Regulation Structure and Construction Method for Root Swelling Deformation of Highway Subgrade and Pavement in Southern Bamboo Forest Area

Abstract

The present invention discloses a control structure and construction method for root swelling deformation of highway subgrade and pavement in southern bamboo forest areas. The structure includes an asphalt pavement structure, an ecological curbstone structure, and a subgrade slope structure. The thickness of the asphalt pavement structure matches the underground growth depth of bamboo rhizomes. The ecological curbstone structure includes a body that is narrow at the top and wide at the bottom and is overall L-shaped. An L-shaped through cavity is provided inside the body. A water passage is provided on the upper surface of the lower body of the body, and both ends of the water passage penetrate along the length direction of the body. Drainage openings are spacedly provided on both the upper body and the lower body of the body, and the drainage openings are communicated with the L-shaped through cavity. The L-shaped through cavity is connected to a side ditch at the bottom of the slope through a chute that is spacedly arranged longitudinally along the road. In the slope filling layer of the subgrade slope structure, the filling amount of residual rhizomes in the soil layer gradually increases from bottom to top. The present invention prevents bamboo rhizomes from growing into the range of the highway subgrade and pavement, overcomes the problem of root swelling damage, controls the deformation of the subgrade and pavement, and improves the durability of the pavement.

Description

Technical Field

[0001] The invention belongs to the technical field of highway construction and maintenance, and relates to a regulation structure and construction method for root swelling deformation of highway subgrade and pavement in southern bamboo forest areas. Background Technique

[0002] Moso bamboo is widely distributed in the Yangtze River Basin and southern provinces of China and is one of the fastest-growing plants in the world. The rhizomes of moso bamboo run horizontally in the soil within a depth of 40 cm below the ground surface, and have the habit of growing towards loose and fertile soil, sunny and warm directions. It likes warm and humid climate, leeward and sunny, humid environment, and acidic soil rich in organic matter and mineral elements.

[0003] Engineering practice has found that roadbed and pavement diseases caused by the horizontal growth of moso bamboo rhizomes are common in highways in southern bamboo forest areas. When building a highway in a bamboo forest area, if it encounters a section with a low terrain, a low embankment form is often adopted. Although the original ground moso bamboo and its broken rhizomes will be removed when building the embankment, due to the tenacious vitality of moso bamboo rhizomes, if the broken rhizomes are not completely removed, the rhizomes will continue to spread in the embankment; at the same time, the rhizomes outside the embankment range may also grow horizontally towards the embankment. Due to the habit of growing upwards along the slope, a large number of rhizomes will grow upwards along the slope after invading the embankment range, and finally invade the road shoulder and even the driving lane of the highway. The growth of rhizomes in the subgrade soil will generate a jacking force on the upper soil layer. Since the subgrade soil has a high degree of compaction and low compressibility, the soil layer jacking force and deformation will continue to be transmitted upwards, causing bulging deformation of the subgrade soil and pavement structure, and then resulting in excessive uplift and cracking of the pavement. Moreover, due to the continuous growth of moso bamboo rhizomes, the problems of pavement uplift and cracking will continue to intensify over time, not only increasing the highway maintenance frequency and causing direct economic losses, but also greatly affecting driving safety and road appearance. The above-mentioned roadbed and pavement diseases are very common in ordinary national highways and local roads in southern mountainous areas and are difficult problems that need to be solved urgently in the quality improvement and transformation of highways in southern bamboo forest areas.

[0004] In summary, in order to prevent the root swelling deformation diseases of highway subgrade and pavement in southern bamboo forest areas and ensure the normal service life of highway pavement, it is very necessary to develop a regulation structure and construction method for root swelling deformation of highway subgrade and pavement in southern bamboo forest areas. Summary of the Invention

[0005] In order to solve the above problems, the invention provides a regulation structure for root swelling deformation of highway subgrade and pavement in southern bamboo forest areas, which prevents the rhizomes from growing into the highway subgrade and pavement range, overcomes the problem of root swelling damage, controls the deformation of the subgrade and pavement, and improves the durability of the pavement.

[0006] Another object of the invention is to provide a construction method for the regulation structure of root swelling deformation of highway subgrade and pavement in southern bamboo forest areas.

[0007] The technical solution adopted by the present invention is a control structure for root swelling deformation of highway subgrade and pavement in southern bamboo forest areas, including:

[0008] An asphalt pavement structure, the thickness of the asphalt pavement structure is matched with the underground growth depth of bamboo rhizomes, and a drainage cross slope is provided on the surface layer of the pavement structure;

[0009] An ecological curb structure, the ecological curb structure includes a body with a narrow upper part and a wide lower part, which is overall L-shaped. An L-shaped through cavity is provided inside the body. A water passage is provided on the upper surface of the lower body of the body, and both ends of the water passage penetrate along the length direction of the body; Drainage ports are spacedly provided on both the upper body and the lower body of the body, and the drainage ports are communicated with the L-shaped through cavity. The L-shaped through cavity is connected to the side ditch at the bottom of the slope through a chute spaced along the longitudinal direction of the road;

[0010] A subgrade slope structure, in which the filling amount of residual bamboo rhizomes in the soil layer of the subgrade slope filling layer gradually increases from bottom to top.

[0011] Further, the raw materials of the ecological curb structure are composed of the following parts by weight: 20-70 parts of excavated stone, 10-20 parts of calcium hydroxide, 8-15 parts of fly ash, 2-5 parts of bamboo and wood fiber, 8-16 parts of portland cement, 5-15 parts of alicyclic epoxy resin, 1-6 parts of water; among them, the bamboo and wood fiber is granular residual bamboo rhizomes of moso bamboo.

