Parallel co-construction structure of flood detention area dike and highway subgrade and construction method

Abstract

This invention relates to the field of water conservancy engineering technology, and in particular to a parallel co-construction structure and construction method for flood storage and detention area dikes and highway subgrades. The parallel co-construction structure includes an existing highway subgrade, a newly constructed dike, a seepage-proof wall, micro-steel pipe piles, foamed concrete, a seepage-proof geomembrane, edging soil, vegetated block slope protection, an existing traffic culvert, a newly constructed sluice gate, an access ramp, a flood control channel pavement, and a guardrail. This invention addresses the situation where a newly constructed dike and an existing highway subgrade are arranged parallel and adjacent to each other, proposing a co-construction structure that balances flood control and traffic functions. This significantly saves land area, reduces project investment, optimizes the layout of safety zones, and improves land resource utilization efficiency. By setting up a sluice gate to connect with the existing traffic culvert, the normal traffic function of the existing road passing under the highway in the parallel co-construction section can be guaranteed. By setting up a stacked beam sluice gate, the sluice gate can ensure flood control and water retention during flood storage.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering technology, and in particular to a parallel co-construction structure and construction method for flood storage and detention area dikes and highway subgrades. Background Technology

[0002] Flood storage and detention areas are an indispensable part of my country's flood control system, and the safety zone dikes are important protective facilities to safeguard the lives and property of the people when flood storage and detention areas are put into use. The road surface elevation of highways built in flood storage and detention areas is generally no lower than the flood level plus the safety superelevation.

[0003] According to the safety zone construction plan, sections of the newly built safety zone embankment may run parallel to and adjacent to the existing highway subgrade. When the new embankment runs parallel to and adjacent to the existing highway subgrade, it is generally constructed separately at a certain distance outside the existing highway subgrade. The new embankment is generally in the form of an earthen embankment. Based on the design flood storage level and safety freeboard requirements, the new embankment is often about 6-8 meters higher than the existing ground level. The top width of embankments of Class 2 and above should not be less than 6 meters, and the slope should not be steeper than 1:3. When the embankment height exceeds 6 meters, a spur must be set on the backwater side. The total width of the earthen embankment is generally about 40-50 meters. Moreover, to avoid the impact of the new embankment load on the highway subgrade, a net distance of about 50 meters is reserved between the toe of the new embankment slope and the toe of the highway subgrade slope. The narrow strip of land between the slope toes, separated by the highway subgrade and the new embankment on both sides, has extremely inconvenient conditions in terms of irrigation, transportation, etc., and the land cannot be used efficiently. The construction of new dikes and highway subgrades is separate and arranged independently. Although this can meet the requirements for flood control and safety, it increases the investment in the project to some extent and wastes land resources.

[0004] Therefore, the existing method of separately arranging newly built dikes and highway subgrades not only increases project investment but also wastes land resources. Summary of the Invention

[0005] The purpose of this invention is to provide a parallel co-construction structure and construction method for flood storage and detention area dikes and highway subgrades, which can solve the technical problems of high project investment and waste of land resources caused by the existing separate arrangement of newly built dikes and highway subgrades.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention designs a parallel co-construction structure for flood storage and detention area dikes and highway subgrades, comprising: Existing roads, used for laying existing highways and embankments on them; An existing expressway is located above an existing road and is used for vehicle traffic. The dike vertically connects the existing road and the existing expressway, and overlaps with the flood storage area side of the existing expressway. The bottom of the dike is constructed parallel to the bottom roadbed of the existing expressway and the existing road. The dike is used to define the flood storage space, restrict the flood range, and ensure the normal operation of the flood storage area and the safety of the surrounding area. Impermeable geomembrane is arranged along the slope of the embankment; The seepage barrier wall is arranged vertically at the bottom of the dike, and the seepage barrier wall is combined with the seepage barrier geomembrane to form a composite seepage barrier system; The existing traffic culvert is located beneath the existing highway; The gate is located at the intersection of the existing traffic culvert and the embankment, and is used to ensure the normal traffic function of the existing road that passes under the expressway in the parallel co-construction section.

