JP2009180018A - Method of constructing cofferdam for underwater structure and structure for cofferdam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further enhance the level of water cut-off by an elastic member when the periphery of an underwater structure is brought into a waterless dry working environment. <P>SOLUTION: This structure for a cofferdam comprises a working caisson 16 having one or more steel shells and the elastic seal member 24 attached to the bottom of the working caisson 16. A lateral deformation prevention member 26 for preventing the elastic seal member 24 from being deformed inward of the working caisson 16 is disposed on at least a part of the inner periphery of the elastic seal member 24. Even if the elastic member 24 hydraulically receives a horizontal force, the fixing water cut-off function of the elastic seal member is not reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a temporary closing method for securing a dry working space in repairing and reinforcing work of underwater structures such as bridge piers constructed underwater, and a temporary closing structure for the same.

  The need for seismic reinforcement is increasing due to aging repairs and revision of seismic design standards for bridge piers constructed in the sea or rivers. In such repair and reinforcement work for underwater structures, it is indispensable to provide a dry working environment without water around the target structure for the purpose of ensuring quality and safety.

  For temporary closing to perform dry work, a method of placing steel sheet piles and steel pipe sheet piles around as a water blocking wall was used, but if there is a restriction on the use of upper space such as bridge piers, It was pointed out that the sheet pile was difficult to lay and the construction period was long.

  In order to solve this problem, as represented by Patent Documents 1 to 6, using a work box made of a double steel shell capable of floating towing, after installing so as to surround the work object (structure), Water is poured into a double steel shell and set, and water is stopped using a water stop jig provided on the work object and the bottom of the work box or on the side of the bottom. Is used.

However, the above prior art has the following problems. That is,
(1) Since the work box itself has a double steel shell structure to make it a buoyant body for floating towing, the outer dimensions of the work box are increased, and the pressure receiving area for tidal and wave forces is increased. The number of beam members to increase Alternatively, when the outer diameter is reduced, the internal work space is narrowed and the work efficiency is reduced.
(2) Also, because of the double steel shell structure, the number of manufacturing steps increases, and the manufacturing cost of the work box increases.
(3) It is necessary to attach a water stop jig to the work object such as a pier footing in advance with a certain degree of accuracy in order to stop the water at the bottom.

  On the other hand, in Patent Document 7, a work box made of an annular steel shell in which a stiffening plate structure pressure-resistant block is assembled in advance and a buoyant body for floating towing / on-site installation are made into separate structures, and the work box is installed. Thereafter, a technique for removing the buoyancy body and a technique for water stopping using an elastic sealing material or a waterproof skirt are described, which solves the problems of the conventional technique.

Japanese Patent No. 3024932 Japanese Patent No. 30659927 Japanese Patent No. 3330018 JP 2002-201649 A Japanese Patent No. 3379391 Japanese Patent No. 3387436 Japanese Patent Laid-Open No. 2006-249585

  However, in order to be able to be applied to repair of piers having footings at deep water depth, it is required to further improve the level of water stoppage by the elastic seal material described in Patent Document 7.

  Therefore, an object of the present invention is to further improve the level of water stopping by the elastic sealing material used when the periphery of the underwater structure is made into a dry working environment without water.

  In order to solve the above problems, the present inventor first conducted a water-stop performance test of the elastic sealing material as shown in FIGS. FIG. 1 is a schematic diagram showing an overview of the water-stop performance test, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along line BB in FIG. As shown in FIG. 3, the shape of the outer periphery of the cross section of the elastic sealing material 200 is a square (750 mm × 750 mm), and the shape of the cross section of the internal space is also a square (450 mm × 450 mm). Moreover, as shown in FIG. 1, the shape of the longitudinal cross-section of the elastic sealing material 200 is a rectangle (width 150 mm × height 210 mm), and the upper end portion is a steel sealing material fixing frame 202 (cross-sectional shape is 60 mm from both sides). × 60 mm) and fixed.

  In carrying out the water-stopping performance test, the elastic sealing material 200 is placed on the upper surface of the concrete 204, the interior space of the elastic sealing material 200 is filled with water 206, and the upper surface of the elastic sealing material 200 has a square shape with a thickness of 19 mm. The steel lid 208 was covered from above. The elastic sealing material 200 is compressed downward in the vertical direction by applying a downward force in the vertical direction with a 35-ton hydraulic jack 216 to the upper surface of the steel lid 208 via the 50-ton load cell 210 and the steel shapes 212 and 214. In addition, pressure was applied to the water 206. Further, the water pressure was gradually applied to the water 206 by the water pressure pump 218 until a predetermined water pressure was reached, and the presence or absence of water leakage and the external shape of the elastic sealing material 200 were observed.

  FIG. 4 is a graph showing the results of this water-stop performance test, in which the horizontal axis represents the compression ratio of the elastic sealing material 200 and the vertical axis represents the water leakage limit water pressure. As can be seen from FIG. 4, the water leakage limit water pressure increases as the compression rate of the elastic sealing material 200 increases. Therefore, it can be seen that in order to obtain a predetermined water leakage limit water pressure, it is necessary to apply a downward force to the elastic sealing material 200 in the vertical direction until the elastic sealing material 200 reaches a predetermined compression rate. Here, the compression rate is a value obtained by dividing the amount (mm) of compression of the elastic sealing material 200 by the height (mm) of the elastic sealing material 200 before compression.