[0012] Further, the asphalt pavement structure adopts a framework-dense structure with a porosity of 4-6%.

[0013] Further, the asphalt pavement structure successively includes a lower base course, an upper base course, a lower surface course, and an upper surface course from bottom to top. The lower base course adopts a lime-fly ash stabilized base course, the upper base course adopts a lime-fly ash stabilized gravel base course, the lower surface course adopts medium-grained asphalt concrete; the upper surface course adopts fine-grained modified asphalt concrete; both between the upper surface course and the lower surface course and between the lower surface course and the upper base course are bonded by a modified emulsified asphalt tack coat.

[0014] Further, the water passage is formed by being recessed downward from the L-shaped turning point along the height direction of the body, and the cross section is arc-shaped.

[0015] Further, the drainage ports include a high-level drainage port and a low-level drainage port. The high-level drainage port is arranged on the upper part of the body and is higher than the water passage; the horizontal height of the low-level drainage port is flush with the pavement structure, and the setting interval of the drainage ports is 15-20 cm.

[0016] Further, the drainage ports are arch-shaped, and arch-shaped anti-pollution nets are provided at the drainage ports, and the aperture of the anti-pollution nets is 5-20 mm.

[0017] Further, the subgrade of the subgrade slope structure successively includes a lower embankment, an upper embankment, a lower subgrade bed, and an upper subgrade bed from bottom to top. Roadside fill layers are filled on both sides of the asphalt pavement structure above the upper subgrade bed; the slopes on both sides of the subgrade successively include a fourth slope fill layer, a third slope fill layer, a second slope fill layer, and a first slope fill layer from bottom to top. The mass fraction of residual bamboo whips added to the slope fill layer is 8% - 14%, showing an increasing trend from bottom to top.

[0018] Further, a slope gravel layer and a vegetation layer are successively provided on the surface of the slope of the subgrade slope structure. Residual bamboo whips with a length of 8 - 10 cm are transversely inserted at intervals in the vegetation layer, and the mass fraction of the added residual bamboo whips is 9% - 11%.

[0019] A construction method for a control structure of root swelling deformation of a highway subgrade and pavement in a southern bamboo forest area includes the following steps:

[0020] S1. Pave the subgrade;

[0021] S2. Lay a slope gravel layer on the outside of the subgrade slope and hang a net on the slope;

[0022] S3. Spray and sow the vegetation layer on the slope gravel layer;

[0023] S4. Lay an asphalt pavement structure on the leveled subgrade, and a drainage cross slope is provided on the surface of the pavement structure surface;

[0024] S5. Set ecological curbstone structures on both sides of the road surface. The buried section of the ecological curbstone structure is buried under the road surface. The exposed section above the road surface is grooved, leveled, tamped and then installed at a position flush with the road surface. An opening is provided every 10 - 15 m to connect the L-shaped through cavity inside the ecological curbstone structure with the catch water channel. The catch water channels are arranged at intervals along the longitudinal direction of the road, and the catch water channels are connected to the side ditch at the bottom of the slope; Caulk between the ecological curbstone structure and the pavement structure.

[0025] The beneficial effects of the present invention are:

[0026] 1. There are two beneficial effects in the subgrade slope structure of the present invention. First, the slope gravel layer is formed by crushing and filling the excavated stones from the road cut or tunnel of the highway on the outside of the subgrade slope, and the growth of bamboo whips is blocked by the interlocking and compaction between the gravels; second, adding residual bamboo whips to the vegetation layer serves the purpose of reinforcing the vegetation layer and inhibiting the growth of bamboo whips in the vegetation layer.

[0027] 2. There are three beneficial effects of the bamboo rhizome aggregate ecological curbstone of the present invention. First, waste materials are fully utilized to make recycled road engineering blocks, achieving true resource utilization of waste materials. Second, according to the characteristics of shallow growth and hardness avoidance of bamboo rhizomes, the buried section of the curbstone buried at a certain depth underground can effectively resist the extension of bamboo rhizomes. Finally, the L-shaped cavity through structure is adopted in the structure, with a large flow rate, and can timely drain the road surface water.

[0028] 3. There are three beneficial effects of the asphalt concrete of the present invention. First, the skeleton-dense structure is adopted in the structure, with a small porosity, which can effectively prevent bamboo rhizomes from entering the road surface and causing damage to the road surface structure. Second, bamboo and wood fibers (granular residual rhizomes) are used as additives in the surface layer material of this asphalt concrete, which has good anti-deformation ability and can effectively resist the road surface deformation caused by the invasion of bamboo rhizomes. Finally, a lime-fly ash stabilized base is adopted, and quicklime in it is easy to form calcium hydroxide when encountering humid air, which can effectively inhibit the growth of bamboo rhizomes. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of an embodiment of the present invention.

[0031] Figure 2 is Figure 1 The right partial view of

[0032] Figure 3 is Figure 1 The left partial view of

[0033] Figure 4 It is a schematic structural diagram of the curbstone in the embodiment of the present invention.

[0034] Figure 5 It is the mechanical property test data of the curbstone in the embodiment of the present invention and the comparative example.

[0035] Figure 6 It is the drainage performance test data of the curbstone in the embodiment of the present invention and the comparative example.