[0007] The bottom of the dike is equipped with a high-pressure jet grouting pile anti-seepage wall. By optimizing the mix ratio of foamed concrete, it has good anti-seepage performance. The high-pressure jet grouting pile anti-seepage wall and the anti-seepage geomembrane are combined to form a composite anti-seepage system, which meets the flood control and seepage prevention requirements of the newly built dike.

[0008] As a preferred embodiment, the gate consists of a gate chamber, a gate, and wing walls. The clear dimensions and elevation of the gate chamber are consistent with the existing traffic culvert, and it is connected to the existing traffic culvert in the form of a construction joint. The gate chamber is opened and closed by the gate. The wing walls are retaining wall structures used to resist the soil pressure on the embankment slope, and their top elevation is consistent with the change of the embankment slope.

[0009] As a preferred embodiment, the gate adopts the form of a stacked beam gate, which is arranged vertically on the side of the wing wall. The upper end of the gate is connected to the top of the dike, and the lower end of the gate is connected to the top of the seepage prevention wall. The gate is used to ensure flood control and water blocking during flood storage.

[0010] As a preferred embodiment, the outer surface of the wing wall serves as a vegetated block slope protection, the wing wall adopts a stepped overlap, and the interior of the wing wall is backfilled with edge-sealing soil; the base of the embankment is reinforced by grouting multiple wire mesh panels and multiple micro steel pipe piles arranged vertically, and the gap between the wire mesh panels and the micro steel pipe piles is backfilled with foamed concrete to reduce the uneven settlement deformation of the existing highway subgrade caused by the new embankment under the action of additional load.

[0011] The edging soil is composed of cohesive soil and the slope is protected by vegetation blocks to protect the foamed lightweight soil seepage core and improve the scour resistance during flood storage.

[0012] As a preferred option, the flood control channel pavement is also included, which is arranged above the gate chamber and above the designed flood storage level. The pavement has a cross slope that slopes towards the water side. The flood control channel pavement is connected to the existing highway roadbed, and the height of the flood control channel pavement is lower than that of the existing highway pavement.

[0013] As a preferred option, the flood control channel pavement adopts a permeable pavement structure, which is laid from top to bottom as permeable asphalt concrete, medium-grained asphalt concrete, and cement-stabilized crushed stone base course to ensure the normal rainwater drainage function of the existing highway subgrade and pavement slope.

[0014] This permeable pavement structure can improve the durability of the embankment top pavement structure and ensure the traffic needs for flood control patrols.

[0015] As a preferred option, a safety barrier is also included, which is arranged between the gate chamber and the existing traffic culvert, on the side of the flood control channel road surface close to the existing highway, to prevent unauthorized personnel from entering the highway through the flood control channel road surface and affecting traffic safety.

[0016] As a preferred embodiment, the permeability coefficient of the impermeable wall is controlled at 10. -6 ~10 -8 cm / s.

[0017] This invention also designs a construction method for a parallel co-construction structure of flood storage and detention area dikes and highway subgrades, including the following steps: Based on the axis and design elevation of the new embankment, measurements and layout were carried out, and the existing foundation and highway subgrade were cleared. Micro steel pipe pile grouting reinforcement was carried out on the existing highway slopes and embankment foundations, and high-pressure jet grouting pile anti-seepage walls were constructed. Lay the bottom impermeable geomembrane of the dike and smooth the bottom cement mortar protective layer; The existing highway slope was excavated in layers from bottom to top, foam concrete was poured in layers, cement mortar protective layer was smoothed, and geomembrane was laid. Smooth the top layer of cement mortar protective layer and lay the top layer of impermeable geomembrane; Layered filling of the edging soil, consisting of cohesive soil; Construction of vegetation block slope protection; For sections of the road where there are existing traffic culverts, new gates will be constructed according to the construction plan. The construction of new gates and corresponding ramps to the embankment will be carried out in parallel with the above steps, and the new gates will be properly connected to the new embankment. The flood control channel pavement structure layers are laid sequentially from bottom to top; Install a safety fence.

[0018] The beneficial effects of this invention are: This invention proposes a parallel co-construction structure and construction method for newly built dikes and existing highway subgrades in flood storage and detention areas. For the situation of parallel co-construction of newly built dikes and existing highway subgrades, while taking into account both flood control safety and traffic operation functions, it not only solves the flood control and seepage prevention problems of the dikes, but also effectively prevents the uneven settlement of the existing highway subgrade that may be caused by the loading of the newly built dikes.

