Rapid slope closing structure for downstream dam slope of concrete faced rockfill dam and construction method

Abstract

The invention relates to a concrete faced rockfill dam downstream dam slope rapid slope closing structure and a construction method.The concrete faced rockfill dam downstream dam slope rapid slope closing structure comprises a cemented sand gravel structure, the cemented sand gravel structure is located on the downstream side of a concrete faced rockfill dam, and the concrete faced rockfill dam comprises an upstream rockfill area and a downstream rockfill area; the cemented sand gravel structure is arranged on the strongly-weathered bed rock on one side of the downstream rockfill area; the cemented sand and gravel structure comprises a cemented sand and gravel wall body, a top slurry adding and vibrating cemented sand and gravel layer and a downstream slurry adding and vibrating cemented sand and gravel layer, the top slurry adding and vibrating cemented sand and gravel layer is arranged on the top of the cemented sand and gravel wall body, and the downstream slurry adding and vibrating cemented sand and gravel layer is arranged on the wall face of the downstream side of the cemented sand and gravel wall body. According to the rapid slope closing structure for the downstream dam slope of the concrete faced rockfill dam, the downstream slope setting space of the concrete faced rockfill dam can be reduced, so that the problems that the concrete faced rockfill dam is limited by the land space, the dam foundation is missing and the land acquisition range is large are solved to a certain extent, and the land acquisition investment is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of water conservancy and hydropower engineering, and particularly relates to a rapid slope reduction structure and construction method for the downstream slope of a concrete face rockfill dam. Background Art

[0002] Earth-rock dams are the most common type of dam in current dam construction and also the type with the fastest development, accounting for more than 95% of the total number of existing dams. There are more than 29,000 earth-rock dams with a height exceeding 15m worldwide, among which more than 15,000 are in China, mainly including homogeneous earth dams, core-wall dams, and concrete face rockfill dams, etc.

[0003] Under the background of accelerating the construction of a new energy system, pumped-storage power stations, as a key link in regulating power supply and demand and enhancing the stability of the power grid, are entering a golden period of rapid development. Due to significant advantages such as controllable cost, convenient construction, and strong deformation adaptability, concrete face rockfill dams are widely used in the construction field of pumped-storage power stations. However, it cannot be ignored that due to geographical and resource constraints, pumped-storage power stations are mostly located in mountain valley and hilly areas. These areas are characterized by crisscrossed mountains and ravines, extremely steep terrain, and complex and changeable topography. Therefore, the slope ratio of the dam foundation is often relatively steep. To ensure the overall stability of the dam, a larger slope space is required for the downstream slope of the dam, which will significantly increase the land acquisition area and filling engineering volume, and further increase the investment in land acquisition and resettlement, material source excavation, dam body filling, etc. In case of lack of terrain, it is difficult for the dam toe to be located on a stable foundation, which has an adverse impact on the structural stability. Summary of the Invention

[0004] The first aspect of the present application provides a rapid slope reduction structure for the downstream slope of a concrete face rockfill dam, which can reduce the downstream slope space of the concrete face rockfill dam.

[0005] The rapid slope reduction structure for the downstream slope of a concrete face rockfill dam provided by the first aspect of the present application includes a cemented gravel structure. The cemented gravel structure is located on the downstream side of the concrete face rockfill dam. The concrete face rockfill dam includes an upstream rockfill area and a downstream rockfill area. The cemented gravel structure is arranged on the strongly weathered bedrock on one side of the downstream rockfill area. The cemented gravel structure includes a cemented gravel wall body, a top slurry-injected and vibrated cemented gravel layer, and a downstream slurry-injected and vibrated cemented gravel layer. The top slurry-injected and vibrated cemented gravel layer is arranged on the top of the cemented gravel wall body, and the downstream slurry-injected and vibrated cemented gravel layer is arranged on the wall surface on the downstream side of the cemented gravel wall body.

[0006] In addition, the rapid slope reduction structure for the downstream slope of a concrete face rockfill dam provided by the present application also has the following additional technical features:

[0007] In an alternative solution, the top of the cemented gravel and sand structure is not lower than the extended surface extending downstream along the slope of the downstream rockfill area. The cemented gravel and sand structure has a first slope surface and a second slope surface. The first slope surface and the second slope surface are respectively located on the upstream side and the downstream side of the cemented gravel and sand structure. The slope range of the first slope surface is 1:0.3 to 0.7, and the slope range of the second slope surface is 1:0.5 to 0.7.

