Highway subgrade slope plant fiber blanket integrated protection construction method

Abstract

The present application relates to the technical field of highway subgrade slope construction, especially to a highway subgrade slope plant fiber blanket integrated protection construction method, comprising the following steps: S1, simultaneously carrying out slope surface layering finishing and slope foot anti-seepage and flow guide layer paving operation within the scope of the slope; S2, segmentally lowering and spreading the double-layer composite fiber blanket coil along the slope, temporarily covering and positioning at the edge of the slope top after spreading in place; S3, carrying out anchoring operation at the fixed point of the middle and lower section of the slope surface, and punching anchoring parts along the positioning ring around the point; S4, simultaneously excavating planting holes at the anchoring point and inserting green plants or sowing seeds; S5, spraying equipment is used to spray and soak the fiber blanket in the whole area of the slope; S6, backfilling and compacting the plain soil in the area of the slope top shoulder, and the plain soil completely covers the overlapping edge of the fiber blanket on the slope top, the whole area of the blind drainage pipe and the drainage branch pipes. The present application forms an upper and lower closed loop water isolation and drainage structure by means of the double-layer straw fiber blanket interlayer free-slotting pre-buried longitudinal blind drainage pipe and the soft drainage branch pipe.

Description

Technical Field

[0001] This invention relates to the field of highway subgrade slope construction technology, and in particular to an integrated protection construction method for highway subgrade slopes using plant fiber blankets. Background Technology

[0002] Currently, the common construction sequence in the construction of plant fiber blankets for highway subgrade slopes is as follows: slope finishing and brushing, slope compaction and leveling, full laying of fiber blankets from top to bottom, installation of anchor nails to fix the blankets throughout the area, unified drilling and insertion of greening seedlings in the later stage, and finally independent completion of backfilling and sealing of the road shoulder edge.

[0003] However, this phased construction method has significant problems in mountainous highway construction conditions such as semi-excavation and semi-fill shady and water-retaining slopes, and roadbed slopes with abundant capillary water during the spring and summer rainy season.

[0004] On the one hand, the soil on the shady, waterlogged slope has been saturated and softened for a long time. The process of nailing and anchoring the entire area before planting cuttings will allow the anchor holes to directly penetrate the waterproof fiber layer of the fiber blanket, forming a capillary water channel from top to bottom. The groundwater on the slope will continuously seep out along the nail holes and wash away the humus in the blanket. This will not only cause the roots of the cuttings to rot from waterlogging and anaerobic conditions, but also weaken the gripping force of the soil around the anchor nails. Combined with the low-frequency resonance of the high-speed lane, it is very easy for a single point of anchor to loosen and for the entire surrounding fiber blanket to shift and slide.

[0005] On the other hand, the backfilling of the independent shoulder in the later stage of the slope makes it difficult to achieve a firm backfilling and sealing of the inner side of the fiber blanket overlap at the top of the slope. After the capillary water on the slope rises, it will accumulate in the interlayer between the blanket and the brushed slope surface, and cannot be quickly drained from the top of the slope. The water in the interlayer continues to soften the loose soil layer reserved in the early brushing. After the project is handed over, the soil base at the bottom of the blanket is easily hollowed out and the blanket at the top of the slope is layered and bulging. The cost of later operation and maintenance is much higher than the cost of conventional slope disease treatment.

[0006] Therefore, it is necessary to design an integrated protection construction method for highway subgrade slopes using plant fiber blankets that is highly adaptable. Summary of the Invention

[0007] To solve one of the above-mentioned technical problems, the present invention adopts the following technical solution: an integrated protection construction method for highway subgrade slopes using plant fiber blankets, comprising the following steps: S1, simultaneously carrying out slope surface layer finishing and slope toe seepage prevention and diversion layer laying operations within the slope area.

[0008] The shallow silt and loose gravel on the slope are removed in layers. The impermeable geotextile is continuously laid along the longitudinal direction of the slope at the toe. Positioning markers are inserted only at the pre-set seedling planting points on the slope. The elevation of the positioning markers and the layout of the drainage blind pipes to be buried on the slope top are completed simultaneously at the top of the slope.

[0009] S2. Two workers simultaneously pull the double-layer composite fiber blanket roll at the top of the slope and lay it down in sections along the slope. The bottom end of the fiber blanket overlaps and covers the surface of the impermeable geotextile at the toe of the slope. After it is laid in place, it is temporarily pressed and positioned at the edge of the top of the slope.

[0010] S3. Anchoring operations are carried out at fixed points in the middle and lower sections of the slope surface. Anchors are driven in along the positioning points. No anchors are installed in non-planted areas of the slope surface or in the sealing area of ​​the top of the slope.

[0011] S4. Simultaneously excavate planting holes at the anchoring points in the middle and lower sections of the slope and insert cuttings of green plants or sow grass seeds.

[0012] The upper interlayer of the double-layer fiber blanket at the top of the slope is lifted, and drainage blind pipes are pre-buried along the longitudinal direction of the slope. Several drainage branch pipes are connected at intervals on the outside of the drainage blind pipes. Each drainage branch pipe is led down the slope out of the upper interlayer and extends along the slope surface to the inside of the drainage ditch at the toe of the slope and above the seepage-proof guide layer. The lower end of the drainage branch pipe is covered with a filter end formed by reverse filter geotextile. After the pipeline is laid, the interlayer vegetation soil is backfilled, and the surface of the fiber blanket is covered and restored.

[0013] S5. Use a spraying device to spray and saturate the fiber blanket over the entire slope area. The spraying medium must evenly saturate the entire structure of the fiber blanket.

[0014] S6. Backfill the slope top and shoulder area with plain soil and compact it manually or with light mechanical static pressure. The plain soil should completely cover the edge of the fiber blanket slope top overlap, the drainage blind pipe and the entire area of ​​each diversion branch pipe.

[0015] Preferably, the specific steps of S1 are as follows: a1. Divide the roadbed slope into a surface treatment layer and a middle compaction layer, peel off the saturated soft soil with a thickness of 8cm to 15cm from the surface layer, and after the soil is peeled off, scrape the middle soil back and forth to level it. The slope deviation of the formed slope is controlled within the range of ±0.05.

[0016] a2. Following the progress of slope trimming, lay the impermeable geotextile in its entirety along the longitudinal direction of the slope. The longitudinal overlap width between two adjacent geotextiles is 30cm to 50cm. The bottom end of the geotextile extends completely to the inside of the drainage ditch at the toe of the slope. After the geotextile is laid, a complete impermeable and diverting layer is formed at the toe of the slope.

[0017] a3. After the seepage prevention and diversion layer is laid in place, position markers are inserted horizontally and vertically along the middle and lower sections of the slope. The horizontal spacing of the position markers is 1.2m to 2.0m, and the vertical spacing is 1.5m to 2.5m. The depth of the position markers in the soil is not less than 25cm.

[0018] The positioning markers can be the same as the layout stakes used during construction.

[0019] a4. After the positioning markers are set up, the vertical elevation of all positioning markers shall be uniformly calibrated, and the layout and positioning of the drainage blind pipe laying path and elevation at the top of the slope shall be completed simultaneously.

[0020] Preferably, S2 is executed after the S1 positioning benchmark elevation calibration and blind tube layout process is completed. The specific steps are as follows:

[0021] b1. Transfer the single roll of double-layer composite fiber blanket to the working surface at the top of the slope. Two workers are positioned on the left and right sides of the fiber blanket width and pull the roll down at a uniform speed. The longitudinal length of the slope surface is 6m to 10m in a single laying.

[0022] b2. During the pulling process, dynamically adjust the pulling force on both sides to avoid unilateral displacement of the fiber blanket and local wrinkle accumulation. After each section of roll material is laid down, manually sweep and press along the bottom surface of the blanket to level it. The overall gap between the blanket and the slope should be controlled within 12mm.

[0023] b3. When the roll material is lowered to the toe of the slope, the bottom edge of the lowered blanket is completely overlapped with the surface of the impermeable geotextile, and the overlap width is 25cm to 40cm. The bottom edge of the blanket does not penetrate into the drainage ditch at the toe of the slope.

[0024] b4. After the single-section fiber blanket is laid, temporary pressing and positioning are carried out at the edge of the slope top to prevent the blanket from sliding due to gravity. No temporary anchors are added in the middle and lower sections of the slope and the entire slope top. The permanent positioning of the blanket is completed after the subsequent anchoring process.

[0025] Preferably, S3 is executed after the S2 segmented carpet laying process is completed. The specific steps are as follows:

[0026] c1. Divide the slope into two independent working sections: the anchoring area in the middle and lower part of the slope and the edge pressing area at the top of the slope. Two construction teams work synchronously in the slope. The team in the middle and lower part of the slope reaches each positioning marker point from bottom to top along the slope surface, while the team at the top of the slope carries out edge preparation and advancement.

[0027] c2. After the team members arrive at the single positioning marker planting point, they will lay U-shaped anchor nails around the outer perimeter of the positioning marker. The number of anchor nails laid around the single positioning point is 3 to 5. The anchor nails are driven into the slope soil at an angle, with a depth of 30cm to 45cm. All the anchor nails will form a closed anchoring ring around the outside of the planting point.

[0028] c3. Anchors are installed only at the planting points corresponding to the positioning markers in the middle and lower sections. The top of the slope and other areas on the slope without positioning markers are not anchored at all, so as to preserve the waterproof fiber layer of the fiber blanket.

[0029] c4. The two processes of laying the fiber blanket and anchoring are carried out in parallel within the slope, and the anchoring work of the current section is started simultaneously as soon as the slope is laid; there is no need to wait for the entire section of fiber blanket to be laid before carrying out the anchoring construction.

[0030] Preferably, S4 is performed after the S3 circumferential anchoring process, and the specific steps are as follows:

[0031] d1. After the anchors are assembled to form a closed anchoring ring, a planting hole is excavated in the center of the anchoring ring. The diameter of the planting hole is 12cm to 20cm and the depth is 20cm to 30cm. The planting hole is then backfilled with mixed humus nutrient soil.

[0032] d2. After the nutrient soil is backfilled, insert green plant seedlings or sow grass seeds into the planting holes; at the same time, lift the surface layer of the double-layer fiber blanket on the top of the slope and lay drainage blind pipes in the interlayer.

[0033] d3. Drainage blind pipes are laid continuously in the longitudinal direction along the top of the slope. The axial overlap length of adjacent blind pipes is not less than 20cm. The water permeable holes of the pipes are uniformly arranged facing the slope soil side. Every 5m to 8m, a drainage branch pipe is connected from the main body of the blind pipe along the slope direction.

[0034] d4. After the drainage branch pipe is led out from the interlayer at the top of the slope, it is laid along the slope direction between the fiber blanket and the slope soil. The bottom end extends to the surface of the impermeable geotextile at the bottom of the slope and is guided to the drainage ditch at the bottom of the slope. The pipe laying path avoids the planting holes on the slope and is separated from the space of the anchor and the plant root system. There is no squeezing or puncture interference. The drainage branch pipe is connected with the impermeable drainage layer at the bottom of the slope to form a three-dimensional drainage channel.

[0035] Preferably, the specific steps of S5 are as follows: e1. Spraying operation is carried out by moving back and forth at a uniform speed along the slope surface from the top to the bottom of the slope. The duration of a single spraying operation on a single slope section is 12 min to 25 min. The spraying medium is room temperature clean water, and the single spraying volume per unit slope surface is controlled at 4 L / m. 2 ~9L / m 2 interval;

[0036] e2. Spraying operations are carried out in two intervals. The first spraying penetrates the straw fiber on the surface of the fiber blanket. After an interval of 30 minutes, a second spraying is carried out to ensure that the water penetrates to the surface soil of the slope below the blanket.