[0036] In the figure, 1. ecological curb structure, 2. asphalt pavement structure, 20. body, 21. high-level drainage outlet, 22. water passage, 23. low-level drainage outlet, 24. exposed section, 25. embedded section, 26. auxiliary drainage channel, 27. main drainage channel, 3. surface layer of pavement structure, 4. upper surface layer, 5. lower surface layer, 6. upper base course, 7. lower base course, 8. roadside fill layer, 9. upper roadbed, 10. lower roadbed, 11. upper embankment, 12. lower embankment; 13. first slope fill layer, 14. second slope fill layer, 15. third slope fill layer, 16. fourth slope fill layer, 17. chute, 18. side ditch, 19. vegetation layer. Detailed implementation mode

[0037] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0038] Embodiment 1

[0039] A root swelling deformation control structure for highway subgrade and pavement in southern bamboo forest areas, as Figure 1 shown, includes an asphalt pavement structure 2, an ecological curb structure 1 and a subgrade slope structure, jointly forming a stable root swelling deformation control structure for the subgrade and pavement.

[0040] As Figure 2 shown, the thickness of the asphalt pavement structure 2 is 40 cm, corresponding to the underground growth depth of bamboo rhizomes. The asphalt pavement structure is composed of a lower base course 7, an upper base course 6, a lower surface layer 5, and an upper surface layer 4 from bottom to top; the asphalt pavement structure includes a surface layer and a base course. From bottom to top, the lower base course 7 uses a 7% lime fly ash stabilized base course, the upper base course 6 uses a 5% lime fly ash stabilized gravel base course, and the lower surface layer 5 uses 8 - 12 cm medium-sized asphalt concrete; the surface layer and the base course are bonded with 50% emulsified asphalt tack coat, and the upper surface layer 4 uses 6 - 10 cm fine-grained modified asphalt concrete; the thickness of the lower base course 7 is 15 - 20 cm, and the thickness of the upper base course 6 is 25 - 30 cm, having sufficient strength to resist bamboo rhizomes.

[0041] Between the upper layer 4 and the lower layer 5, and between the lower layer 5 and the upper base layer 6, a modified emulsified asphalt tack coat is used for bonding, which can strengthen the bond between the surface layers, enabling the adjacent surface layers and base layers to be bonded into a firm whole, preventing sliding or pushing phenomena between adjacent two layers. And in the pavement structure, in order to ensure the compactness of the pavement structure, its water permeability is not strong. Bonding with the modified emulsified asphalt tack coat can play a certain waterproofing role, improving the strength, stability and waterproofing ability of the pavement. The lower seal coat is prepared from modified asphalt with uniformly distributed gravel on the surface. The modified asphalt is SBS modified asphalt, which can effectively change the pavement structure strength and effectively resist the damage of the pavement by plant roots such as bamboo whips.

[0042] In the embodiment, the thickness of the upper layer 4 is 6 - 10 cm, the thickness of the lower layer 5 is 8 - 12 cm, the modified emulsified asphalt tack coat uses PC-3 type emulsified asphalt, and the spreading amount of the PC-3 type emulsified asphalt is 0.4 - 0.6 L / m 2 。

[0043] As Figure 4 shown, the ecological curb structure 1 includes a main body 20 that is wider at the bottom and narrower at the top and is overall L-shaped. There is an L-shaped through cavity inside the main body 20, which increases the water flow passing capacity; on the upper surface of the lower part of the main body 20, there is a water channel 22. Drainage holes are spacedly arranged on both the upper part and the lower part of the main body 20, and the drainage holes are communicated with the L-shaped through cavity; the L-shaped through cavity is connected to the side ditch 18 at the bottom of the slope through a rapid flow channel 17 spaced longitudinally along the road, increasing the drainage strength of the pavement structure.

[0044] Figure 1 The ecological curb structures 1 on the left and right sides in

[0045] are respectively cross-sections of different parts of the overall structure. The right side is the cross-section of the part of the structure that is connected to the rapid flow channel 17; the left side is the cross-section of the part of the structure that is not connected to the rapid flow channel 17, increasing the drainage capacity.

[0046] The water channel 22 is a semi-cylinder (with a circular arc cross-section) formed by being recessed downward from the L-shaped turning point along the height direction of the main body 20. Both ends of the water channel 22 penetrate along the length direction of the main body 20, so as to prevent rainwater from gathering, which may lead to a reduction in soil strength and cause slope instability and damage.

[0047] There is a 5cm wide and 7.5cm high drainage outlet every 15cm. The drainage outlets include a high-level drainage outlet 21 and a low-level drainage outlet 23. The high-level drainage outlet 21 is set on the upper part of the curbstone, higher than the waterway 22; the horizontal height of the low-level drainage outlet 23 is flush with the road surface structure. Each curbstone has a high-level drainage outlet 21 and a low-level drainage outlet 23. The high-level drainage outlet 21 is directly connected to the auxiliary drainage channel 26, and the low-level drainage outlet 23 is directly connected to the main drainage channel 27. A rapids trough 17 is connected every 10m, and the rapids trough 17 is connected to the side ditch 18. When there is less water on the road, the water level is relatively low, and the accumulated water flows from the road surface to the main drainage channel 27; when there is more water on the road (such as sudden heavy rain), the water level is relatively high, and the accumulated water flow is larger than the low-level drainage outlet 23, and the accumulated water flows to the auxiliary drainage channel 26 through the high-level drainage outlet 21, and the accumulated water is discharged to the side ditch 18 through the rapids trough 17, which has the function of draining the accumulated water on the slope protection structure during rainfall and transporting the drained water to other places, thereby removing the accumulated water from the road surface structure.

