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Title:
UNDERGROUND RETAINING WALL FOR PUBLIC WORKS AND METHOD FOR CONSTRUCTING THE SAME
Document Type and Number:
WIPO Patent Application WO/2007/117050
Kind Code:
A1
Abstract:
The present invention relates to an underground earth retaining wall for public works, which is used to endure an outer pressure such as soil pressure, and the like, and a method for con¬ structing the same. The underground earth retaining wall for public works according to the present invention comprises a first pile array, a second pile array, and a first connection member. The first pile array is formed by continuously installing a plurality of piles by socket into the ground around a drilling region in a predetermined interval. The second pile array is also formed by installing a plurality of piles by socket into the ground around the drilling region in a pre determined interval at a predetermined position to the outward direction from the first pile array with respect to the drilling region. The first connection member connects the first pile array and the second pile array on the ground so that they are secured.

Inventors:
LEE, Jae Ho (546-1, Bugok-dong Geumjeong-gu, Busan 609-320, KR)
KIM, Dae Woo (#704, 102dong NewGreen Apt.,Bugok4-dong, Geumjeng-gu, Busan 609-754, KR)
PARK, Lee Keun (#1803, 102dong Kumkang Apt.,Guseo-dong, Geumjeong-gu, Busan 609-310, KR)
Application Number:
KR2006/001359
Publication Date:
October 18, 2007
Filing Date:
April 12, 2006
Export Citation:
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Assignee:
LEE, Jae Ho (546-1, Bugok-dong Geumjeong-gu, Busan 609-320, KR)
KIM, Dae Woo (#704, 102dong NewGreen Apt.,Bugok4-dong, Geumjeng-gu, Busan 609-754, KR)
PARK, Lee Keun (#1803, 102dong Kumkang Apt.,Guseo-dong, Geumjeong-gu, Busan 609-310, KR)
International Classes:
E02D5/34
Foreign References:
JP2002227204A
JPH06248650A
JPH09264024A
KR100414435B1
US6336776B1
US4952097A
Attorney, Agent or Firm:
BAEG, Seung Jun (7F Kyungnam Bldg, 56-4 Jungang-dong,4-ga, Jung-gu, Busan 600-815, KR)
Download PDF:
Claims:

Claims

[1] An underground earth retaining wall for public works, which is used to endure an outer force such as soil pressure, and the like, the earth retaining wall comprising: a first pile array formed by continuously installing a plurality of piles by socket into ground around a drilling region in a predetermined interval; a second file array formed by installing a plurality of piles by socket into the ground around the drilling region in a predetermined interval at a predetermined position to the outward direction from the first pile array with respect to the drilling region; and a first connection member for connecting and securing the first pile array to the second pile array on the ground.

[2] The underground earth retaining wall for public works according to claim 1, wherein the first connection member comprises: a first girth jointed in parallel to the plurality of piles constituting the first pile array, a second girth jointed in parallel to the plurality of piles constituting the second pile array, and a securing bar jointed to the first girth and the second girth at both ends thereof.

[3] The underground earth retaining wall for public works according to claim 1 or 2, further comprising a second securing bar for connecting and securing the first pile array and the second pile array under the ground so that it is positioned at the lower side of the first connection member.

[4] The underground earth retaining wall for public works according to claim 3, further comprising a sub lagging for defining a sub-drilling region communicating from the second pile array to the drilling region, which extends from the ground to a position of installing the second connection member, and installed at the second pile array of the sub-drilling region.

[5] The underground earth retaining wall for public works according to claim 1 or 2, further comprising an underground connection member installed by socket into the ground from the inside of the drilling region through the lagging jointed to the first pile array after the drilling of the drilling region.

[6] The underground earth retaining wall for public works according to claim 1 or 2, further comprising an underground connection member installed by socket into the ground from the inside of the drilling region through the lagging jointed to the first pile array after the drilling of the drilling region, and jointed to the second pile array.

[7] The underground earth retaining wall for public works according to claim 1 or 2, wherein the plurality of piles constituting the first pile array is installed by socket into the ground so that each of them is inclined with respect to the drilling region.

[8] The underground earth retaining wall for public works according to claim 7, further comprising a second securing bar for connecting and securing the first pile array and the second pile array under the ground so that it is positioned at the lower side of the first connection member.

[9] The underground earth retaining wall for public works according to claim 8, further comprising a sub lagging for defining a sub-drilling region communicating from the second pile array to the drilling region, which extends from the ground to a position of installing the second connection member, and installed at the second pile array of the sub-drilling region.

[10] The underground earth retaining wall for public works according to claim 7, further comprising an underground connection member installed by socket into the ground from the inside of the drilling region through the lagging jointed to the first pile array after the drilling of the drilling region.