[0037] e3. After the spraying is completed, let it stand for 20 to 40 minutes. The moisture will help the dry straw fibers absorb water, swell, and entangle with each other, thus reducing the gap between the blanket and the base.

[0038] e4. Spraying operations cover the entire fiber blanket laying area. When encountering the overlap of the geotextile above the slope toe, extend the spraying time to ensure that the fibers in the overlap area are fully soaked and adhered.

[0039] Preferably, the specific steps of S6 are as follows: f1. Clean up the loose fibers, debris and sandbags that were temporarily pressed and positioned on the working surface of the slope top and shoulder in advance, select homogeneous plain soil as the backfill soil material, and lay the soil in layers with a single layer thickness of 10cm to 20cm.

[0040] f2. After the single layer of soil cover is laid, manual or light mechanical static compaction is carried out. The original soil is simultaneously covered downwards to the edge of the fiber blanket slope and the top area of ​​the drainage branch pipe. The horizontal width of the edge of the soil cover blanket is not less than 40cm. The outer side of the soil cover is smoothly connected to the roadbed and the shoulder of the roadway.

[0041] f3. After compaction, the top opening of the fiber blanket interlayer is sealed to block the infiltration path of surface rainwater along the interlayer. The compaction operation is carried out only on the surface of the top layer, and the compaction process does not directly compact the main body of the slope fiber blanket.

[0042] f4. The backfill should avoid disturbing the pre-embedded drainage blind pipes inside the interlayer, as well as the backfill at the top of the slope, the longitudinal main drainage blind pipes in the interlayer, the drainage branch pipes on the slope surface, the double-layer fiber blanket on the slope surface, and the impermeable geotextile at the toe of the slope, which together form a continuous closed drainage protection structure that runs from the top of the slope to the toe of the slope.

[0043] Preferably, the fiber blanket used for paving the slope is a double-layer straw fiber composite mesh blanket;

[0044] The seepage-proof and diversion layer at the slope toe is made of short-fiber geotextile with a unit area mass range of 300g / m². 2 ~400g / m 2 ;

[0045] U-shaped low-carbon steel anchors are used as anchoring components, with the diameter of the anchor rod ranging from 4mm to 6mm.

[0046] For drainage blind pipes, PE porous corrugated pipes are selected, with the outer diameter of the pipe material ranging from 50mm to 80mm and the diameter of the water-permeable holes in the pipe wall ranging from 5mm to 8mm.

[0047] Flexible permeable pipes are selected for drainage branch pipes, with a diameter ranging from 15mm to 25mm.

[0048] Preferably, the longitudinal construction layout and material transfer for the entire slope are planned according to the following steps:

[0049] Construction is carried out in sections along the longitudinal direction of the slope, with each section having a longitudinal length of 6m to 10m. Each section simultaneously and in parallel initiates its own internal S1 base surface repair and seepage prevention paving process.

[0050] The roll material transport vehicles are uniformly parked at the fixed unloading points at the toe of the slope along the entire line. The fiber blanket rolls are linearly and centrally stacked along the toe of the slope and manually carried to the corresponding section of the slope top working surface. No large amount of roll material or anchoring material is piled up at the top of each section of the slope.

[0051] Each section of the slope top has a complete and continuous working surface reserved to simultaneously meet the operational space requirements for lifting the pre-embedded drainage blind pipes in the interlayer and covering and sealing the edges with soil.

[0052] Each section follows a fixed sequence of procedures from top to bottom, while construction proceeds in an inter-section, sequential manner. The overall process avoids material transfer occupying the work surface or work stoppages, making it suitable for long-distance continuous protection of roadbed slopes in the field.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0054] 1. This invention utilizes a double-layer straw fiber blanket interlayer with pre-embedded longitudinal drainage blind pipes without trenching, combined with segmented flexible drainage branch pipes that overlap but do not puncture the impermeable layer, and a 300-400g / m² continuous impermeable guiding layer to form an upper and lower closed-loop water-proof drainage structure; at the same time, only a small number of U-shaped anchor nails are deployed around the seedling planting points in the middle and lower sections of the slope, which greatly reduces the number of seepage holes that puncture the slope, combined with the sealing of anchor holes, the full coverage of the slope top with plain soil to seal the seepage openings in the interlayer, and the multiple seepage control structures of the 25-40cm overlaid impermeable cloth at the bottom of the blanket.

[0055] Unlike conventional slope protection, drainage, and seepage prevention processes that are fragmented and require dense anchoring across the entire slope, this method can guide water flow in layers from the road shoulder and capillary seepage on the slope surface. It avoids continuous rainwater infiltration of soft and weak interlayers, significantly reducing the risk of shallow slope collapse and soil softening and instability. It is suitable for the continuous seepage prevention and water diversion requirements of long-line highway slopes with a length of kilometers.

[0056] 2. This invention limits the standardized longitudinal segmented synchronous start of the base surface repair and seepage prevention paving process to 6-10m. The process within the segment is sequential, and the process between segments is carried out in a cross-flow manner. The fiber blanket is pulled down synchronously and at a uniform speed by two workers at the top of the slope throughout the process, which prevents workers from dragging down the slope, leveling and trampling on the saturated and soft roadbed, which would cause potholes, cracks and secondary seepage channels on the slope. The materials are unloaded at a fixed point at the foot of the slope and transported manually over short distances. There is no large amount of load on the top of the slope to avoid heavy pressure and settlement that would damage the repaired and shaped slope.

[0057] The entire construction organization does not require waiting for the completion of a single section before starting the next process. Multi-segment synchronous operation greatly shortens the total construction cycle of long-distance slopes in the field. At the same time, it protects the integrity of the slope base throughout the construction process and solves the inherent defects of slope seepage and slippage induced by conventional processes such as trampling and loading.

[0058] 3. This invention only excavates planting holes in the center of the closed anchoring ring. The outer anchors enclose and support the planting soil to prevent the holes from collapsing, leaving a cavity for complete root growth. This avoids the anchors cutting or squeezing the main roots of the seedlings, meeting the requirements for short-term vegetation full coverage and slope stabilization for 2-3 months. The permeable holes of the PE multi-hole corrugated pipe at the top of the slope are oriented towards the soil, and the drainage branch pipes go around the planting holes and anchors throughout the entire process. The pipes do not squeeze or interfere with the green plants or anchoring components. The ends of the branch pipes are covered with a reverse filter structure, making it difficult for fine particles of soft soil and straw fibers to enter the pipes and block the drainage channels. Layered gradient spraying promotes the straw fibers to absorb water, expand, and entangle, reducing the space gap of the blanket base and improving the anti-slip ability. Relying on the ecological reinforcement layer formed by the vegetation roots in the later stage, it achieves a seamless connection between the early stage of drainage and seepage prevention engineering protection and the later stage of long-term soil stabilization protection by vegetation roots. It overcomes the multiple problems of conventional processes such as mutual interference between planting, drainage, and anchoring, easy pipe clogging, and limited vegetation growth.

[0059] 4. This invention specifically limits the range of materials used in a complete set, including double-layer fiber blankets, geotextiles of specific weights, small-diameter anchor nails, and soft and hard drainage pipes of different specifications. By matching the specifications of the materials, it achieves less drilling and high impermeability. The slope top is covered with soil using only manual or light mechanical static pressure, and heavy rolling of the flexible drainage pipes in the interlayer is strictly prohibited to avoid flattening and bending of the pipes. The soil cover width at the slope top is not less than 40cm to completely seal the opening of the interlayer, forming a permanent waterproof seal to replace the conventional dense anchor nails at the slope top, and continuously reducing vertical seepage channels.

[0060] The entire solution eliminates the need for frequent dredging and unblocking of drainage pipes and repair of seepage and damage to slopes. The material selection takes into account both protective performance and project cost. After construction, the slope drainage and seepage prevention structure has a longer service life, significantly reducing the investment in later repair, maintenance and operation of highway slopes. Attached Figure Description

[0061] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or components are generally identified by similar reference numerals. In the drawings, the elements or components are not necessarily drawn to scale.

[0062] Figure 1 This is a process flow diagram of the construction method of the present invention.

[0063] Figure 2 This is a schematic diagram of the slope cross-sectional structure after the construction of this invention.

[0064] Figure 3 for Figure 2 A magnified schematic diagram of part A in the middle.

[0065] Figure 4 for Figure 2 A magnified schematic diagram of part B in the middle section.

[0066] Figure 5 This is a schematic diagram of the planting holes and the arrangement of each anchor in this invention.

[0067] In the diagram, 1. Slope; 2. Roadbed; 3. Drainage ditch; 4. Blind pipe; 5. Drainage branch pipe; 6. Geotextile; 7. Fiber blanket; 8. Anchor; 9. Planting hole; 10. Plain soil; 11. Positioning marker; A. Local area at the top of the slope; B. Local area at the toe of the slope. Detailed Implementation

[0068] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore merely examples and should not be used to limit the scope of protection of the present invention. The specific structure of the present invention is as follows: Figures 1-5 As shown in the image.

[0069] Example 1: In order to make the technical solution of the present invention clearer, the present invention will now be further described. The construction method of integrated protection of highway subgrade slope with plant fiber blanket includes the following steps: S1, simultaneously carry out slope surface layer finishing and slope toe seepage prevention and diversion layer laying operations within the slope range.

[0070] The shallow silt and loose gravel on the slope are removed in layers. A seepage-proof geotextile is continuously laid along the longitudinal direction of the slope at the toe. Positioning markers are inserted only at the pre-set seedling planting points on the slope. The elevation of the positioning markers and the layout of the drainage blind pipes to be buried on the top of the slope are completed simultaneously at the top of the slope.

[0071] This invention is specifically designed for the complex working conditions of highway subgrade slopes in long-distance mountainous areas and suburban interchange sections. These scenarios present multiple overlapping pain points that existing conventional slope protection techniques cannot simultaneously address. The unique characteristics of these scenarios are reflected in four aspects: First, the subgrade fill soil often contains shallow saturated silty interlayers, and capillary water continuously seeps upwards during the rainy season, causing soil softening and fiber blanket delamination and slippage on conventional slopes without seepage prevention. Second, the slopes extend longitudinally for hundreds to thousands of meters, and traditional segmented trenching and drainage pipe laying will repeatedly disturb the formed slope surface. Material transportation and overlapping procedures during long-distance field construction can easily cause delays in the construction period. Third, the slopes simultaneously face two sources of rainwater erosion: vertical impact splash erosion from the slope surface and downhill scouring from the top and shoulder of the slope. A single fiber blanket buffer or a single slope toe drainage ditch cannot simultaneously reduce the erosion energy of both types of erosion. Fourth, highway slopes have the dual requirements of short-term construction and protection as well as long-term ecological soil stabilization through vegetation. Conventional techniques either only focus on temporary erosion prevention or only emphasize later planting, lacking an integrated structure that connects the two.

[0072] In the S1 stage, the silt and soft soil on the slope surface are cleared and the single-layer impermeable geotextile is laid horizontally at the toe of the slope. The longitudinal drainage ditch along the outer edge of the impermeable geotextile forms the end drainage receiving base. The slope top is laid out to determine the laying path of the longitudinal drainage blind pipe in the interlayer. The blind pipe is buried in the upper interlayer of the double-layer plant fiber blanket. Multiple drainage branch pipes are laid at intervals along the longitudinal direction. The drainage branch pipes extend downwards along the slope surface, with the end of the branch pipe protruding horizontally for about 5cm. The pipe opening is perpendicular to the road width direction, and the bottom of the pipe is stably abutted against the surface of the impermeable geotextile. The pipe does not puncture or bury inside the impermeable geotextile.

