Highway carbon soft rock high-performance roadbed structure

Abstract

The utility model discloses a high-performance carbonaceous soft rock roadbed structure of an expressway, which relates to the technical field of road construction and comprises an isolating layer, a carbonaceous soft rock filling area, an upper embankment, a roadbed and a pavement which are sequentially arranged from bottom to top, anti-seepage areas are arranged on the two sides of the carbonaceous soft rock filling area, and anti-seepage layers distributed in sequence are arranged in the anti-seepage areas; a groove is formed in the road surface, a sleeper beam is arranged in the groove, two sets of New Jersey guardrails are arranged above the sleeper beam, and a concrete cushion layer, a sand filling layer and a planting soil layer are clamped in the two New Jersey guardrails from bottom to top. By means of the arrangement, the carbon soft rock excavated along the line can be fully utilized as roadbed filler, and the reinforcement and waterproof effects of the geogrid and the composite geotextile, the waterproof effect of the isolation layer at the bottom of the embankment and the water sealing effect of the separation type New Jersey guardrail of the medial strip are fully utilized, so that the stability of a roadbed humidity field is jointly ensured; further, the engineering property of the carbonaceous soft rock filler is kept stable.

Description

Technical Field

[0001] The utility model relates to the technical field of road construction, in particular to a high-performance roadbed structure of carbonaceous soft rock for expressways. Background Technique

[0002] Carbonaceous soft rock is mainly distributed in Guizhou, Hunan, Guangxi and other places in China. In today's expressway construction, green and environmental protection are the bottom lines, and the basic requirement for subgrade filling is "less borrowing and less waste". Under the construction concept of "Safe and Quality Project for a Century", how to scientifically and reasonably use the special filler carbonaceous soft rock to fill the subgrade and ensure the project quality is a technical problem to be solved.

[0003] Carbonaceous soft rock has the engineering properties of being easily disintegrated and slurred when encountering water and a sharp reduction in strength. The action of water will reduce the overall strength of the subgrade and increase the settlement deformation, thus resulting in subgrade and pavement diseases. Therefore, it is crucial to do a good job in the water isolation design of the carbonaceous soft rock subgrade and ensure its humidity stability. Rainfall mainly infiltrates through the subgrade slope and the central isolation belt, part of the rainwater infiltrates through the pavement structure layer, and the capillary water rising from the base affects the humidity stability of the subgrade. Relevant research shows that the influence depth of rainfall on the humidity state of granular subgrades does not exceed 3m; the lateral diffusion influence range of the central isolation belt seepage exceeds 3m, and the vertical diffusion influence depth is 2 - 4m; the capillary water rising height of coarse sand, gravel, etc. is 0.2 - 0.4m. Then, the structural type of the high-performance carbonaceous soft rock subgrade should be determined comprehensively according to factors such as subgrade humidity influencing factors, each part of the subgrade, and subgrade fillers. At present, the carbonaceous soft rock subgrade often uses water-blocking materials such as cohesive soil, lime soil or cement soil for interlayer filling and covering treatment to maintain the stability of the subgrade humidity field. However, in actual projects, there is often a lack of available wrapping cohesive soil around the carbonaceous soft rock subgrade of mountain roads, which involves long-distance transportation, thus increasing the project cost; and it is a practical problem that lime soil or cement soil is not easy to be fully mixed evenly. At the same time, whether it is wrapping cohesive soil, lime soil or cement soil, they are all fillers with different properties from carbonaceous soft rock, and the subgrade is prone to lateral differential settlement due to the difference in fillers, resulting in surface cracking and landsliding of the subgrade slope, and even pavement cracking. Content of the Utility Model

[0004] The purpose of the utility model is to solve the defects existing in the prior art, and to propose a high-performance roadbed structure of carbonaceous soft rock for expressways.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0006] A high-performance roadbed structure of carbonaceous soft rock for expressways includes an isolation layer, a carbonaceous soft rock filling area, an upper embankment, a roadbed and a road surface which are arranged in sequence from bottom to top;

[0007] On both sides of the carbonaceous soft rock filling area, there are anti-seepage areas, and in the anti-seepage areas, there are anti-seepage layers distributed in sequence.