[11] The underground earth retaining wall for public works according to claim 7, further comprising an underground connection member installed by socket into the ground from the inside of the drilling region through the lagging jointed to the first pile array after the drilling of the drilling region, and jointed to the second pile array.

[12] A method for constructing an earth retaining wall for public works, which is used to construct then earth retaining wall for enduring outer force such as soil pressure, and the like, the method comprising the steps of: forming a first pile array by continuously forming a plurality of boring holes around a drilling region in a predetermined interval, and installing a pile by socket into respective boring hole; forming a second pile array by continuously forming a plurality of boring holes around the drilling region in a predetermined interval, and installing a pile by socket into respective boring hole, at a predetermined position to the outward direction from the first pile array with respect to the drilling region; and connecting and securing the first pile array to the second pile array by means of a first connection member on the ground, whereby the underground earth retaining wall is constructed by installing the first pile array and the second pile array around the drilling region to the outward direction with a predetermined interval, and then connecting them by the first connection member.

[13] The method for constructing an earth retaining wall for public works according

to claim 12, further comprising the step of connecting and securing the first pile array and the second pile array by means of a second connection member under the ground so that it is positioned below the first connection member in the course of the drilling of the drilling region.

[14] The method for constructing an earth retaining wall for public works according to claim 13, further comprising the step of forming a sub-drilling region communicating from the second pile array to the drilling region, which extends from the ground to a position at which the second connection member is installed during the drilling of the drilling region.

[15] The method for constructing an earth retaining wall for public works according to claim 14, further comprising the step of installing a sub lagging at the second pile array of the sub-drilling region.

[16] The method for constructing an earth retaining wall for public works according to any one of claim 12 to 15, further comprising the step of installing by socket an underground connection member from the inside of the drilling region to the ground through the lagging, after jointing the lagging to the first pile array when the drilling of the drilling region is completed.

[17] The method for constructing an earth retaining wall for public works according to any one of claim 12 to 15, wherein the step of forming the first pile array is executed so that a plurality of boring holes are formed to have an inclined angle to the drilling region, and the pile is installed by socket into the ground so that it has an inclined angle toward the drilling region.

[18] A method for constructing an earth retaining wall for public works, which is used to construct the earth retaining wall for enduring outer force such as soil pressure, and the like, the method comprising the steps of: forming a first pile array by continuously forming a plurality of boring holes around a drilling region in a predetermined interval and installing a pile by socket into respective boring hole so that it is positioned below the ground by a predetermined depth; forming a second pile array by continuously forming a plurality of boring holes around the drilling region in a predetermined interval, and installing a pile by socket into respective boring hole, at a predetermined position to the outward direction from the first pile array with respect to the drilling region; forming a sub-drilling region at the second pile array at the time of drilling the drilling region, so that it communicates with the drilling region by the depth coming to the top of the first pile array; and connecting and securing the first pile array to the second pile array by means of a first connection member on the ground, whereby the underground earth retaining

wall is constructed by installing the first pile array and the second pile array around the drilling region to the outward direction with a predetermined interval, and then connecting them by the first connection member.

Description:

Description

UNDERGROUND RETAINING WALL FOR PUBLIC WORKS AND METHOD FOR CONSTRUCTING THE SAME

Technical Field

[1] The present invention relates to an underground earth retaining wall for public works and a method for constructing the same, and more particularly, to an underground earth retaining wall for public works, which is used to endure an outer pressure such as soil pressure and the like before performing excavation, and a method for constructing the same. Background Art

[2] In general, when filling the ground, cutting the ground, or drilling, and the like are performed, while a slope surface is generally formed to maintain the stability of the ground, however, when the drilling is performed to improve the utility of the land more effectively or to improve the foundation of the structure in an urban area and construct underground room of a building, a vertical drilling is performed without the formation of the slope surface. In this regard, an earth retaining wall is necessarily installed around the vertical surface to prevent the breakage of the adjoining ground due to the vertical drilling. However, the earth retaining construction method for installing the earth retaining wall should be selected in consideration of the conditions of the earth, conditions of the ground, effect to the surroundings of the ground, construction expense, construction period, and the construction capacity, and the like, and after considering the respective construction method sufficiently.

[3] Nowadays, one of the most generally known method of constructing the earth retaining wall is a strut supporting construction method. Since this construction method is designed to endure the soil pressure by the compression force of the strut, a plurality of struts is installed by an interval of some meter in the longitudinal and transverse directions. Accordingly, in case of a large drilling, a large quantity of steel sheet is used to largely increase the construction expense, and the installed struts obstruct the field works such as the movement of the drilling equipment, transfer of the drilled earth and sand, and the materials, and the like, and they also cause impediments to the steel file of the structure or works of a cast, thereby reducing the working efficiency. Also, in the strut supporting construction method, a plurality of holes produced in the structure causes problems of durability and waterproof property of the accomplished underground structure.

