Steel sheet pile and high-pressure jet grouting pile combined anti-seepage cofferdam structure

Abstract

The utility model discloses a steel sheet pile and high-pressure jet grouting pile combined anti-seepage cofferdam structure, and belongs to the technical field of water conservancy projects. Comprising earth rock cofferdam bodies laid on the two sides of a river; the steel sheet pile anti-seepage cofferdam section is arranged at the lower elevation position of the middle bedrock layer of the river and comprises two rows of steel sheet pile walls laid in the width direction of the river; and the high-pressure jet grouting pile anti-seepage cofferdam section is arranged at the high elevation position of the base rock stratum on the two sides of the river, is located in the earth rock cofferdam body and comprises a plurality of high-pressure jet grouting piles laid in the width direction of the earth rock cofferdam body. According to the utility model, the engineering investment is reduced, the construction progress is accelerated, the occupied area of the cofferdam is reduced, a larger working surface is provided for a foundation pit, the problems that the steel sheet piles at the higher positions of base rock strata on two banks are insufficient in buried depth and cannot be arranged are solved, and a good anti-seepage effect is provided for the two banks; and the seepage flow of the cofferdam shoulder is reduced.

Description

Technical Field

[0001] This utility model relates to a cofferdam structure combining steel sheet piles and high-pressure jet grouting piles for seepage prevention, belonging to the field of water conservancy engineering technology. Background Technology

[0002] In water conservancy projects, cofferdams serve as important temporary water-retaining structures, providing dry-land conditions for the construction of the main structures.

[0003] Currently, for diversion and interception projects in small and medium-sized water conservancy projects, the riverbed strata consist of a permeable layer and a bedrock layer. The elevation of the bedrock layer is higher near the riverbank and lower near the middle of the river.

[0004] Among them, due to the small flood flow and low water level of small and medium-sized water conservancy projects, earth-rock cofferdams and steel sheet pile anti-seepage cofferdams are generally used to block water. For rivers with a certain thickness of permeable layer, high-pressure jet grouting piles and steel sheet piles are generally used as anti-seepage bodies.

[0005] Steel sheet piles offer fast overall construction speed, good seepage prevention, and are recyclable after construction, making them economical. However, due to overall stability requirements, steel sheet piles need to ensure a certain penetration length, making them unsuitable when the bedrock layer is high or the penetration length is insufficient. High-pressure jet grouting piles have a wide range of applications and mature construction experience, but their cost is relatively high. In some small and medium-sized water conservancy projects with lower total investment, this can lead to an excessively high proportion of temporary works costs, resulting in poor economic efficiency.

[0006] Therefore, it is difficult to achieve a good balance between seepage prevention effect and economy when using steel sheet piles or high-pressure jet grouting piles alone. Utility Model Content

[0007] The technical problem to be solved by this utility model is to provide a cofferdam structure for combined seepage prevention using steel sheet piles and high-pressure jet grouting piles. It solves the problems in the prior art where steel sheet piles are not suitable for use when the bedrock layer is high or the penetration length is insufficient due to the overall stability requirements, and high-pressure jet grouting piles lead to excessively high temporary engineering costs and poor economic efficiency in some small and medium-sized water conservancy projects with low total investment.

[0008] On the one hand, the technical problem to be solved by this utility model is achieved by the following technical solution: a cofferdam structure for combined seepage prevention using steel sheet piles and high-pressure jet grouting piles, comprising:

[0009] Earth and stone weirs are laid on both banks of the river;

[0010] The steel sheet pile seepage prevention cofferdam section is set in the middle of the river where the bedrock layer is at a lower elevation, and includes two rows of steel sheet pile walls laid along the width of the river.

[0011] The high-pressure jet grouting pile seepage prevention cofferdam section is set at a high elevation of the bedrock layer on both sides of the river and is located in the earth-rock dam body, including a number of high-pressure jet grouting piles laid along the width of the earth-rock dam body.

[0012] A transition section is provided between the sheet pile seepage prevention cofferdam section and the high-pressure jet grouting pile seepage prevention cofferdam section. The transition section is used to tightly connect the sheet pile seepage prevention cofferdam section and the high-pressure jet grouting pile seepage prevention cofferdam section.

[0013] Furthermore, the earth-rock dam has a trapezoidal cross-section and is composed of a fine stone dam body and a riprap slope laid on the surface of the fine stone dam body.