[0008] There are grooves on the road surface. In the grooves, there are sleeper beams. Above the sleeper beams, there are two groups of Jersey barriers. Between the two Jersey barriers, there are a concrete cushion layer, a sand filling layer, and a planting soil layer from bottom to top. The sand filling layer is wrapped with an anti-filter geotextile.

[0009] Furthermore, the anti-seepage layer includes a composite geotextile and a geogrid. The carbonaceous soft rock is wrapped in the anti-seepage layer. The composite geotextiles and geogrids in each anti-seepage layer are connected by U-shaped nails.

[0010] Furthermore, the road surface includes a graded crushed stone subbase, a cement stabilized crushed stone base course, and a surface course. The grooves are opened on the cement stabilized crushed stone base course and the surface course.

[0011] Even further, the thickness of the graded crushed stone subbase is 15 - 25 cm, the thickness of the cement stabilized crushed stone base course is 35 - 40 cm. The surface course includes a lower surface course, a middle surface course, and an upper surface course. The thickness of the lower surface course is 5 - 10 cm, the thickness of the middle surface course is 5 - 8 cm, and the thickness of the upper surface course is 3 - 5 cm.

[0012] Furthermore, the Jersey barriers are provided with drainage holes. The height of the drainage holes is higher than the height of the upper end face of the grooves. The aperture of the drainage holes is greater than 2 cm, and the slope rate is 2 - 5%.

[0013] Beneficial Effects

[0014] Compared with the prior art, the beneficial effects of the present utility model are as follows: Through the arrangement of the present utility model, the carbonaceous soft rock excavated along the line can be fully utilized as the subgrade filling material, and the disadvantages of the lack of available surrounding edge cohesive soil and environmental pollution caused by chemical improvement can be compensated. By making full use of the reinforcing and waterproof functions of the geogrid and the composite geotextile, the water isolation function of the bottom isolation layer of the embankment, and the water sealing function of the separated Jersey barriers in the central median strip, the stability of the subgrade humidity field can be jointly ensured, and thus the engineering properties of the carbonaceous soft rock filling material can be kept stable. Brief Description of the Drawings

[0015] The drawings are used to provide a further understanding of the present utility model, and constitute a part of the specification. They are used together with the embodiments of the present utility model to explain the present utility model, and do not constitute a limitation to the present utility model.

[0016] Figure 1 It is a schematic diagram of the overall structure of the subgrade structure.

[0017] Figure 2 It is a schematic diagram of the structure of the anti-seepage area on one side of the subgrade structure.

[0018] Figure 3It is a schematic structural diagram of the central divider.

[0019] In the figure: 1 - Bottom isolation layer of the embankment, 2 - Filling area of carbonaceous soft rock, 3 - Anti-seepage area, 4 - Upper embankment, 5 - Roadbed, 6 - Road surface, 7 - Central divider, 8 - Geogrid, 9 - Composite geotextile, 10 - U-shaped nail, 11 - Foundation, 12 - Subbase of graded crushed stone, 13 - Base course of cement stabilized crushed stone, 14 - Surface course, 15 - Crib beam, 16 - New Jersey guardrail, 17 - Drainage hole, 18 - Concrete cushion, 19 - Filter geotextile, 20 - Sand filling layer, 21 - Planting soil. Specific implementation mode

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0021] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0022] Refer to Figure 1 - Figure 3 ,

[0023] The high-performance roadbed structure of carbonaceous soft rock includes an isolation layer, a filling area of carbonaceous soft rock, an upper embankment, a roadbed and a road surface which are arranged in sequence from bottom to top;

[0024] I. Bottom isolation layer 1 of the embankment: Located above the foundation 11, it is used to prevent the migration of moisture caused by the rising of the groundwater level or the capillary water action to the filling area 2 of carbonaceous soft rock.

[0025] II. Filling area 2 of carbonaceous soft rock: Located above the bottom isolation layer 1 of the embankment, it is filled with carbonaceous soft rock in layers, and the filling position of carbonaceous soft rock is the lower embankment part. And a geogrid 8 and a composite geotextile 9 are fully paved on the top surface of the lower embankment.

[0026] III. Anti-seepage area 3: Located on the left and right sides of the filling area 2 of carbonaceous soft rock. Every time a preset thickness of carbonaceous soft rock is filled, the left and right side parts of the filling area 2 of carbonaceous soft rock are wrapped inside by using the geogrid 8 and the composite geotextile 9 to wrap upwards, so as to prevent rainfall and slope runoff from infiltrating into the filling area 2 of carbonaceous soft rock through the two side slopes.

