Construction method of earth rock cofferdam

Abstract

The invention discloses an earth rock cofferdam construction method which comprises the steps that S1, a riverbed or a foundation of a cofferdam construction area is surveyed, a surface soft soil layer is cleaned till a solid soil layer or a rock layer is exposed, a groove is formed in the cleaned area according to the design requirement, and geotextile is laid in the groove, s2, stone and soil which are hard in texture and good in grading are prepared, a bottom waterproof layer is arranged, soil and stone are filled according to a layering method, the thickness of each layer is controlled to range from 30 cm to 50 cm, after each layer of soil and stone is filled, a road roller or a vibration roller is used for compaction, the compaction degree meets the design requirement, slope protection materials are laid on the slope surfaces of the inner side and the outer side of the cofferdam correspondingly, and the slope protection materials are laid on the slope surfaces of the inner side and the outer side of the cofferdam; the inner side slope surface is formed by splicing concrete precast blocks, and a gabion net is arranged on the outer side slope surface; according to the construction method of the earth rock cofferdam, the safety of a construction area is improved, materials used for cofferdam construction can be obtained locally, for example, soil materials and stone materials can be efficiently utilized, and the material transportation and purchase cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering and water conservancy engineering, and in particular to a construction method of an earth-rock cofferdam. Background Art

[0002] In water conservancy projects and infrastructure construction, earth-rock cofferdam construction is a common temporary waterproof structure construction method, which is widely used in engineering scenarios such as river diversion and foundation pit waterproofing. Earth-rock cofferdams are usually composed of natural soil and stone, which use their own gravity and material properties to form a certain waterproof and stabilizing effect. However, the traditional earth-rock cofferdam construction method has obvious shortcomings in practical applications, which affects the construction quality and efficiency of the project.

[0003] First, the stability of traditional earth-rock cofferdams is poor. Under the influence of various factors such as water flow scouring, water level fluctuations and its own gravity, earth-rock cofferdams are prone to landslides and collapses, posing a threat to construction safety and progress. For example, in river areas with high flow rates, the outer slope of the cofferdam is often strongly scoured by water flow, resulting in serious erosion of earth-rock materials, which in turn causes the instability of the cofferdam structure. Secondly, the anti-seepage performance of earth-rock cofferdams is limited. Relying solely on the anti-seepage ability of earth-rock materials themselves is often difficult to meet actual needs, which easily leads to leakage, increases the problem of water accumulation in the construction area, and affects the smooth progress of construction operations. Especially in areas with high groundwater levels, leakage will make it difficult to effectively control the water level in the foundation pit, which will have an adverse impact on the construction progress and quality. In addition, the construction efficiency of traditional earth-rock cofferdam construction methods is low. In the process of filling and compacting earth-rock materials, it often takes a long time due to the lack of reasonable process optimization and construction control methods. For example, in large-scale earth-rock filling, due to the lack of effective layered filling and compaction control methods, construction equipment and processes need to be adjusted frequently, resulting in extended construction time and serious waste of resources. In summary, the shortcomings of traditional earth-rock cofferdam construction methods in terms of stability, anti-seepage performance and construction efficiency make it difficult to fully meet actual needs in complex construction environments. Summary of the invention

[0004] The purpose of the present invention is to provide a construction method for an earth-rock cofferdam to solve the problems existing in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solution: a construction method for an earth-rock cofferdam, the method comprising:

[0006] S1. Survey the riverbed or foundation in the cofferdam construction area, clean the soft soil layer on the surface until the solid soil or rock layer is exposed, dig grooves in the cleaned area according to the design requirements, and lay geotextiles in the grooves;

[0007] S2. Prepare hard and well-graded stone and soil materials, set up a bottom waterproof layer, and fill the soil and stone in layers. The thickness of each layer is controlled to be 30 cm to 50 cm. After each layer of soil and stone is filled, use a roller or vibrating roller to compact it. The compaction degree meets the design requirements. Slope protection materials are laid on the inner and outer slopes of the cofferdam. The inner slope is spliced ​​with prefabricated concrete blocks, and gabions are set on the outer slope;

[0008] S3. Apply bentonite waterproof blanket on the inner slope of the cofferdam and lay waterproof membrane. The waterproof membranes are connected by hot-melt welding. By combining the above anti-seepage materials, ensure that there is no leakage area on the slope;

[0009] S4. Concrete pavement is laid on the top of the cofferdam with a thickness of 20 cm to 30 cm and a width of 3 m to 5 m. Guardrails are installed on both sides of the concrete pavement with a height of 1 m to 1.5 m.

