Combined cofferdam structure of concrete cofferdam and earth-rock cofferdam and construction method

Abstract

The application relates to the field of cofferdam structure technology, in particular to a concrete cofferdam and earth-rock cofferdam combined cofferdam structure and a construction method thereof. The combined cofferdam structure comprises two concrete cofferdams arranged along the longitudinal direction of a river and an earth-rock cofferdam arranged transversely in the river and located between the two concrete cofferdams. A wave-preventing layer is formed by arranging wave-preventing blocks on the water-approaching surface of the earth-rock cofferdam. A buffer net is arranged outside the wave-preventing layer. The buffer net is fixed to the concrete cofferdam, and a plurality of buffer blocks are fixed to the buffer net. The buffer blocks corresponding to the middle position of the earth-rock cofferdam are made of a material with a buoyancy smaller than gravity. The buffer blocks corresponding to the regions of the earth-rock cofferdam towards the two concrete cofferdams are made of a material with a buoyancy larger than gravity and can float. The application optimizes the stability of the earth-rock cofferdam in the combined cofferdam.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cofferdam structure technology, in particular to a concrete cofferdam and earth-rock cofferdam combined cofferdam structure and construction method. BACKGROUND

[0002] The earth-rock cofferdam is a cofferdam formed by earth-rock. The earth-rock cofferdam can utilize excavated spoil and can be directly constructed by the main project excavation and transportation equipment, and is one of the most widely used cofferdam forms. However, the earth-rock cofferdam has low erosion resistance and large land occupation, and is generally used for transverse cofferdam.

[0003] The concrete cofferdam is often used in water conservancy projects built on rock foundation soil. The concrete cofferdam has the characteristics of high water retaining head, small bottom width, large erosion resistance, and overflow on the cofferdam top. In particular, in the segmented cofferdam method for diversion construction, the longitudinal cofferdam made of concrete can block water on both sides, and can be combined with the permanent building as part of the dam body or gate chamber body. However, the concrete cofferdam has high cost.

[0004] In the prior art, in order to reduce the cost under the premise of meeting the design requirements of the cofferdam, a combined cofferdam is adopted by combining the concrete cofferdam and the earth-rock cofferdam. In the combined cofferdam, the concrete cofferdam serves as a longitudinal cofferdam to resist the erosion of longitudinal water flow, and the earth-rock cofferdam serves as a transverse cofferdam.

[0005] However, in actual use, since the cofferdam structure is a ring-shaped structure formed around a fixed building foundation, and the earth-rock cofferdam in the combined cofferdam structure will be subjected to water flow impact on the front side, the water surface in the middle of the earth-rock cofferdam will be lifted compared to the two sides, and will change constantly due to the change of water flow, resulting in relatively serious sand loss on the water-facing surface of the earth-rock cofferdam. After a certain period of use, the risk of piping and other water leakage is extremely easy to occur. Therefore, how to optimize the stability of the earth-rock cofferdam in the combined cofferdam is a problem that needs to be solved at present. SUMMARY

[0006] In order to optimize the stability of the earth-rock cofferdam in the combined cofferdam, the present application provides a concrete cofferdam and earth-rock cofferdam combined cofferdam structure and construction method.

[0007] The concrete cofferdam and earth-rock cofferdam combined cofferdam structure provided by the present application adopts the following technical solution:

[0008] The application discloses a combined cofferdam structure of a concrete cofferdam and an earth-rock cofferdam, which comprises two concrete cofferdams arranged longitudinally along a river channel and an earth-rock cofferdam arranged transversely in the river channel and located between the two concrete cofferdams, wherein a wave-preventing layer is formed by arranging wave-preventing blocks on the water-approaching surface of the earth-rock cofferdam, a buffer net is arranged outside the wave-preventing layer, the buffer net is fixed to the concrete cofferdam, and a plurality of buffer blocks are fixed to the buffer net, wherein the buffer blocks corresponding to the middle part of the earth-rock cofferdam are made of a material with a buoyancy smaller than gravity, and the buffer blocks corresponding to the regions of the earth-rock cofferdam towards the two concrete cofferdams are made of a material with a buoyancy larger than gravity and capable of floating.

