Cofferdam structure and construction method

Abstract

The application discloses a cofferdam structure and a construction method, wherein the cofferdam structure comprises a capsule, the capsule is arranged at the periphery of a soft soil foundation to be treated, a first sealing layer is arranged on the soft soil foundation to be treated, the periphery of the first sealing layer is connected with the capsule, the capsule and the first sealing layer enclose a water storage space for pre-pressing the soft soil foundation to be treated, an inner cavity for air inflation and water injection is arranged in the capsule, a gas vent and a water inlet are arranged on the capsule and are connected with the inner cavity, and a tensioning device for maintaining the stability of the capsule is arranged on the capsule. The cofferdam structure can be applied to soft soil foundations with different shapes, shortens the treatment period of the soft soil foundation, and has the advantages of large loading pressure, reusability, economy and environmental protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the cofferdam technical field, in particular to a cofferdam structure and construction method. BACKGROUND

[0002] The ground in coastal areas is very weak. At present, the depth of soft soil foundation reinforced by vacuum preloading method is very limited, so it needs to be combined with membrane water preloading. The membrane water preloading usually needs to build a cofferdam. The existing cofferdam is usually built by earth and stone, and the height is only 1-2m, which has poor stability and is difficult to resist the lateral thrust of water. After the preloading is completed, the unloading treatment of earthwork is also considered, which is complicated and has a long construction period. In addition, the earth and stone cofferdam formed quickly is easy to cause the sliding instability of soft soil foundation after unloading, which has poor stability and is not suitable for soft soil foundation with insufficient bearing capacity. SUMMARY

[0003] The present application relates to the cofferdam technical field, in particular to a cofferdam structure and construction method.

[0004] The technical scheme adopted by the present application to solve the technical problems is:

[0005] A cofferdam structure, comprising a capsule, the capsule is arranged on the outer periphery of the soft soil foundation to be treated, a first sealing layer is arranged on the soft soil foundation to be treated, the outer periphery of the first sealing layer is connected with the capsule, the capsule and the first sealing layer form a water storage space for preloading the soft soil foundation to be treated, an inner cavity for inflating and water injection is arranged in the capsule, a gas inlet and a water inlet are arranged on the capsule and connected with the inner cavity, and a tensioning device for maintaining the stability of the capsule is arranged on the capsule.

[0006] Preferably, the tensioning device comprises a first cable, a second cable and a connecting frame, the connecting frame is arranged on one side of the capsule close to the soft soil foundation to be treated, the connecting frames arranged oppositely are connected by the first cable, one end of the second cable is connected with the connecting frame, and the other end is connected with the capsule, the gas inlet is located at the top of the capsule, and the water inlet is located at the bottom of the capsule.

[0007] Preferably, a limiting cable for limiting the excessive expansion and deformation of the capsule is arranged in the inner cavity in the horizontal direction, and the two ends of the limiting cable are connected with the capsule.

[0008] Preferably, a buckle is arranged outside the capsule, the buckle is arranged on the inner and outer sides of the capsule opposite to the limiting cable, and the second cable is connected with the capsule through the buckle.

[0009] Preferably, the capsule body comprises a capsule wall for enclosing the inner cavity, the capsule wall comprises an outer wall and an inner wall arranged circumferentially along the capsule body, and a fastening component is arranged between the outer wall and the inner wall and connected with the outer wall and the inner wall.

[0010] Preferably, the fastening component comprises a first rib arranged in a horizontal direction and a second rib arranged in a height direction, one end of the first rib is connected with the outer wall, the other end of the first rib is connected with the inner wall, one side of the second rib is connected with the outer wall, and the other side of the second rib is connected with the outer wall, and the limiting cable is connected with the intersection position of the first rib and the second rib.

[0011] Preferably, a plurality of the first cables and the second cables are arranged in the height direction, and the number of the first cables is less than the number of the second cables.

[0012] Preferably, a cement-soil grille wall is arranged at the edge of the soft soil foundation to be treated, the capsule body is arranged at the top of the cement-soil grille wall, and a groove matched with the bottom of the capsule body is arranged on the cement-soil grille wall.

[0013] Preferably, the tensioning device comprises a third cable, one end of the third cable is connected with the capsule body, and the other end of the third cable is anchored on the existing ground outside the soft soil foundation to be treated.