[0008] In an alternative solution, the composition materials of the cemented gravel and sand wall body include cemented gravel and sand materials, coarse aggregates and cementitious materials. The content of sand materials with a particle size less than 5 mm in the cemented gravel and sand materials is 18% to 35%. The content of aggregates with a particle size of 5 to 40 mm in the coarse aggregates is 35% to 65%. The dosage of the cementitious material is 75 to 85 kg / m 3 .

[0009] In an alternative solution, the top grouted and vibrated cemented gravel and sand layer and / or the downstream grouted and vibrated cemented gravel and sand layer add 6% of neat cement slurry on the basis of the composition materials of the cemented gravel and sand wall body. The top width of the top grouted and vibrated cemented gravel and sand layer is 2 m, and the thickness is 1 m. The horizontal thickness of the downstream grouted and vibrated cemented gravel and sand layer is 1 m.

[0010] In an alternative solution, consolidated grouting is arranged at the bottom of the foundation of the cemented gravel and sand wall body, and the consolidated grouting is arranged in the strongly weathered bedrock. A drain pipe is arranged at the bottom of the cemented gravel and sand wall body. The drain pipe maintains a drainage slope of i = 0.03 inclined towards the wall surface, and an anti-filter geotextile is wrapped around the pipe orifice of the drain pipe.

[0011] In an alternative solution, the downstream rockfill area has a third slope surface on the upstream side. The slope of the third slope surface is 1:0.5. Transition materials, bedding materials and concrete panels are sequentially laid on the upstream slope surface of the concrete face rockfill dam. And curtain grouting is arranged at the toe position on the upstream side of the concrete face rockfill dam.

[0012] The second aspect of the present application provides a construction method for constructing the downstream dam slope rapid slope reduction structure of the concrete face rockfill dam provided in the first aspect. The construction method includes the following steps:

[0013] According to the design requirements, the foundation of the concrete face rockfill dam is excavated and cleaned. The dam foundation and the range of the cemented gravel and sand structure are exposed to the strongly weathered bedrock, and then the consolidated grouting is constructed as required;

[0014] Use a special mixer to mix the composition materials of the cemented gravel and sand structure to form cemented gravel and sand materials. The dosage of the cementitious material in the composition materials is 75 to 85 kg / m 3, the 180d compressive strength can reach 6MPa. After the mixing is completed, the cemented sand and gravel are loaded into the warehouse with a dump truck and leveled with a backhoe excavator;

[0015] Add 6% of cement paste to the cemented gravel structural components and mix them to form cemented gravel with cemented paste and vibration;

[0016] A drainage pipe is pre-buried at the bottom of the cemented gravel structure, with the drainage pipe maintaining a drainage slope of i=0.03 inclined toward the wall. The outlet of the drainage pipe is wrapped with anti-filtration geotextile, and the cemented gravel can be vibrated with slurry near the drainage pipe;

[0017] The downstream rockfill material and the cemented gravel material are sequentially laid from upstream to downstream, and the face rockfill dam and the cemented gravel structure are simultaneously compacted;

[0018] After the cemented gravel structure reaches the designed top elevation, the dam body of the face rockfill dam continues to be filled and compacted according to the designed slope ratio.

[0019] In an optional solution, during the synchronous compaction construction, the panel rockfill dam and the cemented gravel structure are synchronously raised layer by layer. The surface elevation of the panel rockfill dam can be slightly lower than the surface elevation of the cemented gravel structure. The overlap width of the two at the junction is not less than 30 cm, and the cemented gravel structure can be paved more upstream to ensure the structural shape.

[0020] In an optional solution, when constructing the cemented gravel structure, the paved cemented gravel needs to be roughened after final setting and cement mortar with at least one level higher strength is laid before the next layer is laid.

[0021] In one optional solution, the warehouse surface needs to be kept moist during construction. When the sun is strong or the wind is dry, the surface moisture can be compensated by spraying or covered with tarpaulin to keep the surface moist and not white. When the temperature is low, it can be covered with a curing mat to prevent the cemented sand and gravel from freezing.