[4] Meanwhile, there was developed a ground anchor construction method as a construction method of the earth retaining wall without any strut among the conventional

temporary constructing methods. This method has an advantage that following works become easy, since sufficient inside space can be secured. However, this construction method has disadvantages that the conditions for the construction field are restricted because it could not intrude adjoining place, and the construction expense becomes high.

[5] As for still another conventional art, there is a soil nailing construction method, in which boring holes are formed at the rear side of the drilling together with the drilling work, nails are filled into them, and then grouts are filled therein, and the wall surface is injected by shotcrete, thereby forming the earth retaining wall body. Since this construction method is simple in construction, and has no impediment due to struts, there occurred advantages that construction period of the following process can be reduced, and the soil pressure acting on the underground structure is reduced, thereby decreasing the section of the structure. However, in case of a ground having a high underground water height and a ground of subsidence property, there is a possibility of slope breakage, and the modification of the inclined surface due to cutting off of the earth is serious, thereby causing the sinking of the adjoining ground. Also, there occurs a disadvantage that it was impossible to apply to the ground of particular condition, and it requires a careful attention.

[6] As for still another conventional art, there was developed a Raker construction method, in which an earth retaining wall is at first constructed, a slope surface is formed at the inside of it, reverse force is applied to the previously constructed foundation structure, an inclined strut is installed to the earth retaining wall to thereby progress the drill. This construction method is simple in construction, requires less strut holes, short of inclined strut, thereby producing an advantage that contraction or moving joint portion is small. However, there occurred problems that stability of the inclined surface is difficult to secure in a weak ground, it was improper for deep drilling, space is narrow and the workability is bad at the time of constructing a structure in the Raker.

[7] As for still another conventional art, there was developed a prestressed girth

(wooden piece placed sideways across boarding) construction method. This construction method is a technology of widening an interval between the struts by additionally installing a girth above the previously installed girth, thereby tensioning a steel wire, and is to reinforce the additional girth or a flange of the existing H-beam. However, there occurred disadvantages that, since the steel wire is disposed to be linear in such construction method, and a moment produced in the girth due to the soil pressure is different from the resistance moment produced due to prestressing, so that unequal moment is always acted in the members, and the girth is weak to the local unequal load when the length thereof becomes to be long, and it was restricted to

extend the length of the prestressed girth because the rigidity of the installation device was limited so that the increasing of the eccentricity was restricted.

[8] As for still another conventional art, there was developed a truss girth construction method, which is expected to be applicable to a case of relative shallow depth, and in which H-beams were installed doubly in a lattice shape at the adjoining place of the ground surface, so that the soil pressure can be received by the trusses of two layers installed at the upper portion by reinforcing the beams with the vertical members and inclined members. This construction method was devised to overcome difficulties arising in the drilling and construction of the main structure produced in the struts of the temporary structure for supporting the ground, and can be used when a wide structure is disposed at the lower portion of the drilled ground and a narrow structure is disposed at the upper portion. Disclosure of Invention Technical Problem

[9] Accordingly, the present invention was devised to solve such conventional problems, and an object of the present invention is to provide a novel underground earth retaining wall for public works and a method constructing the same, which enable the effective utilization of land, and can improve the economic efficiency and construction efficiency of the following works by removing struts in the drilling region, in which the construction is progressed, solve a problem of intruding into adjoining area, minimize damages caused by the drilling construction by minimizing the ground sinking and displacement due to temporary construction works, and maximize a deepness which can be accomplished by the drilling. Technical Solution

[10] To achieve the above object, the present invention provides an underground earth retaining wall for public works, which is used to endure an outer force such as soil pressure and the like, the retaining wall comprising a first pile array formed by continuously installing a plurality of piles by socket into ground around a drilling region in a predetermined interval; a second pile array formed by installing a plurality of piles by socket into ground around a drilling region in a predetermined interval at predetermined positions in the outward direction from the first pile array with respect to the drilling region; and a first connection member for connecting and securing the first pile array to the second pile array on the ground.

Advantageous Effects

[11] Therefore, according to the underground earth retaining wall for public works and a method for constructing the same according to the present invention, the present invention can improve several disadvantages of the existing temporary construction

method such as the strut supporting construction method or the ground anchor construction method, and the like. In other words, the construction expense can be reduced, the construction period can be shortened, and the construction work using the heavy equipments in the drilling field becomes smooth, and the following scaffold works can be facilitated, thereby improving the construction efficiency, because the amount of the used steel sheet can be decreased due to no use of the strut. Further, it is possible to remove almost all of the construction limitations in the adjoining construction at the downtown area, and the like, because self-installation type temporary construction structure can be installed to solve the problem of intruding into adjoining area produced at the time of installing anchors into the ground, when the present invention is compared with the ground anchor construction method. In addition, when the present invention is compared with the existing temporary construction works, and the like, it is possible to reduce the damage of the adjoining structure due to drilling in comparison with the existing construction method by minimizing the ground sinking and the displacement, and make the deepness accomplished by the drilling deeper than before. Brief Description of the Drawings