[0014] The application also provides a construction method using the cofferdam structure, comprising the following steps:

[0015] Step one: placing the capsule body on the soft soil foundation to be treated, inflating the inner cavity through the air inlet to make the capsule body stand initially and form a three-dimensional structure;

[0016] Step two: keeping the capsule body in a stable state through the tensioning device;

[0017] Step three: injecting water into the inner cavity through the water inlet, keeping the capsule body in a dynamic water balance and a vertical stable state, and injecting water into the water storage space at the same time;

[0018] Step four: injecting water to reach the designed water load height to perform water load preloading on the soft soil foundation to be treated.

[0019] The cofferdam structure is provided with a bladder on the soft soil foundation to be treated, the bladder is supported to form the cofferdam structure by injecting water and air into the inner cavity of the bladder, when the water volume of the bladder is increased, the gas is gradually displaced, the bladder generates a membrane tension and a water extrusion effect by using the water and air pressure, a light cofferdam with a certain surface rigidity is formed, and the fullness of the bladder is maintained, the bladder is connected with a tensioning device for maintaining the stability of the bladder, the cofferdam maintains a balanced state under the action of the lateral water pressure and the tension of the tensioning device, the stability of the bladder is maintained by the tensioning device, the water injection into the water storage space can realize the pre-compaction of the soft soil foundation, the cofferdam structure can be applied to soft soil foundations with different shapes, the treatment period of the soft soil foundation is shortened, and the cofferdam structure has the advantages of large loading pressure, reusability, economy and environmental protection.

[0020] Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and / or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0022] Figure 1 is an embodiment structure schematic diagram of the cofferdam structure of the present application;

[0023] Figure 2 is an embodiment structure schematic diagram of the bladder wall of the present application. DETAILED DESCRIPTION

[0024] This part will describe the specific embodiments of the present application in detail, the preferred embodiments of the present application are shown in the accompanying drawings, the role of the drawings is to supplement the description of the text part with figures, so that people can intuitively and visually understand each technical feature and the overall technical scheme of the present application, but it cannot be understood as a limitation on the protection scope of the present application.

[0025] In the present application, if the direction (up, down, left, right, front and back) is described, it is only for the convenience of describing the technical scheme of the present application, and is not indicative or suggestive of the technical features indicated must have a specific orientation, be constructed and operated in a specific orientation, therefore, it cannot be understood as a limitation on the present application.

[0026] In the present application, the meaning of "several" is one or more, the meaning of "multiple" is two or more, and "greater than", "less than", "more than" and the like are understood as not including the number; "above", "below", "within" and the like are understood as including the number. In the description of the present application, if "first", "second" are described, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0027] In the present application, unless otherwise explicitly limited, the words "set", "install", "connect" and the like should be broadly understood, for example, they can be directly connected, or indirectly connected through an intermediate medium; can be fixedly connected, or can be detachably connected, or can be integrally formed; can be mechanically connected, or can be electrically connected or capable of communicating with each other; can be the communication or interaction relationship between two elements. The skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0028] The embodiment of the present application provides a cofferdam structure, referring to Figure 1 , comprising a capsule 200, the capsule 200 is arranged at the outer periphery of the soft soil foundation 100 to be treated, a first sealing layer 110 is arranged on the soft soil foundation 100 to be treated, the outer periphery of the first sealing layer 110 is connected with the capsule 200, and the capsule 200 and the first sealing layer 110 form a water storage space 120 for prepressing the soft soil foundation 100 to be treated. It can be understood that the capsule 200 can be arbitrarily spliced according to the shape of the soft soil foundation 100 to be treated, and is easy to disassemble and can be reused. An inner cavity 210 for inflating and water injection is arranged in the capsule 200. An air vent 220 and a water inlet 230 are arranged on the capsule 200 and are in communication with the inner cavity 210. The capsule 200 is supported to form a cofferdam structure by injecting water and air into the inner cavity 210. Water is injected into the capsule 200 to form a water injection layer. When the amount of water injected into the capsule 200 increases, the gas is gradually displaced. The water and gas pressure makes the capsule 200 generate a membrane tension and the capsule 200 generates a water extrusion effect, so as to form a light cofferdam with a certain surface stiffness and maintain the full shape of the capsule 200. A tensioning device is arranged on the capsule 200 for maintaining the stability of the capsule 200. The cofferdam maintains a balanced state under the action of lateral water pressure and the tension of the tensioning device. The tensioning device can maintain the stability of the capsule 200. Water is injected into the water storage space 120 to realize the prepressing of the soft soil foundation 100. The cofferdam structure can be applied to soft soil foundations of different shapes, shortens the treatment period of the soft soil foundation, has the advantages of large loading pressure, reusability, economy and environmental protection.