[0009] By adopting the technical scheme, when in use, the earth-rock cofferdam as a whole bears external water pressure and scouring, the water flow concentrates on the middle part of the earth-rock cofferdam, the water flow first surges upwards and then flows downwards towards one side of the concrete cofferdam on the two sides, the buoyancy of the buffer blocks in the middle part is smaller than gravity, the buffer blocks are used for sufficiently slowing down the water flow speed and absorbing the energy of the water flow by sinking and swinging in the water flow, and the scouring is reduced, the buoyancy of the buffer blocks corresponding to the regions of the earth-rock cofferdam towards the two concrete cofferdams is larger than gravity, the buffer blocks are used for slowing down the flow speed of the water flow flowing downwards by floating and swinging in the water flow, further slowing down the flow speed of the water flowing from the gap between the wave-preventing layer, further optimizing the ability of resisting scouring, synchronously reducing the external water pressure, optimizing the stability in use, and enabling the buffer net to be repeatedly used in the next construction.

[0010] Optionally, the earth-rock cofferdam is arc-shaped and protrudes towards the water-approaching side.

[0011] By adopting the technical scheme, when the earth-rock cofferdam bears water pressure, the earth-rock cofferdam is extruded towards the lower side, the earth-rock cofferdam is relatively more compact due to the arc-shaped profile, part of the pressure is applied to the concrete cofferdam, the concrete cofferdam is pulled towards the opposite side due to the buffer net synchronously bearing the initial scouring, the concrete cofferdam is relatively balanced to a certain extent, and the stability in use is optimized.

[0012] Optionally, a base is integrally poured and formed at the bottom of the concrete cofferdam and extends to the bottom of the earth-rock cofferdam as a foundation.

[0013] By adopting the technical scheme, the seepage-proofing effect is achieved from the bottom, and the possibility of leakage is reduced.

[0014] Optionally, at least one connecting part is integrally poured and formed at the side of the concrete cofferdam towards the earth-rock cofferdam towards the upstream end of the river channel, and the intersection surfaces of the two connecting parts and the earth-rock cofferdam gradually approach the middle part of the concrete cofferdam from the side of the corresponding water-approaching surface.

[0015] Through the above technical scheme, the earth-rock cofferdam can transmit force to the connecting part on the concrete cofferdam and reduce the possibility of relative movement.

[0016] Optionally, waterproof geotextile is embedded in the earth-rock cofferdam, and edges of the waterproof geotextile are fixed to the base and the two concrete cofferdams.

[0017] Through the above technical scheme, the earth-rock cofferdam is further optimized for seepage prevention, and the possibility of piping caused by local differences in particle size is avoided.

[0018] Optionally, the waterproof geotextile is arranged horizontally along the river channel, and a supporting net for supporting the waterproof geotextile is embedded in the inside of the earth-rock cofferdam, and the supporting net is fixed to the base and the two concrete cofferdams.

[0019] Through the above technical scheme, the supporting net can transmit the water pressure borne by the waterproof geotextile to the supporting net and reinforce the concrete cofferdam, thereby further significantly reducing the possibility of damage to the waterproof geotextile caused by local concave or excessive pressure.

[0020] Optionally, a plurality of seepage pipes are arranged on the water-facing side of the waterproof geotextile, two ends of the seepage pipes extend toward the side of the concrete cofferdam and extend from inside the concrete cofferdam to the earth-rock cofferdam on the downstream side and then pass out, and the seepage pipes have a downward slope from at least the upstream side of the concrete cofferdam toward the downstream side.

[0021] Through the above technical scheme, the penetrated water can be discharged downstream through the seepage pipes in a timely manner to slow down the seepage pressure during the high water period or when the water level is relatively high.