[0019] By using stepped overlapping, foamed concrete backfilling, and micro steel pipe pile grouting reinforcement at the base, the uneven settlement and deformation of the existing highway subgrade caused by the new embankment under the additional load can be reduced.

[0020] By setting up a high-pressure jet grouting anti-seepage wall in the dike foundation and optimizing the mix proportion of foamed concrete (increasing cement content and reducing water-cement ratio), its permeability coefficient was controlled at 10. -6 ~10 -8 With a flow rate of cm / s, it possesses excellent anti-seepage performance. The high-pressure jet grouting pile anti-seepage wall of the dike foundation is combined with the anti-seepage geomembrane to form a composite anti-seepage system, which meets the flood control and anti-seepage requirements of newly built dikes.

[0021] By using cohesive soil to form the edging soil and planting vegetation blocks for slope protection, the seepage prevention core of foamed lightweight soil can be effectively protected, and the scour resistance during flood storage can be improved.

[0022] By setting up a gate to connect with the existing traffic culvert, the normal traffic function of the existing road that passes under the expressway in the parallel co-construction section can be guaranteed.

[0023] By setting up stacked beam gates, the gate can be guaranteed to prevent flooding and block water during flood storage.

[0024] The embankment top pavement adopts a permeable pavement structure, which does not affect the normal rainwater drainage function of the highway subgrade and road surface slope, and also improves the durability of the embankment top pavement structure, ensuring the needs of flood control patrol traffic.

[0025] This invention proposes a co-construction structure that integrates flood control and transportation functions, significantly saving land area, reducing project investment, optimizing safety zone layout, and improving land resource utilization efficiency. This invention solves the technical problems of high project investment and land resource waste caused by the existing separate construction of new dikes and highway subgrades. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the parallel co-construction building layout.

[0027] Figure 2 This is a schematic diagram of the cross-section of the parallel co-construction structure.

[0028] Figure 3 A cross-sectional schematic diagram of the existing road where a gate is to be set up.

[0029] Figure label: Existing road 1, existing expressway 2 (roadbed embankment slope 21), dike 4 (dike slope 41, dike top 42, dike ramp 43, wing wall 44, flood control channel pavement 45, vegetation block slope protection 46, edge soil 47, wire mesh 48, micro steel pipe pile 49, foam concrete 50), impermeable geomembrane 5, impermeable wall 6, existing traffic culvert 7, gate 9, gate chamber 10, isolation fence 11. Detailed Implementation

[0030] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and not for limiting the present invention. Furthermore, it should be noted that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, not all of them.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0033] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of the invention include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0034] This invention relates to a parallel co-construction structure and construction method for flood detention area dikes and highway subgrades. For situations where newly constructed dikes are parallel and adjacent to existing highway subgrades, this invention proposes for the first time to combine the construction of new dikes with existing highway subgrades, significantly reducing land occupation, saving project investment, optimizing safety zone layout, improving land resource utilization efficiency while ensuring no reduction in flood storage capacity, guaranteeing flood control function, and avoiding or mitigating the impact of new dikes on existing highway subgrades. Based on practical engineering experience, this invention proposes a parallel co-construction structure and construction method for newly constructed dikes and existing highway subgrades in flood detention areas. For situations where new dikes are constructed in parallel with existing highway subgrades, this invention solves the problems of flood control and seepage prevention of dikes while effectively preventing uneven settlement of existing highway subgrades that may be caused by the loading of new dikes.

[0035] This invention provides a parallel co-construction structure for flood storage and detention area dikes and highway subgrades, comprising: Existing Road 1, for the construction of existing highways and embankments on it; Existing Expressway 2 is located above the existing road and is used for vehicle traffic. Dike 4 vertically connects the existing road and the existing expressway, and overlaps with the flood storage area side of the existing expressway. The bottom of the dike is constructed parallel to the bottom roadbed of the existing expressway and the existing road. The dike is used to define the flood storage space, restrict the flood range, and ensure the normal operation of the flood storage area and the safety of the surrounding area. 5. Impermeable geomembrane, arranged along the slope of the embankment; The seepage barrier wall 6 is arranged vertically at the bottom of the dike, and the seepage barrier wall is combined with the seepage barrier geomembrane to form a composite seepage barrier system; Existing traffic culvert 7 is located beneath the existing expressway; The gate is located at the intersection of the existing traffic culvert and the embankment, and is used to ensure the normal traffic function of the existing road that passes under the expressway in the parallel co-construction section.