[0010] Preferably, during the S1 foundation treatment process, the cleaning depth is determined according to the geological survey results, and the cleaning is carried out until a solid soil layer or rock layer is exposed to ensure the stability of the foundation.

[0011] Preferably, the geotextile laid in the trench in the S1 foundation treatment extends outside the trench, with an extension length of 0.5 m to 1.0 m, so as to be better connected with the cofferdam body.

[0012] Preferably, during the filling process of the S2 cofferdam body, the particle size of the soil and stone material ranges from 5 mm to 50 mm, and the moisture content of the soil material is controlled between 8% and 15%.

[0013] Preferably, during the filling of the main body of the S2 cofferdam, when each layer of soil and rock is compacted after filling, the overlapping width of adjacent rolling belts is 20 cm to 30 cm, ensuring that the overall density reaches more than 90%.

[0014] Preferably, during the filling of the S2 cofferdam body, the slope protection material laid on the outer slope of the cofferdam is a gabion mesh, the mesh size of the gabion mesh is 10 cm×10 cm, and blocks of stone are filled in the mesh.

[0015] Preferably, in the S3 anti-seepage treatment, the welding width between the waterproof membranes is controlled to be 10 cm to 15 cm, and a sealing test is performed to ensure that there is no leakage.

[0016] Preferably, during the treatment of the S4 cofferdam top, the concrete pavement is constructed using a segmented pouring process, with each segment being 5 to 10 meters long, and the surface is smoothed after pouring.

[0017] Preferably, in the S4 cofferdam top treatment, the protective railing at the cofferdam top is made of a steel pipe with a diameter of 5 cm to 8 cm, and the railing is fixed to the concrete pavement by welding.

[0018] Preferably, in the S4 cofferdam top treatment, drainage ditches are set on both sides of the concrete pavement at the cofferdam top, and the width of the drainage ditch is 20 cm to 30 cm to prevent rainwater accumulation from affecting the construction.

[0019] It can be seen from the above technical solution that the present invention has the following beneficial effects:

[0020] The construction method of this earth-rock cofferdam ensures that the cofferdam is built on a solid soil or rock layer by investigating the foundation conditions and cleaning the soft soil layer, which effectively enhances the bearing capacity and stability of the foundation. The main body of the cofferdam is filled using the layered method and compaction process, and precast concrete blocks and gabions are laid on the inner and outer slopes respectively, which enhances the overall anti-scouring and anti-slip capabilities of the cofferdam and can maintain structural stability under conditions of water scouring and water level changes. A complete anti-seepage structure is formed by applying bentonite waterproof blanket and laying waterproof membrane on the inner slope of the cofferdam, and using hot-melt welding as the connection method. The anti-seepage treatment effectively reduces water leakage. Even in areas with high groundwater levels or rapid water flows, the water level in the foundation pit can still be kept stable, reducing the problem of water accumulation during construction. Each process is strictly implemented according to the standardized process, with layered filling and compaction of thick The degree is clear, reducing rework caused by non-standard construction operations. The segmented pouring method of the top concrete pavement and the efficient assembly of slope protection materials have significantly shortened the construction time. The construction method design fully considers the rational use of construction equipment and materials, reduces resource waste, and improves the progress of the project. The installation of top protective railings and drainage ditches reduces the safety hazards of high-altitude operations during construction, while preventing rainwater accumulation from affecting the construction environment. Through reasonable slope protection and compaction technology, cofferdam collapse or landslide is avoided, improving the safety of the construction area. The materials used for cofferdam construction can be obtained locally, for example, soil and stone can be used efficiently, reducing the cost of material transportation and procurement. The use of reusable slope protection materials such as gabions and precast concrete blocks further improves resource utilization and reduces damage to the natural environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the construction flow chart of the present invention;

[0022] Figure 2 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] like Figure 1 and Figure 2 As shown, a construction method of an earth-rock cofferdam comprises:

