Earth rock cofferdam adopting CSM construction method curtain
A composite temporary water barrier structure using CSM technology and geotextile membranes addresses the instability issues in sandy gravel bases by ensuring stable construction environments and reducing collapse risks through enhanced structural integrity.
Patent Information
- Application Number
- CN202422399188.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-09-30
AI Technical Summary
In large-particle sand-egg gravel foundations, existing soil and rock cofferdam structures are prone to collapse holes and troughs during construction, resulting in the risk of suspension and collapse of construction platforms. Moreover, the construction of concrete anti-seepage walls is difficult and costly, making it difficult to ensure construction safety and efficiency.
The earth-stone cofferdam structure adopts the CSM curtain, combined with the earth-stone mixed weir body, the CSM method infiltration curtain and geomembrane composite anti-seepage paving, through double-wheel milling and other thick stirred cement soil continuous walls and geomembrane composite anti-seepage paving, a stable anti-seepage structure is formed to avoid the risk of trough construction.
A stable and safe construction environment in large-particle sand gravel foundations is achieved, which reduces construction difficulty and cost, improves construction efficiency and quality, is adaptable and is easy to dismantle.
Smart Images
Figure CN223103685U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a temporary water retaining structure, in particular to a composite temporary water retaining structure combining a CSM (Cutter Soil Mixing) method diaphragm wall and an earth-rock cofferdam applicable to a gravelly pebble foundation, aiming to provide stable and safe dry construction conditions for water-related projects in a gravelly pebble foundation. Background Art
[0002] Generally, the construction of water-related buildings requires the setting of a temporary cofferdam in the construction section to ensure the dry working environment and construction safety of construction personnel and machinery in the foundation pit. The anti-seepage of the cofferdam is one of the key difficulties in such projects.
[0003] In water-related projects, the earth-rock cofferdam structure usually adopts a concrete cut-off wall as an anti-seepage curtain. For a large-particle-size gravelly pebble foundation with a particle size generally above 20 cm, due to the uneven grading of the soil layer, local collapse of the trench is likely to occur during the trench excavation construction. At the same time, the surface layer of the gravelly pebble stratum is long-term scoured by water flow, and there is no bonding medium between the pebbles, which increases its porosity and reduces its integrity. The turbulent flow generated inside the slurry in the trench caused by mechanical construction will increase the risk of trench collapse. The trench collapse will make the top construction platform prone to suspension, increasing the risk and probability of the collapse of the construction platform. Content of the Utility Model
[0004] In order to solve the problems existing in the prior art, the utility model provides an earth-rock cofferdam adopting a CSM method curtain, which can ensure the construction safety of the anti-seepage curtain in a large-particle-size gravelly pebble foundation.
[0005] The utility model adopts the following technical solutions:
[0006] The earth-rock cofferdam adopting a CSM method curtain includes an earth-rock mixture cofferdam body, a CSM method cut-off and seepage prevention curtain, and a geomembrane composite anti-seepage blanket; the CSM method cut-off and seepage prevention curtain adopts a double-wheel milling equal-thickness mixing cement-soil continuous wall, which is arranged on the water-facing side of the earth-rock mixture cofferdam body, and the CSM method cut-off and seepage prevention curtain extends into the impervious layer by 0.5 m; the geomembrane composite anti-seepage blanket includes a vertical connection section and a slope section of the geomembrane composite anti-seepage blanket. The vertical connection section and the slope section of the geomembrane composite anti-seepage blanket are connected. The bottom of the vertical connection section of the geomembrane composite anti-seepage blanket is embedded in the CSM method cut-off and seepage prevention curtain, and the top of the slope section of the geomembrane composite anti-seepage blanket is laid to the top of the earth-rock mixture cofferdam body.
[0007] Further, the top of the CSM method cut-off and seepage prevention curtain is not less than 1.0 m higher than the average water level during the construction period of the cofferdam.
