WO2010104235A1

WO2010104235A1 - Excavation method of underground plaza and submarine plaza using steel casing retaining wall

Info

Publication number: WO2010104235A1
Application number: PCT/KR2009/001559
Authority: WO
Inventors: 정광옥
Original assignee: Chung Kwang-Ok
Priority date: 2009-03-09
Filing date: 2009-03-27
Publication date: 2010-09-16

Abstract

The present invention relates to an excavation method of an underground plaza and a submarine plaza using a steel casing retaining wall, including the steps of: (a) excavating a horizontal or vertical working tunnel (71) for excavating an underground plaza (70) and horizontally excavating the upper space (72) of a planned underground plaza position to be connected to an end of the working tunnel (71); (b) mounting inner and outer wall casings (20,21) of a leading end part which have predetermined length and height in the mounting position of a retaining wall for the excavation of the underground plaza (70) in the upper space (72) of the planned underground plaza position; (c) excavating the ground between the leading-end inner and outer casings (20,21) and simultaneously sinking and digging the leading-end inner and outer casings (20,21) to an excavation bottom surface (50) by the own weight thereof; (d) mounting inner and outer casings (30,31) of an intermediate connection part which have the same shape and length to the top of the leading-end inner and outer casings (20,21) and connecting joints after the digging of the leading-end inner and outer casings (20,21) is completed; and (e) excavating the ground between the leading-end inner and outer casings (20,21) again and simultaneously sinking and digging the leading-end inner and outer casings (20,21) to the excavation bottom surface (50) after the connection between the inner and outer casings (20,21,30,31) of the leading end part and the intermediate connection part is completed.

Description

Underground and Submarine Square Excavation Method Using Steel Casing Earth Walls

The present invention relates to the underground and seabed excavation method using the steel casing earth wall, and more specifically, by using only one work tunnel and a top-down excavation method parallel to the manpower and the machine when constructing the earth wall used for excavation underground underground It is economical and safe, and it is a earth wall used for excavation of underground and submarine plazas, and it uses high tensile and high strength steel casings to withstand the impact and vibrations associated with rock fracture even when rock layers exist during excavation for casing excavation. In addition, the present invention relates to an underground and submarine plaza excavation method using a steel casing earth wall, which is effective in preventing groundwater or seawater inflow as a rigid structure that is resistant to cracks and breakage.

In recent years, when it is necessary to secure a certain space inside underground tunnels such as stockpiling bases such as oil and gas, pumping power plant or waste storage, underground rock foundations and soils should be excavated to form underground plazas of large sections. .

In general, as the underground underground excavation method, conventional upward blasting method using manpower and hydraulic rotary mechanical downward excavation method using a plurality of tunnels are used.

However, conventional upward blasting methods using manpower have a slow working speed, a high risk of falling rocks and falling rocks, and it is difficult to cope with changes in the rock. In addition, the hydraulic rotary mechanical down-drilling method using a plurality of tunnels requires digging a plurality of construction work tunnels for each section in advance on the side of the square before excavating the underground plaza. In addition, there will be a delay in the construction period due to the excavation of a number of such tunnels, and there is no way to efficiently construct a plaza in the deep seabed, but there is room for utilizing a part of the subsea tunnel as a plaza. there was.

Therefore, in the present invention, the steel casing earth wall is used for the excavation of underground and subsea squares. The earth wall is a temporary structure installed for stabilizing the excavation slope and blocking the inflow of groundwater when performing underground construction. There are earth plate method, sheet pile method, CIP method, SCW method and underground continuous wall method.

The earth plate method is a method using a plurality of earth plate and H-PILE drive H-PILE at regular intervals to be excavated in the basement, and sandwich the earth plate of the wood plate between the H-PILE to support the earth and sand on the back, It is a method to install jibo ball for supporting H-PILE.

In addition, the SHEET PILE method is a method of constructing the earth wall by repeatedly inserting the SHEET PILE into the ground vertically and then fitting the end of the other SHEET PILE to the connecting portion of the end and inserting the end into the ground.

