A method for integrated construction of reinforcement of a high and steep slope covering layer foundation downstream of an earth-rock dam and connection of a face plate dam for preventing seepage

Abstract

The application discloses a kind of earth-rock dam downstream high and steep slope covering layer ground vibroflotation reinforcement and panel dam connection anti-seepage integrated construction method, the application discards traditional big excavation to the slope treatment mode of bedrock, relies on original slope deposit covering layer and carries out in-situ reinforcement, including the following steps: demarcate covering layer and bedrock interface along dam axis;Quincunx arrangement vibroflotation crushed stone pile penetrates covering layer and embeds bedrock, and the soil between compaction pile forms composite foundation;Grouting hole is arranged in soil body between piles, and in-situ anti-seepage solidified layer is formed by pouring environment-friendly cementing material, realizes double reinforcement of physical compaction and chemical curing;Multi-stage gradual buffer layer is laid on top of rolled crushed stone cushion, and is smoothly connected with downstream rockfill dam body;Pour inclined concrete anti-seepage panel, and connect with upstream dam body anti-seepage structure through toe plate, and terminal accesses downstream anti-seepage wall;Anti-seepage wall embedded in bedrock is poured at upstream toe plate and downstream end of panel, and anti-seepage retaining wall is poured at the top of panel, to form three-dimensional closed anti-seepage system.

Description

Technical Field

[0001] This invention relates to the field of reinforcement and slope foundation treatment technology for earth-rock dams in water conservancy and hydropower projects, specifically a method for integrating vibro-compaction reinforcement of the foundation of the overburden layer on the downstream high and steep slope of an earth-rock dam with seepage prevention of the panel dam. Background Technology

[0002] In the steep slope area downstream of earth-rock dams, there is often a thick layer of colluvial overburden. This type of soil is loose, highly compressible, and has low shear strength, making it very easy for direct excavation to cause slope collapse.

[0003] Current conventional treatment methods mostly involve large-scale excavation, slope cutting and backfilling, or overall excavation to bedrock followed by pouring of panel foundations, but these methods have the following prominent drawbacks:

[0004] The large-scale excavation project involves a huge amount of work, with significant slope unloading and disturbance, high risk of slope instability, high cost of slope support, and significant safety risks. The overall excavation to bedrock takes a long time, and the cost of transporting excavated soil and disposing of waste is high, resulting in high project investment. Conventional vibro-compacted stone piles are only used for foundation compaction and are not systematically connected with the upstream dam panel seepage prevention structure and the upstream and downstream seepage prevention walls. Uneven settlement cracks are prone to occur at the transition between the pile top filling area and the panel, forming seepage channels and resulting in poor overall seepage prevention. Summary of the Invention

[0005] The purpose of this invention is to provide an integrated construction method for vibro-compaction reinforcement of the foundation of the high and steep slope downstream of an earth-rock dam and seepage prevention by connecting it with the panel dam, aiming to solve the defects of existing technologies such as large disturbance during slope excavation, high cost, and discontinuous seepage prevention system.

[0006] To address the aforementioned technical problems, this invention provides an integrated construction method for vibro-compaction reinforcement of the downstream steep slope overburden foundation of an earth-rock dam and seepage prevention at the connection with the face-face dam, comprising the following construction steps:

[0007] Step 1: Delineate the interface between the overburden soil and the underlying bedrock along the dam axis, trim the working platform at the toe of the slope, retain the original high and steep slope outline, and do not carry out large-scale slope cutting and excavation.

[0008] Step 2: Within the corresponding area of ​​the panel foundation, vibratory compaction stone piles in a quincunx pattern are installed, penetrating the colluvial overburden. The bottom of the piles is embedded in the bedrock, compacting the loose overburden between the piles to form a composite foundation. Crushed stone is backfilled in layers on top of the piles and compacted using a vibratory roller. The vibratory compaction stone piles are arranged in a quincunx pattern, penetrating the entire colluvial overburden and embedding at least 0.5m into the underlying bedrock. During the construction of the vibratory compaction stone piles, a real-time monitoring system is used to collect construction data such as the working current and working depth during the drilling process. The strata are intelligently identified using EMD signal decomposition and K-means clustering algorithms, and the vibratory compaction energy and pile spacing are dynamically adjusted based on the identification results.