[0014] Furthermore, several steel tie rods are installed between the two rows of steel sheet pile walls, and both ends of the steel tie rods extend outward from the outer side of the steel sheet pile wall and are equipped with steel walers.

[0015] Furthermore, clay is backfilled between the two rows of sheet pile walls to form a clay layer.

[0016] Furthermore, the sheet pile wall is composed of several straight-web sheet piles spliced ​​together, and the length of the sheet pile wall inserted into the ground is twice the length exposed above the ground. Adjacent steel tie rods are arranged at 1.5m intervals, and the steel waler is 1.5m away from the top of the sheet pile wall.

[0017] Furthermore, the transition section consists of, from the inside out, high-pressure jet grouting piles, a clay layer, a fine stone dam, and a riprap slope protection.

[0018] Furthermore, the top elevation and width of the steel sheet pile seepage prevention cofferdam section, the high-pressure jet grouting pile seepage prevention cofferdam section, and the earth-rock dam body are consistent.

[0019] Furthermore, the high-pressure jet grouting pile penetrates 0.5m into the ground, the width of the clay layer is 3 times the width of the high-pressure jet grouting pile, the thickness of the riprap slope protection is 30-50cm, and the slope is 1:1.5-1:3.

[0020] The beneficial effects of this invention are as follows: In river channels with significant elevation fluctuations in the bedrock layer, combining sheet piles and high-pressure jet grouting piles as a seepage barrier fully utilizes the advantages of both. Sheet piles, as a seepage barrier, offer excellent seepage prevention, reducing project investment, accelerating construction progress, and minimizing the land area required for the cofferdam, thus providing a larger working surface for the foundation pit. Furthermore, the backfilling of the sheet piles with clay further enhances seepage prevention. The high-pressure jet grouting pile seepage barrier solves the problem of insufficient depth of sheet piles at higher bedrock elevations on both banks, preventing their placement, while also providing excellent seepage prevention for both banks and reducing seepage flow at the cofferdam shoulders. Therefore, this cofferdam structure achieves a good balance in terms of seepage prevention effect, construction speed, and project investment, making it particularly suitable for widespread application in this field, with a very broad market prospect. Attached Figure Description

[0021] Figure 1 This is a top view of the present invention;

[0022] Figure 2 This is a structural schematic diagram of the earth-rock dam body, the high-pressure jet grouting pile seepage prevention cofferdam section, the transition section, and the steel sheet pile seepage prevention cofferdam section in this utility model.

[0023] Figure 3 for Figure 1 Cross-sectional view at point aa;

[0024] Figure 4 for Figure 1 Cross-sectional view at point bb;

[0025] Figure 5 for Figure 1 Cross-sectional view at point cc.

[0026] In the diagram: 1. Earth-rock dam; 11. Fine stone dam; 12. Rockfill slope protection; 2. Steel sheet pile seepage prevention cofferdam section; 21. Steel sheet pile wall; 22. Steel tie rod; 23. Steel waler; 24. Clay layer; 3. High-pressure jet grouting pile seepage prevention cofferdam section; 31. High-pressure jet grouting pile; 4. Transition section. Detailed Implementation

[0027] To facilitate a clear understanding of the technical means, creative features, objectives, and effects of this utility model, the following description, in conjunction with specific illustrations, further elaborates on this utility model.

[0028] like Figure 1 As shown, the cofferdam structure for seepage prevention using a combination of sheet piles and high-pressure jet grouting piles includes:

[0029] Earth-rock weir 1 is laid on both banks of the river, and has a trapezoidal cross section and is composed of fine stone weir 11 and riprap slope protection 12 laid on the surface of fine stone weir 11.

[0030] The steel sheet pile anti-seepage cofferdam section 2 is set in the middle of the river where the bedrock layer is at a lower elevation, and includes two rows of parallel steel sheet pile walls 21 laid along the width of the river. The space between the two rows of steel sheet pile walls 21 is backfilled with clay and forms a clay layer 24.

[0031] The high-pressure jet grouting pile seepage prevention cofferdam section 3 is set at a higher elevation of the bedrock layer on both sides of the river and is located in the earth-rock dam body 1. It includes several high-pressure jet grouting piles 31 laid along the width direction of the earth-rock dam body 1 and parallel to the steel sheet pile wall 21.