[0048] The drainage outlet is arch-type. Both the high-level drainage outlet 21 and the low-level drainage outlet 23 are provided with arch-type trash nets to intercept fallen leaves, debris on the road and soil in the green belt to prevent a large amount of road garbage from flowing away and polluting the slopes. The trash nets are detachable for easy cleaning, and the aperture of the trash nets is 5 to 20 mm.

[0049] The exposed section 24 of each individual L-shaped curbstone on the road surface has an upper portion of 75 cm long, 15 cm wide and 10 cm high, and a lower portion of 75 cm long, 20 cm wide and 15 cm high. The arc radius of the waterway 22 is 5 cm, and the buried section 25 buried under the road surface is 10 cm thick.

[0050] Because the pavement structure is too compact and the pavement water permeability is not strong, the pavement structure surface layer 3 is provided with a 2% drainage slope. The pavement water flows through the curbstone to the rapids groove 17 and finally flows into the side ditch 18, thereby achieving a certain drainage effect while ensuring the resistance of the pavement to the bamboo whip.

[0051] like Figure 3As shown, the roadbed of the roadbed slope structure is composed of an upper roadbed 9, a lower roadbed 10, an upper embankment 11, and a lower embankment 12. The first slope fill layer 13, the second slope fill layer 14, the third slope fill layer 15, and the fourth slope fill layer 16 have different compaction degrees. According to the roadbed and pavement compaction specification, the compaction degree of the upper roadbed 9 is ≥94%, the compaction degree of the lower roadbed 10 is ≥94%, the compaction degree of the upper embankment 11 is ≥93%, and the compaction degree of the lower embankment 12 is ≥90%. From bottom to top, the amount of residual whip filling in the slope fill layer increases, and the filling amount increases by 2% per layer, that is, the mass fraction of residual whip filling from bottom to top is 8%, 10%, 12%, and 14% respectively. The higher you go, the more tiny bamboo whips extend upward through the gaps. At this time, it is necessary to increase the residual whip content, by reducing the soil porosity and using bamboo whips to avoid hardness to resist the bamboo whips from extending upward.

[0052] In some embodiments, since the slope of the slope is 1:1.75, the filling amount of soil layers with different compaction degrees of the shallow fill of the slope is also different. During the roadbed filling process, the compaction degree determined by the rolling test must be strictly controlled. The new upper layer of new material can only be paved after the compaction is qualified. Small compactors are used for compaction in places that cannot be compacted by machinery and in places where the compaction area is too small, and the fill slope must be shaped after the filling is completed.

[0053] In some embodiments, the shallow layer of the slope is layered or reinforced. In the roadbed slope structure, the highway cutting or tunnel excavated stone is crushed and filled on the outside of the roadbed slope to form a slope gravel layer A1. The purpose of hindering the growth of bamboo shoots is achieved by the embedding and compaction between the gravels. Secondly, residual shoots are added to the vegetation layer 19. The bamboo shoots will avoid the residual shoots and other roots. On the one hand, it can enhance the resistance to bamboo shoots and prevent damage to the pavement structure. On the other hand, it can play a reinforcement role to prevent slope collapse while reducing the impact of atmospheric dry-wet cycles on the humidity of the filler. At the same time, the rapids trough 17 on the slope can collect water on the road surface so that it can flow out smoothly and merge into the ditch 18, which further improves the drainage efficiency of rainwater discharged from the road surface, while reducing the erosion of rainwater on the road surface slope and enhancing the stability of the slope.

[0054] While preparing concrete, the fiber bundles of high-strength fibers are evenly mixed into the concrete. Combined with the gelling properties of alicyclic epoxy resins and the filling properties of granular residual whips, the resulting road pavement concrete and curbstone specimen preparation materials have greatly improved flexibility and strength. The concrete material has the advantages of low cost and easy production, as well as good cohesion and density. The concrete is more durable and stronger than traditional concrete, has stronger adaptability to the external environment, and greatly extends the service life of the pavement structure.

[0055] The high-strength fiber is made of polyacrylonitrile fiber with a fiber diameter of 13 microns. It has high tensile strength, large initial modulus, and stable chemical properties. The fiber is resistant to acid and alkali corrosion, light resistance, weather resistance, and has good dispersibility. It can improve the adhesion and fatigue resistance of concrete, enhance the concrete's impermeability, frost resistance, and impact resistance, and enable the concrete to bear more load stress. Its bending toughness is more than 6 times higher than that of plain concrete. It has strong wear resistance and chemical corrosion resistance, and can maintain good mechanical properties under high-intensity exposure-rainfall and other dry-wet cycles in outdoor environments.