[0025] S1. Survey the riverbed or foundation in the cofferdam construction area, clean the soft soil layer on the surface until the solid soil or rock layer is exposed, dig grooves in the cleaned area according to the design requirements, and lay geotextiles in the grooves;

[0026] S2. Prepare hard and well-graded stone and soil materials, set up a bottom waterproof layer, and fill the soil and stone in layers. The thickness of each layer is controlled to be 30 cm to 50 cm. After each layer of soil and stone is filled, use a roller or vibrating roller to compact it. The compaction degree meets the design requirements. Slope protection materials are laid on the inner and outer slopes of the cofferdam. The inner slope is spliced ​​with prefabricated concrete blocks, and the outer slope is equipped with gabions;

[0027] S3. Apply bentonite waterproof blanket on the inner slope of the cofferdam and lay waterproof membrane. The waterproof membranes are connected by hot-melt welding. By combining the above anti-seepage materials, ensure that there is no leakage area on the slope;

[0028] S4. Concrete pavement is laid on the top of the cofferdam with a thickness of 20 cm to 30 cm and a width of 3 m to 5 m. Guardrails are installed on both sides of the concrete pavement with a height of 1 m to 1.5 m.

[0029] The soft soil layer in the construction area is cleaned and geotextiles are laid to enhance the bearing capacity of the foundation. The layered filling and compaction technology is used to ensure the stability of the main structure of the cofferdam. Combined with slope protection materials, bentonite waterproof blankets, waterproof membranes and other materials, the slope of the cofferdam is effectively protected and anti-seepage is achieved. Finally, the use function and safety of the cofferdam are improved by laying concrete pavement on the top and installing protective railings. This method enhances the stability and anti-seepage performance of the cofferdam by strictly controlling the construction steps and material quality. It effectively reduces the risk of leakage, extends the service life of the cofferdam, and improves the safety of construction personnel and equipment through the design of concrete pavement and railings.

[0030] The cleaning depth and material selection can be adjusted according to the geological conditions and engineering requirements of the construction site, such as changing the type of geotextile or adjusting the thickness of the concrete pavement. In addition, different slope protection materials (such as reinforced concrete slabs) can be used instead of gabions to adapt to special environmental conditions.

[0031] During the S1 foundation treatment process, the cleaning depth is determined according to the geological survey results, and the cleaning is carried out until a solid soil layer or rock layer is exposed to ensure the stability of the foundation. The geological conditions of the construction area are determined through geological survey, and the soft soil layer or impurities are cleaned according to the actual situation until a solid soil layer or rock layer that can provide sufficient bearing capacity is exposed to avoid settlement or deformation of the cofferdam due to unstable foundation during the subsequent construction process. This cleaning method ensures the stability of the construction foundation, effectively improves the reliability of the overall structure of the cofferdam, and avoids damage to the cofferdam due to uneven foundation.

[0032] For special geological conditions, reinforcement techniques such as grouting or pile foundation treatment can be used to further enhance the bearing capacity of the foundation.

[0033] The geotextile laid in the trench in the S1 foundation treatment extends outside the trench, with an extension length of 0.5 to 1.0 meters, so as to better connect with the cofferdam body. By extending the geotextile to the outside of the trench, the contact area between the geotextile and the cofferdam body is effectively increased, the stability of the connection is enhanced, and slippage or detachment under the action of water flow or soil pressure is prevented. This design enhances the integrity between the cofferdam and the foundation, improves the construction quality and structural stability. The extension length of the geotextile can be appropriately adjusted according to the design requirements, and other types of reinforcement materials, such as composite geogrids, can also be used to replace the geotextile.

[0034] During the filling process of the main body of the S2 cofferdam, the particle size of the soil and stone materials ranged from 5 mm to 50 mm, and the moisture content of the soil was controlled between 8% and 15%. By controlling the particle size of the filling materials and the moisture content of the soil, the good gradation and compaction performance of the soil and stone materials were ensured, the porosity was reduced, and the density and strength of the filling layer were improved. This material selection and control method significantly improved the stability and anti-seepage performance of the main body of the cofferdam and extended its service life. The particle size range can be adjusted to finer or coarser according to the actual construction conditions, and the moisture content range can be flexibly adjusted in combination with the specific soil characteristics and weather conditions.