The CIP method is a method in which a hole is drilled in the ground with an AUGER, and a reinforcing bar or H-PILE is placed in the hole, and concrete or cement paste is poured to form a continuous concrete column. After the construction, they are excavated with a brace to support the concrete wall to prevent collapse.

In addition, the SCW method is a method of making an underground continuous wall with an AUGER having three axes, and the construction method is almost the same as the CIP.

However, the conventional earth wall construction method is mainly applicable to the soil ground or earth and sand soil layer, and when the construction on the sandstone or all-earth soil layer, the pre-boring method should be performed, and the rock layer has a difficult construction.

In particular, the earth plate method has a weak groundwater blocking effect, so it cannot be used at all when the ground water level on the back of the earth wall is high, and the earth plate is made of wood, which is weak in strength, so that the earth plate is frequently damaged by water pressure and earth pressure. In addition, it is not suitable for being used as a part of a later construction, and it is necessarily accompanied by demolition work.

In addition, in the case of soil wall in the way of placing concrete in the ground, it is difficult to control the quality of concrete in the ground, and it is difficult to repair and reinforce the groundwater leakage after the construction of the ground wall.

The present invention has been made to solve the above problems, an object of the present invention is the rock layer when excavation for excavation of the casing by using a high tensile, high-strength steel casing as the earth wall used for excavation of underground and subsea plaza It is not only able to withstand the impacts and vibrations associated with rock crushing, but it is also a rigid structure that is resistant to cracks and breakage, and provides underground and submarine square excavation methods using steel casing earth walls that are effective for blocking groundwater and seawater inflow. have.

Another object of the present invention is that the earth wall is made of a high strength steel sheet effective to support the external underground stress, excellent construction and safety, easy quality control, underground underground using a steel casing earth wall that can be used as part of the building to be constructed later And it is to provide a subsea square excavation method.

It is still another object of the present invention to provide excellent economics and safety by using only a single construction work tunnel and a top-down excavation method in which a manpower and a machine are used in parallel when constructing an earth wall used for excavation of an underground plaza. Underground plaza using steel casing earth wall to block the case of direct damage to the human body due to environmental pollution caused by spillage of oil or waste stored in the underground, as it is possible to build an independent submarine plaza that can be used as waste storage. And it is to provide a subsea square excavation method.

In order to achieve the above object, the present invention (a) to excavate the construction work tunnel horizontally or vertically to excavate the underground plaza, and horizontally the upper space of the underground plaza planned position to be connected to the end of the construction work tunnel Excavating; (b) mounting the inner and outer wall casings having a predetermined length and height to the earth wall installation position for the excavation of the underground plaza in the upper space of the planned underground plaza; (c) excavating the excavation soil to the outside while excavating the ground between the tip inner and outer wall casings, and simultaneously excavating and excavating the tip inner and outer wall casings to the excavation bottom surface at its own weight; (d) When the excavation of the depth of a certain degree less than the height of the inner and outer wall casings and the excavation of the inner and outer wall casings of the distal end are completed, the inner and outer wall casings having the same length and shape as the upper part of the inner and outer wall casings of the distal end After the step of connecting the joints and the joint process, and (e) when the joint between the inner and outer wall casing of the front end portion and the inner and outer casing of the intermediate portion is completed, again excavating the ground between the inner and outer wall casing of the front end and excavation and At the same time, the inner and outer wall casing sphere is characterized in that consisting of the step of digging down to the excavation bottom surface.