[0073] The construction design of this invention can better cope with rainfall conditions. It is mainly divided into two-stage drainage process: rainwater falling vertically from high altitude onto the slope is first intercepted and buffered by the pores of the double-layer plant fiber blanket, dissipating the splashing kinetic energy of the raindrops. The slope seepage water accumulated in the blanket flows into each drainage branch pipe along the bottom layer of the blanket. Most of the surface runoff collected from the top of the slope, the shoulder, and the mountain is collected into the interlayer longitudinal drainage blind pipe, and then distributed to each slope drainage branch pipe. Both types of water are uniformly discharged from the branch pipe end of the horizontally exposed lower branch pipe to the surface of the impermeable geotextile below. The water flow flows longitudinally along the horizontal impermeable fabric and is collected in the outer matching drainage ditch for centralized discharge within the slope area.

[0074] On the slope, only the planting points of the seedlings positioned by the positioning markers are locally punctured and anchored, and the anchor holes are sealed and filled to prevent seepage, further reducing rainwater seepage into the shallow silty soil of the slope through the anchor puncture holes. Specifically, after the anchor nails penetrate the double-layered plant fiber blanket and are inserted into the subgrade soil to complete the fixation, modified clay cementitious material is immediately used to fill the gaps between the anchor nails, the fiber blanket, and the soil, forming a ring-shaped waterproof sealing layer at the puncture point, blocking the path of rainwater seepage longitudinally down the nail hole. Apart from the planting anchor points, there are no other puncture holes on the entire slope. The double-layered fiber blanket completely and continuously covers the slope, maximizing the retention of the fiber blanket's own buffering and waterproofing capacity, preventing large areas of anchor holes from forming dense seepage channels that continuously infiltrate the silty interlayer of the subgrade, and working in conjunction with the waterproof barrier of the lower horizontal impermeable geotextile. The remaining large areas of fiber blanket... Complete and continuous, the anti-slip fixation is achieved by the self-adhesion process of the blanket and the self-consolidation of straw after spraying and curing. Seedlings are planted at the planting points in the later stage. After 2-3 months, low vegetation covers the slope. In the short term, the fiber blanket and three-dimensional water-draining structure resist rainwater erosion. In the long term, the roots of the interwoven vegetation entwine and consolidate the roadbed soil, forming an integrated protective closed loop that seamlessly connects engineering drainage and seepage prevention with ecological soil stabilization. The whole structure does not require additional trenching to damage the slope soil. Long-distance segmented construction can carry out three processes at the same time: slope trimming, seepage prevention paving, and pipeline layout, which is highly adaptable to the field construction conditions of long-distance highway slopes.

[0075] It should be further explained that, for the special scenarios of soft soil, long continuous slopes, and dual rainwater erosion on highway subgrade slopes, this solution abandons the traditional method of separately trenching and burying slope drainage pipes. Instead, it utilizes a double-layer plant fiber blanket interlayer as a natural carrier for laying drainage blind pipes, constructing a closed drainage chain that runs from top to bottom. This better achieves unified collection and drainage of water seepage from the slope surface and water collected at the top of the slope, solving the problem of disturbing the soft subgrade soil caused by multiple trenching on long slopes. Furthermore, by controlling the installation of anchors only at the seedling planting positioning markers, the solution addresses this issue. The reinforcement system preserves the fiber blanket waterproof buffer layer on a large area of ​​slope, and simultaneously matches the waterproof function of the bottom horizontal impermeable geotextile. This avoids the defects of forming rainwater infiltration channels and softening the silty roadbed soil by creating puncture holes throughout the area, while taking into account both the anti-slip fixation of the fiber blanket and the seepage prevention of the slope. The process of pipeline diversion, seepage prevention paving, fiber blanket laying and seedling planting is integrated, so that the three-dimensional drainage structure provides erosion protection for the bare slope surface in the early stage without vegetation, and the root system of vegetation in the later stage reinforces the slope soil in the reverse, forming a protection system with short-term engineering protection and long-term ecological stability.

[0076] It should be noted that in this solution, the holes left after the positioning markers are removed can be directly cleared and backfilled through the excavation of the planting holes, thus avoiding the creation of independent vertical seepage channels on the slope. This perfectly matches the invention's comprehensive control of puncture holes and reduction of the risk of capillary seepage in saturated silty soft soil. No additional separate sealing process for the marker holes is required; the four processes of anchoring, removing the markers, planting holes, and backfilling are completed simultaneously, simplifying the on-site construction process for long slopes and shortening the segmented construction period.

[0077] Furthermore, existing conventional slope drainage systems only have separate drainage ditches at the toe of the slope, which can only divert a small amount of surface runoff. There are no dedicated collection channels for water collected at the top of the slope or for capillary seepage within the geotextile. Conventional geotextile is only laid at the toe of the slope without supporting upper-layer diversion pipes, so rainwater still seeps down through anchor holes across the entire slope and comes into contact with the soft soil. Unlike traditional solutions, this solution uses layered blind pipes and slope diversion branch pipes to collect rainwater in layers. The water flow only collects laterally on the surface of the geotextile, and the pipes do not puncture the geotextile. This significantly reduces or eliminates rainwater seepage into the soft soil layer of the roadbed. The synergistic effect of layered diversion through branch pipes and the seepage reduction and seepage prevention of the geotextile cannot be achieved by simply laying drainage pipes or geotextile alone.

[0078] Secondly, this solution avoids the continuous soil weakening risks caused by conventional anchoring and puncture techniques, significantly reducing the risk of later landslides and collapses in soft soil slopes. Conventional slope protection requires anchors densely distributed across the entire slope surface to fix the fiber blanket, and the numerous holes create continuous seepage channels. During the rainy season, rainwater continuously infiltrates the shallow soft interlayer through these holes, which can induce shallow landslides in the long run. This solution relies on the interlayer drainage structure to quickly drain the water from the blanket surface, and combined with precise spraying maintenance, it allows the straw fiber blanket to self-consolidate and firmly adhere to the slope surface. Only a few punctures are required at the planting points, reducing rainwater infiltration channels. This solution is specifically designed to eliminate deep landslide risks in soft soil slopes of highway subgrades, achieving a composite protection effect of reducing the number of punctures, spraying to solidify the blanket, and simultaneously protecting the soft subgrade. This is not available in existing conventional slope protection techniques.

[0079] Furthermore, this invention can be adapted to the synchronous and parallel construction of long-distance highway slopes spanning thousands of meters, shortening the construction period in the field by more than 30%, and solving the problems of multiple processes interfering with each other and repeated material transfers for long-distance slopes. Traditional slope protection processes are carried out sequentially, generally by first trimming the slope surface, then trenching and burying pipes, then laying the impermeable cloth, and finally laying the fiber blanket. When constructing long-distance slopes in sections, each section requires repeated trenching operations, multiple visits to the site to disturb the formed roadbed, and time-consuming and labor-intensive material transfers. In this solution, the three processes of cleaning the silty and soft soil on the slope surface, laying the impermeable cloth at the slope toe, and laying out the pipeline at the slope top are carried out simultaneously in the S1 stage. There is no need to trench and bury drainage pipes separately. The pipeline channels are reserved in the fiber blanket interlayer, and long-distance multi-segment operations can be carried out synchronously and in a continuous manner, which greatly reduces the frequency of repeated visits by machinery and personnel. This optimization of the construction period for parallel construction of long-distance slopes is a differentiated engineering effect derived from the special scenario of highway long-distance roadbed slopes. Ordinary short slope conventional slope protection does not have this requirement.

[0080] The blanket rolls are laid down in sections along the slope, and the bottom of the fiber blanket overlaps to cover the surface of the impermeable geotextile at the toe of the slope. After being laid in place, temporary pressing and positioning are carried out at the edge of the top of the slope.

[0081] Segmented laying along the slope can adapt to the on-site construction conditions of steep slopes on long highway subgrades. Laying a whole long blanket at once is prone to wrinkles, local tearing, and bottom suspension and slope fall-off problems. Segmented laying allows a single person to use simple equipment to gently release the roll material, accurately fit the repaired uneven slope surface, eliminate the gap between the blanket and the soil, avoid water accumulation in the hollow area to form local seepage pits, and reduce the lateral convergence of rainwater under the blanket to erode the soft subgrade from the source.

[0082] Segmented laying allows for simultaneous construction of the slope toe impermeable fabric and the pre-embedding of drainage branch pipes, eliminating the need to wait for the entire slope to be completed before laying the carpet. This enables multiple processes to proceed in parallel, shortening the construction cycle for long slopes. The segmented joints can precisely align with the positions of the longitudinal drainage branch pipes, with the bottom of each segment of the carpet corresponding exactly to a set of exposed horizontal branch pipe ends. This ensures that all seepage water within the carpet flows directly into the branch pipes, preventing the segmented gaps from becoming unorganized seepage channels.

[0083] The fiber blanket overlaps at the bottom, covering the surface of the geotextile at the slope toe, forming a continuous, sealed, waterproof system with a fiber buffer layer on the slope and a horizontal waterproof layer at the bottom, eliminating any exposed soil gaps. Rainwater from high altitudes seeping through the fiber blanket, along with capillary water collected longitudinally within the blanket, flows along the bottom surface of the blanket to the overlapping area, landing directly on the horizontal surface of the geotextile. It does not seep into the soft soil layer of the slope subgrade through the gaps between the blanket and the geotextile. In conventional methods, the fiber blanket and geotextile are laid separately without overlap, leaving gaps in the soil. Rainwater can seep down these gaps, softening the shallow soft soil interlayer. This overlapping structure directly seals this weak seepage zone. The overlapping area restricts slope seepage to flow only laterally towards the longitudinal drainage ditch outside the geotextile, preventing water from overflowing from the blanket bottom into the outer slope soil. This achieves unified collection and drainage of rainwater from two sources, forming a complete and continuous drainage chain with the help of diversion branch pipes.

[0084] To mitigate the risk of stress slippage at the toe of the slope, which is the area where soil stress is concentrated and shallow landslides are most likely to occur, the fiber blanket overlaps and presses down on the impermeable cloth at the bottom. The two restrain and limit each other, preventing the impermeable cloth from curling or shifting due to water flow impact. At the same time, the bottom of the fiber blanket relies on the overlapping layer to form a downward pressing friction force, which counteracts the slope sliding force and helps to improve the overall anti-slip stability of the slope.

[0085] S2. Two workers simultaneously pull the double-layer composite fiber blanket roll at the top of the slope and lay it down in sections along the slope. The bottom end of the fiber blanket overlaps and covers the surface of the impermeable geotextile at the toe of the slope. After it is laid in place, it is temporarily pressed and positioned at the edge of the top of the slope.

[0086] The slope of the mountain highway subgrade has a large slope ratio, the soil is loose and easily disturbed after the slope is trimmed, the seepage prevention cloth at the toe of the slope is laid horizontally in one piece, multiple sets of longitudinal horizontal outcrop drainage branch pipes are embedded in the slope, and the shallow soil of the slope is saturated with water and is very easy to collapse when it encounters water. Under these conditions, it is strictly forbidden for workers to step on the slope, it is strictly forbidden to drive temporary anchors on the slope, and it is strictly forbidden to leave gaps between the blanket and the seepage prevention cloth for water seepage. Conventional slope human-machine cooperation, slope lowering, full-area anchor fixing, and pressure-type overlapping process are completely unsuitable.