[0035] During the main filling of the S2 cofferdam, when each layer of soil and rock is compacted after filling, the overlapping width of adjacent rolling belts is 20 cm to 30 cm, ensuring that the overall density reaches more than 90%. By reasonably controlling the overlapping width of the rolling belts, structural weaknesses caused by leakage or insufficient compaction can be avoided, thereby ensuring the uniformity and overall density of the filling layer. This method improves the construction quality, reduces possible leakage paths, and enhances the overall stability and anti-seepage capacity of the cofferdam. The overlapping width of adjacent rolling belts can be appropriately adjusted according to the actual width of the rolling equipment, and different types of rolling equipment can be used to adapt to different filling conditions.

[0036] During the construction of the main body of the S2 cofferdam, the slope protection material laid on the outer slope of the cofferdam is gabion mesh. The mesh size of the gabion mesh is 10 cm × 10 cm, and the mesh is filled with stone blocks. By using gabion mesh to wrap the stone blocks, the anti-scouring ability of the slope protection is enhanced, while ensuring smooth drainage of the slope surface and reducing the impact of water pressure on the cofferdam structure. The choice of this slope protection material effectively improves the anti-scouring ability of the outer slope of the cofferdam, extends the service life of the cofferdam, and is easy to maintain and replace. The mesh size of the gabion mesh can be appropriately adjusted according to the water flow velocity and construction conditions, and the stone blocks can be replaced with other anti-scouring materials, such as precast concrete blocks.

[0037] In the S3 anti-seepage treatment, the welding width between the waterproof membranes is controlled at 10 cm to 15 cm, and a sealing test is performed to ensure that there is no leakage. By properly controlling the welding width and testing the welding quality, the sealing of the waterproof membrane joints is ensured to avoid leakage caused by insufficient welding or defects. The standardized control of the welding width significantly improves the anti-seepage performance of the cofferdam and reduces the need for maintenance and repair. The welding width can be adjusted to wider or narrower according to the material type of the waterproof membrane and the construction conditions, and other connection methods such as bonding or mechanical connection can be used.

[0038] During the S4 cofferdam top treatment process, the concrete pavement was constructed using a segmented pouring process, with each segment being 5 to 10 meters long, and the surface was smoothed after pouring. The segmented pouring process reduces the risk of cracks in the concrete pavement construction and ensures the flatness and surface quality of each segment. This construction process improves the durability and aesthetics of the concrete pavement on the top of the cofferdam and reduces the need for later maintenance. The segment length can be adjusted appropriately according to the concrete characteristics and construction progress, and the smoothing process can be replaced by a surface embossing process to enhance the anti-slip performance.

[0039] In the S4 cofferdam top treatment, the guardrail on the top of the cofferdam is made of steel pipes with a diameter of 5 cm to 8 cm, and the guardrail is fixed to the concrete pavement by welding. By using steel pipes with moderate diameters and welding processes, the firmness and safety of the guardrail are ensured, while facilitating installation and maintenance. This railing design improves the safety of construction and operating personnel and has good durability. The railing material can be replaced with other metals or composite materials, and the connection method can be bolted or plugged to meet special construction conditions.

[0040] In the S4 cofferdam top treatment, drainage ditches are set on both sides of the concrete pavement at the top of the cofferdam. The width of the drainage ditches is 20 cm to 30 cm to prevent rainwater accumulation from affecting construction. By setting up drainage ditches, rainwater can be quickly drained to prevent erosion and damage to the concrete pavement and cofferdam structure caused by accumulated water. The drainage design effectively improves the service life and construction safety of the pavement at the top of the cofferdam, while reducing the maintenance workload. The width of the drainage ditch can be adjusted according to specific drainage needs, and a filter or sand settling well can be set in the drainage ditch to enhance the functionality of the drainage system.