In addition, the present invention (a) by mounting the first inner wall casing of a constant height to the seabed position to build the seabed square using the offshore crane, the inner surface of the lowermost first inner wall casing is long enough to be exposed to the sea Attaching a plurality of excitation guides to the upper end of the first inner wall casing by repeatedly joining the plurality of first inner wall casings to upper and lower adjacent first inner wall casings to expose the upper portion of the uppermost inner wall casing to the design height of the sea; (b) mounting the first outer wall casing having a large cross-section so as to have a predetermined distance from the first inner wall casing on the seabed in a manner that surrounds the first inner wall casing in the same manner as the installation of the first inner wall casing; (c) After pumping up the seawater between the first inner and outer wall casings to the pumping facility, apply coal tar or high quality clay on the sea floor between the first inner and outer wall casings to block the inflow of seawater. Filling a filler such as a sack or pebble concrete to an upper end of the first inner and outer wall casing spheres; (d) laying down a seat sheet around the outer surface of the lowest first outer wall casing mounted on the sea bottom to block the inflow of sea water from below the sea bottom, and building a trowel for fixing the seat sheet thereon; (e) pumping the seawater inside the first inner and outer wall casing spheres to the pumping facility so that the first inner and outer wall casing spheres can act as a temporary film for the construction of the seabed square; and (f) the first inner and outer wall casing spheres. Using the barge docked on the top of the outer wall casing sphere or the first inner and outer wall casing spheres as a workbench to mount the excavation soil lifting equipment and to excavate the bottom of the inner bottom surface of the first inner and outer wall casing spheres Characterized in that the step consisting of using the earth wall.

As described above, the inventors of the underground and subsea square excavation method using the steel casing earth wall of the present invention is economical and safe by using only a top-down excavation method and a single work tunnel for the construction of the earth wall used for underground excavation It is an excellent earth wall used for excavation of underground and submarine plazas, and by using high tensile and high-strength steel casings, it is able to withstand the impact and vibrations associated with rock fracture even when rock layers exist during excavation for casing excavation. As a rigid structure that is resistant to cracks and damages, it is effective in blocking groundwater and seawater inflow, and the earth wall is made of high strength steel sheet which is effective for supporting external underground stresses. Can be used as part of oil, gas, etc. It is possible to build an independent submarine plaza in the deep sea, which can be used as a stockpiling base or a waste storage, thereby preventing the direct damage to the human body due to environmental pollution caused by spillage of oil or waste stored underground.

1 is a cross-sectional view of the construction completed by the underground square excavation method using a steel casing earth wall according to the present invention.

Figure 2 is a completed cross-sectional view of the construction by the seabed square excavation method using the steel casing earth wall in accordance with the present invention.

Figure 3 is a perspective view showing a part of an embodiment of the earth wall structure used in the underground and subsea plaza excavation method according to the present invention.

Figure 4 is a cross-sectional view showing the construction sequence of the earth wall used in the subsea square excavation method using the steel casing earth wall according to the present invention.

5 to 7 is a cross-sectional view showing the procedure of the underground square excavation method using the steel casing earth wall in accordance with the present invention.

8 is a perspective view and a cross-sectional view of an embodiment of the first casing sphere used in the subsea square excavation method using a steel casing earth wall according to the present invention.

9 to 11 is a cross-sectional view showing the procedure of the seabed square excavation method using a steel casing earth wall according to the present invention.

When described in detail with reference to the accompanying drawings a preferred embodiment of the present invention configured as described above are as follows.

As shown in Figures 2, 8 and 9 to 11, in the seabed square excavation method using the steel casing earth wall, first, the steel casing of a predetermined shape is mounted on the seabed at regular intervals, and the steel in the drawing The shape of the casing is shown in a circular shape, but the shape of the steel casing is not limited thereto, and may be variously changed to a square or a polygon.

In the method of installing the double steel casing on the sea floor, the first inner wall casing 24 having a constant height is mounted on the sea floor to build the sea floor square 74 using the offshore crane, but the lowermost first inner wall casing 24 is mounted. A plurality of first inner wall casings 24 are repeatedly attached to the upper surface of the other first inner wall casings 24 by attaching a predetermined number of guides 26 having a length enough to be exposed to the sea on the inner surface of the upper surface. The upper part of the uppermost first inner wall casing 24 is exposed to the design height of the sea.

Here, the end portion of the first inner wall casing 24 is formed in a sawtooth shape, the tooth coupling between the adjacent first inner wall casing 24 is inserted in the state where the sealant 27 is inserted, the external seawater flows into the casing It can be prevented to some extent, and the lowermost 1st inner wall casing 24 can prevent the movement by an ocean current by letting it be fixed to the sea bottom by the self weight to some extent.