[0022] Optionally, a pressure relief pipe is embedded in the earth-rock cofferdam on the upstream side and arranged to pass out of the earth-rock cofferdam from bottom to top, the pressure relief pipe is fixed and communicated with the seepage pipe, and a flow guide channel is arranged on the top of the earth-rock cofferdam for receiving water discharged by the pressure relief pipe.

[0023] Through the above technical scheme, when the seepage pressure is too large, water can be pressed upward and discharged through the flow guide channel.

[0024] Optionally, the top surface of the base gradually rises from the upstream to the downstream, and the top surface of the base is irregular or provided with a plurality of transverse grooves.

[0025] Through the above technical scheme, the bonding force between the earth-rock cofferdam and the base can be significantly increased.

[0026] In a second aspect, the application provides a construction method of a combined cofferdam structure of a concrete cofferdam and an earth-rock cofferdam, which adopts the following technical scheme:

[0027] A construction method of a concrete cofferdam and earth-rock cofferdam combined cofferdam structure is used for building a concrete cofferdam and earth-rock cofferdam combined cofferdam structure, comprising the following steps: S1, marking a construction area: using a marker post, a beacon, etc. to mark the construction area in a river channel;

[0028] S2, temporary cofferdam construction: constructing a temporary cofferdam on the side of the construction area, and pumping out the water inside the temporary cofferdam;

[0029] S3, concrete cofferdam construction: pouring two concrete cofferdams and a base along the longitudinal direction of the river channel inside the temporary cofferdam, the concrete cofferdams being poured at the longitudinal boundary positions of the construction area, and the base being poured at the circumferential boundary positions of the construction area;

[0030] S4, earth-rock cofferdam construction: using earth-rock materials to pile up and tamp to form an earth-rock cofferdam at the inside positions of the two concrete cofferdams corresponding to the upstream and downstream boundary positions of the construction area;

[0031] S5, buffer structure construction: first, using wave-resistant blocks to pile up and lay a wave-resistant layer from bottom to top on the water-facing surface of the earth-rock cofferdam, and then laying a buffer net with buffer blocks on the water-facing surface of the wave-resistant layer, and anchoring the laid buffer net to the base and the concrete cofferdams.

[0032] In summary, the present application has at least one of the following beneficial technical effects:

[0033] In use, since the earth-rock cofferdam as a whole bears external water pressure and scouring, and since the middle part of the earth-rock cofferdam is a position where water flow concentrates and scours, the water flow first surges upward and then flows downward obliquely toward one side of the concrete cofferdam on the two sides, the buoyancy of the buffer blocks at the middle position is smaller than the gravity, so as to sufficiently slow down the water flow speed by the sinking and swinging of the buffer blocks in the water flow, and absorb the energy of the water flow, thereby reducing the scouring. The buoyancy of the buffer blocks corresponding to the earth-rock cofferdam toward the concrete cofferdam area on the two sides is greater than the gravity, so as to slow down the flow speed of the downward flowing water flow by the floating and swinging of the buffer blocks in the water flow, further slow down the flow speed of the water flowing from the gap between the wave-resistant layers, thereby further optimizing the ability to resist scouring, synchronously reducing the external water pressure, optimizing the stability in use, and being able to reuse the buffer net in the next construction. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a top view structural schematic diagram of the embodiment.

[0035] Figure 2 is Figure 1 is a sectional view structural schematic diagram of line A-A in

[0036] Figure 3 is Figure 2 is an enlarged structural schematic diagram of part B.

[0037] Explanation of reference signs: 1, river channel; 2, concrete cofferdam; 21, base; 211, anchor cable; 22, connecting part; 3, earth-rock cofferdam; 301, core wall; 302, sand layer; 303, gravel layer; 304, buffer layer; 32, wave protection layer; 33, buffer net; 331, buffer block; 34, waterproof geotextile; 341, support net; 35, drainage pipe; 36, pressure relief pipe; 361, flow guide channel. DETAILED DESCRIPTION

[0038] The following will be described in detail with reference to the accompanying drawings. Figures 1-3 The application is further described in detail.