  Further, when the water leakage limit water pressure is exceeded when the compressibility of the elastic sealing material 200 is about 70% or more, the elastic sealing material 200 protrudes greatly to the outside, and as the ground contact surface of the elastic sealing material 200 faces the outside, the elastic sealing material 200 increases outward. Water leaked due to deformation that protruded. The mechanism of this deformation is schematically shown in FIG. FIG. 5A shows an initial state where no external force is applied to the elastic sealing material 200, and FIG. 5B shows a downward force in the vertical direction on the elastic sealing material 200 until the compressibility becomes about 70% or more. FIG. 5 (C) shows the state of swelling in the lateral direction (horizontal direction), and FIG. 5 (C) shows the water leakage limit water pressure in the lateral direction (horizontal direction) in the compressed state as shown in FIG. 5 (B). The elastic sealing material 200 is subjected to a water pressure exceeding 1 and is deformed so as to protrude largely in the direction opposite to the side receiving the water pressure, and shows a state where water leakage has occurred.

  In the deformed state shown in FIG. 5C, the elastic sealing material 200 is strongly pressed against the inner peripheral surface of the sealing material fixing frame 202, and the elastic sealing material 200 may be damaged by this pressing.

  After grasping the above-described water leakage mechanism and damage mechanism of the elastic sealing material, the present inventor studied a measure for preventing the occurrence of such a water leakage mechanism and damage mechanism. As a result, it is possible to improve the water leakage limit water pressure by arranging a lateral deformation preventing material that prevents the elastic sealing material from being deformed inward of the work box on at least a part of the inner periphery of the elastic sealing material. I found out that I can. Furthermore, by providing a buffer backup material that prevents an excessive compression force from being applied to a part of the elastic seal material at least partly between the lateral deformation prevention material and the elastic seal material, a large amount of compression is achieved in the vertical direction. Even if it receives a large water pressure in the horizontal direction (horizontal direction) under a force, it can suppress damage to the elastic sealing material, and even if it receives a larger water pressure in the horizontal direction (horizontal direction), water leakage is less likely to occur. I found out.

  The present invention has been made based on such findings.

  In other words, the temporary closing method for an underwater structure according to the present invention includes a work box made of a single-stage or multi-stage steel shell and an elastic sealing material provided on the outer periphery of the bottom of the work box or the lower part of the work box. The detachable outer buoyancy body is attached to the outer periphery of the temporary buoyancy structure, and is floated towed at the site, arranged so as to surround the work object, and water is poured into at least a part of the outer buoyancy body. Or after removing and setting up at least a part of the outer buoyant body, draining the inside of the temporary closing structure, and by the weight of the temporary closing structure or the vertical component of the force due to its own weight and water pressure A temporary closing method for an underwater structure that forms a work space by adhering the temporary closing structure to a work object, and at least a part of the inner circumference of the elastic seal material A lateral deformation preventing material that prevents the sealing material from being deformed inward of the work box. And set, even when subjected to horizontal forces due to water pressure, fixing water-stopping function of the elastic sealing material is characterized in that as hardly lowered.

  In the temporary closing method, a buffer backup material for preventing an excessive compressive force from being applied to a part of the elastic sealing material is provided at least at a part between the lateral deformation preventing material and the elastic sealing material. preferable.

  In the temporary closing method, it is preferable that a stopper for adjusting the descending distance of the work box is provided to prevent part or all of the elastic sealing material from being overcompressed.

  A base boat may be used for floating towing of the temporary deadline structure. In this case, the base boat is provided with an elevating device for sinking the temporary deadline structure to the work object. It is preferable. Specifically, a bar steel whose one end is pin-coupled to the work box is disposed near the bottom of the work box, and the lifting device may be a hydraulic device that lifts and lowers the bar steel.

  It is preferable that a removable inner peripheral buoyancy body is disposed on the inner periphery of the work box to reduce the outer peripheral buoyancy body.

  A first embodiment of a temporary closing structure according to the present invention is a temporary closing structure comprising a work box made of a single-stage or multi-stage steel shell and an elastic sealing material provided at the bottom of the work box. A lateral deformation preventing material for preventing the elastic sealing material from being deformed in the inner direction of the work box is disposed on at least a part of the inner periphery of the elastic sealing material, Even if it receives force, it is characterized in that the sticking water-stopping function of the elastic sealing material is not easily lowered.

  The second embodiment of the temporary closing structure according to the present invention is attached to a work box made of a single-stage or multi-stage steel shell and an outer periphery of a lower part of the work box, and receives a vertical downward force due to water pressure. A temporary closing structure having a pressure receiving widening portion that can be formed and an elastic sealing material provided at the bottom of the pressure receiving widening portion, wherein at least a part of the inner circumference of the elastic sealing material has the elastic seal A lateral deformation prevention material is provided to prevent the material from being deformed in the inner direction of the work box so that even if it receives a horizontal force due to water pressure, the sticking water stop function of the elastic seal material is not easily lowered. It is characterized by that.

  It is preferable that a buffer backup material for preventing an excessive compressive force from being applied to a part of the elastic sealing material is provided at least at a part between the lateral deformation preventing material and the elastic sealing material.