[0041] Working process: First, the construction area is treated with foundation. According to the results of geological survey, the soil or rock layer is cleaned to a solid soil layer or rock layer, and geotextiles extending outside the trench are laid in the cleaned trench to enhance the stability of the foundation. Then, the main body of the cofferdam is filled in layers, and soil and stone materials with a particle size of 5 mm to 50 mm are selected. The moisture content of the soil is controlled between 8% and 15%. After each layer is filled, compaction technology is used, and the rolling belts are ensured to overlap to increase the density. At the same time, gabions are laid on the outside of the cofferdam to protect the slope. Subsequently, in the anti-seepage treatment, a waterproof membrane is laid and the welding width is controlled, and sealing detection is performed to ensure that there is no leakage. Finally, the top of the cofferdam is treated, the concrete pavement is poured in sections, and protective railings and drainage ditches are set up to improve the safety and durability of the structure. Through the above steps, this method achieves high stability, excellent anti-seepage and construction safety of cofferdam construction.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A construction method for an earth-rock cofferdam, characterized in that: The method comprises: S1. Survey the riverbed or foundation in the cofferdam construction area, clean the soft soil layer on the surface until the solid soil or rock layer is exposed, dig grooves in the cleaned area according to the design requirements, and lay geotextiles in the grooves; S2. Prepare hard and well-graded stone and soil materials, set up a bottom waterproof layer, and fill the soil and stone in layers. The thickness of each layer is controlled to be 30 cm to 50 cm. After each layer of soil and stone is filled, use a roller or vibrating roller to compact it. The compaction degree meets the design requirements. Slope protection materials are laid on the inner and outer slopes of the cofferdam. The inner slope is spliced ​​with prefabricated concrete blocks, and gabions are set on the outer slope; S3. Apply bentonite waterproof blanket on the inner slope of the cofferdam and lay waterproof membrane. The waterproof membranes are connected by hot-melt welding. By combining the above anti-seepage materials, ensure that there is no leakage area on the slope; S4. Concrete pavement is laid on the top of the cofferdam with a thickness of 20 cm to 30 cm and a width of 3 m to 5 m. Guardrails are installed on both sides of the concrete pavement with a height of 1 m to 1.5 m.

2. The construction method of an earth-rock cofferdam according to claim 1, characterized in that: During the S1 foundation treatment process, the cleaning depth is determined according to the geological survey results, and the cleaning is carried out until a solid soil layer or rock layer is exposed to ensure the stability of the foundation.

3. The construction method of an earth-rock cofferdam according to claim 1, characterized in that: The geotextile laid in the trench in the S1 foundation treatment extends outside the trench, with an extension length of 0.5m to 1.0m, so as to better connect with the cofferdam body.

4. The construction method of an earth-rock cofferdam according to claim 1, characterized in that: During the filling process of the S2 cofferdam body, the particle size of the soil and stone materials ranges from 5 mm to 50 mm, and the moisture content of the soil is controlled between 8% and 15%.

5. The construction method of an earth-rock cofferdam according to claim 1, characterized in that: During the filling of the main body of the S2 cofferdam, when each layer of soil and rock is compacted after filling, the overlapping width of adjacent rolling belts is 20 cm to 30 cm, ensuring that the overall density reaches more than 90%.

6. The construction method of an earth-rock cofferdam according to claim 1, characterized in that: During the filling of the main body of the S2 cofferdam, the slope protection material laid on the outer slope of the cofferdam is a gabion mesh, the mesh size of the gabion mesh is 10 cm×10 cm, and the mesh is filled with block stones.

7. The construction method of an earth-rock cofferdam according to claim 1, characterized in that: In the S3 anti-seepage treatment, the welding width between the waterproof membranes is controlled to be 10 cm to 15 cm, and a sealing test is performed to ensure that there is no leakage.

8. The construction method of an earth-rock cofferdam according to claim 1, characterized in that: During the treatment of the top of the S4 cofferdam, the concrete pavement is constructed using a segmented pouring process, with each segment being 5 to 10 meters long, and the surface is smoothed after pouring.

9. The construction method of an earth-rock cofferdam according to claim 1, characterized in that: In the S4 cofferdam top treatment, the protective railing on the cofferdam top is made of a steel pipe with a diameter of 5 cm to 8 cm, and the railing is fixed to the concrete pavement by welding.

10. The construction method of an earth-rock cofferdam according to claim 1, characterized in that: In the S4 cofferdam top treatment, drainage ditches are set on both sides of the concrete pavement at the top of the cofferdam. The width of the drainage ditch is 20 cm to 30 cm to prevent rainwater accumulation from affecting construction.

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