[0022] When the corners of the cemented gravel structure are vibrated with cemented gravel, a high-frequency vibrator is used for vibration, a small vibrating roller is used for rolling, or a tamping machine is used for manual compaction to ensure that the corners and surrounding structures are fully compacted.

[0023] The beneficial effects of this application are:

[0024] The rapid slope reduction structure for the downstream slope of the concrete face rockfill dam in this application slopes the downstream slope of the concrete face rockfill dam through a cemented gravel structure. The cemented gravel structure can have a steeper slope while ensuring the structural stability, thus reducing the downstream slope space of the concrete face rockfill dam and the structural range of the dam toe to a certain extent, overcoming the problems of the concrete face rockfill dam being restricted by the land use space, lacking the dam foundation, and having a large land acquisition scope, and reducing the land acquisition investment. When constructing the rapid slope reduction structure for the downstream slope of the concrete face rockfill dam, the filling of the concrete face rockfill dam can be synchronously rolled and constructed with the cemented gravel structure, giving play to the advantage of continuous construction of the cemented gravel and improving the construction efficiency.

[0025] It should be understood that the above general description and the following detailed description are only exemplary and do not limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic layout structure diagram of the rapid slope reduction structure for the downstream slope of the concrete face rockfill dam provided by this application.

[0027] Reference numerals: Cemented gravel structure 1, Cemented gravel wall body 11, Top slurry-added and vibrated cemented gravel layer 12, Downstream slurry-added and vibrated cemented gravel layer 13, First slope 14, Second slope 15, Concrete face rockfill dam 2, Upstream rockfill area 21, Downstream rockfill area 22, Third slope 23, Transition material 24, Bedding material 25, Concrete face 26, Curtain grouting 27, Strongly weathered bedrock 3, Extended surface 4, Consolidation grouting 5, Drain pipe 6, Filter geotextile 7.

[0028] The accompanying drawings herein are incorporated into the specification and form a part of this specification, showing embodiments consistent with this application and used together with the specification to explain the principles of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] For a better understanding of the technical solutions of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0030] It should be clear that the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. All other technical solutions obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0031] The terms used in the embodiments of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms "a", "the" and "said" used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0032] It should be understood that the term "and / or" used herein is merely a description of the associated relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this text generally indicates that the associated objects before and after are in an "or" relationship.

[0033] It should be noted that the orientation terms such as "upper", "lower", "left", and "right" described in the embodiments of this application are described from the perspective shown in the drawings and should not be construed as a limitation on the embodiments of this application. In addition, in the context, it should also be understood that when it is mentioned that one component is connected "above" or "below" another component, it can not only be directly connected "above" or "below" another component, but also be indirectly connected "above" or "below" another component through an intermediate component.

[0034] As Figure 1 As shown, in the first aspect of the embodiment of this application, a rapid slope reduction structure for the downstream slope of a concrete face rockfill dam is provided. The rapid slope reduction structure for the downstream slope of the concrete face rockfill dam mainly includes a cemented gravel structure 1. The cemented gravel structure 1 is located on the downstream side of the concrete face rockfill dam 2. The concrete face rockfill dam 2 includes an upstream rockfill area 21 and a downstream rockfill area 22. The cemented gravel structure 1 is arranged on the strongly weathered bedrock 3 on one side of the downstream rockfill area 22. After the strongly weathered bedrock 3 is exposed by the excavation of the dam foundation, the cemented gravel structure 1 is set at the downstream dam toe of the dam body for rapid slope reduction. The cemented gravel structure 1 includes a cemented gravel wall body 11, a top grouted and vibrated cemented gravel layer 12, and a downstream grouted and vibrated cemented gravel layer 13. The top grouted and vibrated cemented gravel layer 12 is arranged at the top of the cemented gravel wall body 11, and the downstream grouted and vibrated cemented gravel layer 13 is arranged on the wall surface on the downstream side of the cemented gravel wall body 11.