[0036] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0037] like Figure 1-3 As shown, the present invention specifically provides a parallel co-construction structure for newly built dikes and existing highway subgrades in flood storage and detention areas, including: existing road 1, existing highway 2 (subgrade embankment slope 21), dike 4 (dike slope 41, dike top 42, dike ramp 43, wing wall 44, flood control channel pavement 45, vegetation block slope protection 46, edging soil 47, wire mesh 48, micro steel pipe pile 49, foam concrete 50), impermeable geomembrane 5, impermeable wall 6, existing traffic culvert 7, stacked beam gate 9, gate chamber 10, and isolation fence 11.

[0038] The existing expressway 2 has a embankment subgrade located in a flood detention area. It is constructed by layering and compacting well-graded coarse-grained soil. When the embankment height does not exceed 8m, the slope ratio is generally 1:1.5. In this embodiment, the embankment height is 7.5m, and the slope ratio is 1:1.5. The elevation of existing expressways built in flood detention areas is generally not lower than the elevation of newly constructed embankments (i.e., design flood level + safety superelevation). According to highway settlement control requirements, the existing expressway subgrade generally underwent foundation treatment during construction, and after years of operation, the settlement has generally stabilized, but seepage prevention treatment is generally not carried out. The existing expressway consists of earthen shoulders, hard shoulders, carriageways, and a central median strip along its transverse direction. Longitudinally, it consists of the pavement surface layer, pavement base layer, and subgrade. The existing expressway subgrade is laid from top to bottom with plain fill, silty clay, fine sand, gravel, and siltstone.

[0039] The newly constructed dike 4 is a levee designed to ensure the safety zone is not flooded during flood diversion in the flood storage and detention area. The dike crest elevation is the design flood storage level + 0.5m, and the dike crest width is determined according to the dike level, generally not less than 6m, with a water-facing slope ratio of 1:3. In this embodiment, it is a Class 2 dike with a dike crest width of 6m and a water-facing slope ratio of 1:3. When co-constructed with the existing highway subgrade, the newly constructed dike is widened on the flood storage side of the existing highway subgrade. To ensure a good overlap, steps approximately 0.3-0.5m high are excavated on the slope of the existing highway subgrade. One side of the newly constructed dike is the flood storage area, and the other side is the safety zone.

[0040] The cutoff wall 6 is located at the bottom of the newly constructed embankment, maintaining a 1m net distance from the toe of the existing highway embankment slope. The cutoff wall utilizes φ600 high-pressure jet grouting piles, driven at 400mm intervals to ensure effective thickness. The pile tip penetrates at least 1m into the relatively impermeable layer of the foundation or at least 0.5m into the bedrock, and the pile top penetrates at least 0.5m into the newly constructed embankment. The permeability coefficient is 10. -6 ~10 - 7cm / s. The grout uses P·O42.5 ordinary Portland cement with a water-cement ratio of 1:1 to 1.5:1. The thickness of the cutoff wall is T≥H / J. 允 H represents the head difference between the inner and outer sides, which can be taken as the elevation difference between the design flood storage level and the current ground level. J 允 The allowable gradient for the seepage-proof wall material can be taken as 50~100. High-pressure jet grouting piles have good seepage prevention effect, strong adaptability to strata, small construction land occupation, and low vibration, and do not affect the normal operation of the existing highway subgrade.

[0041] In this embodiment, the thickness of the impermeable wall T = 45cm ≥ H / J 允 =11cm, H is the difference in water head between the inner and outer sides, which can be taken as 5.5m, the difference in elevation between the design flood storage level and the current ground level, J 允 The allowable gradient of the seepage-proof wall material is taken as 50, which meets the requirements.

