U.S. patent application number 10/493100 was filed with the patent office on 2004-12-30 for method for constructing scour protection of bridge and stabilization of stream bed using block mat.
Invention is credited to Lee, Byung-Moo, Lee, Keun-Hee.
Application Number | 20040265060 10/493100 |
Document ID | / |
Family ID | 19198465 |
Filed Date | 2004-12-30 |
United States Patent
Application |
20040265060 |
Kind Code |
A1 |
Lee, Keun-Hee ; et
al. |
December 30, 2004 |
Method for constructing scour protection of bridge and
stabilization of stream bed using block mat
Abstract
The method for constructing scour protection of bridge and
stabilization of stream bed using block mat according to the
present invention by constructing a number of block mat structure
consisting of unit blocks interlocked together, and paving said
block mat structures in monolayer or multilayer on a stream bed
around the foundation part of an underwater structure. By the
present invention, it is possible to improve a resistance to a
descending stream at upper and lower region of a pier, to prevent
the ground of a stream bed from being locally scoured by the stream
due to the flexibility of the block mat, and to stabilize the
ground of stream bed since the spaces between the unit blocks are
filled with gravels and sand after several repetitions of a flood
stream and a normal stream and then the mat becomes firm.
Inventors: |
Lee, Keun-Hee; (Kangnam-gu,
KR) ; Lee, Byung-Moo; (Kangnam-gu, KR) |
Correspondence
Address: |
Robert E Bushnell
Attorney -at-Law
1522 K Street N W
Suite 300
Washington
DC
20005-1202
US
|
Family ID: |
19198465 |
Appl. No.: |
10/493100 |
Filed: |
April 20, 2004 |
PCT Filed: |
October 26, 2001 |
PCT NO: |
PCT/KR01/01823 |
Current U.S.
Class: |
405/16 |
Current CPC
Class: |
E02B 3/123 20130101;
E02B 17/0017 20130101; E01D 19/02 20130101 |
Class at
Publication: |
405/016 |
International
Class: |
E02B 003/12 |
Claims
1. A method for constructing a scour protector and for stabilizing
the stream bed, the method comprising: linking a plurality of unit
blocks, each of which is about rectangular in its plan view and has
a body, protrusion parts and concave groove parts adjacent to said
protrusion part formed on the upper and lower faces of the body, a
through-hole having a predetermined size formed in the center of
the body, and an interlocking member for coupling each said unit
block with adjacent unit blocks provided on each of the front,
rear, left and right side faces of its body, in a two-dimensional
direction by said interlocking members to form block mats having a
predetermined size; and paving said block mats on the stream bed in
the vicinity of the foundation of a submerged structure.
2. The method according to claim 1, further comprising: before
paving the block mats, paving a base mat made of an engineering
fiber to avoid a local sinking of the soft ground owing to the
weight of the block mat itself.
3. The method according to claim 1, wherein the block mats are
paved in a multilayer, and the protrusion parts and the concave
groove parts of the unit block are matched with the protrusion
parts and the concave groove parts of the unit blocks positioned
above and below.
4. A method for stabilizing a stream bed and protecting a structure
positioned in the stream bed, comprising: forming a block mat by
linking a plurality of blocks to each other, each said block having
a body, protrusions and grooves adjacent to said protrusions on an
front face and a rear face of said body, a through-hole in the
center of said body, and an interlocking member for coupling said
blocks to each other in order to form the block mat; and laying
said block mat on the stream bed.
5. The method of claim 4, further comprising: before laying said
block mat, paving a base mat made of an engineering fiber to avoid
a local sinking.
6. The method according to claim 4, wherein the block mats are
paved in a multilayer, and the protrusions and the grooves formed
on each block are matched with the protrusions and the grooves
formed on the blocks positioned above and below.
7. The method according to claim 4, wherein the structure is a
foundation of a bridge pier.
8. The method according to claim 4, wherein the structure is an
abutment.
9. The method according to claim 4, wherein the stream bed to be
stabilized is in the fire prevention dam.
10. The method according to claim 4, wherein the structure is a
breakwater.