[0056] Embodiment 2,

[0057] A construction method for a roadbed and pavement root expansion deformation control structure in a southern bamboo forest area, the specific steps are as follows:

[0058] S1. Pave the roadbed; first carry out the slope filling construction, and clean the surface of the site before filling. If there are multiple water pits on the surface, the water on the surface and the soil with too high water content should be removed and replaced before backfilling to ensure the dryness of the road fill. Then use a stacker with an excavator and a bulldozer to fill the soil as a whole. The principle of rolling should be "thin filling, slow driving, multiple times", and the rolling direction should be from the inside to the outside. Pay attention to overlapping routes. During the operation, the vibration rolling machine should be more than 2.0m away from the edge of the fill to prevent sliding and tipping. The upper roadbed 9, lower roadbed 10, upper embankment 11, and lower embankment 12 are compacted in layers, and the compaction parameters determined by the rolling test must be strictly controlled. Only after each layer is compacted and qualified, the new upper layer of new materials is allowed to be paved. During the filling process, the filling should strive to make the entire section rise parallel. When filling in sections, the joints of each layer should be made into a slope surface of 1:1.75, and the rolling signs should overlap by 1m. The upper and lower layers should be staggered in sections, and the staggered distance should not be less than 1m. The fourth side slope fill layer 16, the third side slope fill layer 15, the second side slope fill layer 14, and the first side slope fill layer 13 are filled in sequence on both sides of the roadbed from top to bottom.

[0059] S2. Lay a slope crushed stone layer A1 on the outer side of the roadbed slope, and use the crushed stones from the highway cutting or tunnel excavation for filling and paving; hang a net on the slope, and unwind the net from top to bottom and from left to right, and bind adjacent nets on the same slope layer with wires.

[0060] S3, after the treated plant seeds are mixed with bamboo residues, gelling agent, water retaining agent, nutrient fertilizer and mud, the mixture is evenly sprayed on the gravel layer A1 of the slope by a sprayer to form a vegetation layer 19, and soil and water loss are further prevented through plant ecological protection. The plant seeds are mixed plant seeds, tall fescue, bahia grass and bermudagrass are mixed in a mass ratio of 4:5:1, 1m 2 A total of 30g of plant seeds were placed on the slope, and the amount of bamboo residue was 30g / m2 。The dosage ratio of the gelling agent, water retention agent, nutrient fertilizer, and slurry per 0.1 m 3 of the mixture is 0.05 kg: 0.05 kg: 0.15 kg: 30 kg.

[0061] The spraying is carried out in two times. First, the mixture without seeds is sprayed with a thickness of 7 - 8 cm. Immediately afterwards, the mixture with seeds is sprayed for the second time with a thickness of 2 - 3 cm. The average thickness of the sprayed mixture is 10 cm, with a variation range of 3 - 15 cm. Spray as vertically as possible on the slope to avoid upward spraying, downward spraying or diagonal spraying, and the spraying process should be repeated back and forth, and should not be carried out at a certain point to ensure uniform spraying thickness.

[0062] The residual bamboo whips with a length of 8 - 10 cm are inserted horizontally at intervals in the vegetation layer 19, and the interval range is 10 - 15 cm. The mass fraction of the residual bamboo whips added to the vegetation layer 19 is about 10% (9% - 11%). Exceeding the corresponding range will damage the survival rate of the plants in the vegetation layer, and below the corresponding range, the residual bamboo whips will not play a defensive role. On the premise of being green and environmentally friendly, the "avoidance" of the residual bamboo whips and the gravel layer is achieved by using the property of the bamboo whips to avoid hardness.

[0063] S4. Lay a gravel cushion layer on the leveled embankment. The gravel base layer includes a lower base layer 7 and an upper base layer 6. The lower base layer 7 uses a 7% lime fly ash stabilized subbase, and the upper base layer 6 uses a 5% lime fly ash stabilized gravel base. The thickness of the lower base layer 7 is 200 mm, the thickness of the upper base layer 6 is 300 mm, the thickness of the upper surface layer 4 is 40 mm, and the thickness of the lower surface layer 5 is 60 mm. Roadside fill layers 8 are filled on both sides of the asphalt pavement structure 2 above the upper roadbed 9.

[0064] The depth of the bamboo whips is generally more than 500 mm underground. Among them, the road surface is compacted by rolling, layer by layer, and the compactness > 95%. Before the implementation of the lower base layer 7, first determine the cement dosage. Among them, the lower base layer 7 is centrally mixed and compacted in a single layer, and the compactness ≥ 96%. After the laying of the cement stabilized gravel subbase is completed, maintenance and road surface control must be carried out. During the watering process, strictly control the water volume to prevent waterlogging. The upper base layer 6 is centrally mixed and compacted in two layers, and the compactness ≥ 98%. When the surface becomes slightly dry but not completely hardened, pour a penetrating layer under the road and lay an asphalt subseal in time. The compactness of the upper base layer 6 is greater than 98%, and the compactness of the lower base layer 7 is greater than 96%.

[0065] To better connect the surface layer and the base layer of the asphalt pavement structure 2, highly permeable emulsified asphalt is sprayed on the base layer. Both the prime coat and the seal coat are prepared from PC-3 type emulsified asphalt. The penetration depth of the prime coat reaches more than 5 mm into the surface of the upper base layer 6. The prime coat and the seal coat play roles in transitioning, bonding, and consolidating the surface of the base layer. The use of emulsified asphalt reduces interlayer damage and plays a very important role in improving the durability of the road surface. During the paving process, attention should be paid to the cleaning work between layers to ensure that each layer is cleaned to prevent miscellaneous soil from affecting the bonding between layers. The modified emulsified asphalt tack coat can strengthen the bonding between the upper surface layer 4, the lower surface layer 5, the upper base layer 6, and the lower base layer 7, enabling the adjacent surface layer and base layer to bond into a firm whole to prevent sliding or pushing between adjacent layers. Moreover, in the road surface structure, due to the need to ensure the compactness of the road surface structure and its low water permeability, using the modified emulsified asphalt tack coat for bonding can play a certain waterproofing role.