[0042] The miniature steel pipe piles 49 are located at the bottom of the newly built embankment, serving to reinforce the highway subgrade slope and the embankment foundation, preventing excessive settlement, uneven settlement, or slope slippage and instability under the load of the newly built embankment. The miniature steel pipe piles are arranged in a staggered pattern, with steel pipe diameters preferably selected from φ114~φ200mm and spacing S. p The diameter of the steel pipe should be 3-6 times the diameter of the grout. The lateral treatment range extends from all excavated steps of the existing highway subgrade to the toe of the new embankment slope, exceeding one row of piles. The pile length in the existing horizontal foundation is L1, and the pile length on the highway subgrade slope steps is L2. The grouting pressure is 0.5~2.0MPa, and the grout uses P·O42.5 ordinary Portland cement with a water-cement ratio of 1:1~1.5:1 to ensure that the grout fully splits the soft soil. Grouting is carried out in 2~3 times to avoid grout loss and improve the reinforcement effect.

[0043] In this embodiment, the miniature steel pipe piles are arranged in a quincunx pattern, with steel pipe diameter φ159mm and spacing of S. p =0.8m, the lateral treatment range extends from all excavated steps of the existing highway subgrade to the outer edge of the new embankment slope, exceeding one row of piles. The pile length in the existing horizontal foundation is L1=6m, and the pile length on the highway subgrade slope steps is L2=8m. The grouting pressure is 1.0MPa, and the grout uses P·O42.5 ordinary Portland cement with a water-cement ratio of 1.2:1 to ensure that the grout fully splits the soft soil. Grouting is carried out in two stages to avoid grout loss and improve the reinforcement effect.

[0044] To mitigate the impact of the newly constructed embankment on the existing highway subgrade, the embankment body will be constructed using 50-layer foamed concrete pouring. This will significantly reduce the load on the embankment foundation, minimize settlement and uneven deformation of the soft soil foundation, and improve overall stability. To ensure the embankment's seepage prevention effect, the cement content in the foamed concrete mix design should be appropriately increased (320–380 kg / m³). 3Reduce the water-cement ratio (0.40-0.50) and appropriately increase the density to 700-900 kg / m³. 3 The foaming rate should not be too high (controlled between 40% and 55%), and the permeability coefficient should be controlled at 10. -6 ~10 -8 cm / s. Foamed concrete should be poured in layers, each approximately 0.3-0.5m high, with several layers of wire mesh inside. The wire mesh should be of relatively fine diameter (3-4mm) and small mesh size (50mm×50mm) to avoid internal cracks and through-holes. The upper layer must be poured before the lower layer sets to form a monolithic structure without construction joints. The top layer should have a 2% transverse slope towards the water-facing side.

[0045] In this embodiment, the cement content should be appropriately increased (350 kg / m³) in the foamed concrete mix design. 3 Reduce the water-cement ratio (0.45), density 800 kg / m³ 3 The foaming rate should not be too high (controlled at 45%), and the permeability coefficient should be controlled at 10. -6 ~10 -8 cm / s. Foamed concrete should be poured in layers, each approximately 0.3-0.5m high, with several layers of wire mesh inside. The wire mesh should be of relatively fine diameter (3mm) and small mesh size (50mm×50mm) to avoid internal cracks and through-holes. The upper layer must be poured before the lower layer sets to form a monolithic structure without construction joints. The top layer should have a 2% transverse slope towards the water-facing side.

[0046] To fully ensure the seepage prevention effect of the dike, a geomembrane 5 is used to completely wrap around the foamed concrete, and a cement mortar leveling layer of about 2-3 cm thick is set up to prevent the rough surface or sharp edges of the foamed concrete from puncturing the geomembrane and losing its seepage prevention function. The geomembrane should be properly overlapped with the seepage prevention wall to form a unified and reliable seepage prevention system. The geomembrane should be made of HDPE geomembrane or two layers of fabric and one layer of membrane, with a thickness of 1.0-2.0 mm and a density of 0.940-0.965 g / cm³. 3 Permeability coefficient ≤ 1×10 -13 cm / s, tensile strength ≥25MPa, elongation at break ≥600%, puncture resistance ≥300N, hot-melt welding should be used for the overlap of the impermeable geomembrane, and the overlap width should be ≥10cm (double-track welding).