[12] FIG. 1 is a view for explaining the technical spirit of an underground earth retaining wall for public works according to the present invention;

[13] FIG. 2 is a view for explaining the technical spirit of a method for constructing an underground earth retaining wall for public works according to the present invention;

[14] FIG. 3 is a perspective view showing a constitution of the underground earth retaining wall for public works according to a preferred embodiment of the present invention;

[15] FIG. 4 is a view showing examples of laggings used in the construction of the underground earth retaining wall for public works according to preferred embodiments of the present invention;

[16] FIG. 5 and FIG. 6 are cross-sectional view and a perspective view for explaining an example of the underground earth retaining wall for public works according to a preferred embodiment of the present invention;

[17] FIG.7 and FIG.8 are cross-sectional view and a perspective view for explaining an example of forming a sub-drilling region and installing laggings in the underground earth retaining wall for public works according to a preferred embodiment of the present invention;

[18] FIG. 9 and FIG. 10 are cross-sectional view and a perspective view for explaining a different shape of a second connection member of the underground earth retaining wall for public works according to a preferred embodiment of the present invention;

[19] FIG. 11 and FIG. 12 are cross-sectional view and a perspective view for explaining other shape of the second connection member of the underground earth retaining wall for public works according to a preferred embodiment of the present invention;

[20] FIG. 13 is a cross-sectional view for explaining an underground connection member of the underground earth retaining wall for public works according to a preferred embodiment of the present invention;

[21] FIG. 14 is a perspective view showing a constitution of the underground earth retaining wall for public works according to a preferred different embodiment of the present invention;

[22] FIG. 15 is a view sequentially showing a method for constructing an underground earth retaining wall for public works according to FIG. 14; and

[23] FIG. 16 is a view for explaining an underground earth retaining wall for public works according to modified embodiment of the present embodiment. Best Mode for Carrying Out the Invention

[24] According to the characteristic of the present invention to achieve the above object, the present invention provides an underground earth retaining wall for public works, which is used to endure an outer force such as soil pressure, and the like, the earth retaining wall comprising a first pile array formed by continuously installing by socket a plurality of piles into ground around a drilling region in a predetermined interval; a second pile array formed by installing by socket a plurality of piles into ground around a drilling region in a predetermined interval at a predetermined position in the outward direction from the first pile array with respect to the drilling region; and a first connection member for connecting and securing the first pile array to the second pile array on the ground.

[25] In the underground earth retaining wall for public works of the present invention, the first connection member may include a first girth jointed in parallel to the plurality of piles constituting the first pile array, a second girth jointed in parallel to the plurality of piles constituting the second pile array, and a securing bar jointed to the first girth and the second girth at both ends thereof.

[26] The underground earth retaining wall for public works of the present invention may further include a second securing bar for connecting and securing the first pile array and the second pile array under the ground so that it is positioned at the lower side of the first connection member.

[27] The underground earth retaining wall for public works of the present invention may further include a sub lagging for defining a sub-drilling region communicating from the second pile array to the drilling region, which is disposed from the ground to a position of installing the second connection member, and installed at the second pile

array of the sub-drilling region.

[28] The underground earth retaining wall for public works of the present invention further includes an underground connection member installed by socket into the ground from the inside of the drilling region through the lagging jointed to the first pile array after the drilling of the drilling region.

[29] The underground earth retaining wall for public works of the present invention further includes an underground connection member installed by socket into the ground from the inside of the drilling region through the lagging jointed to the first pile array after the drilling of the drilling region, and jointed to the second pile array.

[30] In the underground earth retaining wall for public works of the present invention, the plurality of piles constituting the first pile array are installed by socket into the ground, so that each of them is inclined with respect to the drilling region.

[31] The underground earth retaining wall for public works of the present invention further includes a second securing bar for connecting and securing the first pile array and the second pile array under the ground so that it is positioned at the lower side of the first connection member.

[32] The underground earth retaining wall for public works of the present invention further includes a sub lagging for defining a sub-drilling region communicating from the second pile array to the drilling region, which extends from the ground to a position at which the second connection member is installed, and installed at the second pile array of the sub-drilling region.

[33] The underground earth retaining wall for public works of the present invention further includes an underground connection member installed by socket into the ground from the inside of the drilling region through the lagging jointed to the first pile array after the drilling of the drilling region.

[34] The underground earth retaining wall for public works of the present invention further includes an underground connection member installed by socket into the ground from the inside of the drilling region through the lagging jointed to the first pile array after the drilling of the drilling region, and jointed to the second pile array.