[0087] This step involves only two personnel stationed at the top of the slope to synchronously and uniformly lower the roll material, with zero foot traffic on the slope. This protects the original soil structure of the already trimmed, soft, and silty slope, preventing uneven compaction and secondary loosening and cracking of the soil. The roll is lowered in fixed-length segments along the slope, with each segment precisely matching the vertical spacing between adjacent drainage branch pipes. This ensures the double-layer fiber blanket completely encloses the longitudinal blind pipes, and the blanket bottom adheres to the drainage branch pipe body on the slope. This allows all seepage water from the slope and water collected in the blind pipes to flow into the branch pipes, with the horizontal outlet at the branch pipe end directly draining to the top of the lower impermeable fabric. Strict adherence to the rule that the bottom of the double-layer fiber blanket overlaps the surface of the impermeable geotextile from top to bottom is maintained, forming an overlay-type water-stopping structure. The seams between the bottom of the blanket and the impermeable fabric are sealed to prevent water from seeping directly into the roadbed soil. The blanket is fixed only by the soil at the top edge of the slope and the temporary pressing of the upper end of the roll with gravel. No temporary anchor nails are added to the slope body or toe. Combined with the early partial puncture at the planting point and the sealing of the anchor hole for seepage prevention, the overall integrity of the double-layer fiber blanket is maximized. The blanket's buffering, energy dissipation, water-proofing and seepage-blocking capabilities are preserved. During the construction stage, the friction of the pressing at the top of the slope and the friction of the overlapping pressing at the toe counteract the shear force of the slope. The blanket can be stabilized without puncturing the slope surface, ensuring that the three-dimensional drainage channel does not deform or shift in the early stage, until the slope top is permanently covered with soil to stabilize the edge and the slope vegetation takes root and stabilizes the soil, completing the full cycle of protection.

[0088] In addition, the overlap of the blanket-pressed cloth to seal the drainage end gaps is matched with the whole set of through drainage structure to guide the drainage flow; thirdly, all temporary anchoring puncture points on the slope are cancelled, and only the top of the slope is temporarily covered and limited, which, together with the overall minimal puncture design, reduces the number of seepage holes from the source of construction.

[0089] Soft, silted slopes immediately develop pits and cracks upon being stepped on, allowing rainwater to seep down and trigger shallow landslides. By covering the fiber blanket with overlapping impermeable fabric and matching the branch pipe locations in sections, seamless water control at the drainage ends is achieved. This method differs from the conventional water-stopping function of geotextile overlaps; the precise overlapping in this section allows for one-to-one adaptation to each group of exposed horizontal branch pipes, ensuring that all water from the branch pipes falls onto the impermeable fabric at the overlap surface. The lower outer edge of the impermeable fabric better guides the water flow to the drainage ditch, directing it into the outer drainage ditch. By relying on temporary unilateral pressing of the blanket at the top of the slope for bidirectional reinforcement, all temporary anchors on the slope are eliminated, significantly reducing the number of manually drilled seepage holes on the slope. This solution combines the downward friction of the blanket pressing at the bottom and the constraint force of the pressing at the top of the slope to bidirectionally counteract the slope's downward force, achieving stability of the blanket without sacrificing the integrity of the slope's impermeability.

[0090] S3. Anchoring operations are carried out at fixed points in the middle and lower sections of the slope surface. Anchors are driven into the positioning points. No anchors are installed in non-planted areas of the slope surface or in the sealing area of ​​the top of the slope.

[0091] The planting area is the area surrounding the pre-marked points on the slope that will be used for sowing grass seeds or planting slope protection seedlings. Anchors are only installed around this area to fix the double-layer composite fiber blanket, leaving space for the growth of vegetation roots. No puncture anchors are installed in non-planting areas where there is no vegetation planting plan on the slope or at the top edge of the slope, so as to minimize the risk of puncturing and damaging the seepage-proof geotextile at the toe of the slope and the seepage-proof structure of the slope soil.

[0092] Unlike typical hard slopes and dry soil slopes on highways, this slope features a complete and interconnected drainage system. Longitudinal drainage blind pipes are pre-embedded in the slope top interlayer, and multiple sets of horizontal drainage branches with overlapping impermeable fabric at the bottom are longitudinally arranged on the slope surface. The pipes are laid flush with the fiber blanket interlayer throughout. Perforated anchors throughout the entire area can easily puncture the pipes, sever the drainage cavities, and disrupt the complete drainage path from top to bottom. The shallow layer of the slope is naturally soft and saturated fill with capillary water. Even unnecessarily punctured holes can form permanent vertical seepage channels. During the rainy season, rainwater seeps down through the anchor holes, continuously softening the roadbed fill, easily inducing shallow slope shear slippage and localized collapse. This design, based on the previous slope stress patterns, shows minimal sliding shear force in the upper section and the slope top sealing area. The bidirectional friction of the temporary overlay at the S2 slope top and the overlapping impermeable fabric under the fiber blanket at the slope toe is sufficient to stabilize the slope. The carpet section requires no anchoring. Since the shear force is greatest in the middle and lower sections of the slope, and the carpet is prone to slippage, anchoring is only carried out at pre-set positioning points in the middle and lower sections. The conventional method of directly anchoring the seedlings in the center is abandoned; instead, anchors are driven in a ring around the positioning points, enclosing the planting area with a central cavity for soil growth. This ensures the grass and seedling roots can grow freely vertically downwards and radially outwards. A strict no-anchoring zone is defined across the entire slope, with zero punctures and zero anchor holes in non-planted bare slope areas and areas sealed by blind pipes at the top. This preserves the drainage space of the blind pipes at the top, ensuring all water collected at the top flows into them. It also maintains the overall water-resistant integrity of the double-layer fiber carpet, preventing unnecessary anchor holes from connecting surface rainwater to the bottom soft soil layer. Only a small amount of ring-shaped anchoring is used to distribute the sliding force in the middle and lower sections.

[0093] Instead of the conventional practice of drilling and anchoring at the center of the planting site, we adopted an outer perimeter anchoring method, which effectively reduces the cutting and squeezing of the main root system by the anchor and accelerates the soil fixation cycle of the plant roots.

[0094] Conventional slope protection anchoring involves directly installing anchors at the planting center. When roots come into contact with the hard anchors, they may branch, rot, or fail to establish sufficient root depth. Within a short period of two months, the vegetation cannot achieve the required soil stabilization strength. This solution, however, anchors around the perimeter, preserving the original soil pores at the planting center. There are no hard objects that obstruct root growth, making it suitable for rapid deep root stabilization of short-term vegetation.

[0095] S4. Simultaneously excavate planting holes at the anchoring points in the middle and lower sections of the slope and insert cuttings of green plants or sow grass seeds.

[0096] The upper interlayer of the double-layer fiber blanket at the top of the slope is lifted, and drainage blind pipes are pre-buried along the longitudinal direction of the slope. Several drainage branch pipes are connected at intervals on the outside of the drainage blind pipes. Each drainage branch pipe is led down the slope out of the upper interlayer and extends along the slope surface to the inside of the drainage ditch at the toe of the slope and above the seepage-proof guide layer. The lower end of the drainage branch pipe is covered with a filter end formed by reverse filter geotextile. After the pipeline is laid, the interlayer vegetation soil is backfilled, and the surface of the fiber blanket is covered and restored.

[0097] It should be noted that the longitudinal direction of the slope refers to the direction along which it extends from the road, parallel to the direction of traffic. In other words, the road is a long linear shape, and the longitudinal direction of the roadbed slope is the long line that extends forward along the road.

[0098] The continuous laying of impermeable geotextile along the longitudinal direction of the slope toe refers to laying a continuous impermeable fabric along the long direction of the road at the bottom of the slope, from beginning to end.

[0099] The transverse slope refers to the direction of slope inclination from the top of the slope down to the bottom of the slope, perpendicular to the direction of the road (i.e., the direction of going up or down the slope).

[0100] The highway has a long, linear structure with slopes extending for kilometers. The longitudinal water volume along the shoulders is large and uniform, making single-point drainage components insufficient to manage the longitudinal runoff. Therefore, a longitudinally continuous drainage system is necessary to accommodate the linear water flow. Secondly, capillary water in the shallow, soft fill of the roadbed continuously rises longitudinally, resulting in uniform seepage across the entire slope. Therefore, diversion branches must be laid along the transverse slope, and the pipe openings must not puncture the longitudinally impermeable geotextile at the slope toe to prevent longitudinal seepage erosion of the roadbed. Thirdly, the project has a short protection period, requiring drainage construction and vegetation planting to be carried out simultaneously. This ensures that 2-3 month old vegetation and drainage structures are formed concurrently; conventional phased construction cannot meet the time requirements. This solution allows for the early formation of S3. In the middle and lower sections, planting holes are directly excavated in situ around the anchoring points for planting grass and seedlings. The anchoring enclosure cavity serves as the planting space, eliminating the need for secondary disturbance to the slope soil. This allows for synchronous construction of anchoring and planting points, reducing secondary excavation disturbance to the slope. The double-layer fiber blanket with its natural hollow interlayer serves as the pre-embedded cavity, eliminating the need for trenching or slope breaking. Simply lift the upper layer of the blanket at the top of the slope to pre-embed drainage blind pipes parallel to the longitudinal direction of the road, conforming to the road alignment and collecting water along the road. The blind pipes are connected to transverse slope-direction drainage branch pipes at intervals on the outside. The branch pipes are entirely contained within the double-layer blanket interlayer and extend down the slope, ending only above the longitudinal impermeable fabric at the toe of the slope and inside the drainage ditch. The impermeable fabric at the toe of the slope is not pierced or cut throughout the entire process.

[0101] Optionally, the lower end of the branch pipe is specially wrapped with a reverse filter geotextile to form an integrated filter end, preventing slope mud and sand and carpet fibers from entering the pipe and clogging it. After the pipe is laid, the interlayer of vegetation soil suitable for vegetation growth is backfilled to restore the closed double-layer fiber carpet, ultimately forming an integrated linkage system in which: the longitudinal blind pipe along the road collects water from the shoulder, the transverse branch pipe on the slope collects water seepage from the carpet, the filtered water from the branch pipe is discharged to the surface of the longitudinal impermeable cloth, the water flow flows into the longitudinal drainage ditch along the impermeable cloth, and the anchoring points simultaneously cultivate the root system of vegetation.

[0102] S5. Use a spraying device to spray and saturate the fiber blanket over the entire slope area. The spraying medium must evenly saturate the entire structure of the fiber blanket.