[0009] Step 3: After the vibro-compacted stone pile construction is completed, anti-seepage reinforcement grouting holes are evenly distributed in the soil between the piles. An environmentally friendly cementitious material with controllable setting is injected into the grouting holes to form an in-situ anti-seepage solidification layer with a certain strength in the loose soil between the piles, achieving a dual reinforcement effect of physical compaction and chemical solidification. The environmentally friendly cementitious material is a glutinous rice-based cementitious material, and its setting time is controlled by adding a retarder or accelerator. The grouting pressure is controlled between 0.3 MPa and 0.8 MPa to ensure that the grout fully fills the pores in the soil between the piles. The anti-seepage reinforcement grouting holes are evenly distributed along the gaps between the vibro-compacted stone piles, with the spacing between the grouting holes being 1 / 2 to 1 / 3 of the spacing between the vibro-compacted stone piles. The grouting depth is consistent with the depth of the bottom of the vibro-compacted stone piles. The grouting sequence adopts a ring-by-ring method from the outside in to prevent grout loss and ensure the continuity and integrity of the grouting area. After grouting is completed, the in-situ permeability coefficient of the soil between the piles is tested. If the permeability coefficient does not meet the design requirements, the spacing between grouting holes is increased or the grouting pressure is increased until the permeability coefficient of the soil between the piles meets the seepage prevention requirements. After the environmentally friendly cementitious material is injected, a geomembrane or geotextile is laid on top of the in-situ seepage prevention and curing layer as an auxiliary seepage prevention layer, forming a double composite seepage prevention structure of grouting curing layer plus geomembrane or geotextile, further blocking the seepage path around the dam.

[0010] Step 4: A coarse transition layer and a fine cushion layer are sequentially laid on top of the compacted crushed stone cushion layer to form a multi-level gradually changing buffer layer. The outer side of the cushion layer smoothly connects to the downstream rockfill dam body. The multi-level gradually changing cushion layer is a two- or more-layer structure that gradually decreases in fineness from crushed stone to graded sand, used to buffer stress concentration between the rigid crushed stone pile foundation and the concrete inclined slab. Based on the particle size distribution of the soil between the piles, the particle size distribution range of the coarse transition layer and the fine cushion layer is calculated and determined layer by layer according to the anti-filtration criterion, ensuring that the particle size of each layer of the cushion layer meets the anti-filtration protection requirements of the soil between the piles, preventing the loss of fine particles.

[0011] Step 5: Cast inclined concrete cut-off panels on the gradient cushion layer. The top of the panels is rigidly connected to the upstream dam cut-off structure via connecting toe plates, and the end of the panels connects to the downstream cut-off wall. At the connection node between the inclined concrete cut-off panels and the cut-off wall, the top of the cut-off wall is wrapped with flexible asphalt concrete with a reserved extra height, allowing the cut-off wall to penetrate into the asphalt concrete under water pressure, converting uneven settlement into flexible deformation and forming a flexible self-adaptive connection structure.

[0012] Step 6: Construct seepage barriers embedded in bedrock at the upstream toe slab and downstream end of the dam panel. Construct a vertical seepage barrier at the top toe slab of the dam panel to form a three-dimensional closed seepage barrier system. The thickness of the top seepage barrier is controlled between 1.0m and 1.2m. One side is integrally cast with the concrete toe slab, while the other side is sealed to the backfill soil of the dam body to block lateral seepage around the top.

[0013] Step 7: Backfill the remaining areas of the slope with soil to restore the slope surface, and install slope drainage and protection measures. After the slope surface is restored with soil, lay vegetation bags or ecological slope protection materials on the slope surface, and install slope interception drainage ditches and blind drain drainage systems to prevent rainwater erosion from causing soil loss between piles or damage to the solidified layer.