[0027] IV. Upper embankment 4 and roadbed 5: The upper embankment 4 is located above the carbonaceous soft rock filling area 2 and the anti-seepage area 3. The roadbed 5 is located above the upper embankment 4.

[0028] V. Pavement 6: The pavement 6 is designed with a conventional graded crushed stone subbase 12 with a thickness of 20 cm, a cement stabilized crushed stone base course 13 with a thickness of 38 cm, and surface courses 14 including a lower surface course, a middle surface course, and an upper surface course with thicknesses of 8 cm, 6 cm, and 4 cm respectively. The cement stabilized crushed stone base course 13 is constructed in two layers.

[0029] VI. Median strip 7: A cast-in-place concrete sleeper beam 15 is provided at the bottom of the median strip 7. The sleeper beam 15 has a thickness of 20 cm. The sleeper beam 15 is located within the cement stabilized crushed stone base course 13, and the top surface of the sleeper beam 15 is flush with the top surface of the cement stabilized crushed stone base course 13. On the sleeper beam 15, a continuous concrete cushion layer 18 with a thickness of 20 cm is paved. On both sides of the continuous concrete cushion layer 18 are separate concrete Jersey barriers 16. The bottom surfaces of the continuous concrete cushion layer 18 and the Jersey barriers 16 are flush and are both located on the sleeper beam 15.

[0030] An anti-filter geotextile 19 is laid above the continuous concrete cushion layer 18 to wrap the sand filling layer 20 therein on all sides; then planting soil 21 is backfilled above it for planting anti-glare trees and greening plants. Drainage holes 17 are provided at the bottom of the Jersey barriers 16 to drain the water inside the median strip 7.

[0031] The construction method of the above-mentioned high-performance roadbed of carbonaceous soft rock for expressways is as follows:

[0032] It includes successively constructing an embankment bottom isolation layer, a lower embankment, an upper embankment, a roadbed, a pavement, and a median strip.

[0033] The specific construction method is as follows:

[0034] I. Embankment bottom isolation layer 1

[0035] An important property of carbonaceous soft rock is that it disintegrates and turns into mud when encountering water, and its strength is greatly reduced. Therefore, preventing carbonaceous soft rock from being soaked by water is an important aspect of improving the stability of the roadbed. On the basis of doing a good job in foundation treatment and ensuring the overall stability of the roadbed, the embankment bottom isolation layer 1 is clearly proposed in the present utility model, and hard and medium-hard permeable materials with good water stability such as gravel and slag are used.

[0036] The embankment bottom isolation layer 1 is horizontally filled in layers starting from the lowest point, with each layer having a thickness of no more than 50 cm. It must be filled horizontally along the transverse direction of the roadbed to ensure that the thickness a of the thinnest part of the embankment bottom isolation layer 1 is ≥ 0.5 m. When there are large changes in the longitudinal terrain of the roadbed and the bottom isolation layer cannot be filled at the same horizontal height longitudinally, steps must be set for lapping. The height of each step is not higher than 0.5 m, and the length of the step and the lapping length are greater than or equal to 3 m.

[0037] II. Lower embankment

[0038] 1. On the upper part of the bottom isolation layer 1 of the embankment, a geogrid 8 and a composite geotextile 9 are fully paved in sequence and fixed with U-shaped nails 10, and then the carbonaceous soft rock is filled above the composite geotextile 9. After filling 1 - 2 m thick carbonaceous soft rock, the geogrid 8 and the composite geotextile 9 on the upper part of the bottom isolation layer 1 are wrapped upwards to the top surface of the carbonaceous soft rock, and the wrapping width b≥1 m.

[0039] Then, the geogrid 8 and the composite geotextile 9 are laid on the left and right sides of the top surface of the carbonaceous soft rock in sequence, the laying width c≥3 m, and fixed with U-shaped nails 10. Then, 1 - 2 m thick carbonaceous soft rock is filled above the composite geotextile 9, and the previously laid geogrid 8 and composite geotextile 9 are wrapped, and the wrapping width b≥1 m. Subsequently, the geogrid 8 and the composite geotextile 9 are laid on the left and right sides of the top surface of the soft rock in sequence again, and the laying width c≥3 m. Repeat the above steps until the filling of the lower embankment is completed, and the carbonaceous soft rock filling area 2 of the lower embankment and the anti-seepage areas 3 on its left and right sides are formed.