  Moreover, it is preferable that a stopper for adjusting the descending distance of the work box is provided so that a part or all of the elastic sealing material is not overcompressed.

  A steel bar having one end connected to the work box is disposed near the bottom of the work box, and a vertical downward force is applied to the steel bar so that it can be sunk into the work object. It is preferable. The force applied vertically downward to the steel bar can be sunk in the work object so that the elastic sealant has a predetermined compressibility by assisting the vertical downward force due to its own weight or water pressure acting on the work box. It may be the power to make it.

  In the temporary closing structure, it is preferable that an outer peripheral buoyancy body is mounted on the outer periphery and an inner peripheral buoyancy body is mounted on the inner periphery.

  It is preferable that a waterproof skirt is provided outside the elastic sealing material.

  The elastic sealing material may be divided into two or more parts in the circumferential direction. In this case, the joints of the divided elastic sealing materials are formed by closely contacting surfaces inclined with respect to a horizontal plane. Preferably it is.

  In the present invention, a lateral deformation preventing material that prevents the elastic sealing material from being deformed in the inner direction of the work box is disposed on at least a part of the inner periphery of the elastic sealing material. Even if a force is applied, the fixing water-stopping function of the elastic sealing material is unlikely to deteriorate, and water can be prevented from entering the work space partitioned by the temporary closing structure.

  Furthermore, when a buffer backup material that prevents an excessive compressive force from being applied to a part of the elastic sealing material is provided at least partly between the lateral deformation preventing material and the elastic sealing material, the elastic sealing material Even if the lateral deformation is forcibly suppressed by the lateral deformation prevention material, excessive stress concentration does not occur in the elastic sealing material, and the elastic sealing material is prevented from being damaged. The water stop function is more stable.

  Furthermore, if a stopper that adjusts the descent distance of the work box is provided to prevent part or all of the elastic seal material from being overcompressed, the elasticity when the temporary closing structure is laid down Nonuniformity in the compression amount of the sealing material is suppressed within a predetermined range, and water leakage is less likely to occur. In addition, the elastic sealing material is hardly damaged, and the life of the elastic sealing material is prevented from being shortened.

  In addition, a steel bar whose one end is pin-coupled to the work box in the vicinity of the bottom of the work box is disposed in the temporary cutting structure, and a vertical downward force is applied to the steel bar, thereby When it is possible to sink the work object, or by applying a downward force to the steel bar to assist the downward force due to its own weight or water pressure acting on the work box, the elastic sealing material is When it is possible to sink the work to the work object so that the compression rate is the same, the temporary closing structure can be stably placed on the work object, and the elastic sealing material is provided when the temporary closing structure is set. Can be prevented from being compressed non-uniformly, and water leakage is less likely to occur.

  When a detachable inner buoyancy body is attached to the inner periphery of the temporary closing structure, the outer buoyancy body attached to the outer periphery can be made smaller, and the buoyancy can be increased when floating towing the temporary closing structure. The entire structure for temporary deadlines including the body can be made compact, and the operability of towing and installation work can be improved, and the buoyancy body can be mounted in small blocks. Uniform descent is less likely to occur.

  When a waterproof skirt is provided outside the elastic seal material, the amount of water leakage can be reduced even if water leaks from the elastic seal material.

  Even if the elastic sealing material is not integrated and is divided into two or more in the circumferential direction, the joints of the divided elastic sealing materials are formed by closely contacting surfaces inclined with respect to the horizontal plane. In such a case, it is possible to ensure the water stoppage equivalent to that of the general part having no joint.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. 1st-5th embodiment is embodiment about the case where a work target object is a bridge pier of a circular section.

  FIG. 6 is a front view showing a state when the outer buoyant body is attached to the outer periphery of the temporary closing structure according to the first embodiment of the present invention and towed to the site, and FIG. 7 is a view of the temporary closing structure. FIG. 8A is an enlarged cross-sectional view showing the details of the structure of the pressure receiving widened portion. FIG. 8A is an enlarged cross-sectional view of the pressure receiving widened portion.

  The temporary closing structure 10 includes a work box 16 in which each pressure-resistant block 12 is assembled with a water-stopping material 14 interposed therebetween, a pressure-receiving widening part 18 projecting outside the bottom of the work box 16, and a pressure-receiving widening part. The water-stopping box cross-section member 20 provided at the bottom of the portion 18, the water-stopping elastic sealing member 24 fitted in the water-stopping box cross-section member 20, and the inner side plate 20A of the water-stopping box cross-section member 20 Provided on the outer surface of the outer side plate 20C of the lateral deformation prevention member 26 provided on the inner side, the buffer backup material 28 provided between the elastic sealing material 24 and the lateral deformation prevention member 26, and the water-stopping cross-section member 20 The waterproof skirt 30 is provided. In order to float and install the temporary closing structure 10, a detachable buoyant body 40 is disposed on the outer periphery of the temporary closing structure 10, and the temporary closing structure 10 is buoyant body 40 and the outer periphery thereof is underwater. Supported by

  The buoyancy body 40 includes an outer peripheral buoyancy body 42 that stores air therein to obtain buoyancy, a steel pipe support 44 attached to the upper portion of the outer periphery buoyancy body 42, and the steel pipe support 44 as a support post. And a work table 46 installed at the end. Since the work table 46 is installed at the top end portion of the temporary closing structure 10, the temporary closing structure 10 can be easily installed on site. As shown in FIG. 7A, one point on the outer periphery of the buoyancy body 40 is a hinge mechanism 40A, and the buoyancy body 40 opens and closes around the hinge mechanism 40A. In FIG. 5, reference numeral 16 </ b> A is a closing part of the work box 16 in a state where the temporary closing structure 10 and the buoyancy body 40 are closed, reference numeral 18 </ b> A is a closing part of the pressure receiving widening part 18, and reference numeral 42 </ b> A is a closing part of the outer peripheral buoyancy body 42. Reference numeral 46A denotes a closing portion of the work table 46.