[0035] In the rapid slope reduction structure for the downstream slope of the concrete face rockfill dam in this embodiment, the downstream slope of the concrete face rockfill dam 2 is reduced by the cemented gravel structure 1. The cemented gravel structure 1 can have a steeper slope while ensuring the structural stability, thereby reducing the downstream slope space of the concrete face rockfill dam 2 and reducing the structural range of the dam toe while ensuring the stability of the slope reduction structure, thus overcoming to a certain extent the problems of the limited land use space of the concrete face rockfill dam 2, the lack of dam foundation, and the large land acquisition scope, and reducing the land acquisition investment. When constructing the rapid slope reduction structure for the downstream slope of the concrete face rockfill dam, the filling of the concrete face rockfill dam 2 can be synchronously rolled and constructed with the cemented gravel structure 1, giving play to the advantage of continuous construction of the cemented gravel and improving the construction efficiency.

[0036] As Figure 1As shown, in a specific embodiment, the top of the cemented gravel structure 1 is not lower than the extended surface 4 extending downstream along the slope surface of the downstream rockfill area 22. The cemented gravel structure 1 has a first slope surface 14 and a second slope surface 15. The first slope surface 14 and the second slope surface 15 are respectively located on the upstream side and the downstream side of the cemented gravel structure 1. The slope of the first slope surface 14 is generally 1:0.3. However, under the condition of meeting the stress stability requirements, the upstream slope ratio can be steeper than 1:0.3, that is, the slope range of the first slope surface 14 is 1:0.3 to 0.7, and the slope range of the second slope surface 15 is 1:0.5 to 0.7.

[0037] In a specific embodiment, the composition materials of the cemented gravel wall body 11 include cemented gravel materials, coarse aggregates and cementitious materials. The content of sand materials with a particle size less than 5 mm in the cemented gravel materials is 18% - 35%. The content of aggregates with a particle size of 5 - 40 mm in the coarse aggregates is 35% - 65%. The dosage of the cementitious materials is about 80 kg / m 3 or so, such as 75 - 85 kg / m 3 . In addition, the top grouted and vibrated cemented gravel layer 12 and / or the downstream grouted and vibrated cemented gravel layer 13 add 6% of neat cement slurry on the basis of the composition materials of the cemented gravel wall body 11. The top width of the top grouted and vibrated cemented gravel layer 12 is 2 m, and the thickness is 1 m. The horizontal thickness of the downstream grouted and vibrated cemented gravel layer 13 is 1 m. The top grouted and vibrated cemented gravel layer 12 and the downstream grouted and vibrated cemented gravel layer 13 can protect the cemented gravel wall body 11 from being washed and damaged by the downstream water flow and rainwater for a long time, enhance the structural durability, and thus improve the service life.

[0038] During construction, the composition materials of the cemented gravel structure 1 can fully utilize the gravel materials at the construction site, and add a small amount of cementitious materials for rolling or vibrating construction, which has the advantages of safety and reliability, low investment, continuous paving, short construction period, environmental friendliness, etc.

[0039] As Figure 1 shown, in a specific embodiment, consolidation grouting 5 is arranged at the bottom of the foundation of the cemented gravel wall body 11, and the consolidation grouting 5 is arranged in the strongly weathered bedrock 3; a Φ100 drain pipe 6 is arranged at the bottom of the cemented gravel wall body 11. The hole spacing of the drainage holes on the drain pipe 6 is 3.0 m. The drain pipe 6 maintains a drainage slope of i = 0.03 inclined towards the wall surface, and an anti-filter geotextile 7 is wrapped around the pipe orifice of the drain pipe 6.

[0040] As Figure 1As shown in the figure, in a specific embodiment, the downstream rockfill area 22 has a third slope surface 23 on the upstream side. The slope of the third slope surface 23 is 1:0.5. The upstream slope surface of the concrete face rockfill dam 2 is successively paved with transition material 24, bedding material 25 and concrete face slab 26, and curtain grouting 27 is arranged at the toe position on the upstream side of the concrete face rockfill dam 2. Generally speaking, the horizontal thickness of the transition material 24 is about 4m, the horizontal thickness of the bedding material 25 is about 3m, and the thickness of the concrete face slab 26 is about 0.4m. There may be certain differences and fluctuations in the specific values, and specific limitations are not made in this article.