The first outer wall casing 25 having a large cross-section so as to have a predetermined distance from the first inner wall casing 24 also surrounds the first inner wall casing 24 in the same manner as the installation of the first inner wall casing 24. Mounted on the sea floor, but if necessary, the horizontal support beams 23 at regular intervals to maintain the gap between the first inner and

outer wall casings

24 and 25 and withstand the water pressure in the water. 24 and 25), and the first inner and outer wall casing spheres 11 are designed and manufactured in consideration of the currents of the positions to be mounted, but the first inner and outer walls are faster than expected. In order to temporarily fix the outer wall casing sphere 11, a cable connecting the sea bottom and the first inner and outer wall casing spheres 11 may be provided at the time of casing mounting.

Next, the seawater between the first inner and

outer wall casings

24 and 25 is pumped up to the pumping facility, and then the sea bottom 75 between the first inner and

outer wall casings

24 and 25 is blocked to prevent seawater inflow. Apply the tar (28) or lay a good quality clay, pile up the soil mound (61) to a certain height on it, and place the cobblestone concrete (62) as a filler on the soil mound (61) for the first inner and outer wall casing sphere (11). ) Pour to the top. Here, the trowel 61 or the pebble concrete 62 is not only limited to an example of a filling material for blocking the inflow of seawater, but may be used as other filling material such as a rock block if the seawater inflow blocking is possible. 1 Since the seawater blocking function of the inner and outer wall casing spheres 11 itself is not perfect, it is preferable that the filling material be introduced quickly.

In addition, by laying the order sheet 63 around the outer surface of the lowermost first outer wall casing 25 mounted on the seabed and by laying a trowel 61 for fixing the order sheet 63 thereon, the bottom surface 75 The effect of blocking the inflow of seawater from below may be exerted to some extent (FIG. 9B).

Next, when the seawater inside the first inner and outer wall casing spheres 11 installed by the above method is pumped up to the pumping facility, the first inner and outer wall casing spheres 11 are used for the construction of the seabed square 74. The temporary film acts as a role, and may be formed around the outer surface of the lowermost first inner wall casing 24 mounted on the seabed, the side opening 64 for drainage of seawater flowing from the seabed (FIG. 10C).

Next, using the barge docked on the upper end of the first inner and outer wall casing spheres 11 or the first inner and outer wall casing spheres 11 as a workbench to mount the excavation soil lifting equipment and construct the seabed square 74. Excavation work of the inner bottom surface 75 of the first inner and outer wall casing spheres 11 is performed by using a steel casing earth wall (FIG. 10D).

On the other hand, the basic structure of the earth wall used in the underground and subsea square excavation method using the steel casing earth wall of the present invention is the front end casing (20, 21) and made of a predetermined length and height, as shown in Figs. Intermediate connection casing (30, 31) of the same length and shape as the front end casing (20, 21) are mutually coupled in the vertical direction, the coupling portion between the front end casing (20, 21) and the intermediate connection casing (30, 31) It is preferable to treat the welding joint 41 or a mechanical joint, and to form the welding groove 40 at the upper and lower ends of each of the casings in the case of the welding joint 41 to correspond to the adjacent casing.

The casing sphere and the second casing sphere (10, 12) consisting of the tip casing (20, 21) and the intermediate connection casing (30, 31) are installed in duplicate while maintaining a constant distance to form a earth wall, if necessary, horizontal support The beam 23 is fixedly installed between the inner and

outer wall casings

20, 21, 30, and 31 at the predetermined intervals, and the lower end 22 of the distal end casing is processed into a V-shape or an inverted trapezoidal shape. This is preferred.

In addition, as shown in FIGS. 5 to 7 and 9 to 11, the inner bottom of the first inner and outer wall casing sphere 11 for the underground excavation method using the steel casing earth wall and the construction of the subsea square 74 The excavation work of the surface 75 is as follows.

First, in the excavation of the underground plaza 70, the construction work tunnel 71 is excavated horizontally or vertically for the excavation of the underground plaza 70, and the plan of the underground plaza is connected to the end of the construction work tunnel 71. Excavate the upper space 72 horizontally, the upper space 72 of the planned underground plaza should be excavated to a certain extent wider than the cross section of the underground plaza 70 to enable the equipment work for the installation and excavation of the casing ( Figure 5a).