[0040] 2. Particle size of carbonaceous soft rock filler and loose paving layer thickness

[0041] The excavation of carbonaceous soft rock generally can be carried out by cold excavation with an excavator. When direct excavation is difficult, blasting can be used. The maximum particle size of the carbonaceous soft rock filler should be controlled within 30 cm. The thickness of the compacted layer should not exceed 40 cm. When loading at the material yard, the coarse and fine materials of each truck should be consciously mixed to make the filler uniform and have a certain gradation.

[0042] 3. Paving and compaction

[0043] (1) When loading the first layer of carbonaceous soft rock, the heavy-duty truck should adopt the backward loading method, and the bulldozer should promptly level the material. The heavy-duty truck should drive on the leveled carbonaceous soft rock layer to avoid directly driving and rolling on the composite geotextile 9.

[0044] (2) During the filling process, the cross slope of the embankment top surface≥4% to ensure the lateral drainage capacity of the embankment top surface.

[0045] (3) Use a heavy roller with a self-weight≥26 t for compaction, adhere to the principle of static compaction first and then vibration compaction, and compaction from both sides to the middle first. The number of compaction passes is determined by the test road, and generally 3 - 4 passes back and forth can be considered as one pass.

[0046] (4) Pay attention to controlling the overlapping length and width during the filling of the transition section and the sectional filling. The joints of each section should be overlapped and compacted with each other, and the longitudinal overlapping length is more than 2 m.

[0047] 4. Compaction standard and quality control

[0048] The maximum particle size of the carbonaceous soft rock fill is generally several tens of centimeters, and the fill is mainly composed of coarse particles. The maximum particle size in the compaction test is 40 mm. Obviously, the proportion of the fill with a particle size less than 40 mm in the carbonaceous soft rock is not high. Therefore, the compaction test results cannot fully reflect the compaction characteristics of the carbonaceous soft rock fill. If the maximum dry density determined by this compaction test result is used as the standard dry density, the compaction degree obtained by the sand replacement method is likely to exceed 100%, losing the significance of evaluation. Therefore, the compaction degree index is not suitable for controlling the carbonaceous soft rock subgrade.

[0049] Regarding the large particle size of the carbonaceous soft rock, it is reasonable to refer to the quality control method of the rock-fill subgrade. That is, the compaction standard of the carbonaceous soft rock is determined through the test road, including: the thickness of the compaction layer, the maximum particle size, the rolling machinery, and the number of rolling passes, etc. The quality control is mainly based on the control of the construction process, and is combined with the control of the compaction settlement difference. Generally, the compaction settlement difference in the last two passes should be ≤ 3 mm.

[0050] 5. Anti-seepage area

[0051] (1) After filling 1 - 2 m thick carbonaceous soft rock, the subgrade slope is trimmed according to the designed slope ratio. Then, the reserved reverse-wrapped geogrid section and the composite geotextile section of the previous layer are wrapped upward along the trimmed slope, and at the same time, a new geogrid 8 is laid. The ends of the reverse-wrapped geogrid and the composite geotextile are straightened and flattened with the newly laid geogrid 8. After tensioning tightly, they are fixed to the carbonaceous soft rock below every 1 m using U-shaped nails 10. Subsequently, a new composite geotextile 9 is laid.

[0052] (2) The width c of the anti-seepage area 3 ≥ 3 m, and the reverse-wrapped width b ≥ 1 m.

[0053] (3) The geogrid 8 is selected as a bidirectional steel-plastic geogrid, and the composite geotextile 9 is a composite geomembrane of two fabrics and one membrane.

[0054] (4) The maximum particle size of the fill within 30 cm of the geosynthetics, namely the geogrid 8 and the composite geotextile 9, should not be greater than 10 cm, and the fill is carbonaceous soft rock. When the first layer of fill is paved on the composite geotextile 9 in the anti-seepage area 3, the truck should use the reverse loading method and should not directly roll on the composite geotextile 9.

[0055] (5) The subgrade slope should be covered with root soil within two days after the reverse wrapping of the geogrid 8 and the composite geotextile 9 to avoid exposure to the sun. The root soil grass seeds on the slope can be plants suitable for the local climate conditions.

