UNDERWATER CONCRETE STRUCTURE FOR PREVENTING SUBSIDENCE AT SEABED SOFT GROUND, AND CONSTRUCTION METHOD THEREFOR

Abstract

An underwater concrete structure for preventing subsidence at seabed soft ground, includes: a main concrete structure installed on an upper part of seabed soft ground on a top of seabed rock, wherein the main concrete structure is spaced apart upward from the seabed rock and has a plurality of vertical penetration holes extending vertically; and a plurality of concrete columns formed continuously along the vertical penetration holes and the seabed soft ground and the seabed rock located under the vertical penetration holes.

Claims

1. A construction method for an underwater concrete structure for preventing subsidence at seabed soft ground, the construction method comprising: installing a main concrete structure having a plurality of vertical penetration holes extending vertically on an upper part of seabed soft ground which is on a top of seabed rock; forming a ground perforated part in the seabed soft ground and the seabed rock by perforating the seabed soft ground and the seabed rock located under each of the vertical penetration holes through the vertical penetration hole after the installing of the main concrete structure; and forming a concrete column along the vertical penetration hole and the ground perforated part by inserting a concrete column formation part, which comprises a concrete reinforcing member extending vertically, a waterproof membrane covering lower and side portions of the concrete reinforcing member, and fresh concrete injected into the waterproof membrane, into the vertical penetration hole and the ground perforated part after the forming of the ground perforated part, wherein the concrete column is divided into a penetration hole concrete column part located in the vertical penetration hole, a soft ground concrete column part located in the seabed soft ground, and a rock concrete column part located in the seabed rock, wherein the soft ground concrete column part is formed to support a lower end of the main concrete structure by having a diameter larger than a diameter of the penetration hole concrete column part.

2. The construction method of claim 1, wherein a waterproof membrane protective cover with a shape of a tube or a basket is provided on an outer side of the waterproof membrane, with an upper end of the waterproof membrane protective cover positioned on a vertical middle of the waterproof membrane.

3. The construction method of claim 2, wherein the waterproof membrane protective cover is formed as a mesh and is coupled to the outer side of the waterproof membrane via a skirt member.

4. The construction method of claim 1, wherein in the forming of the ground perforated part, a protection pipe extending vertically is inserted through the vertical penetration hole, and the inserted protection pipe is positioned across the vertical penetration hole and the ground perforated part; and in the forming of the concrete column, the waterproof membrane is inserted into the vertical penetration hole and the ground perforated part along an interior of the protection pipe, and the protection pipe is removed after the waterproof membrane is inserted.

5. An underwater concrete structure for preventing subsidence at seabed soft ground, the underwater concrete structure comprising: a main concrete structure installed on an upper part of seabed soft ground on a top of seabed rock, wherein the main concrete structure is spaced apart upward from the seabed rock and has a plurality of vertical penetration holes extending vertically; and a plurality of concrete columns formed continuously along the vertical penetration holes and the seabed soft ground and the seabed rock located under the vertical penetration holes, wherein each of the concrete columns is divided into a penetration hole concrete column part located in each of the vertical penetration holes, a soft ground concrete column part located in the seabed soft ground, and a rock concrete column part located in the seabed rock, and the soft ground concrete column part supports a lower end of the main concrete structure by having a diameter larger than a diameter of the penetration hole concrete column part to prevent subsidence of the main concrete structure.

6. The underwater concrete structure of claim 5, wherein the concrete column comprises a concrete reinforcing member formed vertically and arranged across the vertical penetration hole, the seabed soft ground and the seabed rock, a waterproof membrane covering lower and side portions of the concrete reinforcing member, concrete poured and cured inside the waterproof membrane, and a waterproof membrane protective cover with a shape of a tube or a basket located on an outer side of the waterproof membrane and having an upper end positioned on a vertical middle of the waterproof membrane to protect the waterproof membrane located in the seabed soft ground.

7. The underwater concrete structure of claim 6, wherein the waterproof membrane protective cover is formed as a mesh and is coupled to the outer side of the waterproof membrane via a skirt member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a perspective view of a concrete block used in a construction method for an underwater concrete structure for preventing subsidence at seabed soft ground according to a first embodiment of the present disclosure,

[0023] FIG. 2 is a plan view of a main concrete structure formed on the top of the seabed by installing the concrete blocks of FIG. 1,

[0024] FIG. 3 is a cross-sectional conceptual drawing of FIG. 2,

[0025] FIG. 4 is a drawing of a ground perforated part formed after forming the main concrete structure of FIG. 3,

[0026] FIGS. 5 to 8 are drawings illustrating the process of forming a concrete column in sequence after forming the ground perforated part of FIG. 4,

[0027] FIG. 9 is a front view of a waterproof membrane to which a waterproof membrane protective cover of FIG. 5 is attached,

[0028] FIG. 10 is an exploded cross-sectional view of FIG. 9,

[0029] FIG. 11 is a perspective view of a concrete block used in a construction method for an underwater concrete structure for preventing subsidence at seabed soft ground according to a second embodiment of the present disclosure,

[0030] FIG. 12 is a cross-sectional view of a main concrete structure formed by the concrete blocks of FIG. 11,

[0031] FIG. 13 is a cross-sectional view of a ground perforated part and a concrete column formed after the state of FIG. 12, and

[0032] FIG. 14 is a cross-sectional view of a cap concrete formed after the state of FIG. 13.

DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present disclosure belongs can easily embody the present disclosure. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts irrelevant to the description of the present disclosure are omitted in order to clearly describe the present disclosure, and similar reference numerals are assigned to similar parts throughout the specification.

[0034] Throughout the specification, when a part includes a certain component, it means that other components may be further included without being excluded unless specifically stated to the contrary.

[0035] First, a construction method for an underwater concrete structure for preventing subsidence at seabed soft ground according to a first embodiment of the present disclosure will be described.

[0036] FIG. 1 is a perspective view of a concrete block used in a construction method for an underwater concrete structure for preventing subsidence at seabed soft ground according to a first embodiment of the present disclosure, FIG. 2 is a plan view of a main concrete structure formed on the top of the seabed by installing the concrete blocks of FIG. 1, FIG. 3 is a cross-sectional conceptual drawing of FIG. 2, FIG. 4 is a drawing of a ground perforated part formed after forming the main concrete structure of FIG. 3, FIGS. 5 to 8 are drawings illustrating the process of forming a concrete column in sequence after forming the ground perforated part of FIG. 4, FIG. 9 is a front view of a waterproof membrane to which a waterproof membrane protective cover of FIG. 5 is attached, and FIG. 10 is an exploded cross-sectional view of FIG. 9.

(1) Manufacturing a Concrete Block

[0037] As in FIG. 1, a concrete block 20 is manufactured.

[0038] The concrete block 20 may be formed to have various shapes, but preferably includes at least two block penetration holes 21 extending vertically formed therein.

[0039] Each of the block penetration holes 21 extends vertically with a first diameter.

[0040] Depending on an embodiment, the concrete block 20 may have a space formed for filling the inside thereof, or a space for other purposes or a shape for other purposes.

(2) Forming a Main Concrete Structure

[0041] FIG. 2 is a plan view of a main concrete structure 100, and FIG. 3 is a cross-sectional view of the main concrete structure 100.

[0042] A plurality of concrete blocks 20 manufactured in the manufacturing of the concrete block is installed on the upper part of seabed soft ground 12 which is on the top of seabed rock 11 as in FIG. 3, and as in FIG. 2, the plurality of concrete blocks 20 is installed horizontally and continuously to form the main concrete structure 100.

[0043] That is, in this embodiment, the main concrete structure 100 has a plurality of concrete blocks 20 arranged horizontally and continuously.

[0044] According to an embodiment, the main concrete structure 100 may be composed of one concrete block 20.

[0045] As illustrated in FIG. 3, the main concrete structure 100 is installed spaced apart upward from the seabed rock 11.

[0046] The block penetration holes 21 of the concrete blocks 20 constituting the main concrete structure 100 form vertical penetration holes 101 extending vertically with lower end parts thereof blocked by the seabed soft ground 12 and upper end parts thereof open.

[0047] That is, in this embodiment, the concrete blocks are manufactured in large sizes and installed in only one level vertically, and each of the block penetration holes 21 of each of the concrete blocks 20 functions as each of the vertical penetration holes 101 of the main concrete structure 100.

[0048] Accordingly, the vertical penetration hole 101 is in the form of extending vertically with the first diameter.

(3) Forming a Ground Perforated Part

[0049] After the forming of the main concrete structure, as illustrated in FIG. 4, the seabed soft ground 12 and the seabed rock 11 located under the vertical penetration hole 101 are perforated through the vertical penetration hole 101 and thus a ground perforated part 102, which is a space continuous to the vertical penetration hole 101, is formed in the seabed soft ground 12 and the seabed rock 11.

[0050] In this embodiment, when the ground perforated part 102 is formed by perforating the seabed soft ground 12 and the seabed rock 11 located under the vertical penetration hole 101, a protection pipe 30 extending vertically is vertically inserted into the seabed soft ground 12 and the seabed rock 11 through the vertical penetration hole 101.

[0051] The protection pipe 30 inserted in this manner is positioned across the vertical penetration hole 101 and the ground perforated part 102, and the ground perforated part 102 is formed inside the protection pipe 30.