[35] According to another characteristic of the present invention to achieve the above object, the present invention provides a method for constructing an earth retaining wall for public works, which is used to construct the earth retaining wall for enduring outer force such as soil pressure, and the like, the method comprising the steps of forming a first pile array by continuously forming a plurality of boring holes around a drilling region in a predetermined interval, and installing a pile by socket into respective boring hole; forming a second pile array by continuously forming a plurality of boring holes around a drilling region in a predetermined interval, and installing a pile by socket into respective boring hole, at a predetermined position to the outward direction from the

first pile array with respect to the drilling region; and connecting and securing the first pile array to the second pile array by means of a first connection member on the ground, whereby the underground earth retaining wall is constructed by installing the first pile array and the second pile array around the drilling region to the outward direction with a predetermined interval, and then connecting them by the first connection member.

[36] The method for constructing an earth retaining wall for public works of the present invention further includes the step of connecting and securing the first pile array and the second pile array by means of a second connection member under the ground so that it is positioned below the first connection member in the course of the drilling of the drilling region.

[37] The method for constructing an earth retaining wall for public works of the present invention further includes the step of forming a sub-drilling region communicating from the second pile array to the drilling region, which extends from the ground to a position at which the second connection member is installed during the drilling of the drilling region.

[38] The method for constructing an earth retaining wall for public works of the present invention further includes the step of installing a sub lagging at the second pile array of the sub-drilling region.

[39] The method for constructing an earth retaining wall for public works of the present invention further includes the step of installing by socket an underground connection member from the inside of the drilling region to the ground through the lagging, after jointing the lagging to the first pile array when the drilling of the drilling region is completed.

[40] In the method for constructing an earth retaining wall for public works of the present invention, the step of forming the first pile array is executed so that a plurality of boring holes is formed to have an inclined angle toward the drilling region, and the pile is installed by socket into the ground so that it has an inclining angle toward the drilling region.

[41] According to still another characteristic of the present invention to achieve the above object, the present invention provides a method for constructing an earth retaining wall for public works, which is used to construct the earth retaining wall for enduring outer force such as soil pressure, and the like, comprising the steps of forming a first pile array by continuously forming a plurality of boring holes around a drilling region in a predetermined interval and installing a pile by socket into respective boring hole so that it is positioned below the ground by a predetermined depth; forming a second pile array by continuously forming a plurality of boring holes around the drilling region in a predetermined interval, and installing a pile by socket

into respective boring hole, at a predetermined position to the outward direction from the first pile array with respect to the drilling region; forming a sub-drilling region at the second pile array at the time of drilling the drilling region, so that it communicates with the drilling region by a depth coming to the top of the first pile array; and connecting and securing the first pile array to the second pile array by means of a first connection member on the ground, whereby the underground earth retaining wall is constructed by installing the first pile array and the second pile array around the drilling region to the outward direction with a predetermined interval, and then connecting them by the first connection member.

[42] FIG. 1 is a view for explaining the technical spirit of an underground earth retaining wall for public works according to the present invention, and FIG. 2 is a view for explaining the technical spirit of a method for constructing an underground earth retaining wall for public works according to the present invention.

[43] Referring to FIG. 1 and FIG. 2, the underground earth retaining wall and the method for constructing the same according to the present invention are provided to prevent the collapse of the earth and sand occurring at the time of the drilling of the cut-off surface or the underground during the roadwork, subway work and building new construction work, and the like.

[44] The underground earth retaining wall 10 for public works according to the present invention comprises a first pile array 20, a second pile array 30, and a first connection member 40.

[45] According to the present embodiment, the first pile array 20 is formed by installing a plurality of piles 22 by socket into the ground continuously by a predetermined interval around a drilling region. The second pile array 30 is also formed by installing a plurality of piles 22 by socket into the ground continuously in a predetermined interval around the drilling region at a predetermined position to the outward direction from the first pile array 20 with respect to the drilling region. The first connection member 40 connects and secures the first pile array 20 to the second pile array 30 on the ground. Here, the first connection member 40 comprises a first girth 42 jointed in parallel to the plurality of piles 22 constituting the first pile array 20, a second girth 44 jointed in parallel to the plurality of piles 32 constituting the second pile array 30, and a securing bar 46 jointed to the first girth 42 and the second girth 44 at both ends thereof. Of course, the first connection member 40 is installed by using various technologies used in the field of art for connecting and securing two structures installed with separated from each other.