[0047] In this embodiment, a 3cm thick cement mortar leveling layer is provided to prevent the rough surface or sharp edges of the foamed concrete from puncturing the geomembrane and causing it to lose its seepage-proof function. The seepage-proof geomembrane should overlap properly with the seepage-proof wall to form a unified and reliable seepage-proof system. The seepage-proof geomembrane should be made of HDPE, with a thickness of 1.5mm and a density of 0.940-0.965g / cm³.3 Permeability coefficient ≤ 1×10 -13 cm / s, tensile strength ≥25MPa, elongation at break ≥600%, puncture resistance ≥300N, hot-melt welding should be used for the overlap of the impermeable geomembrane, and the overlap width should be ≥10cm (double-track welding).

[0048] To ensure the durability of the foamed concrete, a 1m thick edging soil layer (47) should be installed on the water-facing side of the newly constructed dike. The edging soil should be cohesive, with a clay content of 20%–30%, a plasticity index of 10–18, and an organic matter content of <5%. The consolidated rapid shear test should show a cohesion c ≥ 15 kPa, an internal friction angle φ ≥ 12°, and a compression coefficient a1-2 ≤ 0.5 MPa. -1 The moisture content of the fill material during construction should be controlled within ±2% of the optimum moisture content, and the compaction degree should be controlled according to the dike grade (≥94% for Class 1 dikes and ≥92% for Class 2 dikes).

[0049] To ensure the erosion control effect of the newly built dike and to consider the ecological landscape effect, the 1:3 slope on the water-facing side adopts vegetated block slope protection 46, and the vegetated block slope protection is made of geotextile (400g / m²) from bottom to top. 2 +15~20cm thick gravel cushion layer +15~20cm precast concrete blocks, the vegetation blocks are hexagonal or rectangular interlocking, the concrete strength grade is not lower than C25, and the impermeability grade is ≥P6.

[0050] In this embodiment, the 1:3 slope on the water-facing side is protected by vegetation blocks, and the vegetation block slope protection is made of geotextile (400g / m²) from bottom to top. 2 + 20cm thick gravel cushion layer + 15cm precast concrete block, the vegetation block is hexagonal interlocking, concrete strength C25, impermeability grade P6.

[0051] The existing traffic culvert 7 is a culvert built for rural roads to pass under the existing expressway.

[0052] The newly constructed sluice gate is located at the intersection of the existing traffic culvert and the newly built embankment to ensure the normal passage of the existing rural road passing under the highway. The sluice gate consists of a gate chamber, a gate, and wing walls. The clear dimensions and elevation of the gate chamber are consistent with the existing culvert, and it is connected to the existing culvert in the form of a construction joint. The gate can adopt a stacked beam gate, which has a simple structure, light weight, low lifting force, is easy to transport and install, and has low maintenance costs, making it suitable for flood storage and detention areas with a probability of once every 20 to 30 years. The wing walls are retaining wall structures that resist the earth pressure on the embankment slope, and their top elevation changes in line with the embankment slope.

[0053] The ramp 43 is located on the 1:3 slope on the water-facing side of the dike. It connects the flood control channel on the top of the dike with the ramp that passes under the expressway and the existing rural road. Its function is to facilitate the inspection of newly built sluice gates or gates by going up and down the dike during daily dike patrols.

[0054] The flood control channel pavement 45 is located on top of the newly built embankment's foamed concrete and edging soil. The pavement structure is approximately 40-50cm thick and is entirely above the designed flood storage level. The pavement's cross slope is a 2% one-way slope towards the water-facing side. Since the embankment top pavement structure needs to handle the rainwater drainage function of the highway pavement, to ensure smooth drainage and prevent water accumulation on the surface of the flood control channel, a drainage-type pavement structure is adopted. From top to bottom, it consists of PAC-13 permeable asphalt concrete + AC-16 medium-grained asphalt concrete + cement-stabilized crushed stone base course.

[0055] In this embodiment, the pavement structure is approximately 50cm thick, entirely above the designed flood storage level, and the pavement cross slope is a 2% one-way slope towards the water-facing side. Since the pavement structure on the embankment crest needs to handle rainwater drainage from the highway surface, to ensure smooth drainage and prevent water accumulation on the surface of the flood control channel, a drainage-type pavement structure is adopted. From top to bottom, it consists of 4cm thick PAC-13 permeable asphalt concrete + 5cm thick AC-16 medium-grained asphalt concrete + 36cm cement-stabilized crushed stone base course.