  The outer buoyancy body 42 is detachable from the temporary closing structure 10 and is attached when the temporary closing structure 10 is floated and towed, and when the temporary closing structure 10 is laid on the work object. Can be removed. Further, when the temporary cutoff structure 10 is laid down on the work target, the outer buoyancy body 42 is not removed from the temporary cutoff structure 10, but water is poured into the outer buoyancy body 42, and the temporary cutoff structure 10. Can also be set against the work object.

  As shown in FIG. 6, the temporary closing structure 10 is supported by the detachable buoyancy body 40 in the water and is floated to the site. The buoyancy body 40 is a semi-submersible type in which the outer buoyancy body 42 can be submerged in order to ensure stability during towing and minimize the influence of the tide level difference. The temporary closing structure 10 and the buoyancy body 40 are assembled in an annular shape as shown in FIG. 7A until arrival at the site to ensure stability during towing.

  After arrival at the site, in order to attach the temporary closing structure 10 to the work pier 2 (see FIG. 11E), as shown in FIG. 7A, a hinge mechanism 40A provided on the buoyancy body 40 is provided. Thus, the temporary closing structure 10 is opened in a fan shape (see FIG. 11 (F)), and is installed so as to surround the pier 2 and then closed again by the hinge mechanism 40A at the closing portions 16A, 18A, 42A, 46A, An annular structure is formed (see FIG. 12G).

  The pressure-resistant block 12 is composed of a steel plate 12A that is an outer peripheral surface of the temporary closing structure 10, and a plurality of stiffening plates 12B (see FIG. 8) that stiffen the steel plate 12A from the inner peripheral surface side. Together with the water stop material 14, it becomes a component of the work box 16.

  The work box 16 has an annular steel shell structure in which a plurality of pressure-resistant blocks 12 are assembled, and a water-stopping material 14 such as a rubber sheet is inserted into a joint surface between the pressure-resistant blocks 12 and then fastened with bolts. Yes, it is the main component of the temporary cutoff structure 10.

  As shown in FIG. 8, the pressure receiving widening portion 18 includes a work case bottom plate protruding portion 16 </ b> B which is a portion protruding outward from the bottom plate of the work case 16, and a root of the work case bottom plate protruding portion 16 </ b> B and the main body of the work case 16. A bracket 16C for stiffening the part, a mounting plate 16D attached to the lower surface of the working bottom plate protrusion 16B, an annular water-stop box cross-section member 20 attached to the lower surface of the mounting plate 16D and having an open lower portion; Is the main component. After the temporary closing structure 10 is installed around the pier 2 (see FIG. 11E), the water inside the temporary closing structure 10 is drained, and there is no water below the pressure-receiving widening portion 18. The buoyancy stops working, and the pressure receiving widening portion 18 receives a downward force in the vertical direction due to the water pressure from above (see FIG. 14).

  The water-stop box cross-section member 20 is composed of an inner side plate 20A, a top plate 20B, and an outer side plate 20C, and has a box-like shape with an opening at the bottom. As shown in FIG. It is attached to the lower surface of 16D, and the top plate 20B is attached to the outside of the bottom of the work box 16 with the sheet-like elastic sealing material 22 interposed therebetween. An elastic sealing material 24 is fitted into the lower opening of the water-stop box cross-section member 20, and a waterproof skirt 30 is attached to the outer surface of the outer side plate 20C.

  As shown in FIG. 8, the elastic sealing material 24 is fitted into the opening in the lower part of the water-stopping box cross-section member 20, and the central part and the lower part are opened from the opening in the lower part of the water-stopping box cross-section member 20. It protrudes downward and is provided. The elastic sealing material 24 is in close contact with the upper surface of the footing 4 of the pier 2 (see FIG. 11E), and has a role of preventing water from entering the temporary closing structure 10 from the outside. After the temporary closing structure 10 is installed around the pier 2, buoyancy works when water inside the temporary closing structure 10 is drained and water disappears from below the work box 16 and the pressure receiving widening portion 18. The vertical downward force due to the dead weight of the temporary closing structure 10 and the water pressure applied to the pressure receiving widening portion 18 is applied to the elastic seal material 24 (see FIG. 14), and the elastic seal material 24 is in close contact with the upper surface of the footing 4. Stop the water. The elastic sealing material 24 may be any material having flexibility that can reliably stop water following the unevenness of the footing 4. For example, various synthetic rubbers (for example, polybutadiene-based synthetic rubber) can be used.

  Further, the elastic sealing material 24 may be divided into two or more in the circumferential direction. In this case, the joints of the divided elastic sealing materials 24 are formed by closely contacting surfaces inclined with respect to the horizontal plane. By doing so, it is possible to ensure the water stoppage equivalent to the general part having no joint.