11. The method according to claim 4, wherein the structure is a
foot.
12. The method according to claim 4, wherein the structure is a
pipeline.
13. The method according to claim 4, wherein the structure is a
bank.
14. The method according to claim 4, wherein said interlocking
member comprises an iron loop and a U bolt interlocking said iron
loop and the iron loop of the adjacent block.
15. The method according to claim 4, wherein a plurality of block
mats are formed and positioned adjacently to each other, and the
plurality of block mats are not interlocked to each other.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for the
construction of an anti-scour protection of a bridge and for the
stabilization of stream bed in a river or a stream, particularly to
a method for the construction of an anti-scour protection of a
bridge and for the stabilization of stream bed in a river or a
stream by using block mats, in which said block mats are paved on
stream bed in the vicinity of the foundation of a submerged
structure to prevent the vicinity of submerged bridge piers and
abutments from scouring by the flow of water and to stabilize the
foundation of the bridge piers.
BACKGROUND ART
[0002] In general, scouring continuously happens in the vicinity of
the foundation of submerged structures such as a bridge, a
breakwater or a protecting bank built in a riverside or seaside.
Such scouring may cause an evacuation of the sand and gravels at
the base of the foundations of the submerged structures to give
detrimental effects on the stability of said structures.
[0003] Therefore, it has been devised to riprap the foundations of
submerged structures or the surface of a breakwater or a protecting
bank in a riverside and seaside by using stones or mesh bags filled
with stones. However, such riprapping cannot be a radical
countermeasure of scouring since stones or a mesh bag filled with
stones can be moved or swept away by the waves because of its light
weight compared to its volume.
[0004] In addition, protecting blocks having a weight of about 5
ton or more are thrown at a seaside or breakwater, in which the
velocity of flow and waves are high, to protect the breakwater from
the waves or torrent. Since conventional protecting blocks for
removing waves generally have a star-shaped structure and several
protrusion radially popped out, they are very big and massive.
Further, since there are large rooms between the blocks after
constructing them, there is still a problem that a scouring and an
evacuation of the sand and gravels at the foundations of a
breakwater cannot be prevent in spite of a certain extent of
removing or alleviating the waves or torrents.
[0005] The present invention is envisaged to solve the above
problems. The object of the present invention is to provide a
method for the construction of an anti-scour protection of a bridge
and for the stabilization of stream bed in a river or stream, by
paving block mats on the stream bed in the vicinity of submerged
bridge piers and abutments to prevent the vicinity of submerged
bridge piers and abutments from scouring by the water flow and to
stabilize the ground in the vicinity of the foundations of the
bridge piers.
DISCLOSURE OF THE INVENTION
[0006] In order to achieve the above object, the method for the
construction of an anti-scour protection of a bridge and for the
stabilization of stream bed by using block mats according to the
present invention is characterized by that it comprises:
[0007] linking a large number of unit block, which is nearly
rectangular in its plan view and has protrusion parts and concave
groove parts adjacent to said protrusion part formed on the upper
and lower faces of its body, a through-hole having a predetermined
size formed in the center of its body, and interlocking members for
coupling with an adjacent unit block provided on the front, rear,
left and right side faces of its body, in a two-dimensional
direction by means of said interlocking members to form a large
number of block mats having a predetermined size; and paving said
block mats on stream bed in the vicinity of the foundation of a
submerged structure.
[0008] In the present invention, it is preferable to previously
pave base mat made of an engineering fiber on the overall
construction area of the stream bed to avoid a local sinking of the
soft ground owing to the weight of the block mat itself before the
block mats are paved.
[0009] In addition, when the above block mats are laminated in a
multilayer, it is preferable to position the upper and lower unit
blocks of the block mats so that their protrusion part and the
concave groove part are interlockedly matched together.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is an apparent perspective view of a unit block which
is employed in the method for the construction of an anti-scour
protection of a bridge and for the stabilization of stream bed
according to the present invention.
[0011] FIG. 2 represents a block mat in which a large number of
unit block represented in FIG. 1 are linked.