Of course, the equipment and materials required for the casing and excavation through the work tunnel 71 for construction is carried in or the excavated soil is carried out.

Next, the base casing (20, 21) made to a certain length and height to suit the site conditions, the basement to the inner and outer walls of the earth wall for the excavation of the underground plaza 70 or the subsea plaza (74) is double underground Mounted at the earth wall installation position in the upper space 72 of the planned square (Fig. 4a, Fig. 5b), when excavating the seabed square 74, before the inner and outer wall casing (20, 21) of the tip to block the inflow of seawater High quality clay of a predetermined thickness or more may be installed on the inner bottom surface 75 of the first inner and outer wall casing spheres 11. Here, the double tip inner and

outer wall casings

20 and 21 are sufficiently resistant to underground stresses such as external earth pressure or water pressure when excavating into the ground of the casing, and are effective in blocking groundwater inflow, and fracture the rock between the inner and outer wall casings. In order to prevent cracking and damage of the casing wall from impact and vibration, high tensile and high strength steel sheets of constant thickness should be used in consideration of site conditions. The same applies to the

casings

24 and 25.

In addition, the tip inner and outer wall casing (20, 21) is a steel casing earth wall for the excavation of the underground plaza 70 or the subsea plaza 74 of the present invention, as shown in the embodiment of Figs. The inner and

outer wall casings

20 and 21 may be mounted by being integrally formed in a cross-sectional shape, and in the case of mounting integrally, the tip casing may be divided into sections by dividing sections in case of problems in carrying or mounting the casing. (20, 21) can be manufactured and double mounted.

Further, the lower end toe 22 of the tip casing is preferably fabricated into a V-shape or an inverted trapezoidal shape so that the casing can be easily excavated to the ground.

Subsequently, when excavating the excavated soil while excavating the ground between the inner and

outer wall casings

20 and 21 of the distal end portion or the bottom surface 75, the

distal end casing

20 and 21 at the same time is excavated. It is settled and excavated to the excavation bottom surface 50, and the vertical excavation surface 51 of the ground by excavation is supported by the inner and

outer wall casings

20 and 21 at the same time as excavation and is not exposed to the outside. It is possible to prevent (Fig. 4b, Fig. 6c), and if necessary, it is possible to prevent the collapse of the excavation surface and the fall of the earth wall by installing a rigid support for the support of the inner and outer wall casing (20, 21) in the ground. At this time, if necessary, the inner and

outer wall casings

20 and 21 at the predetermined intervals of the horizontal support beams 23 at regular intervals to maintain the gap between the inner and

outer wall casings

20 and 21 and to withstand the external stresses. If the excavation is made by disposing the

tip casings

20 and 21 by dividing the sections by sections, the tip is formed in such a way that the inner and outer wall casings are closed so that they can withstand the ground stress at both ends of the casing in the longitudinal direction and can be ordered. Casing (20, 21) should be manufactured, and sealant may be injected to block groundwater inflow between adjacent closed tip casing (20, 21) when excavation by section, adjacent closed tip casing (20, 21) 2) The both ends may be cut open so that a welded joint may be formed by applying a steel sheet between the inner and

outer wall casings

20 and 21 of the adjacent sections.

Here, the ground excavation work is made between the inner and

outer wall casings

20 and 21 at the tip portion, and the space between the inner and

outer wall casings

20 and 21 at the tip portion is only required to secure a minimum space for excavation. Therefore, the excavation method is excellent in workability by the manpower excavation or mechanical excavation using the Short Boom / Short Arm Excavator. In the excavation of the seabed square 74, the excavated soil or excavated rock generated at this time is dropped to the outside of the first casing sphere 11 to form the embankment 80 on the outside of the first casing sphere 11, and the inner and outer walls of the tip portion. If there is an inflow of seawater during excavation between the casing (20, 21), the pumping facility should be continuously operated to pump the seawater.