[0032] Among them, a transition section 4 is also provided between the steel sheet pile anti-seepage cofferdam section 2 and the high-pressure jet grouting pile anti-seepage cofferdam section 3. The transition section 4 is used to tightly connect the steel sheet pile anti-seepage cofferdam section 2 and the high-pressure jet grouting pile anti-seepage cofferdam section 3.

[0033] It should be noted that this application is set up in the diversion and interception project of a small and medium-sized water conservancy project with a low flood season flow. The riverbed strata are composed of a permeable layer (generally including permeable strata such as miscellaneous fill, backfill, and medium and fine sand) and a bedrock layer. The elevation of the bedrock layer fluctuates greatly along the cofferdam axis, and the bedrock layer elevation is higher near the riverbank and lower near the middle of the river.

[0034] In river channels with significant elevation fluctuations in the bedrock layer, combining sheet pile walls 21 and high-pressure jet grouting piles 31 as a seepage barrier fully utilizes the advantages of both. Sheet piles, as a seepage barrier, offer excellent seepage prevention, reducing project investment, accelerating construction progress, and minimizing the land area required for the cofferdam, thus providing a larger working surface for the foundation pit. Furthermore, the backfilling of the sheet piles with clay further enhances seepage prevention. The high-pressure jet grouting piles 31 solve the problem of insufficient depth of sheet piles at higher bedrock elevations on both banks, preventing their placement, while also providing excellent seepage prevention for both banks and reducing seepage flow at the cofferdam shoulders. Therefore, this cofferdam structure achieves a good balance in terms of seepage prevention effect, construction speed, and project investment, making it particularly suitable for widespread application in this field, with a very broad market prospect.

[0035] like Figure 5 As shown, several steel tie rods 22 are installed between the two rows of sheet pile walls 21. Both ends of the steel tie rods 22 extend beyond the outer side of the sheet pile wall 21 and are fitted with steel walers 23. Adjacent steel tie rods 22 are spaced 1.5m apart, and the steel walers 23 are 1.5m from the top of the sheet pile wall 21. The sheet pile wall 21 is composed of several straight-web sheet piles spliced ​​together, and the length of the sheet pile wall 21 inserted into the ground is twice the length exposed above the ground.

[0036] By installing steel tie rods 22 and steel walers 23, the connection strength between the two rows of steel sheet pile walls 21 is improved, ensuring the stability of the cofferdam structure.

[0037] like Figure 3 and Figure 4 As shown, transition section 4, from the inside out, consists of high-pressure jet grouting piles 31, a clay layer 24, a fine stone dam 11, and a riprap slope protection 12. High-pressure jet grouting pile seepage prevention cofferdam section 3, from the inside out, also consists of high-pressure jet grouting piles 31, a fine stone dam 11, and a riprap slope protection 12. By backfilling clay into transition section 4, high-pressure jet grouting pile seepage prevention cofferdam section 3 can be tightly connected to sheet pile seepage prevention cofferdam section 2.

[0038] like Figures 3 to 5 As shown, in the cofferdam structure of this application, the axis is perpendicular to the river flow direction, and the top elevation and width of the steel sheet pile anti-seepage cofferdam section 2, the high-pressure jet grouting pile anti-seepage cofferdam section 3, and the earth-rock dam body 1 are consistent.

[0039] In addition, the high-pressure jet grouting pile 31 penetrates 0.5m into the ground, the width of the clay layer 24 is 3 times the width of the high-pressure jet grouting pile 31, the thickness of the riprap slope protection 12 is 30-50cm, and the slope is 1:1.5-1:3.

[0040] The construction method for a cofferdam structure combining sheet piles and high-pressure jet grouting piles for seepage prevention includes the following steps:

[0041] S1. First, determine the location of the cofferdam structure based on the location of the foundation pit, and determine the top elevation of the cofferdam structure that meets the flood control requirements;

[0042] S2. Draw a geological profile of the central axis of the cofferdam structure based on the survey results. Arrange steel sheet pile anti-seepage cofferdam section 2 in the chainage section where the thickness of the permeable layer is greater than or equal to twice the height of the cofferdam structure, and arrange transition section 4 and high-pressure jet grouting pile anti-seepage cofferdam section 3 to connect to both banks.

[0043] S3. Conduct surveying and setting out to determine the central axis of the cofferdam structure, the axis of the sheet pile wall 21, and the starting and ending station numbers of the transition section 4;

[0044] S4. Steel sheet piles are driven one by one using a pile driver to form a steel sheet pile wall 21, and steel tie rods 22 and steel walers 23 are connected and fixed.