[0039] The embodiments of the application disclose a concrete cofferdam and earth-rock cofferdam combined cofferdam structure. Referring to Figure 1 , Figure 2 and Figure 3 , the concrete cofferdam and earth-rock cofferdam combined cofferdam structure comprises two concrete cofferdams 2 arranged longitudinally along a river channel 1 and an earth-rock cofferdam 3 arranged transversely in the river channel 1 and located between the two concrete cofferdams 2. The bottom of the concrete cofferdam 2 is integrally poured to form a base 21, and the base 21 is also integrally poured to the bottom of the earth-rock cofferdam 3 to serve as a seepage prevention and foundation of the bottom of the earth-rock cofferdam 3. The earth-rock cofferdam 3 and the concrete cofferdam 2 are combined to form a ring-shaped closed structure.

[0040] The concrete cofferdam 2 is integrally poured to form a connecting part 22 at least towards one side of the earth-rock cofferdam 3 at an upstream end of the river channel 1. In the embodiment, the two ends of the concrete cofferdam 2 are integrally poured to form connecting parts 22 towards one side of another concrete cofferdam 2, the intersection of the two connecting parts 22 located at the upstream end of the concrete cofferdam 2 and the earth-rock cofferdam 3 gradually approaches from the upstream of the river channel 1, and the intersection of the two connecting parts 22 located at the downstream end of the concrete cofferdam 2 and the earth-rock cofferdam 3 gradually approaches from the downstream of the river channel 1 towards the other end of the concrete cofferdam 2, so that the earth-rock cofferdam 3 located inside the two concrete cofferdams 2 has a trapezoidal outline in a top view and the small ends are arranged towards each other, so that the earth-rock cofferdam 3 can exert part of the pressure on the concrete cofferdam 2 when bearing the water pressure on the side, and reduce the possibility of relative sliding between the concrete cofferdam 2 and the earth-rock cofferdam 3.

[0041] Referring to Figure 1 , Figure 2 and Figure 3Meanwhile, the top surface of the base 21 corresponding to the position of the earth-rock cofferdam 3 is inclined and gradually rises from upstream to downstream, the top surface of the base 21 is irregular or provided with a plurality of transverse grooves, in the embodiment, a plurality of transverse grooves are formed in the top surface of the base 21, so as to increase the adhesion between the base 21 and the earth-rock cofferdam 3 structure, and avoid the possibility of the earth-rock cofferdam 3 sliding downward as a whole relative to the base 21 due to excessive upstream pressure. The junction surfaces of the base 21, the concrete cofferdam 2 and the earth-rock cofferdam 3 are all pre-buried with a plurality of anchor cables 211, the anchor cables 211 extend through the connecting part 22 and are arranged towards the side of the earth-rock cofferdam 3, the earth-rock cofferdam 3 is arc-shaped and protrudes towards the side facing the water, that is, the two earth-rock cofferdams 3 are arranged away from each other and protrude, so that when the earth-rock cofferdam 3 bears water pressure, it will have a tendency to deform inwardly due to the protruding arc-shaped structure, and press the earth-rock cofferdam 3 itself, thereby increasing the pressure-bearing capacity and the anti-erosion capacity.

[0042] With reference to Figure 1 , Figure 2 and Figure 3 , the earth-rock cofferdam 3 comprises a core wall 301 located in the core, a gravel layer 302 formed by laying and tamping sand and gravel on the inside and outside of the core wall 301, a gravel layer 303 formed by laying and tamping gravel, and a buffer layer 304 formed by laying and tamping mixed pebbles and stones, the core wall 301 is a layered tamped and stacked body with a trapezoidal cross section formed by laying and tamping natural fibers such as clay mixed with 10-20 cm long hemp ropes, palm ropes or geosynthetic fibers from bottom to top, so as to enhance the impermeability of the core wall 301 and bear tensile stress, and inhibit lateral deformation and cracking of the core wall 301. The core wall 301 is provided at a position corresponding to the anchor cable 211.