[0012] FIG. 3 represents a construction shape in which several
block mats represented in FIG. 2 are paved on stream bed in the
vicinity of the foundation of a bridge pier and/or abutment.
[0013] FIG. 4 represents a change of stream bed in the vicinity of
the foundation of a bridge pier and/or abutment when the flow
amount is increased (at a flood state) after block mats are paved
as represented in FIG. 3.
[0014] FIG. 5 shows a change of stream bed in the vicinity of the
foundation of a bridge pier when the flow amount is decreasingly
recovered to the original state (at a normal state) after the flood
state of FIG. 4 has passed.
[0015] FIG. 6 is a front view of a debris barrier constructed by
applying the method of the present invention.
[0016] FIG. 7 is a sectional view of a fire prevention dam
constructed by applying the method of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0017] The present invention will be illustrated more specifically
by referencing the drawings attached.
[0018] FIG. 1 is an apparent perspective view of a unit block which
is employed in the method for the construction of an anti-scour
protection of a bridge and for the stabilization of stream bed
according to the present invention.
[0019] Referring to FIG. 1, the block (100) used in the method of
the present invention is nearly rectangular in its plan view, and
the upper and lower faces of its body are provided with protrusion
parts (101) and concave groove parts (102) adjacent to said
protrusion part, by which the block is somewhat stuck into the
ground of stream bed to resist the water flow and maintain the
paving state as well as a unit block is matched with the upper and
lower blocks so that the overall integrated structure of blocks
becomes firm. Further, a through-hole (103) having a predetermined
size is formed in the center of the body of the block, by which the
buoyancy of the block is reduced when it is submerged under water
as well as the stream bed can be stabilized due to a deposition of
sand or small gravels therein. And an interlocking member (104) for
coupling with the adjacent unit block is provided at each side face
of the front, rear, left and right of the body. Said interlocking
member (104) can be made of deformed bar. When the block is used in
see water (salty water), the deformed bar can be covered with a
stainless steel or the interlocking member itself can be made of a
stainless steel.
[0020] In the method for the stabilization of stream bed of the
present invention using the above-described unit blocks (100),
several unit blocks (100) are linked in a two-dimensional direction
by means of their-iron loop (104) to form a block mat (200) having
a predetermined size (area) and several block mats are prepared by
the same procedure as described above. At this time, the
interlocking between unit blocks is achieved by using a U bolt
(110). Of course, other similar interlocking means can be employed.
FIG. 2 represents an interlocking mode in which 9 unit blocks (100)
are interlocked together. The number of unit blocks (100) to be
interlocked can be changed and thus 12, 15, 16 or more unit blocks
can be linked together to form a block mat structure (200),
depending on the construction working plan considering the flow
velocity or scour status at the construction area.
[0021] Thus prepared block mats (200) are paved in a single layer
or multilayer on the stream bed in the vicinity of the foundation
of a submerged structure (300) (for example, bridge pier and/or
abutment). A block mat structure (200) having a weight of several
tens tons is lifted by a specially designed crane having a lifting
frame apparatus and then positioned under water. Said lifting frame
apparatus and a method of constructing concrete block using the
same are specifically described in U.S. Pat. No. 6,293,730.
[0022] Before the above block mat structures (200) are paved on a
stream bed, it is preferable to previously pave base mat (400) made
of an engineering fiber on the overall construction area of the
stream bed to avoid a local sinking of the soft ground owing to the
weight of the block mat (200) itself. When the water is very deep,
the base mat (400) is attached under the block mat structure (200),
which is then dropped and positioned.
[0023] Block mat structures (200) are positioned adjacently
together (for example, with a distance between block mats of 30
cm.+-.10 cm), but they are not interlocked together.
[0024] Meanwhile, FIG. 4 shows a change of a stream bed in the
vicinity of the foundation of a bridge pier when the flow amount is
increased (at a flood state) after block mats are paved as
represented in FIG. 3.