[0045] S5. Backfill and compact the clay inside the two rows of steel sheet pile walls 21 and the clay in the transition section 4 layer by layer.

[0046] S6, the fine stone dam body 11 and riprap slope protection 12 of the high-pressure jet grouting pile seepage prevention cofferdam section 3, which are filled and compacted layer by layer and smoothly connected to the steel sheet pile seepage prevention cofferdam section 2.

[0047] S7. Construct high-pressure jet grouting piles 31 from top to bottom at the top of transition section 4 and the high-pressure jet grouting pile anti-seepage cofferdam section 3.

[0048] It should be noted that the construction requirements of the high-pressure jet grouting pile 31, the construction process of the steel sheet pile wall 21, and the specific filling requirements of the earth-rock dam 1 in this embodiment of the present invention are carried out in accordance with general technical standards.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of this utility model. All such changes and modifications fall within the scope of protection claimed by this utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A cofferdam structure combined with steel sheet piles and high-pressure jet grouting piles for seepage prevention, characterized in that, it comprises: a soil and rock cofferdam body (1) laid on both banks of a river; a steel sheet pile seepage prevention cofferdam section (2) arranged at a lower elevation of a bedrock layer in the middle of the river and comprising two rows of steel sheet pile walls (21) laid along the width direction of the river; a high-pressure jet grouting pile seepage prevention cofferdam section (3) arranged at a higher elevation of a bedrock layer on both banks of the river and located in the soil and rock cofferdam body (1), comprising a plurality of high-pressure jet grouting piles (31) laid along the width direction of the soil and rock cofferdam body (1); wherein a transition section (4) is further arranged between the steel sheet pile seepage prevention cofferdam section (2) and the high-pressure jet grouting pile seepage prevention cofferdam section (3), and the transition section (4) is used to tightly combine the steel sheet pile seepage prevention cofferdam section (2) and the high-pressure jet grouting pile seepage prevention cofferdam section (3).

2. The steel sheet pile, high-pressure jet grouting pile combined anti-seepage cofferdam structure according to claim 1, characterized in that: The soil and rock cofferdam body (1) has a trapezoidal cross section and is composed of a fine slag cofferdam body (11) and a block stone revetment (12) laid on the surface of the fine slag cofferdam body (11).

3. The steel sheet pile, high-pressure jet grouting pile combined anti-seepage cofferdam structure according to claim 1, characterized in that: A plurality of steel tie rods (22) are arranged between the two rows of steel sheet pile walls (21), and the two ends of the steel tie rods (22) extend out of the outer side of the steel sheet pile walls (21) and are arranged with steel enclosing purlins (23).

4. The steel sheet pile, high-pressure jet grouting pile combined anti-seepage cofferdam structure according to claim 1, characterized in that: The space between the two rows of steel sheet pile walls (21) is backfilled with clay to form a clay layer (24).

5. The steel sheet pile, high-pressure jet grouting pile combined anti-seepage cofferdam structure according to claim 3, characterized in that: The steel sheet pile wall (21) is composed of a plurality of straight abdominal steel sheet piles connected to each other, and the length of the steel sheet pile wall (21) inserted into the ground is twice the length exposed to the ground, the adjacent steel tie rods (22) are arranged at an interval of 1.5 m, and the steel enclosing purlin (23) is 1.5 m away from the top of the steel sheet pile wall (21).

6. The steel sheet pile, high-pressure jet grouting pile combined anti-seepage cofferdam structure according to claim 4, characterized in that: The transition section (4) is composed of, from the inside to the outside, a high-pressure jet grouting pile (31), a clay layer (24), a fine slag cofferdam body (11), and a block stone revetment (12).

7. The steel sheet pile, high-pressure jet grouting pile combined anti-seepage cofferdam structure according to claim 1, characterized in that: The top elevations and widths of the steel sheet pile seepage prevention cofferdam section (2), the high-pressure jet grouting pile seepage prevention cofferdam section (3), and the soil and rock cofferdam body (1) are consistent.

8. The steel sheet pile, high-pressure jet grouting pile combined anti-seepage cofferdam structure according to claim 6, characterized in that: The high-pressure jet grouting pile (31) penetrates the ground by 0.5 m, the width of the clay layer (24) is 3 times the width of the high-pressure jet grouting pile (31), the thickness of the block stone revetment (12) is 30-50 cm, and the slope is 1:1.5-1:3.

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