[0103] This solution uses a double-layer hollow fiber blanket as the natural carrier for laying drainage blind pipes. The interlayer is backfilled with vegetation soil. The blanket, the interlayer backfill, and the bottom slope soil form a multi-layered composite structure. If only the surface is locally watered, the water cannot penetrate the interlayer. The hardened vegetation soil in the interlayer will block the drainage gaps between the longitudinal blind pipes and the drainage branches, directly disrupting the entire continuous drainage channel. Furthermore, the shallow slope layer consists of soft, silty fill with continuously rising capillary water. Initially, there are tiny gaps between the blanket and the slope surface, trapping dry air. This easily forms a waterproof interlayer, preventing seepage from the slope surface from converging into the drainage branches. Only by evenly saturating the entire blanket structure can air resistance be eliminated, ensuring... The drainage system ensures smooth water flow. Since this scheme only opens puncture holes and provides sealing and seepage prevention filling at a few planting anchor points, there are no anchor holes in non-planting areas. Rainwater on the slope can only rely on the fiber blanket itself for infiltration and conduction. Spraying and soaking can pre-explode the straw fibers of the fiber blanket to absorb water and expand. After the fibers expand, they tightly adhere to the slope, reducing the gap between the blanket and the soil, and reducing the local runoff and scouring of the soft roadbed caused by natural rainfall in the later period. The project requires full vegetation coverage within 2 months. The interlayer of vegetation soil and the planting soil in the planting holes need a stable and moist environment to ensure the germination of grass seeds and seedlings. Local intermittent watering will cause severe alternation between dry and wet, causing the seedling roots to dehydrate and wither, making it impossible to achieve the ecological soil stabilization and protection effect on schedule.

[0104] After completing all civil engineering procedures, including pipeline installation, backfilling, and anchoring, this plan employs a full-coverage spraying method. This method controls the spray flow and coverage to ensure water thoroughly permeates the three layers of the double-layer fiber blanket: the surface layer, the interlayer of vegetation, and the bottom layer of the blanket. This allows the straw and plant fibers of the double-layer fiber blanket to fully absorb water and expand, tightly adhering to the smoothed, soft slope surface, eliminating hollow cavities at the bottom of the blanket and preventing later rainfall from eroding and softening the roadbed. Simultaneously, the water evenly soaks the vegetation inside the interlayer, saturating it and clearing soil pores around blind pipes and drainage branches, preventing... To prevent dry soil particles from falling off and clogging drainage pipes, ensuring that the longitudinal blind pipes at the top of the slope and the drainage branch pipes on the slope form a continuous and unobstructed water channel; at the same time, uniform immersion throughout the entire area can simultaneously provide a stable water environment for grass seeds and seedlings in the planting holes at the anchoring points in the middle and lower sections. The water distribution across the entire slope is balanced, with no localized drought or waterlogging areas. It will not aggravate the saturation and instability of the soft soil due to excessive water accumulation, nor will it delay vegetation germination due to water shortage. After spraying, the fiber blanket absorbs water and solidifies to form an overall buffer and waterproof cushion layer, which, together with the impermeable geotextile at the foot of the slope, the drainage branch pipes on the slope, and the drainage blind pipes at the top of the slope, constitutes an integrated and collaborative protection system for drainage, seepage prevention, and ecological maintenance.

[0105] S6. Backfill the slope top and shoulder area with plain soil and compact it manually or with light mechanical static pressure. The plain soil should completely cover the edge of the fiber blanket slope top overlap, the drainage blind pipe and the entire area of ​​each diversion branch pipe.

[0106] After completing all the procedures of spraying and soaking, planting greenery and laying pipelines, the plain soil is backfilled in layers at the top of the slope and the shoulder. The plain soil is laid to completely cover the overlapping edge of the fiber blanket at the top of the slope, the longitudinal drainage blind pipes in the interlayer, and the top access section of all the drainage branch pipes. There are no exposed interlayers, pipes, or edges of the blanket. After the backfilling is completed, manual compaction or light static pressure equipment is used to compact the soil in layers to form a dense and impermeable top soil sealing layer. On the one hand, the compacted subsoil isolates the road shoulder and surface drainage from the rainwater at the top of the slope, preventing water from seeping into the soft soil layer of the roadbed through the interlayer openings and the edge of the blanket. It works in conjunction with the longitudinal impermeable geotextile at the toe of the slope to construct a double-layer water barrier on the slope. On the other hand, the fully covered compacted subsoil permanently fixes the upper end of the double-layer fiber blanket, replacing the conventional dense anchor piercing fixation at the top of the slope. There is no need to add additional piercing holes at the top of the slope, which continuously maintains the integrity of the slope's impermeability. At the same time, the lightweight static pressure compaction load is controllable, which can make the subsoil fit tightly against the blanket and the outer wall of the pipe, eliminating the gaps inside the cover soil to avoid rainwater accumulation, and will not squeeze or damage the water flow section of the blind pipe and diversion branch pipe in the interlayer. It maintains the longitudinal water collection capacity at the top of the slope for a long time, forming a complete and undamaged closed drainage loop from top to bottom with the slope diversion branch pipe, the impermeable drainage layer at the toe of the slope, and the outer drainage ditch. It works in conjunction with a small amount of anchoring on the slope, full-area spraying maintenance, and short-term vegetation soil stabilization structure to achieve a synergistic protective effect.

[0107] To make the technical solution of the present invention clearer, the present invention will now be further described. The specific steps of S1 are as follows: a1. Divide the shaped roadbed slope into a surface treatment layer and a middle compaction layer. Peel off the saturated soft soil with a thickness of 8cm to 15cm from the surface layer. After the soil is peeled off, scrape the middle soil back and forth. The slope deviation of the shaped slope is controlled within the range of ±0.05.

[0108] a2. Following the progress of slope trimming, lay the impermeable geotextile in its entirety along the longitudinal direction of the slope. The longitudinal overlap width between two adjacent geotextiles is 30cm to 50cm. The bottom end of the geotextile extends completely to the inside of the drainage ditch at the toe of the slope. After the geotextile is laid, a complete impermeable and diverting layer is formed at the toe of the slope.

[0109] The bottom edge of the geotextile refers to the lowest transverse edge of the geotextile near the drainage ditch on the outer side of the roadbed; it corresponds to the lowest side of the slope from top to bottom, that is, the edge of the fabric that contacts the ground at the toe of the slope and extends into the drainage ditch.

[0110] a3. After the seepage prevention and diversion layer is laid in place, position markers are inserted horizontally and vertically along the middle and lower sections of the slope. The horizontal spacing of the position markers is 1.2m to 2.0m, and the vertical spacing is 1.5m to 2.5m. The depth of the position markers in the soil is not less than 25cm.

[0111] The positioning markers can be the same as the layout stakes used during construction.

[0112] a4. After the positioning markers are set up, the vertical elevation of all positioning markers shall be uniformly calibrated, and the layout and positioning of the drainage blind pipe laying path and elevation at the top of the slope shall be completed simultaneously.

[0113] Among them, drainage blind pipes, also known as drainage blind ditches or plastic blind pipes, are underground drainage materials made of hydrophobic materials such as synthetic fibers, plastics and synthetic rubber, and are chemically inert.

[0114] Drainage blind pipes, as tubular drainage components buried on the inner side of the slope top, are used to intercept surface water and seepage water from the mountain top, preventing water from flowing along the slope surface and eroding the fiber blanket and seeping into the roadbed.

[0115] The a1 process involves layering and peeling away the 8-15cm saturated, soft, and silty surface layer to remove the weak soil with inherent seepage risks. Then, the intermediate compacted layer is meticulously leveled, and the slope ratio is strictly controlled to ±0.05. This provides a stable and regular base for subsequent fiber blanket bonding and smooth laying of the geotextile, eliminating water-prone areas on the slope from the source. Simultaneously with slope repair, the a2 process involves laying a longitudinal, full-width geotextile, using 30-50cm wide longitudinal overlaps to eliminate seams and prevent leakage. The lowest transverse edge of the geotextile extends completely into the drainage ditch at the toe of the slope, forming a seamless horizontal seepage-proof and diversion layer along the entire highway. This intercepts downward-seeping slope water, preventing continuous water infiltration into the soft, silty intermediate soil. After the geotextile base is sealed, the a3 process is executed, where positioning stakes are driven only in the lower and middle sections of the slope at fixed horizontal and vertical intervals, with a considerable depth. To ensure the positioning markers remain within 25cm, the only permissible points for subsequent puncture anchoring and seedling planting are precisely located, avoiding the risk of arbitrarily installing anchors that could puncture the waterproofing fabric and interlayer drainage pipes. Finally, the elevation of all positioning markers is uniformly calibrated using A4 paper, and the laying trajectory and control elevation of the drainage blind pipes at the top of the slope are simultaneously laid out. This integrates slope planting positioning and drainage pipeline layout into the preliminary preparation process, allowing subsequent processes such as carpet laying, pipe burial, anchoring, and greening to be carried out based on the preliminary layout benchmarks. This achieves seamless integration of four preliminary processes: slope base reinforcement, bottom longitudinal seepage prevention, planting point locking, and top drainage pipeline planning. This lays a precise, leak-free, and undisturbed foundation for the subsequent S2-S6 interlayer drainage, minimal puncture anchoring, full-area spraying, and top-slope sealing protection system.

[0116] In addition, this solution addresses the instability of soft soil when exposed to water by specifically stripping away the high-water-content weak layer and regularizing the slope shape to prevent water accumulation at the bottom of the blanket from eroding the middle soil layer later. A longitudinally continuous, long-width, overlapping waterproof fabric is laid, with the bottom extending into the drainage ditch to form a long, continuous waterproof and diversion layer. This continuous laying along the driving direction, with 30-50cm wide overlaps, eliminates longitudinal seepage joints, and the bottom reaches the drainage ditch for unified drainage of leaks. This solution is specifically designed to meet the comprehensive waterproofing requirements of long, linear highway slopes, while short, scattered slopes lack the long-line continuous waterproofing capability. The slope planting and positioning markers are laid out, and the elevation of the blind pipes at the top of the slope is simultaneously calibrated to pre-lock the puncture area, achieving coordinated protection between the minimal-puncture waterproofing system and the interlayer drainage network.

[0117] To make the technical solution of the present invention clearer, the present invention will now be further described. After the completion of the S1 positioning benchmark elevation calibration and blind tube layout process, S2 is executed. The specific steps are as follows:

[0118] b1. Transfer the single roll of double-layer composite fiber blanket to the working surface at the top of the slope. Two workers are positioned on the left and right sides of the fiber blanket width and pull the roll down at a uniform speed. The longitudinal length of the slope surface is 6m to 10m in a single laying.

[0119] b2. During the pulling process, dynamically adjust the pulling force on both sides to avoid unilateral displacement of the fiber blanket and local wrinkle accumulation. After each section of roll material is laid down, manually sweep and press along the bottom surface of the blanket to level it. The overall gap between the blanket and the slope should be controlled within 12mm.

[0120] b3. When the roll material is lowered to the toe of the slope, the bottom edge of the lowered blanket is completely overlapped with the surface of the impermeable geotextile, and the overlap width is 25cm to 40cm. The bottom edge of the blanket does not penetrate into the drainage ditch at the toe of the slope.

[0121] b4. After the single-section fiber blanket is laid, temporary pressing and positioning are carried out at the edge of the slope top to prevent the blanket from sliding due to gravity. No temporary anchors are added in the middle and lower sections of the slope and the entire slope top. The permanent positioning of the blanket is completed after the subsequent anchoring process.

