A mattress structure employing a cemented sand-gravel foundation

Abstract

The application relates to a apron structure with a cemented sand gravel foundation, which mainly comprises cemented sand gravel, an apron and an anti-scouring groove. The cemented sand gravel is arranged on a pebble layer or a stratum with a bearing capacity higher than a preset value after the covering layer of the ground is removed. A mortar layer is arranged between the pebble layer or the stratum and the cemented sand gravel. The cemented sand gravel has a preset laying thickness, and the bottom of the cemented sand gravel is at least partially lower than the scouring bottom line. The apron is arranged on one side of the top of the cemented sand gravel. The anti-scouring groove is arranged on the downstream side of the apron, the bottom of the anti-scouring groove is lower than the bottom of the apron, and the anti-scouring groove is filled with large stones and / or concrete tetrahedrons. The apron structure with the cemented sand gravel foundation has higher stability and can reduce the risk of damage of the apron caused by scouring.

Description

Technical Field

[0001] This application relates to the field of water conservancy and hydropower engineering technology, specifically to a revetment structure using a cemented gravel foundation. Background Technology

[0002] In water conservancy and hydropower projects, concrete abutments are typically installed downstream of spillway structures such as sluices and spillways to protect the riverbed from erosion and other damage. The high flow velocity and turbulent flow patterns within the abutment necessitate sufficient strength and resistance to scour and abrasion, and the abutment foundation must be solid and reliable. The abutment foundation usually rests on the overburden layer, and a large rock-filled revetment is installed downstream of the abutment to protect the riverbed. However, considering the relative difficulty in guaranteeing the durability and reliability of the revetment, scour pits can easily form in the downstream riverbed during operation, causing deformation of the abutment foundation and damage to the abutment. This risk is particularly high for high-flow, low-head sluice gate and dam projects, where the risk of revetment damage due to erosion is extremely high. Utility Model Content

[0003] This application provides a tanker structure based on cemented gravel, which has higher stability and can reduce the risk of tanker damage from erosion.

[0004] The revetment structure based on cemented gravel provided in this application includes: cemented gravel, which is arranged on a pebble layer or a stratum with a bearing capacity higher than a preset value after the surface overburden is removed; a mortar layer is laid between the pebble layer or the stratum and the cemented gravel; the cemented gravel has a preset laying thickness; and the bottom of the cemented gravel is at least partially lower than the scour line.

[0005] A protective barrier is provided on one side of the top of the cemented gravel;

[0006] The anti-scour channel is located on the downstream side of the apron, with its bottom lower than the bottom of the apron, and is filled with large stones and / or concrete tetrahedrons.

[0007] In addition, the abutment structure based on cemented gravel provided in this application also has the following additional technical features:

[0008] In one alternative, the slope of the revetment from the upstream side to the downstream side is 2%, the revetment is a reinforced concrete structure, and the surface of the revetment is covered with a layer of erosion-resistant concrete of a predetermined thickness, the aggregate of which is hard natural pebbles or artificial crushed stone.

[0009] In one alternative, the mortar layer is 20mm to 30mm thick, the erosion-resistant concrete is 50cm thick, and the erosion-resistant concrete is continuously poured onto the reinforced concrete structure after the abutment is completed.

[0010] In one alternative embodiment, the cemented gravel comprises water, cement, fly ash, gravel, and cementing materials. The maximum particle size of the gravel is no more than 150 mm, and the content of sand with a particle size less than 5 mm is 18% to 35%, while the content of coarse aggregate with a particle size of 5 mm to 40 mm is 35% to 65%.

[0011] In one alternative, the particle size of the large stones and / or concrete tetrahedrons backfilled in the anti-scouring trench is 1.5m to 2m, and after backfilling, the top of the large stones and / or concrete tetrahedrons is flush with the top of the anti-scouring trench.

[0012] The beneficial effects of this application are as follows:

[0013] The revetment structure in this application adopts a cemented gravel seat structure foundation at the bottom of the revetment. The cemented gravel is located on a pebble layer or a stratum with good bearing capacity below the scour line. The compressive strength, elastic modulus and other properties of cemented gravel are basically equivalent to those of concrete. The revetment foundation is reliable and is not affected by downstream scour. Compared with concrete, cemented gravel has a lower amount of cementitious material, a lower hydration temperature rise, can be continuously laid, has a faster construction progress, and can save investment. In addition, the downstream of the revetment is backfilled with large stones and / or concrete tetrahedrons to set up anti-scour channels. The layout range of the anti-scour channels is significantly shortened compared with the seafloor, and less large stones are used, thereby reducing the land area and saving investment.