[0066] Emulsified asphalt is a liquid asphalt in which asphalt and emulsifier react under certain technological conditions to form an oil-in-water or water-in-oil structure. Structurally, the emulsifier is an amphiphilic molecule composed of a non-polar hydrophobic group and a polar hydrophilic group. This structure enables the emulsifier to form an oriented and closely packed layer at the surface (interface) of the solution, changing the surface (interface) chemical properties of the system and better solving problems such as asphalt being prone to flowing and bleeding at high temperatures and being brittle and cracking at low temperatures.

[0067] The surface of the surface layer 3 of the road surface structure presents a certain inclination angle, with an inclination angle of 2% from the inside to the outside (i.e., the drainage cross slope). Due to the compactness of the road surface structure, a certain inclination angle can increase the drainage capacity of the road surface.

[0068] S5. An ecological curbstone structure 1 is set on both sides of the road surface. The foundation of the ecological curbstone structure 1 is filled, excavated, and compacted simultaneously with the road surface base layer. The buried section 25 of the ecological curbstone structure 1 is buried under the road surface to further resist shallow bamboo rhizomes. The exposed section 24 above the road surface is grooved, leveled, and compacted at a position flush with the road surface before being installed. An opening is set every 10 m to connect the L-shaped through cavity inside the ecological curbstone structure 1 with the catch basin 17. The catch basins 17 are arranged at intervals along the longitudinal direction of the road, and the catch basins 17 are connected to the side ditch 18 at the bottom of the slope to facilitate the drainage of water on the road surface.

[0069] There is a need to seal the joints (seal the joints with original mortar) between the ecological curb structure 1 and the road surface structure. The original mortar material refers to the preparation material of the bamboo whip aggregate ecological curb. The installation joint of the curb is 1 cm. Use 1:2 cement mortar to fill and solidify the joint completely. The saturation degree ≥ 80%, and the consistency is 14 - 18 s. When sealing the joints, pay attention to protecting the curbs from being polluted by the mortar. You can first stick plastic strips on both sides of the curb joints and then start sealing the joints. The curbs should be installed firmly, with a flat top surface, uniform joint width, dense joint sealing, smooth lines, and ensure that the exposed height is about 150 mm.

[0070] Example 3

[0071] Weigh 40 parts of the highway cutting or tunnel excavation stone, 10 parts of calcium hydroxide, 10 parts of fly ash, 3 parts of bamboo and wood fiber, 10 parts of portland cement, 8 parts of alicyclic epoxy resin, and 5 parts of water according to the following weight parts. The bamboo and wood fiber is the residual whip of Phyllostachys pubescens with a length of 10 mm.

[0072] The ecological curb structure 1 of the embodiment of the present invention uses local waste stone, calcium hydroxide, and fly ash as the base layer, and residual whip fiber as the enhanced compressive material, and is pressed into curbs under the action of bidirectional high pressure.

[0073] Specific production method:

[0074] First, crush the bamboo and wood fiber (residual whip) and the highway cutting or tunnel excavation stone, and sieve out fine aggregate with a particle size of 0.075 - 2 mm and coarse aggregate with a particle size of 5 - 20 mm through sieve holes of different particle sizes, and screen out impurities;

[0075] Weigh the excavation stone, calcium hydroxide, fly ash, bamboo and wood fiber, portland cement, epoxy resin, and water according to the corresponding weight parts; feed them into a mixer and stir for 6 min to obtain a mixture;

[0076] Pour the stirred mixture into the curb mold and statically press it into shape under a bidirectional high pressure of 35 - 40 MPa;

[0077] Let the statically pressed ecological curbs be naturally cured for 7 - 14 days.

[0078] Example 4

[0079] Weigh 50 parts of the highway cutting or tunnel excavation stone, 15 parts of calcium hydroxide, 12 parts of fly ash, 4 parts of bamboo and wood fiber, 13 parts of portland cement, 12 parts of alicyclic epoxy resin, and 5 parts of water according to the following weight parts; prepare the ecological curb structure 1 according to the method of Example 3. The bamboo and wood fiber is the residual whip of Phyllostachys pubescens with a length of 10 mm.

[0080] Example 5

[0081] Weigh the following parts by weight of the highway cutting or tunnel excavation stone: 70 parts, calcium hydroxide 20 parts, fly ash 15 parts, bamboo fiber 5 parts, portland cement 16 parts, alicyclic epoxy resin 15 parts, water 5 parts; Prepare the ecological curb structure 1 according to the method of Example 3; The bamboo fiber is the remaining whip of bamboo with a length of 6 mm.

[0082] Example 6,

[0083] Weigh the following parts by weight of the highway cutting or tunnel excavation stone: 20 parts, calcium hydroxide 5 parts, fly ash 8 parts, bamboo fiber 2 parts, portland cement 8 parts, alicyclic epoxy resin 5 parts, water 1 part; Prepare the ecological curb structure 1 according to the method of Example 3; The bamboo fiber is the remaining whip of bamboo with a length of 8 mm.

[0084] Comparative Example 1,

[0085] The ecological curb does not contain bamboo fiber, alicyclic epoxy resin, and calcium hydroxide in the raw materials, and the rest is the same as in Example 3.

[0086] The compressive and tensile strength test data of Examples 3-6 and Comparative Example 1 are shown in Table 1, and the drainage performance test data of Examples 3-6 and Comparative Example 1 are shown in Table 2. Figure 5 、 6 as shown.