[0029] Preferably, the capsule 200 is provided with a joint at the head and tail, and the joint is sealed after connection, so that the capsule 200 is combined to form a three-dimensional structure, and the capsule 200 surrounding the outer periphery of the soft soil foundation 100 to be treated can also be assembled and arranged according to the shape of the soft soil foundation 100 to be treated, such as a rectangle, etc. The capsule 200 filled with water forms a gravity type cofferdam with a certain self-stability, and the cross section of the cofferdam is trapezoidal or other cross section forms with low gravity center, so as to improve the self-stability of the cofferdam structure.

[0030] Referring to Figure 1 , the tensioning device comprises a first cable 400, a second cable 500 and a connecting frame 300, the connecting frame 300 is arranged on the side of the capsule 200 close to the soft soil foundation 100 to be treated, the connecting frames 300 arranged oppositely are connected by the first cable 400, one end of the second cable 500 is connected with the connecting frame 300, and the other end is connected with the capsule 200, the connecting frame 300 can reduce the amount of the first cable 400 and reduce the probability of the first cable 400 and the second cable 500 being knotted, so that the whole cofferdam structure is more stable. In some embodiments, the connecting frame 300 is a triangular or rectangular steel frame, the steel frame is arranged along the direction of the cofferdam, is spaced by 3-5 m, and is connected with each other to form a row of truss structures. Preferably, the cross section of the capsule 200 is trapezoidal with the top narrow and the bottom wide, the air vent 220 is located at the top of the capsule 200, and the water inlet 230 is located at the bottom of the capsule 200. It can be understood that the cross section of the capsule 200 can also be elliptical, quadrilateral or other shapes with low gravity center, and the height of the cross section is not more than 6 m. The water inlet 230 is connected with a water inlet pipe and a water outlet pipe, the water inlet pipe is connected with a water inlet valve and a water meter, the water outlet pipe is provided with a water outlet valve, the air vent 220 is connected with an air inlet pipe and an air outlet pipe, the air inlet pipe is provided with an air inlet valve and a pressure gauge, and the air outlet pipe is provided with an air outlet valve.

[0031] Referring to Figure 1 , the capsule 200 is provided with a limiting cable 240 for limiting excessive deformation of the capsule 200, the limiting cable 240 is arranged in the inner cavity 210 in the horizontal direction, and both ends of the limiting cable 240 are connected with the capsule 200. It can be understood that the length of the limiting cable 240 is the allowable inflation width of the capsule 200 after deformation at the position corresponding to the height. The limiting cable 240 is in a tensioned state when the capsule 200 is full, so as to limit the capsule 200 from excessive inflation deformation.

[0032] Referring to Figure 1 , the capsule 200 is provided with a buckle 250, the buckle 250 is arranged on the inner and outer sides of the capsule 200 opposite to the limiting cable 240, and the second cable 500 is connected with the capsule 200 through the buckle 250, so as to ensure the stability of the cofferdam structure. Preferably, the capsule 200 is provided with a rubber anchor pad, and the rubber anchor pad is arranged between the capsule 200 and the buckle 250.

[0033] Referring toFigure 2 The capsule 200 comprises a capsule wall 260 for enclosing the inner cavity 210, the capsule wall 260 comprises an outer wall 261 and an inner wall 262 arranged circumferentially along the capsule 200, and a fastening component 270 is arranged between the outer wall 261 and the inner wall 262, the fastening component 270 is connected with the outer wall 261 and the inner wall 262, preferably, the fastening component 270 is made of a high elastic modulus reinforcing material with an elastic modulus not less than 30 GPa, the embedding of the fastening component 270 in the capsule wall 260 enhances the tensile resistance of the capsule 200, and the limiting cable 240 arranged at the intersection of the horizontal first rib 271 and the vertical second rib 272 of the fastening component 270 can prevent the capsule 200 from excessive deformation and expansion.