[0014] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0015] Figure 1 A schematic diagram of the tank protection structure provided in this application in a specific embodiment.

[0016] Attached reference numerals: 1. Cemented gravel; 2. Pebble layer; 3. Mortar layer; 4. Scour line; 5. Revetment; 6. Anti-scour trench; 7. Large stone; 8. Revetment reinforcement; 9. Abrasion-resistant concrete.

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0018] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0019] It should be understood that the described embodiments are merely some embodiments of this application, and not all embodiments. All other technical solutions obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0020] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” 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.

[0021] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0022] It should be noted that the directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0023] like Figure 1 As shown in the embodiment of this application, a revetment structure using a cemented gravel foundation is provided to solve the safety and reliability problem of the revetment cover layer foundation when the downstream apron and riverbed are eroded and form scour pits. Specifically, the revetment structure using a cemented gravel foundation mainly includes cemented gravel 1, a revetment 5, and an anti-scour trench 6. The cemented gravel 1 is arranged on a pebble layer 2 or a stratum with a bearing capacity higher than a preset value after the surface cover layer is removed. A mortar layer 3 is laid between the pebble layer 2 or the stratum and the cemented gravel 1. The cemented gravel 1 has a preset laying thickness, and the bottom of the cemented gravel 1 is at least partially lower than the scour line 4. The revetment 5 is set on the top side of the cemented gravel 1. The anti-scour trench 6 is set on the downstream side of the revetment 5. The bottom of the anti-scour trench 6 is lower than the bottom of the revetment 5, and the anti-scour trench 6 is filled with large stones 7 and / or concrete tetrahedrons.

[0024] like Figure 1As shown, in a more specific embodiment, the cemented gravel 1 is arranged after the original sand and pebble layer 2 and the original sand layer are removed from the ground. The bottom of the cemented gravel 1 is lower than the scour line 4. The specific location of the scour line 4 can be obtained from model tests, so this paper does not specify the exact location. A mortar layer 3 is laid between the cemented gravel 1 and the pebble layer 2. A scour trough 6 with large stones 7 is set downstream of the revetment 5. Therefore, the arrangement range of the scour trough 6 is significantly shorter and the depth is deeper than that of the apron, which can be used to protect the riverbed adjacent to the downstream of the revetment 5.

[0025] In this embodiment, the revetment structure uses cemented gravel 1 as the base structure at the bottom of the revetment 5. The cemented gravel 1 is located on the pebble layer 2 or a layer with good bearing capacity below the scour line 4. The compressive strength, elastic modulus and other properties of the cemented gravel 1 are basically equivalent to those of concrete. The foundation of the revetment 5 is reliable and is not affected by downstream scour. Compared with concrete, the cemented gravel 1 has a lower amount of cementitious material, a lower hydration temperature rise, can be continuously laid, has a faster construction progress and can save investment. In addition, the downstream of the revetment 5 is backfilled with large stones 7 and / or concrete tetrahedrons to set up anti-scour channels 6. The layout range of the anti-scour channels 6 is significantly shortened compared with the seafloor, and less large stones 7 are used, thereby reducing the footprint and saving investment.

[0026] like Figure 1 As shown, in one specific embodiment, the slope of the abutment 5 from the upstream side to the downstream side is 2%, meaning the abutment 5 slopes downstream along the river at a 2% gradient. The abutment 5 is a reinforced concrete structure (with multiple abutment reinforcement bars 8 inside), and its surface is covered with a layer of erosion-resistant concrete 9 of a predetermined thickness. The bottom layer is normal concrete. The concrete abutment 5 has high strength, and by setting the erosion-resistant concrete 9 on the surface layer, the abutment structure is more reliable and has better erosion resistance. The erosion-resistant concrete 9 preferably uses high-strength concrete, and the aggregate of the erosion-resistant concrete 9 should be hard natural pebbles or artificial crushed stone. Furthermore, the mortar layer 3 has a thickness of 20mm to 30mm, the erosion-resistant concrete has a thickness of 50cm, and the erosion-resistant concrete 9 is continuously poured onto the reinforced concrete structure after the reinforced concrete structure of the abutment 5 is poured.