  As shown in FIG. 8, the lateral deformation preventing material 26 is a steel material attached to the inside of the inner side plate 20 </ b> A of the water-stopping box cross-section member 20, and even if the elastic sealing material 24 receives water pressure from the outside, the water pressure is reduced. It has a role of preventing the elastic sealing material 24 from being greatly deformed on the side opposite to the receiving side.

  The temporary closing structure 10 is installed around the pier 2 and the water inside is drained, the elastic sealing material 24 is in a compressed state, and further receives water pressure from the outside toward the inside of the temporary closing structure 10. The elastic sealing material 24 tends to be greatly deformed in the direction opposite to the side receiving the water pressure, but when the lateral deformation preventing material 26 is provided, this deformation is suppressed. However, since the lateral deformation preventing material 26 forcibly presses the elastic sealing material 24 that is to be deformed in the lateral direction, when the elastic sealing material 24 is in direct contact with the lateral deformation preventing material 26, the elastic sealing material 24 in the contacted portion is contacted. In this case, an excessive compressive stress is generated, and the elastic sealing material 24 may be damaged.

  In order to prevent this damage, as shown in FIG. 8, a buffer backup material 28 is provided between the elastic seal material 24 and the lateral deformation prevention material 26. The buffer backup material 28 is a softer material than the elastic seal material 24, and for example, urethane foam can be used. Even if the elastic sealing material 24 compressed to a predetermined compression rate is deformed to the side opposite to the side receiving the water pressure, the presence of the buffer backup material 28 makes the elastic sealing material as shown in FIG. The sealing material 24 does not come into direct contact with the lateral deformation preventing material 26. Further, the buffer backup material 28 is softer than the elastic seal material 24. For this reason, even if the lateral deformation is forcibly suppressed by the lateral deformation preventing material 26, excessive stress concentration does not occur in the elastic sealing material 24, and the elastic sealing material 24 is prevented from being damaged. In FIG. 9, the waterproof skirt 30 is not shown for convenience of illustration.

  In the state where compression is applied to the elastic sealing material 24 to a predetermined compression rate, the distance L (see FIG. 9) between the lower end portion of the lateral deformation preventing material 26 and the surface of the footing 4 is about 20 mm or more. It is preferable. If this distance is less than about 20 mm, the elastic sealing material 24 that is compressed and protrudes in the lateral direction may be crushed between the lower end portion of the lateral deformation preventing material 26 and the surface of the footing 4. .

  As shown in FIG. 8, the waterproof skirt 30 is provided on the outer side of the elastic seal member 24 with the upper end portion attached to the upper portion of the outer side plate 20 </ b> C of the water blocking cross-section member 20 by the attachment plate 30 </ b> A and bolt 30 </ b> B. In the case where water leaks from the elastic sealing material 24, the amount of water leakage is reduced as much as possible. The waterproof skirt 30 may be any material having flexibility that can follow the unevenness of the footing 4. For example, various synthetic rubbers can be used. In addition, if the state of the upper surface of the footing 4 of the bridge pier 2 with which the elastic sealing material 24 comes into contact is good, the waterproof skirt 30 is not used, and the water stop of only the elastic sealing material 24 may be used.

  When the temporary closing structure 10 is repeatedly used, the water-stopping box cross-section member 20 is replaced with the elastic seal materials 22 and 24, the lateral deformation prevention material 26, the buffer backup material 28, and the waterproof skirt 30 to temporarily The water stopping performance of the deadline structure 10 can be recovered.

  Next, the construction procedure from assembling the temporary deadline structure 10 to installing it on site will be described.

  10 to 12 are front views showing a construction procedure from assembly work on the land portion of the temporary deadline structure 10 to on-site installation, and FIGS. 13 and 14 show the temporary deadline structure 10 and the work object ( The half section seen from the front for explaining the water stop method by the elastic sealing material 24 and the waterproof skirt 30 which are attached to the pressure receiving widening portion 18 of the temporary closing structure 10 in advance for water stop with the pier 2). FIG.

  First, as shown in FIG. 10A, the work box 16 is assembled on the land portion only in the first stage of the pressure-resistant block 12, and is assembled in an annular shape. Next, as shown in FIG. 10 (B), the assembled pressure-resistant block 12 is sequentially inserted into the internal space of the buoyant body 40 moored on the quay, and is assembled on the water. This is because a large set of work boxes 16 on the land will increase the weight and require a large lifting machine 60. If there is a margin in the lift and capacity of the lifting machine 60, the whole can be assembled on land and mounted on the buoyancy body 40 by lump lifting.

  To ensure stability during towing to the site, as shown in FIG. 10 (C), the work box 10 and the buoyant body 40 are assembled in an annular shape, and as shown in FIG. Floating towed on towed carrier ship 62.

  After the temporary closing structure 10 and the buoyancy body 40 arrive at the site, the temporary closing structure 10 and the buoyancy body 40 are moved to the tip of the towing table ship 62 and fixed again as shown in FIG. Then, in this state, as shown in FIG. 11 (F), the hinge mechanism 40A provided in the buoyancy body 40 is used for opening, and it is installed so as to surround the pier 2 as the work object, and then closed again. Then, a water stop rubber is inserted into the closing portion 16A of the work box 16 and is fastened with a bolt to form an annular structure as shown in FIG.