In addition, the excavation portion 52 between the casing and the vertical excavation surface 51 for preventing the collapse of the vertical excavation surface 51 and the dispersion of underground stresses acting outside the casing and the friction between the casing and the vertical excavation surface 51 is reduced. ) Fills the filling material 53 such as fine aggregates or coarse aggregates, and in case of severe groundwater leakage, the groundwater or seawater is reduced by filling with soil or clay. If the filler 53 is stacked in advance on each outer surface before excavation, the filler 53 flows naturally into the excavation portion 52 at the same time as the excavation portion 52 is generated during excavation.

Next, when the excavation of the depth and the excavation of the tip inner and outer wall casing (20, 21) to a certain degree less than the height of the tip inner and outer wall casing (20, 21) is completed, the tip inner and outer wall casing (20, 21) The inner and

outer wall casings

30 and 31 of the same length and shape are installed on the upper part, and then the joints are preferably treated by welding seam 41. However, if the groundwater or seawater can be blocked, the front end and the middle The joints between the inner and

outer wall casings

20, 21, 30 and 31 of the connection portion are not limited to welding but may be mechanical joints (Figs. 4C and 6D).

Excavation at a depth smaller than the height of the inner and

outer wall casings

20 and 21 at the tip portion facilitates the welding joint 41 between the inner and

outer wall casings

20, 21, 30 and 31 at the tip portion. To work on

Here, the weld joint 41 between the inner and

outer wall casings

20 and 21 of the tip portion and the inner and

outer wall casings

30 and 31 of the intermediate portion exhibits strength equal to or greater than that of the casing sphere or the

second casing sphere

10, 12. This should be possible, and for this purpose, the upper and lower ends of each of the casing is manufactured so that the welding groove 40 is formed to correspond to the adjacent casing.

Furthermore, when the weld joint 41 between the inner and

outer wall casings

20 and 21 of the distal end portion and the inner and

outer wall casings

30 and 31 of the intermediate portion is completed, the ground between the inner and

outer wall casings

20 and 21 of the distal end portion is again obtained. The bottom of the sea floor 75 is excavated, and at the same time, the inner and outer wall casing spheres and the

second casing spheres

10 and 12 are sedimented and excavated to the excavation bottom surface 50 (Figs. 4D and 7E).

On the other hand, the front end inner and outer wall casing (20, 21) and the intermediate connection inner and outer wall casing (30, 31) is preferably made of a structure having a long length in the transverse direction compared to the height for the purpose of the earth wall construction, The present invention is not limited to the illustrated shape, and may be manufactured in a curved shape, a straight line shape, or a complex type in which straight lines and curves are mixed according to the design shape of the earth wall.

Finally, after repeating the joint and excavation process to the design depth of the earth wall for the excavation of the underground plaza 70 or the subsea plaza 74, the inner wall casing to form a space of the underground plaza 70 or the seabed plaza 74 When the ground adjacent to (20, 30) is excavated to the design depth, the inner wall casings (20, 30) are exposed to the design depth and the earth wall and the underground plaza (70) or the submarine square (74) using the steel casing of the desired height. By this completion, the present invention is an excavation method of the underground plaza 70 and the seabed plaza 74 using the earth wall of the front steel casing system excellent in workability and safety. Furthermore, by placing concrete in close contact with the casing sphere 10 on the basement floor bottom 73, it is preferable to prevent the inflow of groundwater from the basement floor bottom 73 (FIG. 7F). The location is preferably formed in the rock layer, and as described above, the excavated soil or the excavated rock is dropped out of the first casing sphere 11 to form the embankment 80 outside the first casing sphere 11 (FIG. 11E). .

In addition, in the case of filling the interior of the casing sphere or the second casing sphere (10, 12), which is the earth wall for the excavation of the underground plaza 70 or the subsea plaza 74 with concrete 60 or aggregate, bearing capacity against external underground stresses This increasing effect can be expected and can be used later as part of the structure or part of the structure to be constructed in the underground plaza 70 or the subsea plaza 74, so that the dismantling of the casing spheres or the

second casing spheres

10 and 12 is performed. There are also advantages that are not needed.