[0056] The isolation fence 11 is located on the side of the flood control channel road surface close to the highway, with a height of not less than 1.8m. Its function is to prevent unauthorized personnel from entering the highway through the flood control channel road surface and affecting traffic safety.

[0057] This invention provides a construction method for a parallel co-construction structure of newly built dikes and existing highway subgrades in flood storage and detention areas, comprising the following steps: S1. Conduct surveying and setting out according to the axis and design elevation of the new embankment, and clear the existing foundation and highway subgrade. S2. Reinforce the existing highway slopes and embankments with micro steel pipe pile grouting and construct high-pressure jet grouting anti-seepage walls. S3. Lay the bottom impermeable geomembrane of the embankment and smooth the bottom cement mortar protective layer. S4. Excavate steps for the existing highway slope in layers from bottom to top, pour foamed concrete in layers, smooth the cement mortar protective layer, and lay the geomembrane. S5. Smooth the top layer of cement mortar protective layer and lay the top layer of impermeable geomembrane; S6, The edging soil is composed of cohesive soil in layers; S7. Construction of vegetation block slope protection; S8. For sections of the road where there are existing traffic culverts, new gates shall be constructed in a timely manner according to the construction organization. The construction of new gates and corresponding ramps to the embankment can be carried out in parallel with the above steps. The new gates and the new embankment should be properly connected. S9. Lay the flood control channel pavement structure layer from bottom to top; S10. Install the isolation fence.

[0058] It should be understood that the specific order or hierarchy of steps in the process disclosed in this invention is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the specific order or hierarchy described.

[0059] The advantages of this invention are as follows: This invention relates to a construction structure and method for the parallel co-construction of newly built dikes and existing highway subgrades in flood storage and detention areas. Addressing the situation where newly built dikes are arranged parallel and adjacent to existing highway subgrades, this invention proposes a co-construction structure that balances flood control and traffic functions, significantly saving land area, reducing project investment, optimizing safety zone layout, and improving land resource utilization efficiency. Through stepped joints, foamed concrete backfilling, and micro-steel pipe pile grouting reinforcement at the base, the uneven settlement and deformation of the existing highway subgrade under additional loads caused by the newly built dike can be mitigated. By setting up a high-pressure jet grouting pile anti-seepage wall at the dike foundation and optimizing the mix ratio of foamed concrete to achieve good impermeability, a composite anti-seepage system is formed by combining it with an anti-seepage geomembrane and anti-seepage wall, meeting the flood control and seepage prevention requirements of the newly built dike. Using cohesive soil as the edging soil and vegetated blocks for slope protection effectively protects the foamed lightweight soil anti-seepage core, improving the erosion resistance during flood storage. By connecting the sluice gate with the existing traffic culvert, the normal traffic function of the existing road passing under the expressway in the parallel co-construction section can be guaranteed. By installing the stacked beam gate, the sluice gate can be guaranteed to prevent flooding and block water during flood storage. The pavement on the top of the embankment adopts a permeable pavement structure, which does not affect the normal rainwater drainage function of the expressway subgrade and pavement slope, and also improves the durability of the pavement structure on the top of the embankment, ensuring the traffic needs of flood control patrols.

[0060] All other undescribed parts belong to the prior art. The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention, and these should also be considered within the scope of protection of the present invention. The above-described embodiments only illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A structure for the parallel construction of flood storage and detention area dikes and highway subgrades, characterized in that, include: Existing roads, used for laying existing highways and embankments on them; An existing expressway is located above an existing road and is used for vehicle traffic. The dike vertically connects the existing road and the existing expressway, and overlaps with the flood storage area side of the existing expressway. The bottom of the dike is constructed parallel to the bottom roadbed of the existing expressway and the existing road. The dike is used to define the flood storage space, restrict the flood range, and ensure the normal operation of the flood storage area and the safety of the surrounding area. Impermeable geomembrane is arranged along the slope of the embankment; The seepage barrier wall is arranged vertically at the bottom of the dike, and the seepage barrier wall is combined with the seepage barrier geomembrane to form a composite seepage barrier system; The existing traffic culvert is located beneath the existing highway; The gate is located at the intersection of the existing traffic culvert and the embankment, and is used to ensure the normal traffic function of the existing road that passes under the expressway in the parallel co-construction section.