[0122] This process is applied in scenarios where the remaining middle layer after the surface layer of the roadbed has been stripped is saturated, soft, and compacted soil with low bearing capacity. This soil is prone to softening and cracking under foot traffic. If workers drag or level the fiber blanket downhill, they will directly trample and damage the regular slope base, creating a potential hazard of water seepage and slippage later on. Conventional dry, hard slopes allow workers to work downhill without the instability caused by foot traffic. The hollow interlayer within the double-layer composite fiber blanket serves as the sole laying channel for longitudinal blind pipes at the top of the slope. If large wrinkles or localized gaps occur during blanket laying, the interlayer cavity will twist and deform, preventing the subsequent straight laying of blind pipes and blocking the entire water drainage path. Ordinary single-layer fiber blanket slope protection lacks this interlayer drainage structure. The construction does not require strict control of the bonding gap of the geotextile. The longitudinally continuous impermeable geotextile at the toe of the slope is the only bottom-layer water barrier for the entire slope. If the bottom end of the fiber blanket invades the drainage ditch, or if the reverse overlap of the fiber blanket is used with the impermeable fabric on top, the seepage water on the slope will seep down along the joint and erode the soft subgrade. Conventional short slope seepage prevention structures do not have long-line continuous water barrier requirements, and there are no mandatory constraints on the overlapping method. The core design concept of this invention is to minimize the number of puncture holes on the slope. Temporary anchors will create a large number of additional vertical seepage channels, which will increase the risk of soft soil sliding when it encounters water. Conventional slope protection will densely install temporary anchors along the slope height to prevent the geotextile from sliding down, and there is no construction constraint of avoiding temporary punctures.

[0123] After slope dredging, seepage prevention laying, positioning markers, and blind pipe layout are completed via S1, the fiber blanket is centrally transported to the top of the slope via b1. Two personnel are positioned on either side of the blanket width and pull it synchronously and at a uniform speed, lowering it in segments of 6m to 10m at a time to shorten the sliding force of a single section of blanket and reduce the probability of blanket stretching and displacement. Personnel do not leave the slope during the entire process to prevent damage from trampling on the soft base surface. B2 dynamically balances the pulling force on both sides to eliminate unilateral displacement and wrinkle accumulation. After lowering, manual sweeping and leveling are performed to control the gap between the blanket and the slope surface within 12mm, significantly reducing water accumulation cavities at the bottom of the blanket and preventing rainwater from continuously soaking the roadbed. At the same time, it ensures the regular shape of the double-layer blanket interlayer, providing a good foundation for subsequent blind pipe pre-laying. Provide a straight cavity; execute b3 to limit the fiber blanket bottom end to be superimposed on the surface of the impermeable geotextile from top to bottom, with an overlap width of 25cm to 40cm and the blanket does not extend into the drainage ditch, forming an overlying water-stopping overlap strip. All seepage water on the slope flows along the bottom surface of the blanket to the overlap area, collects uniformly to the impermeable fabric and then leads to the drainage ditch, completely sealing the weak seepage gaps between the blanket and the impermeable fabric; finally, rely on b4 to temporarily press and limit the slope top, without installing any temporary anchors in the middle and lower sections of the slope or the entire slope top, relying entirely on the slope top pressing constraint force and the slope toe overlap pressing friction force to bidirectionally offset the downward force of the blanket, without adding any temporary puncture seepage holes, and wait for the S3 planting point to be anchored around to achieve permanent fixation.

[0124] This solution targets shallow saturated silty soil slopes where anchor holes can create long-term capillary seepage channels, potentially triggering shallow landslides. Therefore, all temporary anchoring of the slope is abandoned. Instead, the solution relies on segmented, short-amplitude lowering to reduce sliding tension and bidirectional friction at both ends to offset sliding shear force, stabilizing the carpet without creating new seepage holes.

[0125] To make the technical solution of the present invention clearer, the present invention will now be further described. After the completion of the S2 segmented carpet laying process, S3 is executed. The specific steps are as follows:

[0126] c1. Divide the slope into two independent working sections: the anchoring area in the middle and lower part of the slope and the edge pressing area at the top of the slope. Two construction teams work synchronously in the slope. The team in the middle and lower part of the slope reaches each positioning marker point from bottom to top along the slope surface, while the team at the top of the slope carries out edge preparation and advancement.

[0127] c2. After the team members arrive at the single positioning marker planting point, they will lay U-shaped anchor nails around the outer perimeter of the positioning marker. The number of anchor nails laid around the single positioning point is 3 to 5. The anchor nails are driven into the slope soil at an angle, with a depth of 30cm to 45cm. All the anchor nails will form a closed anchoring ring around the outside of the planting point.

[0128] c3. Anchors are installed only at the planting points corresponding to the positioning markers in the middle and lower sections. The top of the slope and other areas on the slope without positioning markers are not anchored at all, so as to preserve the waterproof fiber layer of the fiber blanket.

[0129] c4. The two processes of laying carpet and anchoring are carried out in sections and in parallel within the slope. The anchoring operation of the current section is started simultaneously as soon as the slope is laid.

[0130] There is no need to wait until all the segmented fiber blankets are laid before carrying out the anchoring construction.

[0131] After the S2 segmented carpet laying process completes the foundation laying of a single slope section, c1 rigidly divides the slope into two independent sections: the middle and lower slope anchoring zone and the top slope edge pressing zone. Two teams are assigned to carry out the work simultaneously in each section. The anchoring team proceeds from bottom to top along the slope to each pre-marked positioning marker planting point, while the top slope team simultaneously carries out the carpet edge straightening work, ensuring that the two processes do not interfere with each other spatially. c2 surrounds each positioning marker with 3-5 U-shaped anchor nails, which are driven into the soil at an angle to a depth of 30cm-45cm. Multiple anchor nails together form a complete closed anchoring ring, with all anchor nails avoiding the planting cavity in the center of the positioning marker, reserving complete soil space for the later root growth of green plants. The inclined soil insertion method can improve soil quality compared to vertical anchoring. Lateral gripping force achieves the same anti-slip limiting effect with fewer anchors; by defining a rigid no-anchor zone through C3, anchors are only installed at the positioning marker planting points in the middle and lower sections, ensuring zero anchors and zero punctures in the slope top area and blank slopes without positioning markers, thus completely preserving the overall waterproof fiber layer of the double-layer fiber blanket, preventing excess nail holes from connecting surface rainwater to the bottom soft subgrade, and avoiding anchors puncturing the interlayer drainage pipes and the impermeable geotextile at the slope toe; relying on C4, the laying and anchoring of the blanket can be carried out in parallel and sequential manner in different zones. Once the fiber blanket of a single section is laid, the anchoring operation of that section can be started simultaneously, without waiting for the entire slope to be laid before centralized anchoring, which greatly reduces the interval time between processes and reduces the probability of the laid fiber blanket being exposed to rainwater, wind erosion, and slippage deformation for a long time without fixed protection.

[0132] This scheme achieves segmented paving and immediate segmented anchoring, eliminating long-term unsecured exposed blankets. Simultaneously, two work teams operate in separate zones, adapting to the simultaneous construction of multiple sections on long, linear highway slopes. Furthermore, 3-5 anchors are driven at an angle around the positioning markers to form a closed band, increasing soil grip friction and achieving an equivalent limiting effect with fewer puncture holes. This also preserves the central planting soil cavity, facilitating rapid rooting and development of short-term vegetation. Based on slope shear distribution and drainage pipe layout, this scheme manages anchoring points in zones, anchoring only a small number of points in the middle and lower sections with the greatest sliding shear. No anchors are installed at the top of the slope or on unvegetated, unplanned slope areas. This significantly reduces the number of vertical capillary seepage channels, mitigating the risk of soft soil slippage, and avoids interlayer blind pipes, drainage branches, and slope toe impermeable fabric throughout the entire process.

[0133] To make the technical solution of the present invention clearer, the present invention will now be further described. S4 is performed after the S3 circumferential anchoring process, and the specific steps are as follows:

[0134] d1. After the anchors are assembled to form a closed anchoring ring, a planting hole is excavated in the center of the anchoring ring. The diameter of the planting hole is 12cm to 20cm and the depth is 20cm to 30cm. The planting hole is then backfilled with mixed humus nutrient soil.

[0135] d2. After the nutrient soil is backfilled, insert green plant seedlings or sow grass seeds into the planting holes; at the same time, lift the surface layer of the double-layer fiber blanket on the top of the slope and lay drainage blind pipes in the interlayer.

[0136] d3. Drainage blind pipes are laid continuously in the longitudinal direction along the top of the slope. The axial overlap length of adjacent blind pipes is not less than 20cm. The water permeable holes of the pipes are uniformly arranged facing the slope soil side. Every 5m to 8m, a drainage branch pipe is connected from the main body of the blind pipe along the slope direction.

[0137] d4. After the drainage branch pipe is led out from the interlayer at the top of the slope, it is laid along the slope direction between the fiber blanket and the slope soil. The bottom end extends to the surface of the impermeable geotextile at the bottom of the slope and is guided to the drainage ditch at the bottom of the slope. The pipe laying path avoids the planting holes on the slope and is separated from the space of the anchor and the plant root system. There is no squeezing or puncture interference. The drainage branch pipe is connected with the impermeable drainage layer at the bottom of the slope to form a three-dimensional drainage channel.

[0138] The impermeable drainage layer serves as a transitional layer between water isolation and drainage. It is laid on the surface of the soil at the toe of the slope and inside the drainage ditch to receive all the seepage water falling from each diversion branch pipe. It is impermeable itself, preventing water from seeping down and softening the roadbed. At the same time, it guides the water flowing out of the branch pipe laterally, and finally receives the water that is laterally dispersed by the impermeable drainage layer through the drainage ditch at the toe of the slope, and discharges it uniformly within the slope area.

[0139] The S3-formed closed anchoring ring structure involves d1, where planting holes are excavated only at the center of the anchoring ring, with the surrounding soil protected by the outer anchoring ring to prevent hole collapse, wall cracking, and water seepage. Backfilling with humus-rich soil improves the soil quality at the planting site, promoting rapid root development of fast-growing vegetation. d2 allows for simultaneous and parallel planting and pipe laying, eliminating interference between planting and slope top blind pipe installation. This saves time and two separate processes; blind pipes can be laid simply by lifting the surface layer of the slope top fiber blanket, without damaging the waterproof structure of the blanket's underlying surface. d3 ensures longitudinal laying of the blind pipes along the road with a ≥20cm axial overlap, preventing leakage of longitudinal water catchment. The permeable holes are oriented towards one side of the slope to specifically absorb capillary seepage from the roadbed at the top and lateral seepage from the mountainside, preventing the holes from being blocked by plant fibers drawn into them. (5-8) Standardized branch pipes with m-sized spacing are used to divert water evenly to the slope. The d4 control path of the branch pipes avoids planting holes, anchor rings, and plant roots throughout, ensuring that drainage components, stabilization components, and greening components are spatially independent and do not interfere with each other. The bottom of the branch pipe rests smoothly on the waterproof surface of the seepage-proof geotextile layer at the foot of the slope without piercing or cutting into the seepage-proof geotextile. All water from the branch pipe falls into the seepage-proof geotextile layer, where it blocks water from seeping into the roadbed and diverts water laterally, eventually flowing into the drainage ditch at the foot of the slope. This forms a dedicated three-dimensional drainage channel from top to bottom: seepage from the mountain and shoulder - collection by blind pipes at the top of the slope - drainage diversion pipes along the slope - waterproof diversion layer - drainage ditch at the foot of the slope. At the same time, the anchoring and protection of planting holes, the pipes avoiding roots, and the strict control of soil breaking points throughout the area take into account multiple linkage effects of drainage, ecological greening, soil seepage prevention, and component protection.