[0027] like Figure 1 As shown, in one specific embodiment, the cemented gravel 1 comprises water, cement, fly ash, gravel, and cementitious materials. Its mix proportions are determined through production tests, and its compressive strength can reach over 6 MPa, with an elastic modulus close to that of concrete of equivalent strength. The maximum particle size of the gravel does not exceed 150 mm, and the content of sand with a particle size less than 5 mm is 18%–35%, while the content of coarse aggregate with a particle size of 5 mm–40 mm is 35%–65%.

[0028] like Figure 1 As shown, in one specific embodiment, the particle size of the large stones 7 and / or concrete tetrahedrons backfilled in the anti-scour trench 6 is 1.5m to 2m. After backfilling, the top of the large stones 7 and / or concrete tetrahedrons is flush with the top of the anti-scour trench 6. Generally speaking, it is preferred to backfill with large stones 7, and concrete tetrahedrons are used to supplement when there are not enough large stones 7.

[0029] The revetment structure using a cemented gravel foundation described in this application can be constructed according to the following steps:

[0030] S1. Remove the overburden layer at section 5 of the retaining wall down to the gravel layer 2 or a stratum with good bearing capacity below the scour line 4, and clean the surface to remove plant debris, mud, and concentrated sand.

[0031] S2. Lay a mortar layer 3 with a thickness of 20mm to 30mm on the surface of the gravel layer 2 according to the design requirements. Before the initial setting of the mortar layer 3, lay cemented gravel 1. The cemented gravel 1 is mixed by the mixing plant. The cemented gravel 1 is compacted with rolling equipment as it is laid. Because the amount of cementing material used in cemented gravel 1 is small and the hydration temperature rise is low, no special temperature control measures are required. It can be continuously laid up to the bottom elevation of the revetment 5.

[0032] S3. Fabricate and install the apron reinforcement 8 according to the design requirements, erect the formwork and pour the apron concrete. The impact-resistant concrete 9 of the apron surface layer should be poured continuously with the normal concrete at the bottom, and no cold joints should be generated.

[0033] Downstream of S4 and the tank 5, an anti-scour trench 6 is excavated according to the design requirements. After the excavation is completed, it is backfilled with large stones 7 and then compacted and leveled.

[0034] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A revetment structure employing a cemented gravel foundation, characterized in that, include: Cemented gravel, which is placed on a pebble layer or a stratum with a bearing capacity higher than a preset value after the surface overburden is removed. A mortar layer is laid between the pebble layer or the stratum and the cemented gravel. The cemented gravel has a preset laying thickness, and the bottom of the cemented gravel is at least partially below the scour line. A protective barrier is provided on one side of the top of the cemented gravel; The anti-scour channel is located on the downstream side of the apron, with its bottom lower than the bottom of the apron, and is filled with large stones and / or concrete tetrahedrons.

2. The revetment structure using a cemented gravel foundation as described in claim 1, characterized in that, The slope of the revetment from the upstream side to the downstream side is 2%. The revetment is a reinforced concrete structure, and the surface of the revetment is covered with a layer of erosion-resistant concrete of a predetermined thickness. The aggregate of the erosion-resistant concrete is hard natural pebbles or artificial crushed stone.

3. The revetment structure using a cemented gravel foundation as described in claim 2, characterized in that, The thickness of the mortar layer is 20mm~30mm, the thickness of the erosion-resistant concrete is 50cm, and the erosion-resistant concrete is continuously poured onto the reinforced concrete structure after the reinforced concrete structure of the apron is poured.

4. The revetment structure based on cemented gravel foundation according to any one of claims 1-3, characterized in that, The cemented gravel is composed of water, cement, fly ash, gravel, and cementing materials. The maximum particle size of the gravel is no more than 150 mm, and the content of sand with a particle size of less than 5 mm is 18% to 35%, and the content of coarse aggregate with a particle size of 5 mm to 40 mm is 35% to 65%.

5. The revetment structure based on cemented gravel foundation according to any one of claims 1-3, characterized in that, The large stones and / or concrete tetrahedrons backfilled in the anti-scouring trench have a particle size of 1.5m to 2m. After backfilling, the top of the large stones and / or concrete tetrahedrons is flush with the top of the anti-scouring trench.

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