[0043] The buffer layer 304 is formed into a wave protection layer 32 by laying and tamping wave protection blocks from bottom to top on the outside of the buffer layer 304, the wave protection blocks can be selected from concrete stone cages, four-corner wave protection blocks, etc., so as to resist erosion and slow down the flow rate of water flowing to the buffer layer 304, and preliminarily optimize the erosion resistance. Meanwhile, a buffer net 33 is laid on the outside of the wave protection layer 32, the buffer net 33 is anchored to the concrete cofferdam 2 or the connecting part 22, and the buffer net 33 is arranged on the wave protection layer 32, which fixes the wave protection layer 32 to some extent and reduces the possibility of the wave protection blocks of the wave protection layer 32 rolling due to increased water flow rate or impact.

[0044] With reference to Figure 1 , Figure 2 and Figure 3In addition, the buffer net 33 is fixed with several buffer blocks 331, the buffer blocks 331 corresponding to the middle position of the earth and rock cofferdam 3 are made of materials with smaller buoyancy than gravity, the position is the position where the water flow concentrates and flows upwards and then downwards to one side of the concrete cofferdam 2, the buffer blocks 331 can be made of block structures of specific materials such as ceramsite blocks, EVA foam blocks, high-density polyethylene, water-quenched slag, etc. with smaller buoyancy than gravity, so as to sufficiently slow down the water flow speed by the sinking and swinging of the buffer blocks 331 in the water flow. The buffer blocks 331 corresponding to the area of the earth and rock cofferdam 3 towards the two sides of the concrete cofferdam 2 are made of materials that can float with greater buoyancy than gravity, the buffer blocks 331 can be made of block structures of specific materials such as foam blocks, rubber, plastic, etc. with greater buoyancy than gravity, so as to slow down the flow speed of the downward flowing water flow by the floating and swinging of the buffer blocks 331 in the water flow, further slow down the flow speed of the water flowing from the gap of the wave prevention layer 32, thereby further optimizing the ability to resist erosion, and being able to be reused in the next construction.

[0045] The waterproof geotextile 34 is embedded in the core wall 301, and the surface of the waterproof geotextile 34 is coated with an elastic compression plate to increase the compression resistance, so as to reduce the possibility of the waterproof geotextile 34 being crushed and damaged. At the same time, the edge of the waterproof geotextile 34 is bent towards the side of the earth and rock cofferdam 3 protruding in an arc shape and is overlapped on the base 21 and the connecting part 22, so that when bearing the water pressure on the water-facing side, the waterproof geotextile 34 is pressed and combined with the base 21 or the connecting part 22.

[0046] Referring to Figure 1 , Figure 2 and Figure 3 In addition, in order to further increase the compression resistance of the earth and rock cofferdam 3 as a whole, the waterproof geotextile 34 is arranged straight along the transverse direction of the river channel 1, that is, it is laid straight along the transverse direction of the river channel 1, and the waterproof geotextile 34 is parallel to the outer surface of the core wall 301 towards the water-facing side. The supporting net 341 for supporting the waterproof geotextile 34 is embedded in the inside of the earth and rock cofferdam 3, and the supporting net 341 is anchored to the base 21 and the two concrete cofferdams 2 by the anchor cable 211, so as to be able to prevent seepage while bearing the external water pressure, and to be able to transmit the bearing water pressure to the concrete cofferdams 2, thereby pulling the two concrete cofferdams 2 towards each other. At this time, since the two concrete cofferdams 2 also bear the tension away from each other exerted by the earth and rock cofferdam 3 as a whole, a state of relative balance is achieved, the ability of the earth and rock cofferdam 3 as a whole to bear water pressure and prevent seepage is increased, the stability of the earth and rock cofferdam 3 is optimized, and the possibility of piping and other causes leading to collapse of the earth and rock cofferdam 3 is reduced.