[0056] (6) Filling speed

[0057] The carbonaceous soft rock subgrade should be filled and constructed quickly, and the construction should be completed before the rainy season arrives to provide a longer natural settlement time.

[0058] III. Upper embankment and roadbed

[0059] After the lower embankment is completed, a geogrid 8 and a composite geotextile 9 are successively laid on its top surface, and then the upper embankment 4 and the roadbed 5 are filled.

[0060] Generally, the CBR value of carbonaceous soft rock is between 8 and 10, just meeting the minimum requirements of the specification for fillers. However, as the connection part between the subgrade and the pavement, using carbonaceous soft rock as the roadbed filler, its strength standard is undoubtedly on the low side, which is not conducive to the stress distribution and transfer between the pavement and the subgrade. On the other hand, when using carbonaceous soft rock as the roadbed, it is also very difficult to meet the design requirements for the deflection index during the subgrade acceptance. The resilient modulus of the subgrade mainly depends on the roadbed and the upper embankment, and there is a good positive correlation between the resilient modulus and the filler CBR. Therefore, in order to ensure the resilient modulus of the subgrade, the CBR values of the roadbed and upper embankment fillers are increased. The lower embankment mainly plays a role in filling and has little influence on the resilient modulus of the subgrade, so the CBR of the carbonaceous soft rock used as the lower embankment filler is not adjusted.

[0061] Based on the above considerations, in order to ensure the high performance of the subgrade filled with carbonaceous soft rock, it is proposed that for expressways and first-class highways, the upper 1.5 m below the top surface of the upper embankment 4 and the roadbed 5 should be filled with hard graded crushed stones, gravels and other fillers with good water stability and high strength, and the minimum bearing ratio CBR of the filler for the upper embankment 4 should be ≥ 5, and the minimum bearing ratio CBR of the filler for the roadbed 5 should be ≥ 10. This is higher than the relevant regulations in the "Code for Design of Highway Subgrade" JTGD30-2015, which states that "for expressways and first-class highways, the minimum bearing ratio CBR of the upper roadbed filler should be ≥ 8, the minimum bearing ratio CBR of the lower roadbed filler should be ≥ 5, and the minimum bearing ratio CBR of the upper embankment filler should be ≥ 4".

[0062] The maximum particle size of the rock fill for the upper embankment 4 shall not exceed 15 cm, and that for the roadbed 5 shall not exceed 10 cm. The filler should have a certain gradation, and there should be no obvious concentration of coarse aggregate particles observed by the naked eye. The self-weight of the vibratory roller should be greater than or equal to 30 t, and the number of rolling passes should be no less than 6 times, with no wheel marks on the surface. The compaction thickness of the upper embankment 4 shall not exceed 40 cm, and the compaction thickness of the roadbed 5 shall not exceed 30 cm, and the compaction thickness of the last layer on the top surface of the roadbed 5 shall not be less than 10 cm. The pores on the top surface of the roadbed 5 should be filled and leveled with hard and medium-hard stone chips, and fine-grained soil should not be used for skin leveling. The compaction quality of the upper embankment 4 and the roadbed 5 is jointly controlled by construction process parameters and compaction settlement difference, and the compaction settlement difference in the last two passes should be ≤ 2 mm.

[0063] IV. Pavement

[0064] The road surface 6 is paved above the roadbed 5. The road surface 6 is designed with a conventional graded crushed stone subbase 12 with a thickness of 20 cm, a cement stabilized crushed stone base course 13 with a thickness of 38 cm, and a surface course 14 with a lower surface course, a middle surface course, and an upper surface course with thicknesses of 8 cm, 6 cm, and 4 cm respectively. Among them, the cement stabilized crushed stone base course 13 is paved in full width and constructed in two layers.

[0065] V. Median Strip

[0066] When the median strip 7 adopts a conventional corrugated beam guardrail, longitudinal drainage ditches, anti-seepage layers, catch basins, anti-seepage geotextiles, etc. are arranged inside it. The sleeves are usually pre-buried and installed by drilling. The drilling depths vary, and the drilling penetrates the surface course, and even penetrates the base course and subbase until the roadbed. In this way, rainwater is easily infiltrated along the pipes, penetrates through the roadbed and the upper embankment until the lower embankment, and then softens the filler of the lower embankment, carbonaceous soft rock. Therefore, a method of using a separated precast New Jersey guardrail 16 for the median strip 7 is proposed to completely seal the median strip 7 and prevent rainwater from infiltrating.