  After installing the temporary closing structure 10 and the buoyancy body 40 so as to surround the pier 2, as shown in detail in FIG. 13A, water is poured into the outer buoyancy body 42 of the buoyancy body 40. As shown at 12 (H), the pier 2 is sunk until reaching the footing 4 of the pier 2. Here, the upper surface of the footing 4 with which the elastic sealing material 20 of the temporary closing structure 10 comes into contact is previously cleaned with sediment or the like so that the bottom water stop is completely performed.

  As shown in FIG. 13B, after confirming that the temporary closing structure 10 has been set in place, the water 6 in the temporary closing structure 10 is drained, and the temporary closing structure 10 Get a working space. Further, by draining the water 6 in the temporary closing structure 10, as shown in FIG. 14C, buoyancy is not exerted on the temporary closing structure 10, and the pressure-receiving widening portion 18 is vertically driven by water pressure. The elastic sealing material 24 and the waterproof skirt 30 attached to the pressure-receiving widened portion 18 are compressed by receiving a force in the downward direction, and the water stop effect is enhanced. For convenience of illustration, the outer peripheral buoyancy body 42 is not drawn in FIG.

  Next, a temporary cutoff structure according to a second embodiment of the present invention will be described. As shown in an enlarged view of the main part in FIG. 15, the temporary closing structure 80 is provided with the elastic seal member 24 directly below the lower end portion of the work box 16 without providing the pressure receiving widening portion 18. It is different from the temporary closing structure 10 according to one embodiment. Since the pressure-receiving widening portion 18 is not provided, even if the water in the temporary closing structure 80 is drained and no longer receives buoyancy, the vertical pressure downward force is not received by the water pressure. The elastic sealing material 24 is compressed by its own weight to stop water. It is disadvantageous in that the vertical downward force due to water pressure cannot be used, but it is advantageous in that it is easy to float tow and easy to apply to small piers because the pressure receiving widening portion 18 is not provided. is there.

  Next, a temporary cutoff structure according to a third embodiment of the present invention will be described. As shown in an enlarged view of the main part in FIG. 16, the temporary deadline structure 90 is different from the temporary deadline structure 10 of the first embodiment in that a stopper 92 is provided immediately below the lower end of the work box 16. Different.

  As a result of the experiment, the inventor has found that when the elastic sealing material 24 is compressed non-uniformly, the elastic sealing material 24 may be greatly deformed and leaks on the side opposite to the side receiving the water pressure. Is heading. Therefore, in this temporary closing structure 90, when the stopper 92 is provided and the temporary closing structure 90 is sunk on the footing 4 of the pier 2, only a part of the elastic sealing material 24 is tilted or the like. Even in the case of large compression, the portion is prevented from being compressed by a predetermined amount or more, and the non-uniformity of the compression amount is suppressed within a predetermined range so that water leakage does not occur.

  Further, if the elastic sealing material 24 undergoes a compressive deformation larger than the allowable amount of compressive deformation (for example, the amount of compressive deformation at the time of elastic limit), residual deformation may remain and the life of the elastic sealing material 24 may be shortened. In addition, there may be a case where a tensile stress exceeding the tensile strength is locally applied to cause a local breakage, or a punched shear damage occurs at the end of the steel shell, making it unusable. By providing the stopper 92 as in the present embodiment, it is possible to prevent such a problem from occurring.

  Next, a temporary cutoff structure according to a fourth embodiment of the present invention will be described. As shown in FIG. 17 (partial cross-sectional view seen from the front), the temporary closing structure 100 according to the fourth embodiment is formed on the outer surface of the lower part of the lower pressure block 12. A plurality of brackets 102 are provided at intervals, and the lower ends of the steel bars 104 are connected to the hinges 102A of the plurality of brackets 102, respectively. Then, the steel bar 104 is lowered by the lifting device installed on the carriage 62, and the temporary closing structure 100 is stably laid so that the elastic sealing material 24 is compressed to a predetermined compression rate. Be able to. Here, until the temporary closing structure 100 is laid on the footing 4 of the pier 2 and the internal water is drained, buoyancy is acting on the temporary closing structure 100. In this embodiment, A force that resists buoyancy can be applied by lowering the steel bar 104 by the lifting device. For this reason, a force assisting the vertically downward force applied by the water pressure can be applied by the lifting device, and the vertically downward force applied by the water pressure in the stage before the water inside the temporary closing structure 100 is completely drained. Even when the force is small, the temporary closing structure 100 can be stably deposited at a predetermined position. Further, as described above with reference to FIG. 4, the water leakage limit water pressure increases as the compressibility of the elastic sealing material 24 increases. Therefore, in order to drain the water inside the temporary closing structure 100, the elastic sealing material is used. Although it is necessary to compress 24 to a predetermined compression rate, it becomes easy to compress the elastic sealing material 24 to a predetermined compression rate by applying a vertically downward force auxiliary by the lifting device. FIG. 17 is a partial cross-sectional view seen from the front, and only one bracket 102 is drawn, but as described above, a plurality of brackets 102 are provided at equal intervals.