2. The parallel co-construction structure of flood storage and detention area dikes and highway subgrade as described in claim 1, characterized in that: The gate consists of a gate chamber, a gate, and wing walls. The clear dimensions and elevation of the gate chamber are consistent with the existing traffic culvert, and it is connected to the existing traffic culvert in the form of a construction joint. The gate chamber is opened and closed by the gate. The wing walls are retaining wall structures used to resist the soil pressure on the embankment slope, and their top elevation is consistent with the change of the embankment slope.

3. The parallel co-construction structure of flood storage and detention area dikes and highway subgrade as described in claim 2, characterized in that: The gate adopts the form of a stacked beam gate, which is arranged vertically on the side of the wing wall. The upper end of the gate is connected to the top of the dike, and the lower end of the gate is connected to the top of the seepage prevention wall. The gate is used to ensure flood control and water blocking during flood storage.

4. The parallel co-construction structure of flood storage and detention area dikes and highway subgrade as described in claim 3, characterized in that: The outer surface of the wing wall serves as a vegetation block slope protection, and the wing wall adopts a stepped overlapping method. The interior of the wing wall is backfilled with edge soil. The base of the embankment is reinforced by grouting multiple wire mesh panels and multiple micro steel pipe piles arranged vertically. The gap between the wire mesh panels and the micro steel pipe piles is backfilled with foamed concrete to reduce the uneven settlement deformation of the existing highway subgrade caused by the new embankment under the action of additional load.

5. The parallel co-construction structure of flood storage and detention area dikes and highway subgrade as described in claim 4, characterized in that: It also includes a flood control channel road surface, which is arranged above the gate chamber and above the designed flood storage level. The road surface has a unidirectional slope that slopes towards the water side. The flood control channel road surface is connected to the existing highway roadbed, and the height of the flood control channel road surface is lower than that of the existing highway road surface.

6. The parallel co-construction structure of flood storage and detention area dikes and highway subgrade as described in claim 5, characterized in that: The flood control channel road surface adopts a permeable pavement structure, which is laid from top to bottom as permeable asphalt concrete, medium-grained asphalt concrete, and cement-stabilized crushed stone base course to ensure the normal rainwater drainage function of the existing highway subgrade and pavement slope.

7. The parallel co-construction structure of flood storage and detention area dikes and highway subgrade as described in claim 6, characterized in that: It also includes a safety fence, which is arranged between the gate chamber and the existing traffic culvert, located on the side of the flood control channel road surface close to the existing highway, to prevent unauthorized personnel from entering the highway through the flood control channel road surface and affecting traffic safety.

8. The parallel co-construction structure of flood storage and detention area dikes and highway subgrade as described in claim 1, characterized in that: The permeability coefficient of the seepage barrier is controlled at 10. -6 ~10 -8 cm / s.

9. A construction method for a parallel co-construction structure of flood detention area embankments and highway subgrades, characterized in that, Includes the following steps: Based on the axis and design elevation of the new embankment, measurements and layout were carried out, and the existing foundation and highway subgrade were cleared. Micro steel pipe pile grouting reinforcement was carried out on the existing highway slopes and embankment foundations, and high-pressure jet grouting pile anti-seepage walls were constructed. Lay the bottom impermeable geomembrane of the dike and smooth the bottom cement mortar protective layer; The existing highway slope was excavated in layers from bottom to top, foam concrete was poured in layers, cement mortar protective layer was smoothed, and geomembrane was laid. Smooth the top layer of cement mortar protective layer and lay the top layer of impermeable geomembrane; Layered filling of the edging soil, consisting of cohesive soil; Construction of vegetation block slope protection; For sections of the road where there are existing traffic culverts, new gates will be constructed according to the construction plan. The construction of new gates and corresponding ramps to the embankment will be carried out in parallel with the above steps, and the new gates will be properly connected to the new embankment. The flood control channel pavement structure layers are laid sequentially from bottom to top; Install a safety fence.

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