensuring the stability and reliability of the gate. At the same time, the smoothness of opening and closing of the gate and the ease of operation of the U-shaped handle are checked.

[0073] This invention proposes a dam-type roadbed structure design optimized for the unique terrain and climate conditions of the Loess Plateau region. This design not only considers the stability and traffic function of the roadbed but also effectively integrates water conservancy functions. Through a rational dam structure and drainage system, it enhances water storage capacity and reduces soil erosion. This design is particularly suitable for the complex terrain of the Loess gullies, fully utilizing local topographical advantages and improving the overall benefits of the roadbed. This invention optimizes the drainage system of traditional dam-type roadbeds. Through a rational culvert design and a tiered drainage and storage scheme, it avoids the drainage system blockage problem caused by siltation, which is common in traditional designs, thus improving the efficiency and water storage capacity of the drainage system. Simultaneously, the design of dynamically controlling the water storage height allows for effective regulation of water resources during drought periods, avoiding resource waste caused by excessively low or high water levels. Through the rational optimization of the structure and drainage system, the construction and subsequent maintenance costs of the dam-type roadbed are reduced. Compared with traditional designs, the dam-type roadbed designed in this invention, while ensuring stability, reduces unnecessary construction waste, lowering construction costs by approximately 15%, and also reducing subsequent maintenance and management costs.

[0074] This invention proposes a highway dam-type roadbed structure with tiered drainage and storage functions, which not only improves soil and water conservation and water resource regulation but also exhibits significant eco-friendliness. By regulating the regional microclimate and promoting vegetation growth, it reduces soil erosion and effectively prevents sediment from flowing into downstream rivers, thus promoting ecosystem stability. Furthermore, this design can provide a stable water source for surrounding agriculture and residents, alleviating water shortages and meeting the requirements of ecological civilization construction.

[0075] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A highway dam-type roadbed structure with graded drainage and water storage functions, characterized in that, The roadbed includes a road base, the bottom of which is covered with a roadbed layer; the water-facing side of the road base is a sloping structure and is equipped with slope protection measures; and a drainage culvert and a water control gate are installed within the road base.

2. A highway dam-type roadbed structure with graded drainage and water storage function according to claim 1, characterized in that, The bottom layer of the roadbed subbase is filled with rubble, the top layer of which is a stone slag subbase, and the top layer of which is a non-woven permeable geotextile.

3. A highway dam-type roadbed structure with graded drainage and water storage function according to claim 1, characterized in that, The slope protection measures include a concrete seepage prevention zone from below the design flood level +0.5m to the original ground surface, a vegetation slope protection zone from above the design flood level +0.5m to the road surface, and a cement concrete foundation for the intermediate slope platform.

4. A highway dam-type roadbed structure with graded drainage and water storage function according to claim 3, characterized in that, The concrete seepage prevention zone includes a cement-soil cushion layer, a composite geomembrane, and cement concrete laid sequentially from the bottom of the slope upwards; the vegetation slope protection zone is a cement concrete arched framework combined with vegetation protection.

5. A highway dam-type roadbed structure with graded drainage and water storage function according to claim 4, characterized in that, The composite geomembrane includes a middle layer of non-woven geotextile and two upper and lower layers of polyethylene film.

6. A highway dam-type roadbed structure with graded drainage and water storage function according to claim 4, characterized in that, The thickness of the cement-soil cushion layer is 60cm.

7. A highway dam-type roadbed structure with graded drainage and water storage function according to claim 4, characterized in that, The net thickness of the cement concrete in the concrete seepage prevention zone is 3cm, and a 15cm*15cm steel mesh is arranged therein.

8. A highway dam-type roadbed structure with graded drainage and water storage function according to claim 1, characterized in that, The drainage square culverts are laid in the area at or below the design flood level +0.5m, with the bottom of the uppermost drainage square culvert being level with the design flood level +0.5m; a drainage square culvert is laid in the middle of the middle slope platform, and a drainage square culvert is laid in the middle of each of the two side slope platforms.

9. A highway dam-type roadbed structure with graded drainage and water storage function according to claim 1, characterized in that, The drainage culvert has a square cross-section with an inner diameter of 1m and a single-sided wall thickness of 200mm. A water control gate is provided at the water-facing end of the drainage culvert, and grooves are left on the left, right and below where the drainage culvert contacts the water control gate.

10. A highway dam-type roadbed structure with graded drainage and water storage function according to claim 1, characterized in that, The water control gate is made of stainless steel, with a length of 102cm, a height of 150cm, and a thickness of 5cm. The top of the water control gate has a U-shaped handle with a handle height of 10cm.

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