  Further, in the present embodiment, by uniformly lowering the plurality of steel bars 104 arranged at equal intervals, the elastic sealing material 24 can be prevented from being compressed non-uniformly, and water leakage is less likely to occur. Can do.

  The lifting device is arranged on a floating trolley and the position is not fixed, so that the lifting device moves to some extent in the horizontal direction while lowering the steel bar 104 using the lifting device. Need to be considered. Therefore, in this embodiment, the steel bar 104 is pin-coupled to the hinge 102A of the bracket 102.

  The lifting device used in the present embodiment is not particularly limited, and for example, a hydraulic jack or a screw jack can be used. Since the hydraulic jack can output a large driving force with a compact size, it is suitable for applying a force against buoyancy.

  Note that, depending on the swinging state of the carriage 62, an excessive compressive force may be applied to the elastic sealing material 24. Therefore, it is preferable to use the stopper 92 of the third embodiment also in this embodiment.

  Next, a temporary cutoff structure according to a fifth embodiment of the present invention will be described.

  As shown in FIG. 18, the temporary closing structure 110 according to the fifth embodiment is provided with an inner peripheral buoyancy body 112 therein. By providing the inner peripheral buoyant body 112 inside, the size of the outer peripheral buoyant body 42 can be reduced, and when the temporary closing structure is towed, the entire temporary closing structure including the buoyant body is removed. It can be made compact, and the operability of the towing and installation work is improved, and the buoyancy body is attached in a small block, so that uneven descent is less likely to occur when the temporary closing structure is set.

  The inner buoyancy body 112 is detachable from the temporary deadline structure 110, and is attached when the temporary deadline structure 110 is floated and towed, so that the temporary deadline structure 110 is set against the work object. Sometimes it can be removed. Further, when the temporary deadline structure 110 is laid down on the work target, the inner circumferential buoyant body 112 is poured into the inner circumferential buoyant body 112 without removing the inner circumferential buoyant body 112 from the temporary deadline structure 110, thereby It is also possible to sink the body 110 with respect to the work object.

  In the first to fifth embodiments described above, the shape of the cross section of the pier 2 as a work object is circular, and the shape of the temporary closing structure is also cylindrical, but the shape of the cross section of the pier 2 is In the case of an oval or rectangular shape, a linear work box pressure-resistant block 120 is inserted between the semicircular portions of the circular section work box 16 as in the sixth embodiment shown in FIG. The linear buoyancy body 122 is inserted between the semicircular portions of the buoyancy body 40, and the connection portions 120A and 122A are respectively fastened with bolts, so that it is possible to easily cope with it.

  Further, the shape of the temporary closing structure is not limited to the shape of the first to sixth embodiments, and may be, for example, a quadrangular prism shape (seventh embodiment). When the shape of the temporary closing structure is a quadrangular prism, the waterproof skirt 30 is as shown in FIG. 20 (schematic view of the corner of the pressure receiving widened portion of the temporary closing structure according to the seventh embodiment from above). In addition, it is preferable to connect the end portions 30A with each other in terms of enhancing the water stop effect.

  Also, if the cross section of the pier 2 that is the work target is large and it is difficult to float the tow structure as a single unit and install it around the pier 2, split it into two or more units. Then, floating tow may be installed around the pier 2.

Schematic diagram showing the overall outline of the still water performance test AA sectional view of FIG. BB sectional view of FIG. A graph showing the results of the still water performance test Diagram showing the mechanism of water leakage from the elastic sealing material The front view which shows the state when attaching an outer periphery buoyancy body to the outer periphery of the structure for temporary closing of 1st Embodiment of this invention, and towing to the spot (A) plan view and (B) half cross-sectional view as seen from the front, showing a state when the temporary deadline structure is installed The expanded sectional view which shows the detail of the structure of the pressure receiving wide part of this structure for temporary deadlines An enlarged cross-sectional view schematically showing a state in which lateral (horizontal) water pressure is applied to the outside of the elastic sealing material in a state where the elastic sealing material of the temporary closing structure is compressed to a predetermined compression rate. The front view which shows a part of construction procedure from the assembly work in the land part of this temporary deadline structure to field installation Front view showing another part of the construction procedure from assembly work on the land part of the temporary deadline structure to field installation The front view which shows the remainder of the construction procedure from the assembly work in the land part of this temporary deadline structure to field installation Half sectional view seen from the front for explaining the water stopping method between the temporary closing structure and the work object Half sectional view seen from the front for explaining the water stopping method between the temporary closing structure and the work object The expanded sectional view which shows the principal part of the structure for temporary deadlines of 2nd Embodiment of this invention The expanded sectional view which shows the principal part of the structure for temporary deadlines of 3rd Embodiment of this invention The expanded sectional view which shows the principal part of the structure for temporary deadlines of 4th Embodiment of this invention The top view which shows typically the structure for temporary deadlines of 5th Embodiment of this invention The top view which shows typically the structure for temporary deadlines of 6th Embodiment of this invention The schematic diagram which looked at the corner | angular part of the pressure-receiving widening part of the structure for temporary closing of 7th Embodiment of this invention from upper direction