[0008] Further, the lap length of the bottom of the geomembrane composite anti-seepage blanket embedded in the CSM method cut-off and seepage prevention curtain is not less than 0.5 m.
[0009] Furthermore, large boulders are laid on the water-facing side of the earth-rock mixture cofferdam body for slope protection, with a thickness of not less than 1.0 m.
[0010] The construction method of the present utility model includes the following steps:
[0011] S1. Clean and level the foundation;
[0012] Before filling the cofferdam, remove the boulders and large-sized floating stones on the riverbed surface and level them.
[0013] S2. Build the construction platform for the cut-off curtain;
[0014] Fill the earth-rock mixture cofferdam body to the initial filling elevation, which is more than 1.0 m above the average water level during the construction period of the cofferdam. Roll and level the top of the cofferdam, and lay the roadbed steel plates to form a construction platform.
[0015] S3. Construct the cut-off curtain;
[0016] Carry out the construction operation of the CSM cut-off curtain method, with its bottom extending into the impervious layer and the top constructed to the top of the construction platform.
[0017] Before the initial setting of the CSM cut-off curtain, embed the anti-seepage slot template connected to the geotextile membrane composite anti-seepage blanket at the top of the CSM cut-off curtain. The width of the anti-seepage slot is distributed along the axis of the CSM cut-off curtain. The height of the anti-seepage slot can be adjusted according to the actual implementation situation.
[0018] S4. Remove the anti-seepage slot template;
[0019] Wait until the CSM cut-off curtain reaches the design strength and then remove the anti-seepage slot 21 template.
[0020] S5. Embed the anti-seepage blanket;
[0021] Embed the anti-seepage geotextile membrane in the geotextile membrane composite anti-seepage blanket into the anti-seepage slot, and at the same time fill the anti-seepage slot with concrete.
[0022] S6. Construct the vertical connection section of the anti-seepage blanket;
[0023] Construct the vertical connection section of the geotextile membrane composite anti-seepage blanket, which is composed of the anti-seepage geotextile membrane and well-graded medium-coarse sand on both sides.
[0024] S7. Complete the filling of the cofferdam body;
[0025] Continue to fill the earth-rock mixture cofferdam body to the design elevation, and simultaneously follow up the slope section of the geotextile membrane composite anti-seepage blanket. The slope section of the geotextile membrane composite anti-seepage blanket is composed of the anti-seepage geotextile membrane and the gravel transition layer.
[0026] The anti-seepage geomembrane is laid along the vertical axis direction (force-bearing direction) in the length direction (warp direction), and it is required to be laid in one piece without splicing. It is laid with an overlap in the non-force-bearing direction (weft direction). After the geomembrane is laid, the construction of its protective layer should be carried out as soon as possible to ensure that the exposure time of the geomembrane does not exceed 7 days. Otherwise, effective measures should be taken to avoid direct sunlight. If damage or holes are found during construction, they should be repaired in time with the same material. Seam connection is preferred on land, and overlap connection is used on water.
[0027] S8. Lay the riprap slope protection.
[0028] Lay large-sized riprap on the upstream water-facing side of the earth-rock mixture cofferdam body.
[0029] The beneficial effects of the present utility model are as follows:
[0030] Based on the earth-rock mixture cofferdam body, the present utility model adopts the double-wheel milling equal-thickness mixing cement-soil continuous wall of the CSM method as the cut-off curtain, and cooperates with the geomembrane composite anti-seepage blanket to solve the anti-seepage problem of the diversion structure on the large-particle-size sand-gravel foundation. The structure of the present utility model has good adaptability to the large-particle-size sand-gravel foundation. By adopting the in-situ milling and mixing technology, the technical risks in the trench construction are avoided. Compared with the concrete diaphragm wall, the CSM method has lower requirements for the bearing capacity of the foundation, higher construction efficiency, lower cost, and is also easier to demolish than the concrete diaphragm wall. It has significant advantages in terms of construction period, construction efficiency, and construction quality. Description of the Drawings
[0031] Figure 1 It is a typical cross-sectional view of the structure of the present utility model;
[0032] Figure 2 For Figure 1 Detail drawing of part A;
[0033] Figure 3 It is a typical structural cross-sectional view of the construction platform;
[0034] Figure 4 It is a flow chart of the method of the present utility model.