[0067] The cement stabilized crushed stone base course 13 is paved in full width and constructed in two layers. After the first layer of the cement stabilized crushed stone base course 13 is paved, a cast-in-place concrete sleeper beam 15 is constructed above it. The sleeper beam has a thickness of 20 cm and a concrete grade of C20. After the sleeper beam 15 reaches 75% of the design strength, the second layer of the cement stabilized crushed stone base course 13 on its left and right sides is paved in half width, and the top surface of the sleeper beam 15 is flush with that of the second layer of the cement stabilized crushed stone base course 13.

[0068] After the sleeper beam 15 reaches the design strength, the separated precast New Jersey guardrail 16 is installed. Drainage holes with a diameter of 2 cm and a slope rate of 2% are reserved at the bottom of the New Jersey guardrail 16 to ensure that the accumulated water inside the median strip 7 can be drained.

[0069] After the New Jersey guardrail 16 is installed, a concrete cushion layer 18 is constructed in a full-width paving manner above the New Jersey guardrail 16 and above the sleeper beam 15. The cushion layer has a thickness of 20 cm and a concrete grade of C20.

[0070] After the concrete cushion layer 18 reaches the design strength, an anti-filter geotextile 19 is laid above it, and then a sand filling layer 20 with a thickness of 30 - 40 cm is filled. After being compacted by rolling, the anti-filter geotextile 19 should wrap the sand filling layer 20 inside it on all sides.

[0071] Then, planting soil 21 is backfilled above the anti-filter geotextile 19 for planting anti-glare trees and greening plants.

[0072] VI. Subgrade Settlement Monitoring

[0073] During the subgrade filling period, a settlement monitoring system for the high-performance subgrade of carbonaceous soft rock should be constructed to conduct surface settlement monitoring of the subgrade. Observation points can be arranged in the center, left, and right sides of the subgrade to track the settlement and stability status of the subgrade in real time and provide reliable data support for the time node of pavement paving.

[0074] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A high-performance subgrade structure for carbonaceous soft rock on expressways, characterized in that It includes an isolation layer, a carbonaceous soft rock filling area, an upper embankment, a roadbed and a road surface which are arranged successively from bottom to top; Impervious zones are arranged on both sides of the carbonaceous soft rock filling area, and impervious layers are arranged successively in the impervious zones. Grooves are formed on the road surface, sleeper beams are arranged in the grooves, two sets of New Jersey guardrails are arranged above the sleeper beams, a concrete cushion layer, a sand filling layer and a planting soil layer from bottom to top are clamped between the two New Jersey guardrails, and an anti-filter geotextile is coated outside the sand filling layer.

2. The high-performance subgrade structure for carbonaceous soft rock on expressways according to claim 1, characterized in that, The impervious layer includes a composite geotextile and a geogrid, carbonaceous soft rock is coated in the impervious layer, and the composite geotextile and the geogrid in each impervious layer are connected by U-shaped nails.

3. A high-performance subgrade structure for carbonaceous soft rock on expressways according to claim 1, characterized in that, The road surface includes a graded crushed stone subbase, a cement stabilized crushed stone base course and a surface course, and the grooves are formed in the cement stabilized crushed stone base course and the surface course.

4. A high-performance subgrade structure for carbonaceous soft rock on expressways according to claim 3, characterized in that, The thickness of the graded crushed stone subbase is 15 - 25 cm, the thickness of the cement stabilized crushed stone base course is 35 - 40 cm, the surface course includes a bottom surface course, a middle surface course and an upper surface course, the thickness of the bottom surface course is 5 - 10 cm, the thickness of the middle surface course is 5 - 8 cm, and the thickness of the upper surface course is 3 - 5 cm.

5. A high-performance roadbed structure for carbonaceous soft rock on expressways according to claim 1, characterized in that, Drainage holes are formed in the New Jersey guardrail, the height of the drainage holes is higher than the height of the upper end face of the groove, the aperture of the drainage holes is greater than 2 cm, and the slope rate is 2 - 5%.

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