[46] Referring to FIG. 1 and FIG. 2, the earth retaining wall 10 with the structure as described above, is formed through the construction method as described below. In other words, according to the method of constructing the underground earth retaining

wall for public works of the present invention, which is used to construct the earth retaining wall to endure the outer force such as the soil pressure, and the like, a plurality of boring holes 21 is formed continuously around the drilling region at a predetermined interval at first, and then piles 22 are installed into respective hole 21 by socket, thereby defining a first pile array 20. In addition, a plurality of boring holes 31 is continuously formed around the drilling region at a predetermined position to the outward direction from the first pile array 20 with respect to the drilling region, and then a plurality of piles 32 is installed into the boring holes 31 by socket, thereby forming the second pile array 30. In this instance, boring, installing by socket, or striking socket of the piles 22, 32 can be executed by using equipments for boring and installing by socket of the piles. Also, the order and method of executing the boring and installing by socket works of the piles to form the first pile array 20 and the second pile array 30 can be adjusted in consideration of the convenience of works. In addition, while the second pile array 30 is described to be disposed in only one array, which can be applied in general, in the detailed description of the present invention, it can be disposed in a plurality of arrays, if required, and it is not depart from the technical spirit of the present invention. Then, the first pile array 20 and the second pile array 30 are connected and secured by using the first connection member 40 on the ground, after the formation of the first pile array 20 and the second pile array 30, thereby forming the underground earth retaining wall of the present invention by disposing the first pile array 20 and the second pile array 30 around the drilling region to the outside direction with a predetermined interval, and connecting them by using the first connection member 40.

[47] Meanwhile, the ground, on which the first connection member 40 of the earth retaining wall 10 is installed, can be provided in various shapes in the present invention. For instance, the sub-drilling region is formed at the original ground, and the first connection member 40' is installed on the sub-drilling region in the modified embodiment (cf. FIG. 16) of the present invention. Mode for the Invention

[48] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to appending FIG. 3 to FIG. 16.

[49] Meanwhile, drawings and detailed description about the constitution, action and effect arising from the constitution, which can be easily discerned from the general earth retaining construction method and related technologies applied to the present invention, are briefly accomplished or omitted, and it is drawn with respect to the related parts of the present invention.

[50] FIG. 3 is a perspective view showing a constitution of the underground earth

retaining wall for public works according to a preferred embodiment of the present invention, and FIG. 4 is a view showing examples of laggings used in the construction of the underground earth retaining wall for public works according to a preferred embodiment of the present invention.

[51] Referring to FIG. 3 and FIG. 4, the earth retaining wall 10 according to a preferred embodiment of the present invention comprises a first pile array 20, a second pile array 30, a first connection member 40, and laggings 60 installed at the inside of a drilling region together with the drilling of the drilling region as is the conventional earth retaining wall.

[52] According to the present embodiment, the first pile array 20 is formed by installing a plurality of piles 22 by socket into the ground continuously by a predetermined interval around the drilling region. The second pile array 30 is also formed by installing a plurality of piles 32 by socket into the ground continuously by a predetermined interval around the drilling region at predetermined positions in the outward direction from the first pile array 20 with respect to the drilling region. The first connection member 40 connects and secures the first pile array 20 to the second pile array 30 on the ground. Here, the first connection member 40 comprises a first girth 42 jointed in parallel to the plurality of piles 22 constituting the first pile array 20, a second girth 44 jointed in parallel to the plurality of piles 32 constituting the second pile array 30, and a securing bar 46 jointed to the first girth 42 and the second girth 44 at both ends thereof. The first girth 42, the second girth 44, and the securing bar 46 of the first connection member 40 are generally jointed to each other by means of welding, bolts and the like, and are installed to be secured to the respective piles 22, 32 of the first and second pile arrays 20, 30 by using a bracket 48, and the like.

[53] Referring again to FIG. 3, brackets 48 are installed to respective piles 22, 32 of the first pile array 20 and the second pile array 30, and the first girth 42 and the second girth 44 are disposed on the brackets 48 and are locked by using bolts. The securing bar 46 is operated to joint the first girth 42, and the second girth 44 disposed along the first pile array 20 and the second pile array 30 to each other. In this instance, although it was not shown, a brace can also be installed to reinforce the binding force of the securing bar 46. As for the jointing method of the fist girth 42, the second girth 44, and the securing bar 46, while a bolt jointing method is generally used to dismantle the temporary construction and to achieve the convenience of construction, a jointing method such as welding, and the like can also be selected according to the field conditions and, if required.

[54] As shown in FIG. 4, the laggings 60 applied to the earth retaining wall 10 according to the present invention and the sub lagging 60' are selected from wooden lagging (a), a steel sheet (b), or a deck plate (c), and the like as one used generally.

[55] FIG. 5 and FIG. 6 are cross-sectional view and a perspective view for explaining an example of the underground earth retaining wall for public works according to a preferred embodiment of the present invention, FIG. 9 and FIG. 10 are cross-sectional view and a perspective view for explaining a different shape of a second connection member of the underground earth retaining wall for public works according to a preferred embodiment of the present invention, and FIG. 11 and FIG. 12 are cross- sectional view and a perspective view for explaining other shape of the second connection member of the underground earth retaining wall for public works according to a preferred embodiment of the present invention.