[0140] The anchor ring surrounds and supports the planting hole, providing fixed-point planting and achieving triple-coupled protection: hole collapse prevention, hole wall seepage prevention, and root confinement. This is not the conventional function of planting grass during slope excavation. Conventional slope protection planting holes are arbitrarily excavated without external support, making them extremely prone to collapse in soft soil. The hole walls directly form new seepage channels, and the planting hole is separated from the anchor point, doubling the number of soil breaches on the slope. This solution involves a single fixed-point hole within the anchor ring, with the outer closed anchor ring tightening the soft soil around the hole opening to prevent collapse. The design minimizes cracking and strictly controls the total number of soil breaking and puncture points across the entire slope. Each anchoring point corresponds to only one planting point, allowing for multiple uses of a single hole to reduce seepage channels on the slope. This design better suits the unique characteristics of saturated silty soil, which is susceptible to disturbance and prone to slippage due to multiple openings. The permeable holes in this design are specifically oriented towards the soil to absorb only clean water and prevent debris from entering the pipe. At the same time, the branch pipes bypass the anchoring and greening areas throughout the entire process, thus avoiding the problems of root growth wrapping around the pipes and anchors squeezing and deforming the pipes later on. This design is suitable for the compact slope layout that integrates anchoring, greening, and drainage in this invention.

[0141] To make the technical solution of the present invention clearer, the present invention will now be further described. The specific steps of S5 are as follows: e1. Spraying operation is carried out by moving back and forth at a uniform speed along the slope surface from the top to the bottom of the slope. The duration of a single spraying operation on a single slope section is 12 min to 25 min. The spraying medium is room temperature clean water, and the single spraying amount per unit slope surface is controlled at 4 L / m. 2 ~9L / m 2 interval;

[0142] e2. Spraying operations are carried out in two intervals. The first spraying penetrates the straw fiber on the surface of the fiber blanket. After an interval of 30 minutes, a second spraying is carried out to ensure that the water penetrates to the surface soil of the slope below the blanket.

[0143] e3. After the spraying is completed, let it stand for 20 to 40 minutes. The moisture will help the dry straw fibers absorb water, swell, and entangle with each other, thus reducing the gap between the blanket and the base.

[0144] e4. Spraying operations cover the entire fiber blanket laying area. When encountering the overlap of the geotextile above the slope toe, extend the spraying time to ensure that the fibers in the overlap area are fully soaked and adhered.

[0145] e1. Quantitative control of spray flow rate, spray volume, and single-cycle duration ensures uniform, full-area spraying, avoiding water flow impact and disturbance of the soft slope surface and preventing soil erosion and collapse. e2. Two differentiated spraying sessions with a 30-minute interval are employed. The first spray shallowly wets the surface straw fibers, while the second spray penetrates the interlayer and soaks the underlying undisturbed soil, creating layered seepage channels to ensure smooth flow of seepage water into the drainage pipes. e3. After spraying, the system is left to stand and slowly release moisture, allowing the straw fibers of the double-layer blanket to absorb water, swell, intertwine, and clump together, actively reducing the blanket's size. By creating a gap with the slope frame, it further conforms to the slope soil. Combined with slope top overlay, slope toe overlap, and anchor ring limiting, it further enhances the anti-slip stability of the carpet in the non-anchored area. The e4 system specifically extends the spraying time in the carpet overlap area at the slope toe, allowing the fibers at the overlap to fully expand and compact, closing the gap between the carpet and the seepage-proof cloth, and preventing seepage water from seeping into the soft soil layer of the roadbed. Ultimately, it achieves self-consolidation of the fiber carpet, no gaps at the bottom of the carpet, seamless overlap, balanced vegetation moisture, and unobstructed drainage channels, linking the entire three-dimensional drainage and seepage prevention system to operate stably.

[0146] Among them, the double-interval gradient spraying breaks down the air resistance at the bottom of the blanket and enables the pipe network to collect water in a directional manner, which is not the conventional function of watering to moisturize. It penetrates layer by layer to release air, allowing the seepage water on the slope to flow into the drainage branch pipes in a directional manner, which is specially adapted to the diversion requirements of the interlayer embedded drainage pipe network. Then, the double-interval spraying breaks down the air resistance at the bottom of the blanket and opens up the seepage path of the interlayer pipe network to ensure the drainage efficiency of the three-dimensional drainage channel. The controllable expansion of water achieves the self-interlocking and consolidation of fibers, eliminating the need for temporary anchors to assist in fixing the blanket. Unlike the conventional function of watering, which only maintains the slope without stabilizing it, it uses the water absorption and entanglement characteristics of straw to reduce the gaps in the frame space and increase the friction of the slope. Combined with the whole-area structure that eliminates the need for temporary anchors, it reduces the seepage channels in the anchor holes.

[0147] In addition, the directional extension of the spray at the overlap point closes the seepage-proof gap, and differentially seals the weak seepage zone at the end of the slope. This is different from the general water-stopping effect of uniform spraying throughout the entire area. Conventional spraying has a uniform water volume throughout the entire area and ignores the potential for water seepage at the overlap gap of the blanket. Water can easily invade the roadbed along the overlap gap. This solution specifically wets the overlap area, allowing the overlap fibers to expand and seal the gap, guarding the last water-proof barrier at the toe of the slope. It is specially adapted to the overlap structure of the blanket-pressed seepage-proof cloth of this invention.

[0148] To make the technical solution of the present invention clearer, the present invention will now be further described. The specific steps of S6 are as follows: f1. Clean up the loose fibers, loose debris and sandbags that were temporarily pressed and positioned in the early stage on the working surface of the slope top and shoulder in advance. Select homogeneous plain soil as the backfill soil material. Lay the soil in layers, and the thickness of a single layer of soil is 10cm to 20cm.

[0149] f2. After the single layer of soil cover is laid, manual or light mechanical static compaction is carried out. The original soil is simultaneously covered downwards to the edge of the fiber blanket slope and the top area of ​​the drainage branch pipe. The horizontal width of the edge of the soil cover blanket is not less than 40cm. The outer side of the soil cover is smoothly connected to the roadbed and the shoulder of the roadway.

[0150] f3. After compaction, the top opening of the fiber blanket interlayer is sealed to block the infiltration path of surface rainwater along the interlayer. The compaction operation is carried out only on the surface of the top layer, and the compaction process does not directly compact the main body of the slope fiber blanket.

[0151] f4. The backfill should avoid disturbing the pre-embedded drainage blind pipes inside the interlayer, as well as the backfill at the top of the slope, the longitudinal main drainage blind pipes in the interlayer, the drainage branch pipes on the slope surface, the double-layer fiber blanket on the slope surface, and the impermeable geotextile at the toe of the slope, which together form a continuous closed drainage protection structure that runs from the top of the slope to the toe of the slope.

[0152] This plan involves: f1) thoroughly cleaning the temporary sandbags, fiber debris, and loose soil at the top of the slope to prevent debris from entering the interlayer and clogging the drainage holes; using homogeneous plain soil in layers, strictly controlling the thickness of each layer to 10cm-20cm to avoid compressing the interlayer pipes with heavy soil pressure; f2 using manual or light mechanical static compaction to limit the horizontal coverage of the soil over the edge of the blanket to ≥40cm, fully covering the top of the branch pipes and the overlapping edge of the blanket at the top of the slope to ensure a seamless and smooth connection between the soil and the hardened shoulder, preventing water from seeping down the shoulder; and f3 only statically compacting the surface soil without compaction. The main body of the slope blanket is sealed with dense subsoil to completely block the opening at the top of the double-layer fiber blanket interlayer, thus completely cutting off the infiltration path of road shoulder rainwater and surface water into the interlayer, preserving the original fit and waterproof integrity of the slope fiber blanket; the entire process of the f4 is meticulously controlled to cover the soil spreading and compaction range, avoiding the connection points of blind pipes and branch pipes inside the interlayer, without moving, misaligning, or squeezing the drainage components, maintaining the original overlapping relationship of the blind pipes at the top of the slope, the drainage branch pipes on the slope, the double-layer fiber blanket, and the impermeable geotextile at the bottom of the slope, and completely preserving the top-to-bottom continuous closed drainage protection structure.

[0153] To make the technical solution of this invention clearer, the invention will now be further described. Specifically, the fiber blanket laid on the slope is a double-layer straw fiber composite mesh blanket; the seepage-proof and diversion-ensuring layer at the slope toe is made of short-fiber geotextile with a unit area mass range of 300g / m². 2 ~400g / m 2 The anchoring components are U-shaped low-carbon steel anchors with a rod diameter ranging from 4mm to 6mm; the drainage blind pipes are PE multi-hole corrugated pipes with an outer diameter ranging from 50mm to 80mm and a permeable hole diameter ranging from 5mm to 8mm; the drainage branch pipes are flexible permeable pipes with a diameter ranging from 15mm to 25mm.

[0154] In this scheme, a double-layer straw fiber composite mesh is formed by the upper and lower layers of the mesh, creating a stable hollow interlayer that provides a sealed laying cavity for PE porous corrugated pipes and flexible permeable pipes. The straw fibers swell and entangle upon contact with water, and a small number of U-shaped anchors are used to limit the slope. 300-400g / m² short-fiber geotextile is laid at the toe of the slope to form a complete seepage-proof and drainage base, receiving all the seepage water discharged from the flexible permeable pipes, preventing vertical seepage of water and softening the silty roadbed, while simultaneously distributing water evenly laterally into the outer drainage ditch. 4-6mm diameter U-shaped low-carbon steel anchors are driven into the soil at an angle around the planting point, achieving sufficient soil grip at the cost of small-diameter holes, forming a closed anchor ring to protect the planting hole, while minimizing the penetration seepage channel. 50-80mm outer diameter PE porous corrugated pipes at the top of the slope collect seepage water from the road shoulder and hillside longitudinally along the road, while 5-8mm directional pipes... The permeable holes only absorb clean water from the soil, preventing large debris from clogging the main pipe. Every 5-8m, 15-25mm flexible permeable pipes are connected from the main blind pipe to guide water from the interlayer and slope surface seepage. The flexible pipes fit the slope surface without rigid bends or blockages. All material specifications and spatial dimensions are matched to each other, constructing a complete drainage and seepage prevention system integrating slope water collection, longitudinal water flow, slope diversion, and slope toe water isolation and diversion. By bidirectionally constraining material specifications, the lower limit of geotextile weight ensures puncture resistance strength, preventing long-term erosion and puncture of the seepage prevention and diversion layer by the diversion branch pipes. The upper limit of the anchor nail diameter strictly controls the size of the puncture holes, minimizing vertical capillary seepage channels. In addition, the large-sized PE porous corrugated pipes in this scheme handle the main water collection along the entire line, while the small-sized flexible permeable pipes divert slope seepage in sections. The 5-8mm permeable holes form a particle filtration barrier, allowing only clean water to enter the pipeline.

[0155] Example 2: Based on Example 1, the present invention further includes:

[0156] The longitudinal construction layout and material transfer for the entire slope are planned according to the following steps.

[0157] Construction is carried out in sections along the longitudinal direction of the slope, with each section having a longitudinal length of 6m to 10m. The internal S1 base surface repair and seepage prevention paving processes are started simultaneously and in parallel in each section.

[0158] Roll material transport vehicles are uniformly parked at fixed unloading points at the toe of the slope along the entire line. Fiber blanket rolls are stacked linearly along the toe of the slope and manually carried short distances to the corresponding section of the slope top working surface. No large amounts of roll materials or anchoring materials are piled up at the top of each section of the slope.

[0159] Each section of the slope has a complete and continuous working surface reserved along the top, which simultaneously meets the operational space requirements for opening the pre-buried drainage blind pipes in the interlayer and covering and sealing the edges with soil.

[0160] Each section follows a fixed sequence of procedures from top to bottom, while construction proceeds in an inter-section, sequential manner. The overall process avoids material transfer occupying the work surface or work stoppages, making it suitable for long-distance continuous protection of roadbed slopes in the field.