[0014] This invention abandons the large-scale excavation method for steep slopes, employing in-situ reinforcement of a thick overburden layer using vibro-compacted piles. This eliminates the need for large-area slope cutting and overburden removal, significantly reducing earthwork excavation and avoiding the risk of slope instability under unloading, thus greatly improving construction safety. It achieves integrated continuous processes for foundation reinforcement, cushion layer transition, panel connection, and seepage prevention and locking, with compact process connections, shortening the overall construction period by more than 25%. A multi-level gradually grading cushion layer serves as a rigid-flexible transition buffer layer, resolving the stress abrupt change problem between the rigid composite foundation of crushed stone piles and the inclined concrete panel, preventing settlement cracks at the connection point, and improving the durability of the panel structure. A three-dimensional closed seepage prevention system is adopted, with upstream and downstream double seepage barriers embedded in bedrock and a top seepage retaining wall. The crushed stone pile composite foundation acts as a permeable drainage layer in conjunction with the outer rigid seepage prevention structure, utilizing the piles for drainage and pressure reduction while blocking seepage paths around the dam, resulting in seepage prevention reliability superior to conventional single seepage barrier schemes. Furthermore, this invention introduces environmentally friendly grouting combined with curing technology, superimposing chemical curing on physical compaction to form an in-situ seepage-proof curing layer, which, together with the geomembrane, forms a double composite seepage-proof structure, effectively solving the seepage problem of loose overburden layers; it also improves the quality of foundation treatment by dynamically adjusting construction parameters through intelligent stratum identification technology; and it enhances the long-term durability of the seepage-proof system under harsh geological conditions by converting rigid nodes into flexible nodes through flexible adaptive connection technology.

[0015] In summary, due to the adoption of the above-mentioned technologies, the beneficial effects of this invention are as follows: In terms of safety benefits, it reduces large-scale excavation and unloading of steep slopes, avoiding the geological risk of landslides, and is particularly suitable for the reinforcement and renovation of old earth-rock dams, without disturbing the original main structure of the dam. In terms of investment benefits, it reduces the amount of earthwork excavation, spoil removal, and slope anchor support work, reducing the overall construction and installation investment by 18% to 25%. In terms of construction period benefits, it eliminates slow processes such as large-scale excavation, temporary slope support, and large-area replacement, enabling streamlined on-site operations and significantly shortening the overall construction period. In terms of structural durability, the composite foundation has good uniformity, the rigid-flexible transition cushion layer eliminates stress cracks, the three-dimensional closed seepage prevention system has no weak points, and the workload of later operation and maintenance is small. Attached Figure Description

[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention, making other features, objects, and advantages of the invention more apparent. The illustrative embodiments of the invention illustrated in the drawings and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1This is a longitudinal section along the dam axis, showing the layout of the dam body, the overburden layer of the steep slope, the vibro-compacted stone piles, the front toe corner working platform, and the interface between the soil and the bedrock.

[0018] Figure 2 This is a cross-sectional structural diagram showing the connection relationship between the vibro-compacted piles embedded in the bedrock, the graded cushion layer, the gradually changing concrete panel, the upstream and downstream seepage barriers, and the top seepage retaining wall. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be understood that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0021] This embodiment provides an integrated construction method for vibro-compaction reinforcement of the foundation of a high and steep slope downstream of an earth-rock dam and seepage prevention by connecting it with a panel dam. It is applicable to a high and steep slope area downstream of an earth-rock dam, where there is a colluvial overburden layer with a thickness of about 15m to 25m. The soil is loose and highly compressible. The method of this invention is used for integrated foundation reinforcement and seepage prevention construction. The specific steps are as follows.

[0022] Step 1: Preliminary Boundary Delineation and Slope Pretreatment. The interface between the soil and bedrock is delineated along the longitudinal section of the dam axis. Topsoil and loose vegetation on the slope are cleared, and the working platform at the front toe angle is prepared, reserving space for vibratory roller operation. Large-scale slope cutting and excavation are avoided on steep slopes; the original slope outline is preserved to minimize unloading disturbance. The thickness of the overburden layer and the depth of the bedrock are determined using ground-penetrating radar or drilling, providing a basis for the subsequent design of vibratory compaction piles and grouting hole depths.