[0047] Referring to Figure 1 , Figure 2 and Figure 3 Figure 1 Figure 2 Figure 3Finally, in order to further alleviate the water seepage pressure, optimize the stability, the waterproof geotextile 34 is embedded with a plurality of seepage pipes 35 on the side facing the water, that is, the seepage pipes 35 are located in the core wall 301, the two ends of the seepage pipes 35 extend towards the two sides of the concrete cofferdam 2 respectively and extend into the concrete cofferdam 2 from the corresponding connecting part 22, then pass out after extending from the concrete cofferdam 2 to the earth-rock cofferdam 3 on the downstream side, and the seepage pipes 35 have a certain downward slope at least from the upstream side of the concrete cofferdam 2 towards the downstream side.

[0048] The earth-rock cofferdam 3 on the upstream side of the two earth-rock cofferdams 3 is embedded with a pressure relief pipe 36 arranged from bottom to top and passing out of the earth-rock cofferdam 3, the pressure relief pipe 36 is fixed and communicated with the seepage pipe 35, and the top of the earth-rock cofferdam 3 is provided with a flow guide channel 361 for receiving water discharged by the pressure relief pipe 36. Wherein, the seepage pipe 35 and the pressure relief pipe 36 are both coated with water-permeable geotextile for filtering effect.

[0049] Since piping occurs when the seepage gradient (i.e. the water head loss per unit length) is greater than the critical value allowed by the soil, the seepage force can drive fine particles to move between the pores, thereby triggering piping. At this time, the seepage pipes 35 can reduce the pressure by discharging water downward under strong seepage pressure, in addition, the coated water-permeable geotextile can also reduce the clay of the core wall 301 carried by the water flowing in the seepage pipes 35, thereby increasing the hidden danger. The pressure relief pipe 36 can discharge water to the flow guide channel 361 under strong seepage pressure, thereby further reducing the pressure and significantly reducing the possibility of piping, and optimizing the stability of the earth-rock cofferdam 3.

[0050] Finally, in order to further increase the recycling rate, the seepage pipes 35 and the pipes in the concrete cofferdam 2 are flange connected, so that the seepage pipes 35 and the pressure relief pipes 36 can be recycled when necessary.

[0051] The implementation principle of the combined cofferdam structure of the concrete cofferdam and the earth-rock cofferdam is: when in use, the earth-rock cofferdam 3 as a whole bears the external water pressure and scour, and since the middle part of the earth-rock cofferdam 3 is the position where the water flow concentrates, the water flow first surges upward and then flows downward obliquely towards the side of the concrete cofferdam 2 on both sides, the buoyancy of the buffer block 331 at the middle position is less than the gravity, so as to sufficiently slow down the water flow speed and absorb the energy of the water flow by the sinking and swinging of the buffer block 331 in the water flow, thereby reducing the scour. The buoyancy of the buffer block 331 corresponding to the earth-rock cofferdam 3 towards the region of the concrete cofferdam 2 on both sides is greater than the gravity, so as to slow down the flow speed of the downward flowing water flow by the floating and swinging of the buffer block 331 in the water flow, further slow down the flow speed of the water flowing from the gap of the wave protection layer 32, thereby further optimize the ability to resist scour, and the buffer net 33 can be recycled in the next construction.

[0052] The water flow after the flow rate is slowed down successively contacts the wave prevention layer 32, does secondary buffering, and finally successively contacts the buffering layer 304, the gravel layer 303, the sand layer 302 and the core wall 301. In this process, the gap gradually decreases, so as to achieve the purpose of full buffering and layer-by-layer compaction. At the same time, due to the setting of the buffering net 33 and the waterproof geotextile 34, the earth and rock cofferdam 3 bears the water pressure on the front surface. At this time, the earth and rock cofferdam 3 is arc-shaped, which on the one hand transmits the pressure to the concrete cofferdam 2, and on the other hand, the penetration pressure generated by the front water pressure is discharged through the seepage drainage pipe 35 and the pressure relief pipe 36, so as to slow down the erosion of the sand material in the earth and rock cofferdam 3 and optimize the overall stability.

[0053] The application further discloses a construction method of the combined cofferdam structure of the concrete cofferdam and the earth and rock cofferdam.

[0054] S1, marking the construction area: marking the construction area by using a marker and a beacon in the river 1 to determine the construction range of the cofferdam structure.