[0034] As a preferred embodiment of the present application, referring to Figure 2 The fastening component 270 comprises a first rib 271 arranged in the horizontal direction and a second rib 272 arranged in the height direction, one end of the first rib 271 is connected with the outer wall 261, the other end of the first rib 271 is connected with the inner wall 262, one side of the second rib 272 is connected with the outer wall 261, the other side of the second rib 272 is connected with the outer wall 261, the limiting cable 240 is connected with the intersection of the first rib 271 and the second rib 272, the first rib 271 and the second rib 272 are made of high elastic modulus geotechnical material and are integrated with the outer wall 261 and the inner wall 262, for increasing the tensile strength of the capsule 200 and increasing the lateral wall stiffness of the capsule 200.

[0035] As a preferred embodiment of the present application, referring to Figure 1 The first cable 400 and the second cable 500 are both provided in plurality, the plurality of first cables 400 and the second cables 500 are both arranged in the height direction, and the number of the first cables 400 is less than the number of the second cables 500.

[0036] Referring to Figure 1 The edge of the soft soil foundation to be treated is provided with a cement-soil grille wall 600, the capsule 200 is arranged at the top of the cement-soil grille wall 600, the cement-soil grille wall 600 is provided with a groove 610 matched with the bottom of the capsule 200, the width of the cement-soil grille wall 600 is 0.5 m to 1 m wider than the width of the bottom of the capsule 200, before hardening, a second sealing layer is laid on the groove 610, and clay is filled in the groove 610, after the cement-soil grille wall 600 is hardened, the construction of the capsule 200 and other structures is carried out, the cement-soil grille wall 600 not only can be used as an isolation wall for vacuum preloading to prevent water vapor outside the treatment range from entering the soft soil foundation to be treated, but also can be used as a foundation for bearing the cofferdam structure, the permeability of the clay is small, which can press the second sealing layer and prevent water in the cofferdam from seeping out from the bottom, in addition, the clay also serves as a cushion layer between the capsule 200 and the cement-soil grille wall 600, preferably, the second sealing layer and the first sealing layer 110 are integrated.

[0037] Referring to Figure 1 The soft soil foundation 100 to be treated is provided with a drainage plate and a drainage cushion, so that water on the surface of the soft soil foundation 100 to be treated can be discharged after preloading of the soft soil foundation 100 to be treated is completed, and a settlement monitoring device is buried in the soft soil foundation 100 to be treated.

[0038] Referring to Figure 1 The tensioning device comprises a third cable 700, one end of the third cable 700 is connected with the buckle 250 on the bladder 200, and the other end is anchored on the existing ground outside the soft soil foundation 100 to be treated, and the third cable 700 maintains the overall stability of the cofferdam structure system.

[0039] The application further provides a construction method using the cofferdam structure, comprising the following steps:

[0040] Step one: the cement-soil lattice wall 600 is constructed, the drainage plate is arranged, the first sealing layer 110 is laid, and the edge of the first sealing layer 110 is pressed in the groove 610. After the cement-soil lattice wall 600 is hardened, the bladder 200 is placed on the soft soil foundation 100 to be treated, the bladder 200 is inflated through the air inlet 220 into the inner cavity 210, and the bladder 200 is initially erected to form a three-dimensional structure;

[0041] Step two: the bladder 200 is kept in a stable state through the tensioning device, specifically, one end of the second cable 500 is connected with the bladder 200, and the other end is connected with the connecting frame 300, and the connecting frames 300 located at both ends of the soft soil foundation 100 to be treated are connected through the first cable 400;

[0042] Step three: water is injected into the inner cavity 210 through the water inlet 230, and the water dynamic balance in the bladder 200 and the vertical stability of the bladder 200 are kept, and water is injected into the water storage space 120, preferably, in the water injection process, the water is injected into the water storage space 120 and the bladder 200 layer by layer, the height of each layer is controlled according to the monitored settlement rate, and the water level in the bladder 200 is kept 25-30 cm higher than the water level in the water storage space 120 at all times, the water loading time is determined according to the deformation amount required by the design and the deformation monitoring, so that the water dynamic balance in the bladder 200 is kept, and the shape of the bladder 200 is ensured to be full, and the second cable 500 needs to be adjusted after each layer of water injection is completed, and the appropriate tension of each cable is determined according to the balance relationship between the tension of the second cable 500 and the lateral water pressure of the bladder 200, so as to keep the bladder 200 vertically stable;