[0023] Step 2: In-situ reinforcement using vibro-compacted stone piles arranged in a quincunx pattern. From the bedrock interface upwards to the foundation area, vibro-compacted stone piles are arranged in a quincunx pattern, with pile diameters ranging from 0.8m to 1.2m and pile spacing from 2.0m to 2.5m. The piles penetrate the entire colluvial overburden layer and embed at least 0.5m into the underlying bedrock. A vibro-compactor is used to compact the loose overburden between the piles, forming a composite foundation. Crushed stone is backfilled in layers above the pile tops, each layer not exceeding 0.5m in thickness. Vibratory rollers are used to compact the layers, forming a uniform composite bearing layer and eliminating the risk of uneven settlement. During the construction of the vibro-compacted stone piles, a real-time monitoring system is used to collect construction data such as working current and working depth during the drilling process. EMD signal decomposition and K-means clustering algorithms are used for intelligent identification of the strata. Based on the identification results, the vibro-compacting energy and pile spacing are dynamically adjusted to ensure sufficient compaction of the piles in the soft strata.

[0024] Step 3: In-situ grouting combined with pile solidification. After the vibro-compacted stone piles are constructed, anti-seepage reinforcement grouting holes are evenly distributed in the soil between the piles. The grouting holes are evenly distributed along the gaps between the vibro-compacted stone piles, with a spacing of 1 / 2 to 1 / 3 of the pile spacing. The grouting depth is consistent with the bottom depth of the vibro-compacted stone piles. The grouting sequence adopts a ring-by-ring method from the outside to the inside to prevent grout loss and ensure the continuity and integrity of the grouting area. An environmentally friendly cementitious material with controllable setting is injected into the grouting holes. In this embodiment, glutinous rice-based cementitious material is used, and its setting time is controlled by adding a retarder or accelerator. The grouting pressure is controlled between 0.3 MPa and 0.8 MPa to ensure that the grout fully fills the pores of the soil between the piles. After grouting, the loose soil between the piles forms an in-situ anti-seepage solidification layer with a certain strength, achieving a dual reinforcement effect of physical compaction and chemical solidification. After grouting is completed, the in-situ permeability coefficient of the soil between the piles is tested. If the permeability coefficient does not meet the design requirements, the spacing between grouting holes is increased or the grouting pressure is increased until the permeability coefficient of the soil between the piles meets the seepage prevention requirements. After the environmentally friendly cementitious material is injected, a geomembrane or geotextile is laid on top of the in-situ seepage prevention and curing layer as an auxiliary seepage prevention layer, forming a double composite seepage prevention structure of grouting curing layer plus geomembrane or geotextile, further blocking the seepage path around the dam.

[0025] Step 4: Set up a multi-level gradual transition cushion layer. A coarse transition layer and a fine cushion layer are laid sequentially above the compacted stone cushion layer, forming a gradually grading material from coarse to fine. This avoids stress concentration and cracking caused by direct hard contact between the top surface of the rigid crushed stone piles and the concrete panel. Based on the particle size distribution of the soil between the piles, the particle size distribution range of the coarse transition layer and the fine cushion layer is calculated and determined layer by layer according to the anti-filtration criterion. This ensures that the particle size of each layer of the cushion layer meets the anti-filtration protection requirements of the soil between the piles, preventing the loss of fine particles. The outer side of the cushion layer smoothly connects to the downstream rockfill dam body, achieving a gentle transition between the rockfill area of ​​the dam body and the panel foundation.

[0026] Step 5: Casting the Gradient Connection Panel Structure. An inclined concrete panel is cast above the gradient cushion layer. The top of the panel is rigidly connected to the upstream dam's seepage-proof toe plate via a connecting plate, toe plate structure, and the same structure, forming a continuous seepage-proof panel system. The end of the panel connects to the downstream seepage-proof wall, creating a bidirectional lock between upstream and downstream. At the connection point between the inclined concrete seepage-proof panel and the seepage-proof wall, the top of the seepage-proof wall is wrapped with flexible asphalt concrete with a reserved extra height. This allows the seepage-proof wall to penetrate into the asphalt concrete under water pressure, converting uneven settlement into flexible deformation and forming a flexible, self-adaptive connection structure. This effectively solves the industry problem of large settlement of the overburden foundation leading to cracking of the panel toe plate.