Accordingly, the subsea plaza 74 may be utilized as a stockpiling base or waste storage such as oil and gas, and if necessary, the embankment 80 may be deposited over a predetermined cross-sectional area or the subsea plaza 74 and the first and second parts may be used. The interior of the

casing spheres

11 and 12 may be backfilled and used as artificial islands.

Furthermore, the seabed 74 excavation method is not limited to being applicable only to the deep sea, but may be applicable to rivers.

While specific preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the above-described embodiments, and a person skilled in the art to which the present invention pertains has the technical gist of the present invention. Various changes can be made without departing.

Claims

(a) Excavating the construction work tunnel 71 horizontally or vertically to excavate the underground plaza 70, and horizontally the upper space 72 of the planned underground plaza to be connected to the end of the construction work tunnel 71 Excavating;

(b) mounting the inner and outer wall casings (20, 21) at the predetermined length and height to the earth wall installation position for excavating the underground plaza (70) in the upper space (72) of the underground plaza planned location;

(c) Excavating soil is taken out while excavating the ground between the tip inner and outer wall casings 20 and 21, and at the same time as the excavation, the inner and outer wall casings 20 and 21 are excavated with their own weight. Sinking to);

(d) When the excavation of the depth to a certain degree less than the height of the tip inner and outer wall casings 20 and 21 and the excavation of the tip inner and outer wall casings 20 and 21 are completed, the tip inner and outer wall casings 20 and 21 are completed. Installing the intermediate inner and outer casings 30 and 31 of the same length and shape on the upper part of the joint), and then joining the joints;

(e) When the joint between the inner and outer wall casings 20 and 21 of the tip part and the inner and outer wall casings 30 and 31 of the intermediate part is completed, the ground between the inner and outer wall casings 20 and 21 of the tip part is again excavated. Simultaneously with the excavation, the inner and outer wall casing sphere (10) is underground underground excavation method using a steel casing earth wall, characterized in that the step consists of sinking down to the excavation bottom surface (50).
(a) Mounting the first inner wall casing 24 of a constant height to the seabed position to build the seabed square 74 by using the offshore crane, but the inner surface of the lowermost first inner wall casing 24 may be exposed to the sea A number of guides 26 having a predetermined length are attached to each other so that the plurality of first inner wall casings 24 are repeatedly attached to the upper ends of the first inner wall casings 24 adjacent to each other vertically. Allowing the top of 24 to be exposed to the design height of the sea;

(b) The first outer wall casing 25 having a large cross-section so as to have a predetermined distance from the first inner wall casing 24 may also be used to install the first inner wall casing 24 in the same manner as the installation of the first inner wall casing 24. Mounting on the seabed in a surrounding form;

(c) pumping seawater between the first inner and outer wall casings 24 and 25 to the pumping facility and then applying a coal to the sea bottom 75 between the first inner and outer wall casings 24 and 25 to block the inflow of seawater. Applying tar (28) or laying high-quality clay, and filling the filling material such as trowel 61 or pebble concrete 62 to the upper end of the first inner and outer wall casing spheres 11;

(d) for securing the order sheet 63 on the periphery of the outer periphery of the lowermost first outer wall casing 25 mounted on the ocean floor to block the inflow of seawater from below the sea bottom 75; Stacking the trowel (61);

(e) the first inner and outer wall casing sphere 11 pumping seawater inside the first inner and outer wall casing sphere 11 to the pumping facility so as to act as a temporary film for construction of the seabed square 74; , And

(f) Using the barge docked on the upper end of the first inner and outer wall casing spheres 11 or the first inner and outer wall casing spheres 11 as a workbench to mount the excavation soil lifting equipment and to construct the seabed square 74 A method for excavating an undersea square using a steel casing earth wall, wherein the excavation work of the first inner and outer wall casing sphere 11 is performed by using a steel casing earth wall.
The method of claim 2,

Construction of the steel casing earth wall of the step (f),

(g) mounting the front end casings 20 and 21 having a predetermined length and height to a subsea earth wall installation position so as to form an inner and an outer wall of the earth wall for excavating the seabed square 74;