[0035] In the figures: 11 - earth-rock mixture cofferdam body; 12 - cut-off curtain of the CSM method; 13 - geomembrane composite anti-seepage blanket; 14 - large-sized riprap slope protection; 15 - initial filling elevation; 21 - anti-seepage slot; 22 - vertical connection section of the geomembrane composite anti-seepage blanket; 23 - anti-seepage geomembrane; 24 - slope section of the geomembrane composite anti-seepage blanket; 31 - construction platform; 32 - roadbed steel plate. Detailed Implementation Modes
[0036] In order to enable those skilled in the art to better understand the technical solutions of the present utility model, the present utility model will be further described below in conjunction with specific embodiments.
[0037] As Figures 1 to 3 shown, the earth-rock cofferdam adopting the CSM method curtain of the present utility model comprises an earth-rock mixture cofferdam body 11, a CSM method cut-off curtain 12 and a geomembrane composite impervious blanket 13; the CSM method cut-off curtain 12 adopts a double-wheel milling equal-thickness mixing cement-soil continuous wall, which is arranged on the water-facing side of the earth-rock mixture cofferdam body 11, and the CSM method cut-off curtain 12 extends into the impervious layer by 0.5 m; the geomembrane composite impervious blanket 13 comprises a geomembrane composite impervious blanket vertical connection section 22 and a geomembrane composite impervious blanket slope section 24, the geomembrane composite impervious blanket vertical connection section 22 and the geomembrane composite impervious blanket slope section 24 are connected, the bottom of the geomembrane composite impervious blanket vertical connection section 22 is embedded in the CSM method cut-off curtain 12, and the top of the geomembrane composite impervious blanket slope section 24 is laid to the top of the earth-rock mixture cofferdam body 11.
[0038] As Figure 4 shown, the construction method of the earth-rock cofferdam adopting the CSM method curtain of the present utility model comprises the following steps:
[0039] S1. Foundation cleaning and leveling
[0040] Before the cofferdam is filled, the boulders and large-sized floating stones on the riverbed surface shall be removed. The maximum particle size of the filling stones does not exceed 15 cm, the stone content is not less than 50%, and the organic matter content of the soil is less than 5%.
[0041] S2. Filling the curtain construction platform
[0042] The earth-rock mixture cofferdam body 11 is filled to the initial filling elevation 15, which is more than 1.0 m above the average water level during the construction period of the cofferdam. The top of the cofferdam is rolled and leveled, and the roadbed steel plates 32 are laid to form a construction platform 31. The roadbed steel plates are composed of single 6 m × 1.5 m × 0.02 m steel plates lapped together.
[0043] S3. Cut-off curtain construction
[0044] The construction operation of the CSM method cut-off curtain 12 is carried out, and its bottom extends into the impervious layer by more than 0.5 m, and the top is constructed to the top of the construction platform 31.
[0045] Before the CSM method cut-off curtain 12 starts to set, the formwork of the anti-seepage groove 21 connected with the geomembrane composite impervious blanket 13 is buried at the top of the CSM method cut-off curtain 12, and the width of the anti-seepage groove 21 is distributed along the axis of the CSM method cut-off curtain 12.
[0046] The height of the anti-seepage groove 21 can be adjusted according to the actual implementation situation, and the minimum height is not less than 0.5 m.
[0047] S4. Removing the formwork of the anti-seepage groove
[0048] After the cut-off curtain 12 of the CSM method reaches the design strength, remove the formwork of the anti-seepage slot 21.