[56] Referring to FIG. 5, FIG. 6, and FIG. 9 to FIG. 12, the earth retaining wall 10 according to a preferred embodiment of the present invention, further comprises second connection members 50, 50', 50" for securing the first pile array 20 and the second pile array 30 at the lower side together with the first connection member 40 for securing the first pile array 20 and the second pile array 30 at the upper side. The second connect members 50, 50', 50" are secured by connecting the first pile array 20 and the second pile array 30 below the ground so that they are basically positioned below the first connection member 40. In this instance, the second connection members 50, 50', 50" can be disposed in the ground in the present embodiment, and also they can be disposed on the ground as described below when they form the sub- drilling region. Also, the second connection members 50, 50', 50" can be installed instantly at a region of installing the lagging 60 as is an underground connection member 70, which will be described below.

[57] Referring again to FIG. 5, FIG. 6, and FIG. 9 to FIG. 12, the second connection members 50, 50', 50" according to the present embodiment invention, can be constituted variously.

[58] For instance, as shown in FIG. 5 and FIG. 6, the second connection member 50 can be constructed of a horizontal girth 52 jointed to the first pile array 20, and a vertical girth 56, one side of which is jointed to the horizontal girth 52 by means of a support bracket 58, and the like, and the other side thereof is jointed to the second pile array 30. Also, as shown in FIG. 9 and FIG. 10, the second connection member 50' can be constructed of a holding beam 54 formed with hooking groove 55 and installed and secured at the second pile array 30, and a vertical bar 56' caught and jointed to the hooking groove 55 of the holding beam 54 by means of the horizontal girth 52'. In this instance, the vertical bar 56' has a stopper 57 caught by the holding beam 54 after it is installed by socket into the hooking groove 55 of the holding beam 54 and rotated. In addition, as shown in FIG.l 1 and FIG.12, the second connection member 50" can be constructed that holes 59 are formed at the piles 32 constituting the second pile array 30, and hooking grooves 55' are formed at the vertical bar 56' jointed to the holes

vertically, so that a locking bar 53 is installed by socket along the piles 32 from the ground so as to jointed to the hooking groove 55' of the vertical girth 56'. In practice, the earth retaining wall 10 shown in FIG. 5 and FIG. 6 is a form comprising the second connection member 50".

[59] FIG. 13 is a cross-sectional view for explaining an underground connection member of the underground earth retaining wall for public works according to a preferred embodiment of the present invention.

[60] Referring to FIG. 13, the earth retaining wall of the present embodiment employs an underground connection member 70 so that the constituting element of the earth retaining wall can be more firmly installed to the ground. Thus, the underground connection member 70 is installed by socket into the ground from the inside of the drilling region through the lagging 60 jointed to the first pile array 20 after the drilling of the drilling region, or can be installed by socket into the ground from the inside of the drilling region so as to be locked to the second pile array 30.

[61] Thus, it is possible to improve the deepness of the drilling because the second connection members 50, 50', 50" and the underground connection member 70 can be constructed to improve the binding of the first pile array 20 and the second pile array 30 to each other, and the constituting elements of the earth retaining wall 10 can be more strongly supported on the ground, so that more stable earth retaining wall structure can be formed.

[62] FIG.7 and FIG.8 are a cross-sectional view and a perspective view for explaining an example of forming a sub-drilling region and installing laggings in the underground earth retaining wall for public works according to a preferred embodiment of the present invention.

[63] Referring to FIG. 7 and FIG. 8, the earth retaining wall 10 according to the present embodiment, is provided with a sub-drilling region communicating from the second pile array 30 to the drilling region, in other words, from the ground to where the second connection member 50 is jointed, and sub laggings 60' installed at the second pile array 30. Thus, it is possible to reduce the effect of the soil pressure acting on the lower portion of the drilling region.

[64] FIG. 14 is a perspective view showing a constitution of an underground earth retaining wall for public works according to a preferred different embodiment of the present invention, and FIG. 15 is a view sequentially showing a method for constructing an underground earth retaining wall for public works according to FIG. 14.

[65] Referring to FIG. 14 and FIG. 15, the underground earth retaining wall 10 for public works according to other preferred embodiment of the present invention is constructed that a plurality of piles 22 constituting the first pile array 20 is installed by socket into the ground so that it is inclined toward a direction of the drilling region.

Thus, the earth retaining wall 10 can define more stable temporary construction earth retaining wall body, thereby increasing the drilling deepness, so that it becomes a construction method economic and more excellent at construction efficiency than any other existing temporary construction earth retaining wall construction method, thereby drastically reducing the expense used in the temporary construction. Instantly, the effect can be enhanced by applying the present invention to the preferred embodiments.