[0087] Table 1 Mechanical property test data of the curb

[0088] Average compressive strength / MPa Average tensile strength / MPa Example 3 35.8 5.2 Example 4 36.4 4.9 Example 5 35.9 5.1 Example 6 36.2 5.0 Comparative Example 1 32.1 4.3

[0089] Table 2 Drainage performance test data of the curb

[0090]

[0091] The raw materials of the ecological curb structure 1 adopt environment-friendly materials and are composed of the following parts by weight: 20-70 parts of the highway cutting or tunnel excavation stone, 10-20 parts of calcium hydroxide, 8-15 parts of fly ash, 2-5 parts of bamboo fiber, 8-16 parts of portland cement, 5-15 parts of alicyclic epoxy resin, and 1-6 parts of water; Among them, the bamboo fiber is the granular remaining whip of bamboo to enhance the resistance of the road surface to the bamboo whip, strengthen the compaction degree of the road surface structure, and enhance the density of the road surface structure. Exceeding the corresponding range will damage the strength and service life of the curb; If the raw material composition exceeds the range, the concrete components of the precast curb cannot be formed; For example, if the proportion of the highway cutting or tunnel excavation stone as the coarse aggregate is too large, the curb is prone to cracking, and if it is too small, the strength is insufficient; If the incorporation amount of sodium hydroxide exceeds the corresponding range, it will corrode the portland cement and damage the curb structure; If the incorporation amount of alicyclic epoxy resin exceeds the corresponding range, it will reduce the toughness of the curb and cause it to crack easily.

[0092] In the embodiment, medium sand with a fineness modulus of 2.7 - 3.3 and a particle size of 0.075 - 2 mm is selected as the fine aggregate for the curbstone; waste pavement panel construction waste with a maximum particle size not greater than 20 mm and a minimum particle size not less than 5 mm, as well as the excavated stone from the road cutting or tunnel of this highway, etc. are selected as the coarse aggregate, which can save costs and enhance the strength of the curbstone. The fine aggregate and the coarse aggregate together constitute the excavated stone, and the mass ratio of the fine aggregate to the coarse aggregate is 5:1.

[0093] The proportion of fly ash is about 20%; among them, residual whips with a size of 2 - 10 mm are incorporated, and the residual whips of appropriate sizes are selected and ground in the natural state to make them segmented; the cement is Portland cement with a strength grade of 42.5; using alicyclic epoxy resin can enhance the gelling property and anti-bending property between concretes. It not only has the characteristics of high adhesion and good mechanical properties of the cured product, but also has strong durability to temperature. Whether in a high-temperature environment or an ultra-low-temperature environment, it has a high bonding strength, can improve the adhesion between high-strength special fibers and cement mortar while improving the adaptability of concrete components to outdoor temperature; the residual whip particles as fillers can effectively fill the internal pores of the coarse and fine aggregates of the concrete, reduce the porosity of the concrete and the cracks and bends generated during the use of the concrete, improve the flexibility of the concrete components, play a role of framework and filling in the concrete and mortar, increase stability, and play a role in resisting root damage while reducing costs and saving the environment; (sodium hydroxide) is incorporated to make the curbstone have good dry shrinkage performance, good freeze-thaw resistance, strong anti-seepage performance, and reduce the creep of the concrete. The excavated stone from the road cutting or tunnel of the highway is used as the coarse aggregate, and bamboo fiber (residual whip particles) is used as the filler. When pouring concrete, sodium hydroxide and alicyclic epoxy resin are added to improve the concrete components. The raw materials cooperate with each other and work together to further enhance the strength of the curbstone components, improve the compressive strength, have strong durability to temperature, thus resisting the cracks and bends of the curbstone caused by temperature changes, and having strong drainage capacity.

[0094] In this embodiment, during the process of filling the slope, the excavated stone from the road cutting or tunnel of this highway is crushed and filled outside the subgrade slope to form a slope gravel layer, and the purpose of hindering the growth of bamboo whips is achieved through the interlocking and compaction between the gravels; secondly, residual whips are added to the vegetation layer 19 to achieve the purpose of reinforcing the vegetation layer and inhibiting the growth of bamboo whips in the vegetation layer. While ensuring the reinforcing effect, it plays a role in preventing slope collapse, increasing the overall strength of the slope and resisting the roots. For the rolling method and ramming method used for slope filling, the rolling method uses the pressure of the mechanical roller to compact the soil to make it reach the required density; the ramming method uses the impact force of the free fall of the rammer to ram the soil, and the pores of the soil body are compressed, and the soil particles are arranged more closely. The combination of the two methods makes the slope filling more compact and can resist the lateral growth of bamboo whips. Thus, the role of resisting root damage is achieved.

[0095] Due to the lateral growth characteristics of bamboo rhizomes, the growth range is large. If concrete devices are used for root fixation, it is very difficult to provide comprehensive protection, the involved range is too large, and the cost increases significantly. In the embodiments of the present invention, the ecological curb structure 1, the asphalt pavement structure 2, and the roadbed slope structure are improved, and the three cooperate with each other and complement each other to form a harmonious and stable protection system. Without damaging the performance of the pavement structure, its strength is enhanced, the growth of bamboo rhizome roots through the gaps is resisted, and at the same time, the water circulation is increased and the drainage performance is improved. While comprehensive protection can be provided, the construction cost can also be reduced. In the embodiments of the present invention, by utilizing the characteristic of bamboo rhizomes "avoiding hard objects and diving downward", by increasing the buried depth of the curb and the thickness of the pavement structure, and reducing the porosity of the pavement structure layer (4-6%), the extension direction is changed, and through root swelling deformation control, the bamboo rhizomes are controlled to grow downward and bend.