[0041] In the second aspect of the embodiments of the present application, a construction method is provided for constructing the rapid slope reduction structure of the downstream dam slope of the concrete face rockfill dam in the first aspect of the embodiments. The construction method mainly includes the following steps:

[0042] According to the design requirements, the foundation of the concrete face rockfill dam 2 is excavated and cleaned, and the foundation and the range of the cemented gravel structure 1 are exposed to the strongly weathered bedrock 3, and then the consolidation grouting 5 is constructed as required;

[0043] Use a special mixer to mix the constituent materials of the cemented gravel structure 1 to form cemented gravel material. The dosage of the cementitious material in the constituent materials is 75-85 kg / m 3 , and the 180-day compressive strength can reach 6 MPa. After mixing is completed, load the cemented gravel into the bin with a 20-25t dump truck and level it with a backhoe excavator;

[0044] Add 6% of neat cement slurry to the constituent materials of the cemented gravel structure 1 for mixing to form slurry-injected vibrated cemented gravel;

[0045] Embed a drain pipe 6 at the bottom of the cemented gravel structure 1. The drain pipe 6 maintains a drainage slope of i = 0.03 towards the wall surface. The pipe orifice of the drain pipe 6 is wrapped with a filter geotextile 7 for filtration. To avoid damage to the drain pipe 6 due to rolling, slurry-injected vibrated cemented gravel can be considered near the drain pipe 6;

[0046] Successively spread the downstream rockfill material and the cemented gravel material from the upstream to the downstream direction, and carry out synchronous rolling construction on the concrete face rockfill dam 2 and the cemented gravel structure 1;

[0047] After the cemented gravel structure 1 reaches the design top elevation, continue to fill and roll the dam body of the concrete face rockfill dam 2 according to the design slope ratio.

[0048] In a specific embodiment, when carrying out synchronous rolling construction, the concrete face rockfill dam 2 and the cemented gravel structure 1 rise layer by layer synchronously. The layer surface of the concrete face rockfill dam 2 can be slightly lower than the layer elevation of the cemented gravel structure 1. The lap width at the joint part of the two is not less than 30 cm, and the cemented gravel structure 1 can be spread more on the upstream side to ensure the structural shape.

[0049] In a specific embodiment, when constructing the cemented gravel structure 1, after the initially laid cemented gravel material has finally set, it is necessary to perform scarifying and lay cement mortar with a strength at least one grade higher, and then proceed with the laying construction of the next layer. In addition, during the construction process, it is necessary to keep the surface of the placement area moist. When the sunlight is strong or the wind is dry, surface moisture compensation is carried out by spraying or the surface is covered with a tarpaulin to keep the surface from turning white and in a moist state; when the temperature is relatively low, it is covered with curing mats to prevent the cemented gravel from freezing; in addition, when using slurry-added vibration compaction of cemented gravel at the corner parts of the cemented gravel structure 1, a high-frequency vibrator is required for vibration compaction, a small vibratory roller for rolling or a rammer for manual ramming to ensure that the corners and the surrounding structures are fully compacted.

[0050] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A rapid slope reduction structure for the downstream slope of a concrete face rockfill dam, characterized in that It includes a cemented gravel structure which is located on the downstream side of the concrete face rockfill dam. The concrete face rockfill dam includes an upstream rockfill area and a downstream rockfill area. The cemented gravel structure is arranged on the strongly weathered bedrock on one side of the downstream rockfill area. The cemented gravel structure includes a cemented gravel wall body, a top grout-injected and vibrated cemented gravel layer, and a downstream grout-injected and vibrated cemented gravel layer. The top grout-injected and vibrated cemented gravel layer is arranged on the top of the cemented gravel wall body, and the downstream grout-injected and vibrated cemented gravel layer is arranged on the wall surface on the downstream side of the cemented gravel wall body.

2. The rapid slope reduction structure for the downstream slope of the concrete face rockfill dam according to claim 1, wherein The top of the cemented gravel structure is not lower than the extended surface where the slope of the downstream rockfill area extends towards the downstream side. The cemented gravel structure has a first slope and a second slope. The first slope and the second slope are respectively located on the upstream side and the downstream side of the cemented gravel structure. The slope range of the first slope is 1:0.3 - 0.7, and the slope range of the second slope is 1:0.5 - 0.

7.

3. The downstream slope rapid slope reduction structure of the concrete face rockfill dam according to claim 1 or 2, characterized in that, The composition materials of the cemented gravel wall include cemented gravel materials, coarse aggregates and cementitious materials. The content of sand materials with a particle size less than 5 mm in the cemented gravel materials is 18% - 35%. The content of aggregates with a particle size of 5 - 40 mm in the coarse aggregates is 35% - 65%. The dosage of the cementitious materials is 75 - 85 kg / m 3 .