[66] Referring again to FIG. 14 and FIG. 15, the first pile array 20 is at first bored to form boring holes 21 by a predetermined interval along the inside drilling work line, and piles 22 are installed by socket therein, and the vacant spaces of the boring holes are filled compactly by using filling materials. Also, the second pile array 30, which is installed at the rear side of the first pile array 20 with spaced apart from by a predetermined interval, is bored to form holes 31 by a predetermined interval along the drilling work line, and then piles 32 are installed by socket therein, and the vacant spaces of the boring holes are compactly filled by using the filling materials. When the piles are installed by socket into the ground by boring (or, striking, pressure-fitting), the piles 22 (the boring holes 21' are formed identically) are generally vertically installed by socket, however, the piles of the first pile array 20 are installed to have a predetermined inclined angle (about 10°). Undoubtedly, the second pile array 30 can be constituted as described above. The fist pile array 20 and the second pile array 30 are in general installed in the ground by a predetermined interval of about two meters, and continuously worked along the drilling plan line. In this instance, the representative materials used for the piles 22, 32 can be suggested as an H-beam, which is very good at construction efficiency and economic efficiency, so that almost all of the consumers select it. Also, sand is used in general as filling materials to fill the vacant spaces of the boring holes after installing by socket the piles, however, mortar, and the like can be used instead. The filling can be primarily performed by using man-power, and the filling works can be complemented by using a vibration strengthening device. Then, the first pile array 20 and the second pile array 30 constructed as described above, are jointed together by using the first connection member 40. When the construction of the first connection member 40 is completed, soil and sand are removed by using the drilling device to a predetermined depth, and a sub lagging 60' is installed along the second pile array 30. The second connection member 50 is installed after the primary stage drilling. Also, after the installation of the second connection member 50, a connection reinforcing member for transversely connecting a front end of the first connection member 40 and a front end of the second connection member 50 can be installed to perform the additional reinforcement. Thus, after the primary stage drilling of the second array of piles 30, the drilling region is drilled on the basis of the first pile

array 20, and instantly the lagging 60 is sequentially installed along the first pile array 20, which is progressed as a secondary stage drilling work to the finally drilling planned height. Then, the earth retaining temporary construction work can be completed by constructing the underground connection member 70 installed by socket into the drilling rear side by boring through the sub lagging 60' or the lagging 60, after or in the course of the drilling works.

[67] FIG. 16 is a view for explaining an underground earth retaining wall for public works according to modified embodiment of the present embodiment.

[68] Referring to FIG. 16, the earth retaining wall 10 of the present invention is constructed to define the sub-drilling region in the original ground, and the first connection member 40' is installed on the sub-drilling region, thereby reducing the raw materials. In this regard, the construction process is progressed by continuously forming a plurality of boring holes around the drilling region by a predetermined interval, and then installing by socket the piles 22' into respective holes so that the piles 22' are disposed at positions below the ground by a predetermined depth to define the first pile array 20.

[69] Furthermore, a plurality of boring holes is continuously formed around the drilling region by a predetermined interval at a predetermined position outwardly from the first pile array with respect to the drilling region, and installs by socket the respective pile 32' into the boring holes to form the second pile array. Next, a sub-drilling region is formed to the second pile array so that it is communicated with the drilling region by a depth arriving at the top of the first pile array, when the drilling region is drilled. Also, the first pile array and the second pile array are connected and secured to each other by the first connection member 40' on the ground of the sub-drilling region.

[70] As described above, while the present underground earth retaining wall and the method for constructing the same according to the preferred embodiment of the present invention have been described in connection with the detailed description and the drawings, they are only illustrative purposes, and it should be understood by those skilled in the art that various modifications and changes can be made without departing from the scope of the technical spirit of the present invention. Industrial Applicability

[71] As described above, according to the underground earth retaining wall for public works and a method for constructing the same according to the present invention, the present invention improves several disadvantages of the existing temporary construction method such as the strut supporting construction method or the ground anchor construction method, and the like. In other words, the construction expense can be reduced, the construction period can be shortened, the construction work using the

heavy equipments in the drilling field becomes smooth, and the following scaffold works can be facilitated, thereby improving the construction efficiency, because the amount of the used steel sheet can be decreased due to no use of the strut. Further, it is possible to remove almost all of the construction limitations in the adjoining construction at the downtown area, and the like, because self-installation type temporary construction structure can be installed to solve the problem of intruding into adjoining area produced at the time of installing anchors into the ground, when the present invention is compared with the ground anchor construction method. In addition, when the present invention is compared with the existing temporary construction work, and the like, it is possible to reduce the damage of the adjoining structure due to drilling in comparison with the existing construction method by minimizing the ground sinking and the displacement, and make the deepness accomplished by the drilling deeper than before.