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Pier 4 ... Footing 6 ... Water 10, 80, 90, 100, 110 ... Temporary shutoff structure 12 ... Pressure-resistant block 12A ... Steel plate 12B ... Stiffening plate 14 ... Water stop material 16 ... Work box 16A, 18A, 42A , 46A ... Closing part 16B ... Working box bottom plate projection 16C ... Bracket 16D ... Mounting plate 18 ... Pressure receiving widening part 20 ... Water stop cross section member 20A ... Inner side plate 20B ... Top plate 20C ... Outer side plate 20D ... Bolts 22, 24 DESCRIPTION OF SYMBOLS ... Elastic sealing material 26 ... Side deformation prevention material 28 ... Buffer backup material 30 ... Waterproof skirt 30A ... Mounting plate 30B ... Bolt 40 ... Buoyancy body 40A ... Hinge mechanism 42 ... Outer buoyancy body 44 ... Steel pipe support 46 ... Worktable 60 ... Lifting Heavy machine 62 ... Boat 120 ... Linear work box pressure block 122 ... Linear buoyancy body 120A, 122A ... Connecting part 200 ... Elastic sealing material 2 2 ... sealing member fixing frame 204 ... concrete 206 ... Water 208 ... steel lid 210 ... load cell 212, 214 ... shaped steel 216 ... hydraulic jack 218 ... hydraulic pump

Claims (14)

A temporary closing structure having a work box made of one or multi-stage steel shells and an elastic seal material provided on the outer periphery of the bottom of the work box or the lower part of the work box can be attached to and detached from the outer periphery. Equipped with an outer peripheral buoyant body and floating towed on site, placed so as to surround the work object, poured water into at least a part of the outer peripheral buoyant body, or removed at least a part of the outer peripheral buoyant body, After laying down, drain the interior of the temporary deadline structure, and fix the temporary deadline structure to the work object by the weight of the temporary deadline structure or by the vertical component of the force of the dead weight and water pressure. A temporary closing method for an underwater structure that stops water and forms a work space,
A lateral deformation preventing material for preventing the elastic sealing material from being deformed in the inner direction of the work box is disposed on at least a part of the inner periphery of the elastic sealing material, and a horizontal force due to water pressure is received. A temporary closing method for an underwater structure, wherein the adhesive water-stopping function of the elastic sealing material is not easily lowered.   The buffer backup material for preventing an excessive compressive force from being applied to a part of the elastic sealing material is provided at least at a part between the lateral deformation preventing material and the elastic sealing material. The temporary closing method of the underwater structure according to 1.   The underwater structure according to claim 1 or 2, wherein a stopper for adjusting a descending distance of the work box is provided to prevent part or all of the elastic sealing material from being overcompressed. The temporary closing method.   A trolley is used for floating towing of the temporary deadline structure to the site, and a lift device is provided on the craft to sink the temporary deadline structure to the work object. The temporary closing method for an underwater structure according to any one of claims 1 to 3.   5. A steel bar having one end connected to the work box and a pin is disposed in the vicinity of the bottom of the work box, and the lifting device is a hydraulic device that lifts and lowers the steel bar. The temporary closing method for underwater structures.   The temporary closing method for an underwater structure according to any one of claims 1 to 5, wherein an inner buoyant body that can be attached to and detached from the inner circumference of the work box is disposed to reduce the outer buoyant body. . A temporary closing structure having a work box made of a single-stage or multi-stage steel shell, and an elastic sealing material provided at the bottom of the work box,
At least a part of the inner periphery of the elastic sealing material is provided with a lateral deformation preventing material for preventing the elastic sealing material from being deformed in the inner direction of the work box. A structure for temporary fastening, characterized in that the sticking water-stopping function of the elastic sealing material is not easily lowered. A work box made of a single or multi-stage steel shell, a pressure receiving widening part that is attached to the outer periphery of the lower part of the work box and can receive a downward force in the vertical direction due to water pressure, and provided at the bottom of the pressure receiving widening part A temporary closing structure having an elastic sealing material,
At least a part of the inner periphery of the elastic sealing material is provided with a lateral deformation preventing material for preventing the elastic sealing material from being deformed in the inner direction of the work box. A structure for temporary fastening, characterized in that the sticking water-stopping function of the elastic sealing material is not easily lowered.   A buffer backup material for preventing an excessive compressive force from being applied to a part of the elastic sealing material is provided at least partly between the lateral deformation preventing material and the elastic sealing material. The temporary closing method of the underwater structure according to claim 7 or 8.   The stopper which adjusts the descent | fall distance of the said work box is arrange | positioned, and it is made for the one part or all part of the said elastic sealing material not to be overcompressed, The any one of Claims 7-9 characterized by the above-mentioned. Temporary deadline structure.   A steel bar having one end connected to the work box is disposed near the bottom of the work box, and a vertical downward force is applied to the steel bar so that it can be sunk into the work object. The temporary closing structure according to any one of claims 7 to 10, wherein the structure is temporarily closed.   The structure for temporary fastening according to any one of claims 7 to 11, wherein an outer peripheral buoyant body is attached to the outer periphery, and an inner peripheral buoyant body is attached to the inner periphery. body.   The temporary closing structure according to any one of claims 7 to 12, wherein a waterproof skirt is provided outside the elastic sealing material.   The elastic sealing material is divided into two or more in the circumferential direction, and the divided joints of the elastic sealing materials are formed by closely contacting surfaces inclined with respect to a horizontal plane. The temporary closing structure according to any one of claims 7 to 13.

Images