[0161] The entire long slope was divided longitudinally into standardized independent construction units of 6m to 10m. All sections simultaneously initiated two preliminary foundation processes: dredging the S1 slope surface and laying geotextile at the slope toe for seepage prevention. Simultaneous completion of the base seepage prevention treatment avoided misalignment of the seepage-proofing layer and longitudinal leakage joints caused by differences in the order of section construction. Fixed unloading points were uniformly designated at the slope toe throughout the entire line. Fiber blanket rolls were neatly stacked linearly at the slope toe and transported manually over short distances to the corresponding section's slope top. This prevented large-area material accumulation at the slope top from generating additional loads that could damage the soft slope surface. Only a small amount of material required for a single construction session was left at the top of each section, keeping the working surface open. A complete, continuous, and unobstructed working area was reserved at the top of each section. The system simultaneously reserves operational space for lifting the double-layer fiber blanket interlayer, laying longitudinal blind pipes, and later layered static pressure backfilling of the subgrade. This prevents drainage pipes from being bent or the backfilling from being inadequately compacted due to material obstruction. Within each section, a fixed sequence of procedures from top to bottom is strictly followed to ensure that slope repair, seepage prevention, blanket laying, anchoring, planting, spraying, pipe laying, and backfilling proceed gradually without disrupting the formation logic of the three-dimensional drainage and seepage prevention system. Adjacent sections adopt a cross-flow advancement mode. When the S3 anchoring process is completed in the previous section, the S1 base surface repair is carried out simultaneously in the next section. Materials are uniformly allocated and transferred from the slope foot, eliminating situations where transport vehicles occupy the work passage for extended periods or work processes are suspended for long periods while waiting for materials to arrive. The entire longitudinal layout and transportation plan is adapted to the needs of long-distance continuous field construction. It not only ensures that the internal drainage and seepage prevention structure of each section is fully formed according to the process standards, but also compresses the overall construction period through simultaneous construction and cross-flow, while avoiding secondary diseases such as cracking of soft soil and blockage of pipeline caused by overloading on the top of the slope and unloading at multiple points.

[0162] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. For those skilled in the art, any alternative improvements or transformations made to the implementation of the present invention fall within the protection scope of the present invention.

[0163] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A construction method for integrated protection of highway subgrade slopes with plant fiber blankets, characterized in that, Includes the following steps: S1. Simultaneously carry out slope surface layer finishing and slope toe seepage prevention and diversion layer laying operations within the slope area; S2. Two workers simultaneously pull the double-layer composite fiber blanket roll at the top of the slope and lay it down in sections along the slope. The bottom end of the fiber blanket overlaps and covers the surface of the impermeable geotextile at the toe of the slope. After it is laid in place, it is temporarily pressed and positioned at the edge of the top of the slope. S3. Conduct anchoring operations at fixed points in the lower section of the slope surface, driving anchors into the surrounding area. No anchors are installed in non-planted areas or the top sealing area of ​​the slope. The specific steps for S3 are as follows: c1. Divide the slope into two independent working sections: the anchoring area in the middle and lower part of the slope and the edge pressing area at the top of the slope. Two construction teams work synchronously in the slope. The team in the middle and lower part of the slope reaches each positioning marker point from bottom to top along the slope surface, while the team at the top of the slope carries out edge preparation and advancement. c2. After the team members arrive at the single positioning marker planting point, they will lay U-shaped anchor nails around the outer perimeter of the positioning marker. The number of anchor nails laid around the single positioning point is 3 to 5. The anchor nails are driven into the slope soil at an angle, with a depth of 30cm to 45cm. All the anchor nails will form a closed anchoring ring around the outside of the planting point. c3. Anchors are installed only at the planting points corresponding to the positioning markers in the middle and lower sections. The top of the slope and other areas on the slope without positioning markers are not anchored at all, so as to preserve the waterproof fiber layer of the fiber blanket. c4. The two processes of laying carpet and anchoring are carried out in sections and in parallel within the slope. The anchoring operation of the current section is started simultaneously as soon as the slope is laid. S4. Simultaneously excavate planting holes at the anchoring points in the middle and lower sections of the slope and insert cuttings of green plants or sow grass seeds. S5. Use a spraying device to spray and saturate the fiber blanket over the entire slope area. The spraying medium must evenly saturate the entire structure of the fiber blanket. S6. Backfill the slope top and shoulder area with plain soil and compact it manually or with light mechanical static pressure. The plain soil should completely cover the edge of the fiber blanket slope top overlap, the drainage blind pipe and the entire area of ​​each diversion branch pipe.

2. The construction method according to claim 1, characterized in that, The specific steps of S1 are as follows: a1. Divide the roadbed slope into a surface treatment layer and a middle compaction layer. Remove the saturated silty soft soil with a thickness of 8cm to 15cm from the surface layer. After the soil is removed, scrape the middle soil layer repeatedly. Control the slope deviation of the formed slope within the range of ±0.

05. a2. Following the progress of slope trimming, lay the impermeable geotextile in its entirety along the longitudinal direction of the slope. The longitudinal overlap width between two adjacent geotextiles is 30cm to 50cm. The bottom end of the geotextile extends completely to the inside of the drainage ditch at the toe of the slope. After the geotextile is laid, a complete impermeable and diverting layer is formed at the toe of the slope. a3. After the seepage prevention and diversion layer is laid in place, position markers are inserted horizontally and vertically along the middle and lower sections of the slope. The horizontal spacing of the position markers is 1.2m to 2.0m, and the vertical spacing is 1.5m to 2.5m. The depth of the position markers in the soil is not less than 25cm. a4. After the positioning markers are set up, the vertical elevation of all positioning markers shall be uniformly calibrated, and the layout and positioning of the drainage blind pipe laying path and elevation at the top of the slope shall be completed simultaneously.

3. The construction method according to claim 2, characterized in that, The specific steps of S2 are as follows: b1. Transfer the single roll of double-layer composite fiber blanket to the working surface at the top of the slope. Two workers are positioned on the left and right sides of the fiber blanket width and pull the roll down at a uniform speed. The longitudinal length of the slope surface is 6m to 10m in a single laying. b2. During the pulling process, dynamically adjust the pulling force on both sides to avoid unilateral displacement of the fiber blanket and local wrinkle accumulation. After each section of roll material is laid down, manually sweep and press along the bottom surface of the blanket to level it. The overall gap between the blanket and the slope should be controlled within 12mm. b3. When the roll material is lowered to the toe of the slope, the bottom edge of the lowered blanket is completely overlapped with the surface of the impermeable geotextile, and the overlap width is 25cm to 40cm. The bottom edge of the blanket does not penetrate into the drainage ditch at the toe of the slope. b4. After the single-section fiber blanket is laid, temporary pressing and positioning are carried out at the edge of the slope top to prevent the blanket from sliding due to gravity. No temporary anchors are added in the middle and lower sections of the slope and the entire slope top. The permanent positioning of the blanket is completed after the subsequent anchoring process.

4. The construction method according to claim 3, characterized in that, The specific steps for S4 are as follows: d1. After the anchors are assembled to form a closed anchoring ring, a planting hole is excavated in the center of the anchoring ring. The diameter of the planting hole is 12cm to 20cm and the depth is 20cm to 30cm. The planting hole is then backfilled with mixed humus nutrient soil. d2. After the nutrient soil is backfilled, insert green plant seedlings or sow grass seeds into the planting holes; at the same time, lift the surface layer of the double-layer fiber blanket on the top of the slope and lay drainage blind pipes in the interlayer. d3. Drainage blind pipes are laid continuously in the longitudinal direction along the top of the slope. The axial overlap length of adjacent blind pipes is not less than 20cm. The water permeable holes of the pipes are uniformly arranged facing the slope soil side. Every 5m to 8m, a drainage branch pipe is connected from the main body of the blind pipe along the slope direction. d4. After the drainage branch pipe is led out from the interlayer at the top of the slope, it is laid along the slope direction between the fiber blanket and the slope soil. The bottom end extends to the surface of the impermeable geotextile at the bottom of the slope and is guided to the drainage ditch at the bottom of the slope. The pipe laying path avoids the planting holes on the slope and is separated from the space of the anchor and the plant root system. There is no squeezing or puncture interference. The drainage branch pipe is connected with the impermeable drainage layer at the bottom of the slope to form a three-dimensional drainage channel.

5. The construction method according to claim 4, characterized in that, The specific steps for S5 are as follows: e1. Spraying operation is carried out by moving back and forth at a uniform speed along the slope from the top to the bottom. The duration of a single spraying session on a single slope section is 12 to 25 minutes. The spraying medium is room temperature clean water, and the spraying volume per unit slope is controlled at 4 L / m. 2 ~9L / m 2 interval; e2. Spraying operations are carried out in two intervals. The first spraying penetrates the straw fiber on the surface of the fiber blanket. After an interval of 30 minutes, a second spraying is carried out to ensure that the water penetrates to the surface soil of the slope below the blanket. e3. After the spraying is completed, let it stand for 20 to 40 minutes. The moisture will help the dry straw fibers absorb water, swell, and entangle with each other, thus reducing the gap between the blanket and the base. e4. Spraying operations cover the entire fiber blanket laying area. When encountering the overlap of the geotextile above the slope toe, extend the spraying time to ensure that the fibers in the overlap area are fully soaked and adhered.

6. The construction method according to claim 5, characterized in that, The specific steps for S6 are as follows: f1. Clean up the loose fibers, debris and sandbags that were temporarily pressed and positioned in the early stage on the working surface of the slope top and shoulder in advance. Select homogeneous plain soil as the backfill soil material, and lay the soil in layers. The thickness of a single layer of soil is 10cm to 20cm. f2. After the single layer of soil cover is laid, manual or light mechanical static compaction is carried out. The original soil is simultaneously covered downwards to the edge of the fiber blanket slope and the top area of ​​the drainage branch pipe. The horizontal width of the edge of the soil cover blanket is not less than 40cm. The outer side of the soil cover is smoothly connected to the roadbed and the shoulder of the roadway. f3. After compaction, the top opening of the fiber blanket interlayer is sealed to block the infiltration path of surface rainwater along the interlayer. The compaction operation is carried out only on the surface of the top layer, and the compaction process does not directly compact the main body of the slope fiber blanket. f4. The backfill should avoid disturbing the pre-embedded drainage blind pipes inside the interlayer, as well as the backfill at the top of the slope, the longitudinal main drainage blind pipes in the interlayer, the drainage branch pipes on the slope surface, the double-layer fiber blanket on the slope surface, and the impermeable geotextile at the toe of the slope, which together form a continuous closed drainage protection structure that runs from the top of the slope to the toe of the slope.

7. The construction method according to claim 6, characterized in that, in, Double-layer straw fiber composite mesh blankets are selected for paving fiber blankets on slopes; The seepage-proof and diversion layer at the slope toe is made of short-fiber geotextile with a unit area mass range of 300g / m². 2 ~400g / m 2 ; U-shaped low-carbon steel anchors are used as anchoring components, with the diameter of the anchor rod ranging from 4mm to 6mm. For drainage blind pipes, PE porous corrugated pipes are selected, with the outer diameter of the pipe material ranging from 50mm to 80mm and the diameter of the water-permeable holes in the pipe wall ranging from 5mm to 8mm. Flexible permeable pipes are selected for drainage branch pipes, with a diameter ranging from 15mm to 25mm.

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