[0043] Step four: after the water reaches the design water loading height, the water level is kept stable, the water levels in the bladder 200 and the water storage space 120 are kept stable, if the water pressure or air pressure decreases, the water injection or air injection is opened in time until the design level is restored, the soft soil foundation 100 to be treated is preloaded by water, and the preloading period is reached until the predetermined preloading period is reached;

[0044] Step five: the pre-pressing period is over, the pre-pressing is completed, the water in the bladder 200 and the water storage space 120 is discharged to the drainage ditch in layers, the water level in the bladder 200 and the water storage space 120 is lowered synchronously, until the water level is close to the bottom of the bladder 200, then the operation is reversed, and the bladder 200 can be removed.

[0045] In the description of the present specification, the description referring to the terms "example", "embodiment" or "some embodiments" or the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0046] Of course, the present application is not limited to the above-described embodiments, and those skilled in the art can make equivalent modifications or replacements without departing from the spirit of the present application, and these equivalent modifications or replacements are included in the scope defined by the claims of the present application.

Claims

1. A cofferdam structure, characterized by: The device includes a capsule, which is disposed on the outer periphery of the soft soil foundation to be treated. A first sealing layer is provided on the soft soil foundation to be treated. The outer periphery of the first sealing layer is connected to the capsule. The capsule and the first sealing layer form a water storage space for pre-compressing the soft soil foundation to be treated. The capsule has an inner cavity for air inflation and water injection. The capsule has an air vent and a water inlet connected to the inner cavity. The air vent is located at the top of the capsule, and the water inlet is located at the bottom of the capsule. The capsule is equipped with a tensioning device for maintaining the stability of the capsule. The tensioning device includes a first cable, a second cable, and a connecting frame. The connecting frame is located on the side of the capsule near the soft soil foundation to be treated. The connecting frames arranged opposite each other are connected by the first cable. One end of the second cable is connected to the connecting frame, and the other end is connected to the capsule. The connecting frame is a triangular or rectangular steel frame. The steel frames are arranged along the direction of the cofferdam, spaced 3 to 5 meters apart, and connected to each other to form a row of truss structures. The bladder is provided with a limiting cable for limiting excessive expansion and deformation of the bladder. The limiting cable is arranged horizontally in the inner cavity, and both ends of the limiting cable are connected to the bladder. The bladder is provided with a buckle, which is arranged opposite to the limiting cable on the inner and outer sides of the bladder. The second cable is connected to the bladder through the buckle. The capsule includes a capsule wall for forming the inner cavity. The capsule wall includes an outer wall and an inner wall arranged circumferentially along the capsule. A fastening member is provided between the outer wall and the inner wall. The fastening member is connected to the outer wall and the inner wall. The fastening member includes a first rib arranged horizontally and a second rib arranged vertically. One end of the first rib is connected to the outer wall, and the other end of the first rib is connected to the inner wall. One side of the second rib is connected to the outer wall, and the other side of the second rib is connected to the outer wall. The limiting cable is connected to the intersection of the first rib and the second rib.

2. The cofferdam structure of claim 1, wherein: There are multiple first cables and multiple second cables, and the multiple first cables and multiple second cables are arranged along the height direction. The number of first cables is less than the number of second cables.

3. The cofferdam structure according to claim 1, characterized in that: A cement-soil grid wall is provided at the edge of the soft soil foundation to be treated. The capsule is located on the top of the cement-soil grid wall, and the cement-soil grid wall has a groove that matches the bottom of the capsule.

4. The cofferdam structure according to claim 1, characterized in that: The tensioning device includes a third cable, one end of which is connected to the capsule, and the other end is anchored to the existing ground outside the soft soil foundation to be treated.

5. A construction method using the cofferdam structure of claim 1, characterized in that... Includes the following steps: Step 1: Place the capsule on the soft soil foundation to be treated, and inflate the inner cavity through the vent to make the capsule stand up initially and form a three-dimensional structure; Step 2: Use a tensioning device to stabilize the capsule. Step 3: Inject water into the inner cavity through the water inlet, maintain the dynamic balance of water and air inside the bladder and ensure the bladder is upright and stable, and simultaneously inject water into the water storage space; Step 4: Inject water to the designed water load height and perform water load preloading on the soft soil foundation to be treated.

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