[0027] Step 6: Close the upstream and downstream cutoff walls and seal the top edge for wave and seepage prevention. A longitudinal cutoff wall is cast at the upstream toe slab location and embedded in the bedrock. A similar cutoff wall is constructed at the downstream end, extending deep into the bedrock to block circumferential seepage. A cutoff retaining wall with a thickness of 1.0m to 1.2m is cast at the top toe slab location of the dam panel. One side is integrally cast with the concrete toe slab, while the other side is sealed to the backfill soil of the dam body, sealing the lateral seepage channels at the top and forming a three-dimensional closed seepage prevention system.

[0028] Step 7: Slope restoration and slope protection finishing touches. Backfill the remaining slope area outside the panel with the original excavated qualified backfill soil to restore the slope outline. Lay vegetation bags or ecological slope protection materials on the slope surface, and install a slope intercepting drainage ditch and blind ditch drainage system to prevent rainwater from eroding the cover layer and causing soil loss between piles or damage to the solidified layer.

[0029] Through the above construction methods, this embodiment realizes the integrated construction of vibro-compaction reinforcement of the overburden foundation of the downstream high and steep slope of the earth-rock dam and the seepage prevention of the panel dam. It avoids large-scale excavation, shortens the construction period by about 30% compared with the traditional scheme, and reduces the project investment by about 20%. The bearing capacity of the composite foundation meets the design requirements and there are no weak points for leakage, achieving good engineering results.

Claims

1. A method for integrating vibro-compaction reinforcement of the foundation of the overburden layer on the downstream high and steep slope of an earth-rock dam with seepage prevention of the face-faced dam, characterized in that: The construction steps include the following: S1: Delineate the interface between the overburden soil and the underlying bedrock along the dam axis, repair the toe-angle work platform of the slope, retain the original high and steep slope outline, and do not carry out large-scale slope cutting and excavation. S2: Within the corresponding range of the panel foundation, quincunx-shaped vibratory compaction stone piles are laid through the colluvial cover layer, with the bottom of the piles embedded in the bedrock to compact the loose overburden between the piles and form a composite foundation; the pile tops are backfilled with crushed stone in layers and compacted by vibratory rolling. S3: After the vibratory crushing stone pile construction is completed, anti-seepage reinforcement grouting holes are evenly distributed in the soil between the piles. Environmentally friendly cementitious material with controllable curing is injected into the grouting holes to form an in-situ anti-seepage solidification layer with a certain strength in the loose soil between the piles, so as to achieve the dual reinforcement effect of physical compaction and chemical solidification. S4: A coarse transition layer and a fine cushion layer are laid sequentially on the crushed stone cushion layer to form a multi-level gradual buffer layer. The outer side of the cushion layer is smoothly connected to the downstream rockfill dam body. S5: An inclined concrete anti-seepage panel is poured on the gradient cushion layer. The top of the panel is rigidly connected to the upstream dam anti-seepage structure through a connecting toe plate, and the end of the panel is connected to the downstream anti-seepage wall. S6: Construct anti-seepage walls embedded in bedrock at the upstream toe plate position and the downstream end of the panel; construct a vertical anti-seepage retaining wall at the top toe plate of the panel to form a three-dimensional closed anti-seepage system; S7: Backfill the vacant areas of the slope with soil to restore the slope surface, and provide supporting slope drainage and protection.

2. The integrated construction method for vibro-compaction reinforcement of the downstream steep slope overburden foundation of an earth-rock dam and seepage prevention connecting it to a panel dam, as described in claim 1, is characterized in that... In step 3, the environmentally friendly cementitious material is a glutinous rice-based cementitious material. Its setting time is controlled by adding a retarder or a quick-setting agent. The grouting pressure is controlled at 0.3MPa to 0.8MPa so that the grout can fully fill the pores of the soil between the piles.