[0052] In this case, the protection pipe 30 prevents the surrounding seabed soft ground 12 from collapsing into the ground perforated part 102 or prevents various types of foreign substances from being introduced into the ground perforated part 102 during or after the perforating operation.

[0053] In addition, the protection pipe 30 serves to protect the waterproof membrane 112 when a waterproof membrane 112 to be described later is inserted into the protection pipe 30.

(4) Forming a Concrete Column

[0054] After the forming of the ground perforated part, a concrete column 110 is formed along the vertical penetration hole 101 and the ground perforated part 102.

[0055] The forming of the concrete column in this embodiment is performed step by step as illustrated in FIGS. 5 to 8.

[0056] A concrete column formation part, which includes a concrete reinforcing member 111 extending vertically, the waterproof membrane 112 covering lower and side portions of the concrete reinforcing member 111, fresh concrete 113 injected into the waterproof membrane 112, and a waterproof membrane protective cover 114 coupled to the outer side of the waterproof membrane 112, is inserted into the vertical penetration hole 101 and the ground perforated part 102 so as to form the concrete column 110 along the vertical penetration hole 101 and the ground perforated part 102.

[0057] First, as illustrated in FIGS. 5 and 6, the concrete reinforcing member 111, such as a reinforcing bar assembly extending vertically, is inserted into the vertical penetration hole 101 and the ground perforated part 102.

[0058] In this embodiment, since the protection pipe 30 is already positioned in the vertical penetration hole 101 and the ground perforated part 102, the concrete reinforcing member 111 is inserted into the protection pipe 30.

[0059] In this case, while the lower and side portions of the concrete reinforcing member 111 is covered by the waterproof membrane 112, the concrete reinforcing member 111 is inserted into the vertical penetration hole 101 and the ground perforated part 102.

[0060] Meanwhile, the waterproof membrane protective cover 114 is provided on the outer side of the waterproof membrane 112 via a skirt member 115.

[0061] The waterproof membrane protective cover 114 is in the form of a tube or basket (the form of a basket in the present embodiment) with an upper end thereof positioned on the vertical middle of the waterproof membrane 112, and a lower end portion of the waterproof membrane 112 (specifically, a portion to be positioned in the seabed soft ground) is positioned inside the waterproof membrane protective cover 114.

[0062] The waterproof membrane protective cover 114 may be a mesh which is woven from wire or carbon fiber and formed into the shape of a tube or a basket.

[0063] Here, the tube shape is a cylindrical shape with the top and bottom open, and the basket shape is a cylindrical shape with the top open and the bottom closed.

[0064] The skirt member 115 is provided between the waterproof membrane protective cover 114 and the waterproof membrane 112.

[0065] The upper end of the skirt member 115 is joined to the vertical middle of the outer side of the waterproof membrane 112, and the upper end of the waterproof membrane protective cover 114 is coupled to the lower end of the skirt member 115 by means of stitching or the like.

[0066] Accordingly, after the concrete reinforcing member 111 covered by the waterproof membrane 112 is inserted into the protection pipe 30, the concrete 113 is poured inside the waterproof membrane 112 to form the concrete column 110 as illustrated in FIGS. 7 and 8.

[0067] FIG. 7 is a drawing showing a state in which the protection pipe 30 is slightly raised while some of the fresh concrete 113 is poured inside the waterproof membrane 112.

[0068] That is, in FIG. 7, the protection pipe 30 is raised so that the lower end of the protection pipe 30 is just outside the ground perforated part 102, and the fresh concrete 113 required for the ground perforated part 102 is poured inside the waterproof membrane 112.

[0069] In this case, the waterproof membrane 112 located in the seabed soft ground 12 has a diameter increased by the pressure of the fresh concrete 113.

[0070] In FIG. 7, extent to which the diameter of the waterproof membrane 112 located in the seabed soft ground 12 increases is greatly exaggerated, and in reality, as the fresh concrete 113 is gradually injected into the waterproof membrane 112, the pressure of the fresh concrete 113 located in the seabed soft ground 12 gradually increases. As the pressure gradually increases, the diameter of the waterproof membrane 112 located in the seabed soft ground 12 gradually increases, and this increase of the diameter of the waterproof membrane 112 continues until the fresh concrete 113 is fully injected into the waterproof membrane 112, as illustrated in FIG. 8.

[0071] The waterproof membrane 112 is required to have a structure that allows for the diameter increase structurally (e.g., a structure that unfolds from a folded state) or through a material (e.g., a stretchable elastic material) in consideration of the increase of a diameter.

[0072] In addition, the waterproof membrane protective cover 114 prevents the waterproof membrane 112 from being damaged due to excessive diameter increase by allowing the waterproof membrane 112 to expand in diameter only within a certain limit.

[0073] In addition, the waterproof membrane protective cover 114 is made as mesh and prevents air or water from remaining between the waterproof membrane 114 and the waterproof membrane 112.