4. The rapid slope reduction structure for the downstream slope of the concrete face rockfill dam according to claim 3, wherein 6% of neat cement slurry is added to the composition materials of the cemented gravel wall body for the top grout-injected and vibrated cemented gravel layer and / or the downstream grout-injected and vibrated cemented gravel layer. The top width of the top grout-injected and vibrated cemented gravel layer is 2m, and the thickness is 1m. The horizontal thickness of the downstream grout-injected and vibrated cemented gravel layer is 1m.

5. The rapid slope reduction structure for the downstream slope of a concrete face rockfill dam according to claim 1 or 2 or 4, characterized in that, Consolidation grouting is arranged at the bottom of the foundation of the cemented gravel wall body within the strongly weathered bedrock. A drain pipe is arranged at the bottom of the cemented gravel wall body. The drain pipe maintains a drainage slope of i = 0.03 inclined towards the wall surface, and the pipe orifice of the drain pipe is wrapped with an anti-filter geotextile.

6. The downstream slope rapid slope reduction structure of the concrete face rockfill dam according to claim 5, characterized in that The downstream rockfill area has a third slope on the upstream side, and the slope of the third slope is 1:0.

5. The upstream slope of the concrete face rockfill dam is successively paved with transition material, bedding material, and concrete face. And curtain grouting is arranged at the toe position on the upstream side of the concrete face rockfill dam.

7. A construction method, characterized in that, For the construction of the rapid slope reduction structure of the downstream dam slope of the concrete face rockfill dam described in any one of claims 1 - 6, the construction method includes the following steps: According to the design requirements, excavate and clean the foundation of the concrete face rockfill dam, expose the dam foundation and the range of the cemented gravel structure to the strongly weathered bedrock, and then construct consolidation grouting as required; Use a special mixer to mix the constituent materials of the cemented gravel structure to form cemented gravel materials. The dosage of the cementitious material in the constituent materials is 75 - 85 kg / m 3 , and the 180-day compressive strength can reach 6 MPa. After mixing is completed, load the cemented gravel into the bin with a dump truck and level it with a backhoe excavator; Add 6% of neat cement slurry to the composition materials of the cemented gravel structure for mixing to form grout-injected and vibrated cemented gravel; Embed a drain pipe at the bottom of the cemented gravel structure. The drain pipe maintains a drainage slope of i = 0.03 inclined towards the wall surface. The pipe orifice of the drain pipe is wrapped with an anti-filter geotextile for anti-filtration. The grout-injected and vibrated cemented gravel can be used near the drain pipe; Successively spread the downstream rockfill material and the cemented gravel material from the upstream to the downstream direction, and perform synchronous rolling construction on the concrete face rockfill dam and the cemented gravel structure; After the cemented gravel structure reaches the designed top elevation, continue to fill and roll the dam body of the concrete face rockfill dam according to the designed slope ratio.

8. The construction method according to claim 7, characterized in that, During the synchronous rolling construction, the face rockfill dam and the cemented gravel structure rise layer by layer synchronously. The elevation of the surface of the face rockfill dam can be slightly lower than that of the cemented gravel structure. The lap width at the joint between the two is not less than 30 cm, and the cemented gravel structure can be paved more on the upstream side to ensure the structural shape.

9. The construction method according to claim 7 or 8, characterized in that, During the construction of the cemented gravel structure, after the laid cemented gravel material has finally set, it is necessary to carry out scarifying and lay cement mortar with at least one higher strength grade, and then carry out the laying construction of the next layer.

10. The construction method according to claim 7 or 8, characterized in that, During the construction process, the surface of the bin should be kept moist. When the sunlight is strong or the wind is dry, surface moisture compensation is carried out by spraying or covered with tarpaulins to keep the surface from turning white and in a moist state; when the temperature is low, it is covered with curing mats to prevent the cemented gravel from freezing; When the corner parts of the cemented gravel structure are vibrated and cemented with mortar, a high-frequency vibrator should be used for vibration, a small vibrating roller for rolling or a rammer for manual ramming to ensure that the corners and the surrounding structures are fully compacted.

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