3. The integrated construction method for vibro-compaction reinforcement of the downstream steep slope overburden foundation of an earth-rock dam and seepage prevention connecting it to a panel dam, as described in claim 1, is characterized in that... In step 3, the anti-seepage reinforcement grouting holes are evenly arranged along the gaps between the vibratory crushed stone piles, and the spacing between the grouting holes is 1 / 2 to 1 / 3 of the spacing between the vibratory crushed stone piles. The grouting depth is consistent with the bottom depth of the vibratory crushed stone pile. The grouting sequence adopts the method of pouring in circles from the outside to the inside to prevent grout loss and ensure the continuity and integrity of the grouting area.

4. The integrated construction method for vibro-compaction reinforcement of the downstream steep slope overburden foundation of an earth-rock dam and seepage prevention connecting it to a panel dam, as described in claim 1, is characterized in that... In step 2, the vibro-compacted stone piles are arranged in a quincunx pattern, with the piles penetrating the entire colluvial overburden and embedded in the underlying bedrock for no less than 0.5m. During the construction of the vibro-compacted stone piles, the working current and working depth data during the drilling process are collected using a real-time monitoring system. The strata are intelligently identified through EMD signal decomposition and K-means clustering algorithm. The vibro-compacting energy and the spacing between piles are dynamically adjusted based on the identification results.

5. The integrated construction method for vibro-compaction reinforcement of the downstream steep slope overburden foundation of an earth-rock dam and seepage prevention connecting it to a panel dam, as described in claim 1, is characterized in that... In step 4, the multi-level gradient cushion layer is a structure of two or more layers that gradually become finer from crushed stone to graded sand. Based on the particle size distribution of the soil between piles, the particle size distribution range of the coarse transition layer and the fine cushion layer is calculated and determined layer by layer according to the reverse filtration criterion, so that the particle size of each layer of the cushion layer meets the reverse filtration protection requirements with the particle size of the soil between piles, and prevents the loss of fine particles.

6. The integrated construction method for vibro-compaction reinforcement of the downstream steep slope overburden foundation of an earth-rock dam and seepage prevention connecting it to a panel dam, as described in claim 1, is characterized in that... In step 6, the thickness of the top anti-seepage retaining wall is controlled between 1.0m and 1.2m. One side is cast as a whole with the concrete toe slab, and the other side is sealed and connected with the backfill soil of the dam body to block lateral seepage around the top.

7. The integrated construction method for vibro-compaction reinforcement of the downstream steep slope overburden foundation of an earth-rock dam and seepage prevention connecting it to a panel dam, as described in claim 1, is characterized in that... In step 3, after the environmentally friendly cementitious material is injected, a geomembrane or geotextile is laid on top of the in-situ seepage-proof and curing layer as an auxiliary seepage-proof layer to form a double composite seepage-proof structure, further blocking the seepage path around the dam.

8. The integrated construction method for vibro-compaction reinforcement of the downstream steep slope overburden foundation of an earth-rock dam and seepage prevention connecting it to a panel dam, as described in claim 1, is characterized in that... In step 5, at the connection node between the inclined concrete anti-seepage panel and the anti-seepage wall, the top of the anti-seepage wall is wrapped with flexible asphalt concrete and a height allowance is reserved so that the anti-seepage wall can penetrate into the asphalt concrete under water pressure, converting uneven settlement into flexible deformation and forming a flexible self-adaptive connection structure.

9. The integrated construction method for vibro-compaction reinforcement of the downstream steep slope overburden foundation of an earth-rock dam and seepage prevention connecting it to a panel dam, as described in claim 1, is characterized in that... In step 3, after the grouting construction is completed, the in-situ permeability coefficient of the soil between the piles is tested. If the permeability coefficient does not meet the design requirements, the spacing between the grouting holes is increased or the grouting pressure is increased until the permeability coefficient of the soil between the piles meets the seepage prevention requirements.

10. The integrated construction method for vibro-compaction reinforcement of the downstream steep slope overburden foundation of an earth-rock dam and seepage prevention connecting it to a panel dam, as described in claim 1, is characterized in that... In step 7, after the slope is covered with soil and restored, vegetation bags or ecological slope protection materials are laid on the slope surface, and a slope interception and drainage ditch and blind ditch drainage system are installed to prevent rainwater erosion from causing soil loss between piles or damage to the solidified layer.

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