[0055] S2, temporary cofferdam construction: constructing a temporary cofferdam, such as a temporary earth and rock structure cofferdam and a steel sheet pile, on the side of the construction area, and pumping out the water on the inner side of the temporary cofferdam.

[0056] S3, concrete cofferdam 2 construction: pouring two concrete cofferdams 2 and a base 21 along the longitudinal direction of the river 1 on the inner side of the temporary cofferdam, pouring the concrete cofferdam 2 at the longitudinal boundary position of the construction area, and pouring the base 21 at the circumferential boundary position of the construction area, and performing layer-by-layer pouring and layer-by-layer tamping during the pouring process.

[0057] S4, earth and rock cofferdam 3 construction: forming the earth and rock cofferdam 3 by piling and tamping the earth and rock material on the inner side of the two concrete cofferdams 2 at the upstream and downstream boundary positions of the construction area.

[0058] Specifically, the clay is mixed with 10-20cm long natural fibers such as hemp rope, palm rope and geosynthetic fibers, and then is layered and tamped from bottom to top to form a first piling body on the base 21 on the inner side of the two concrete cofferdams 2. The surface of the upstream side of the first piling body is an inclined plane. Then, the supporting net 341 is laid and anchored to the connecting part 22 through the anchor cable 211, and the waterproof geotextile 34 is laid on the upstream side of the supporting net 341.

[0059] Finally, the clay is mixed with 10-20 cm long hemp rope, palm rope and other natural fibers or geosynthetic fibers evenly, and then is layered and rammed from bottom to top on the base 21 and the waterproof geotextile 34 on the inner side of the two concrete cofferdams 2 to form a second masonry, and the second masonry covers the waterproof geotextile 34 and the top surface of the first masonry to form a complete core wall 301, and the cross section of the core wall 301 is a trapezoidal masonry, which is an isosceles trapezoid in this embodiment. Thereafter, the sand and gravel layer 302 is formed by layering and ramming sand and gravel inside and outside the core wall 301, the gravel layer 303 is formed by layering and ramming gravel, and the buffer layer 304 is formed by layering and ramming mixed pebbles and blocks.

[0060] S5, buffer structure construction: the wave protection blocks are layered and rammed from bottom to top on the water-facing surface of the earth-rock cofferdam 3 to form a wave protection layer 32, then the buffer net 33 with the buffer blocks 331 is laid on the water-facing surface of the wave protection layer 32, and the laid buffer net 33 is anchored to the base 21 and the concrete cofferdam 2.

[0061] The above are preferred embodiments of the present application, and do not limit the protection scope of the present application, so that: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A composite cofferdam structure of a concrete cofferdam and an earth-rockfill cofferdam, characterized by: The application relates to a combined cofferdam structure of a concrete cofferdam (2) and a soil-rock cofferdam (3), which comprises two concrete cofferdams (2) longitudinally arranged along a river channel (1) and a soil-rock cofferdam (3) transversely arranged in the river channel (1) and located between the two concrete cofferdams (2), wherein a wave-preventing layer (32) is formed by arranging wave-preventing blocks on the water-approaching side of the soil-rock cofferdam (3), a buffer net (33) is arranged on the outer side of the wave-preventing layer (32), the buffer net (33) is fixed to the concrete cofferdam (2), a plurality of buffer blocks (331) are fixed to the buffer net (33), and the buffer blocks (331) corresponding to the middle position of the soil-rock cofferdam (3) are made of a material with a buoyancy smaller than gravity; and the buffer blocks (331) corresponding to the regions of the soil-rock cofferdam (3) towards the two sides of the concrete cofferdam (2) are made of a material with a buoyancy greater than gravity.

2. The concrete and earth rockfill cofferdam combination cofferdam structure in accordance with claim 1, wherein: The soil-rock cofferdam (3) is arc-shaped and protrudes towards the water-approaching side.