[0096] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A regulation structure for root swelling deformation of highway subgrade and pavement in southern bamboo forest areas, characterized in that Comprising: An asphalt pavement structure (2), the thickness of the asphalt pavement structure being matched with the underground growth depth of the bamboo rhizomes, and a drainage cross slope being provided on the surface layer (3) of the pavement structure; An ecological curb structure (1), the ecological curb structure (1) including a main body (20) that is narrow at the top and wide at the bottom and is overall L-shaped. An L-shaped through cavity is provided inside the main body (20). A water passage (22) is provided on the upper surface of the lower body of the main body (20), and both ends of the water passage (22) penetrate along the length direction of the main body (20); drainage openings are provided at intervals on the upper body and the lower body of the main body (20), and the drainage openings are communicated with the L-shaped through cavity. The L-shaped through cavity is connected to a side ditch (18) at the bottom of the slope through a rapid flow channel (17) arranged at intervals along the longitudinal direction of the road; A subgrade slope structure, the filling amount of residual rhizomes in the soil layer of the slope filling layer of the subgrade slope structure gradually increasing from bottom to top; The raw materials of the ecological curb structure (1) are composed of the following parts by weight: 20-70 parts of excavated stone, 10-20 parts of calcium hydroxide, 8-15 parts of fly ash, 2-5 parts of bamboo and wood fiber, 8-16 parts of portland cement, 5-15 parts of alicyclic epoxy resin, and 1-6 parts of water; among them, the bamboo and wood fiber is granular residual rhizomes of moso bamboo; The asphalt pavement structure (2) adopts a framework-dense structure with a porosity of 4-6%; The drainage openings include a high-level drainage opening (21) and a low-level drainage opening (23). The high-level drainage opening (21) is arranged at the upper part of the main body (20) and is higher than the water passage (22); the horizontal height of the low-level drainage opening (23) is flush with the pavement structure, and the setting interval of the drainage openings is 15-20 cm; The drainage openings are arch-shaped, and arch-shaped anti-pollution nets are provided at the drainage openings, and the aperture of the anti-pollution nets is 5-20 mm.

2. The root swelling deformation control structure for the roadbed and pavement in the southern bamboo forest area according to claim 1, wherein The asphalt pavement structure (2) sequentially includes a lower base course (7), an upper base course (6), a lower surface course (5), and an upper surface course (4) from bottom to top. The lower base course (7) adopts a lime-fly ash stabilized base course, the upper base course (6) adopts a lime-fly ash stabilized gravel base course, the lower surface course (5) adopts medium-grained asphalt concrete; the upper surface course (4) adopts fine-grained modified asphalt concrete; between the upper surface course (4) and the lower surface course (5), and between the lower surface course (5) and the upper base course (6), they are bonded through a modified emulsified asphalt tack coat.

3. The root swelling deformation control structure for the roadbed and pavement in the southern bamboo forest area according to claim 1, characterized in that, The water passage (22) is formed by being recessed downward from the L-shaped turning point along the height direction of the main body (20), and the cross section is arc-shaped.

4. The root swelling deformation control structure for the roadbed and pavement in the southern bamboo forest area according to claim 1, characterized in that, The subgrade of the subgrade slope structure sequentially includes a lower embankment (12), an upper embankment (11), a lower subgrade bed (10), and an upper subgrade bed (9) from bottom to top. Roadside filling layers (8) are filled on both sides of the asphalt pavement structure (2) above the upper subgrade bed (9); the slopes on both sides of the subgrade sequentially include a fourth slope filling layer (16), a third slope filling layer (15), a second slope filling layer (14), and a first slope filling layer (13) from bottom to top. The mass fraction of residual rhizomes added to the slope filling layer is 8%-14%, showing an increasing trend from bottom to top.

5. The root swelling deformation control structure for the roadbed and pavement in the southern bamboo forest area according to claim 1, characterized in that, On the slope surface of the subgrade slope structure, there are successively arranged a slope gravel layer and a vegetation layer (19). In the vegetation layer (19), residual whips with a length of 8 - 10 cm are inserted transversely at intervals, and the mass fraction of the added residual whips is 9% - 11%.

6. The construction method of the control structure for root swelling deformation of highway subgrade and pavement in southern bamboo forest areas as described in claim 1, characterized in that, It includes the following steps: S1. Pave the subgrade; S2. Lay the slope gravel layer on the outside of the subgrade slope and install a wire mesh on the slope; S3. Spray and sow the vegetation layer (19) on the slope gravel layer; S4. Lay the asphalt pavement structure (2) on the leveled subgrade, and a drainage cross slope is provided on the surface of the pavement structure surface layer (3); S5. Set ecological curb structures (1) on both sides of the road surface. The buried section (25) of the ecological curb structure (1) is buried under the road surface. The exposed section (24) above the road surface is grooved, leveled, tamped and then installed at a position flush with the road surface. An opening is provided every 10 - 15 m to connect the L-shaped through cavity inside the ecological curb structure (1) with the chute (17). The chutes (17) are arranged at intervals along the longitudinal direction of the road, and the chutes (17) are connected to the side ditch (18) at the bottom of the slope; Caulk between the ecological curb structure (1) and the pavement structure.

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