[0074] In this manner, the protection pipe 30 is gradually raised while the fresh concrete 113 is gradually poured inside the waterproof membrane 112, and finally, as illustrated in FIG. 8, the protection pipe 30 is completely removed, and the pouring of the fresh concrete 113 throughout the vertical penetration hole 101 and the ground perforated part 102 is completed.

[0075] That is, the protection pipe 30 is removed before the fresh concrete 113 that has been poured is hardened.

[0076] When the fresh concrete 113 is poured into the waterproof membrane 112 in this way, the waterproof membrane 112 is brought into close contact with the seabed rock 11 and the concrete block 20 (or the main concrete structure 100) by the pressure of the fresh concrete 113, and has a diameter increased significantly in the seabed soft ground 12 increases, and then goes through a curing process to be the concrete column 110.

[0077] In this way, the concrete column 110 is formed in the main concrete structure 100, thereby completing an underwater concrete structure 200.

[0078] That is, the concrete column 110 includes a penetration hole concrete column part 110a located in the vertical penetration hole 101 and extending vertically with the first diameter, a soft ground concrete column part 110b located in the seabed soft ground 12 and extending vertically with a second diameter, and a rock concrete column part 110c located in the seabed rock 11 and extending vertically with a third diameter.

[0079] In addition, since the soft ground concrete column part 110b has a diameter larger than the diameter of the penetration hole concrete column part 110a, the soft ground concrete column part 110b supports the lower end of the main concrete structure 100, thereby preventing the main concrete structure 100 from subsiding.

[0080] That is, according to the present disclosure, the main concrete structure 100 may be prevented from subsiding without performing separate soft ground improvement work on the seabed soft ground 12. Hereinafter, a second embodiment of the present disclosure will be described.

[0081] FIG. 11 is a perspective view of a concrete block used in a construction method for an underwater concrete structure for preventing subsidence at seabed soft ground according to a second embodiment of the present disclosure, FIG. 12 is a cross-sectional view of a main concrete structure formed by the concrete blocks of FIG. 11, FIG. 13 is a cross-sectional view of a ground perforated part and a concrete column formed after the state of FIG. 12, and FIG. 14 is a cross-sectional view of a cap concrete formed after the state of FIG. 13.

[0082] Below, only differences from the first embodiment are mainly explained, and the descriptions of parts that are the same as the first embodiment are omitted.

(1) Manufacturing a Concrete Block

[0083] In this embodiment, the concrete block 20 as illustrated in FIG. 11 is manufactured.

[0084] The concrete block 20 of the present embodiment has a plurality of block penetration holes 21 formed therein, and each of the block penetration holes 21 has the shape of a corrugated pipe extending vertically as illustrated in FIG. 12.

(2) Forming a Main Concrete Structure

[0085] The concrete blocks 20 are stacked vertically to form the main concrete structure 100 as illustrated in FIG. 12. The concrete blocks 20 are stacked in 7 layers.

[0086] Compared to the first embodiment, in the second embodiment, water depth is greater, and the layer of the seabed soft ground 12 is thicker.

[0087] In this case, since the block penetration hole 21 of the concrete block 20 has the shape of a corrugated pipe that extends vertically, the vertical penetration hole 101 of the main concrete structure 100 also has the shape of a corrugated pipe that extends vertically.

[0088] The vertical penetration hole 101 in the form of a corrugated pipe enhances bonding strength with the concrete column 110.

[0089] As described above, the main concrete structure 100 may be formed by stacking a plurality of concrete blocks 20 vertically.

(3) Forming a Ground Perforated Part and Forming a Concrete Column

[0090] After the state of FIG. 12, the ground perforated part is formed through the vertical penetration hole 101 of the main concrete structure 100, and the concrete column 110 is formed along the vertical penetration hole 101 and the ground perforated part to obtain a state as in FIG. 13.

[0091] This step is substantially the same as the first embodiment, so a detailed description thereof is omitted.

(4) Forming Cap Concrete

[0092] After the state of FIG. 13, a cap concrete 120 is formed on the top of the main concrete structure 100.

[0093] The reinforcing bar assembly of the cap concrete 120 is connected to the concrete reinforcing member 111 of the concrete column 110.

[0094] The above description of the present disclosure is only for illustrative purposes, and those skilled in the art will appreciate that various modifications are possible without departing from the scope and spirit of the present disclosure. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

[0095] The scope of the present disclosure is indicated by the claims to be described later rather than the detailed description, and it should be interpreted that all changes or modified forms derived from the meaning and scope of the claims and concept equivalent thereto are included in the scope of the present disclosure.

[0096] The present disclosure may be used as an underwater concrete structure installed underwater for various purposes, such as berthing facilities for ports, coastal wave-dissipating structures, and breakwaters.