[0049] S5. Install the anti-seepage blanket
[0050] Bury the anti-seepage geomembrane 23 in the geocomposite anti-seepage blanket 13 into the anti-seepage slot 21. At the same time, fill the anti-seepage slot 21 with C20W6 concrete.
[0051] S6. Construct the vertical connection section of the anti-seepage blanket
[0052] Construct the vertical connection section 22 of the geocomposite anti-seepage blanket. The vertical connection section 22 of the geocomposite anti-seepage blanket is composed of the anti-seepage geomembrane 23 and well-graded medium and coarse sand within 0.5 m on both sides.
[0053] S7. Complete the filling of the weir body
[0054] Continue to fill the earth-rock mixture weir body 11 to the design elevation, and simultaneously follow up the slope section 24 of the geocomposite anti-seepage blanket. The slope section 24 of the geocomposite anti-seepage blanket is composed of the anti-seepage geomembrane 23 and gravel transition layers with a thickness of 0.25 m each on the upper and lower sides.
[0055] For the anti-seepage geomembrane 23, the length direction (warp direction) of the geomembrane is laid along the vertical axis direction (the stress direction), and it is required to be laid in one whole piece without splicing. The non-stress direction (weft direction) is lapped and laid. After the geomembrane is laid, the construction of its protective layer should be followed up as soon as possible to ensure that the exposure time of the geomembrane does not exceed 7 days. Otherwise, effective measures should be taken to avoid direct sunlight. If damage or holes are found during construction, they should be repaired in time with the same material. Seam connection is preferred on land, and lap joint is used on water. The repair area should not be less than 5 times the damaged area.
[0056] S8. Lay the rubble slope protection
[0057] Lay large rubble slope protection 14 on the water-facing side of the earth-rock mixture weir body 11, with a thickness of not less than 1.0 m.
[0058] For the large rubble slope protection 14, it is required to use fresh and intact stones. The uniaxial saturated compressive strength of the stones is required to be not less than 35 MPa, and the softening coefficient is required to be not less than 0.70.
[0059] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Any simple modification or equivalent change made to the above embodiments based on the technical essence of the present invention falls within the protection scope of the present invention.
Claims
1. An earth-rock cofferdam adopting the CSM method curtain is characterized in that: It includes an earth-rock mixture cofferdam body, a CSM method cutoff curtain, and a geomembrane composite impervious blanket; the CSM method cutoff curtain adopts a double-wheel milling equal-thickness mixing cement-soil continuous wall, which is arranged on the water-facing side of the earth-rock mixture cofferdam body, and the CSM method cutoff curtain extends 0.5 m into the impervious layer; the geomembrane composite impervious blanket includes a vertical connection section and a slope section of the geomembrane composite impervious blanket. The vertical connection section and the slope section of the geomembrane composite impervious blanket are connected. The bottom of the vertical connection section of the geomembrane composite impervious blanket is embedded in the CSM method cutoff curtain, and the top of the slope section of the geomembrane composite impervious blanket is laid to the top of the earth-rock mixture cofferdam body.
2. The earth-rock cofferdam adopting the CSM method curtain according to claim 1, wherein: The depth that the CSM method cutoff curtain extends into the impervious layer is 0.5 m.
3. The earth-rock cofferdam adopting the CSM method curtain according to claim 1 or 2, characterized in that: The top of the CSM method cutoff curtain is not less than 1.0 m higher than the average water level during the construction period of the cofferdam.
4. The earth-rock cofferdam adopting the CSM method curtain according to claim 1, characterized in that: The lap length that the bottom of the geomembrane composite impervious blanket is embedded in the CSM method cutoff curtain is not less than 0.5 m.
5. The earth-rock cofferdam adopting the CSM method curtain according to claim 1, characterized in that: Large block stone revetments are laid on the water-facing side of the earth-rock mixture cofferdam body, with a thickness of not less than 1.0 m.