3. The concrete cofferdam and earthfill cofferdam combined cofferdam structure in accordance with claim 1, wherein: The bottom of the concrete cofferdam (2) is integrally poured and formed with a base (21) which extends to the bottom of the soil-rock cofferdam (3) as a foundation.

4. The concrete cofferdam and earthfill cofferdam combined cofferdam structure in accordance with claim 1, wherein: The concrete cofferdam (2) is integrally poured and formed with a connecting part (22) on at least one side of the soil-rock cofferdam (3) towards the upstream end of the river channel (1), and the intersection of the two connecting parts (22) and the soil-rock cofferdam (3) gradually approaches the middle of the concrete cofferdam (2) from the side of the corresponding water-approaching surface.

5. The concrete cofferdam and earthfill cofferdam combined cofferdam structure in accordance with claim 3, wherein: The soil-rock cofferdam (3) is embedded with waterproof geotextile (34), and the edge of the waterproof geotextile (34) is fixed to the base (21) and the two concrete cofferdams (2).

6. The concrete cofferdam and earthfill cofferdam combined cofferdam structure in accordance with claim 5, wherein: The waterproof geotextile (34) is arranged horizontally along the river channel (1), and the inner side of the soil-rock cofferdam (3) is embedded with a supporting net (341) for supporting the waterproof geotextile (34), and the supporting net (341) is fixed to the base (21) and the two concrete cofferdams (2).

7. The concrete cofferdam and earthfill cofferdam combined cofferdam structure in accordance with claim 5, wherein: The waterproof geotextile (34) is provided with a plurality of seepage pipes (35) on the water-approaching side, the two ends of the seepage pipes (35) extend towards the side of the concrete cofferdam (2) and are arranged to extend into the soil-rock cofferdam (3) on the downstream side from the concrete cofferdam (2) and then extend out, and the seepage pipes (35) have a downward inclination from at least the upstream side of the concrete cofferdam (2) towards the downstream side.

8. The concrete cofferdam and earthfill cofferdam combined cofferdam structure in accordance with claim 7, wherein: The upstream side of the soil-rock cofferdam (3) is embedded with a pressure relief pipe (36) arranged to extend out of the soil-rock cofferdam (3) from bottom to top, the pressure relief pipe (36) is fixed to and communicates with the seepage pipe (35), and the top of the soil-rock cofferdam (3) is provided with a flow guide channel (361) for receiving water discharged by the pressure relief pipe (36).

9. The concrete cofferdam and earthfill cofferdam combined cofferdam structure in accordance with claim 3, wherein: The top surface of the base (21) gradually rises from the upstream to the downstream, and the top surface of the base (21) is irregular or provided with a plurality of transverse grooves.

10. A method of constructing a composite cofferdam structure of a concrete cofferdam and an earth-rockfill cofferdam, characterized by: The application further discloses a method for constructing the combined cofferdam structure of the concrete cofferdam and the soil-rock cofferdam, which comprises the following steps: S1, marking the construction area: marking the construction area by using markers and light markers on the river channel (1); S2, temporary cofferdam construction: constructing a temporary cofferdam on the side of the construction area, and pumping out the water on the inner side of the temporary cofferdam; S3, concrete cofferdam (2) construction: pouring two concrete cofferdams (2) and bases (21) along the longitudinal direction of the river (1) inside the temporary cofferdam, the concrete cofferdam (2) is poured corresponding to the longitudinal boundary position of the construction area, and the base (21) is poured along the circumferential boundary position of the construction area; S4, earth-rock cofferdam (3) construction: earth-rock materials are used to pile and tamp to form an earth-rock cofferdam (3) at the inner side position of the upstream and downstream boundary positions of the two concrete cofferdams (2) corresponding to the construction area; S5, buffer structure construction: first, a wave protection layer (32) is formed by stacking and laying wave protection blocks from bottom to top on the water-facing surface of the earth-rock cofferdam (3), then a buffer net (33) with buffer blocks (331) is laid on the water-facing surface of the wave protection layer (32), and the laid buffer net (33) is anchored to the base (21) and the concrete cofferdam (2).

Images