(h) Excavating excavation soil or excavation rock to the outside while excavating the seabed 75 ground between the inner and outer wall casings 20 and 21 of the distal end, and simultaneously with the excavating the inner and outer wall casings 20 and 21 of the distal end. Sinking and digging to the excavation bottom surface 50 at its own weight;

(i) When the excavation of the depth of the tip portion and the excavation of the tip inner and outer wall casings 20 and 21 is completed, the tip inner and outer wall casings 20 and 21 are completed. Connecting the inner and outer wall casings 30 and 31 of the same length and shape to the upper part of the joint;

(j) When the joint between the tip inner and outer wall casings 20 and 21 and the intermediate connecting inner and outer wall casings 30 and 31 is completed, the bottom surface 75 between the tip inner and outer wall casings 20 and 21 is again present. Excavating the ground and simultaneously drilling the second casing sphere 12 to sink down to the excavation bottom surface 50, and

(k) After repeating the joint and excavation process between the inner and outer wall casings (30, 31) of the intermediate connection to the design depth of the earth wall for excavation of the seabed square (74), the inner wall casing to form a space for the seabed square (74) A steel casing earth wall comprising the steps of excavating the sea floor 75 adjacent to (20, 30) to the design depth and filling the interior of the second casing sphere 12, which is the earth wall, with concrete 60 or aggregate Submarine plaza excavation method using
The method of claim 3, wherein

The excavated soil or excavated rock has a step of dropping to the outside of the first casing sphere 11 to form the embankment 80 on the outside of the first casing sphere 11 subsea square using a steel casing earth wall Excavation method.
The method of claim 2,

End portions of the first inner and outer wall casings 24 and 25 are formed in a sawtooth shape, and tooth coupling is performed between seals 27 inserted between adjacent first inner and outer wall casings 24 and 25. Submarine plaza excavation method using steel casing earth wall.
The method according to claim 1 or 2,

The inner and outer wall casings (20, 21, 30, 31) and the first inner and outer wall casings (24, 25) of the front end portion and the intermediate connecting portion are made of a steel casing earth wall, characterized in that composed of a high tensile steel sheet and a high strength steel sheet having a constant thickness. Underground and Submarine Plaza Excavation
The method according to claim 1 or 3,

The lower end portion 22 of the inner and outer wall casing of the tip portion is an underground square and submarine square excavation method using a steel casing earth wall, characterized in that the V-shape or inverted trapezoidal shape to facilitate the excavation of the casing to the ground.
The method according to claim 1 or 3,

The overhang portion 52 between the casing and the vertical excavation surface 51 for preventing the collapse of the vertical excavation surface 51 and for dispersing ground stresses acting outside the casing and reducing friction between the casing and the vertical excavation surface 51. Underground plaza using a steel casing earth wall, characterized in that the step of stacking the filler 53 before the excavation on the outer surface of each of the inner and outer wall casing (20, 21) of the front end portion to fill the filler 53 and Subsea Square Excavation.
The method according to claim 1 or 3,

After the connection and excavation process between the inner and outer wall casings 30 and 31 of the intermediate connection part is repeated to the design depth of the earth wall for excavation of the underground plaza 70 or the subsea plaza 74, the underground plaza 70 or the submarine plaza ( 74) excavating the ground adjacent to the inner wall casing (20,30) to the design depth to form a space, and filling the interior of the earth casing sphere or the second casing sphere (10,12) with concrete 60 or aggregate Underground square and submarine square excavation method using a steel casing earth wall, characterized in that further comprises.
The method according to claim 1 or 2,

In order to maintain a gap between the first inner and outer wall casings 24 and 25 or between the front end and the intermediate connection inner and outer wall casings 20, 21, 30 and 31 and to withstand external stresses, the first inner and outer wall casings ( Steel casing earth wall using the steel casing, characterized in that the horizontal support beam 23 is additionally fixed at regular intervals between the 24 and 25 or between the inner and outer wall casings (20, 21, 30, 31) of the front end and the intermediate connection portion. Underground and submarine plaza construction method.