[0025] As represented in FIG. 4, when the flow amount and velocity
of a river or a stream are increased at a flood state, local scours
then happen at the front end of the upstream flow and at the rear
end of the downstream flow. However, since unit blocks (100) are
interlocked together by iron loops (104) to form a block mat
structure (200), which is flexible due to their weight. When a
local scour happens, unit blocks (100) bend down along to the
inclined surface of a local scour hole generated. As such, an
enlargement or spread of the local scour into the inside of the
foundation of a bridge pier is avoided.
[0026] FIG. 5 shows a change of a stream bed in the vicinity of the
foundation of a bridge pier when the flow amount is decreasingly
recovered to the original state (at a normal state) after a flood
state of FIG. 4 has passed.
[0027] As represented in FIG. 5, a reduction of the flow amount and
velocity is accompanied with a deposition of sand and gravels into
local scour holes which have been generated at said front end and
said rear end, and an insertion thereof into the space between the
unit blocks of said block mats (200). Said deposition and insertion
will make the ground of the stream bed firm and solid. As a normal
state and a flood state are repeated, the ground of the stream bed
is further stabilized against scour and any local scour can be
avoided.
[0028] Meanwhile, comparing the unit block and the block mats of
the present invention with the conventionally used stones or
gravels in terms of the construction concerns such as coefficient
of roughness, the coefficient of roughness of stones or a mesh bag
of stones is 0.033.about.0.036 and that of the block of the present
invention is 0.018.about.0.031. Therefore, it is concluded that the
drainage of the block of the present invention is much more stable
than that of the mesh bag of stones.
[0029] Comparing the hydrographic characteristic of stones or
gravels, the tolerated shear stress for the block is calculated to
about 10 times more than that of stones having a diameter of
10.about.30 cm. Therefore, it is confirmed that the flow resistance
for the block is more stable than that for the stones.
[0030] In addition, the blocks may be used as a "wear". In such
case, since the flow parameters tend to have a regular relation
with the water depths of upstream and downstream areas, a "wear"
for a concrete-integrated structure can be effectively used in the
measurement of the flow amount.
[0031] In the above, embodiments in which the method of the present
invention is applied to stream bed in the vicinity of the
foundations of a bridge pier and/or an abutment are illustrated,
but the present invention is not limited only to such applications
and can also be applied to the constructions of a debris barrier
and a fire prevention dam as shown in FIGS. 6 and 7,
respectively.
[0032] FIGS. 6 and 7 show a debris barrier and a fire prevention
dam, respectively, which are constructed according to the method of
the present invention. FIG. 6 is a front view of a debris barrier
and FIG. 7 is a sectional view of a fire prevention dam.
[0033] As represented in FIGS. 6 and 7, when the method of the
present invention is applied to the construction of a debris
barrier or a fire prevention dam, the block mats (200) are
basically on the ground of stream bed, as in the construction for
the stabilizing stream bed in the vicinity of bridge. Further,
since they should have a function to reserve water as a dam, the
block mats (200) having various size are prepared and then
laminated in a multilayer. When the block mats (200) are laminated
in a multilayer, an upper unit block and a lower unit block are
positioned so that their protrusion part (101) and the concave
groove part (102) formed on each unit block are matched together.
The reference number 600 described in FIGS. 6 and 7 represents a
mat for restoring water.
INDUSTRIAL APPLICABILITY
[0034] The method for the construction of an anti-scour protection
of a bridge and for the stabilization of stream bed in a river or a
stream which uses block mats according to the present invention can
improve a resistance to a descending stream at an upstream region
of a pier and to a turbulent stream at a downstream region of a
pier, prevent the ground of stream bed from being locally scoured
by the stream because of the flexibility of the block mat due to
the weight of each of the unit blocks interlocked with each other
by means of U-type bolts, and to stabilize the ground of stream
bed, and stabilize the ground of stream bed, since gravels and sand
fill the spaces between the unit blocks to make them firm after
several repetitions of a flood state and a normal state.
[0035] The present invention can also be applied to a constructions
for preventing of scour and erosion, a construction for resisting
of dropping water, a breakwater, etc. in a river, a seaside and a
port, and various other fields including an erosion control work.
etc.
* * * * *