Open shield aircraft and its assembly method

Abstract

This invention provides an open shield machine and its assembly method that are cheaper than conventional open shield machines because they use temporary materials, have better assembly workability, and can be assembled and launched even in confined spaces because there is no need to construct a launch shaft. [Solution] The main body of the open shield machine 1 is formed by an earth retaining structure consisting of upper and lower support materials consisting of a bracing member 21 and a bracing member 22 assembled with bolts, a support member 24 that is vertically connected and fixed to the bracing member 21 by bolt assembly, and an earth retaining panel 20 that is installed on the outer surface of the bracing member via an attachment provided with multiple tapped holes, and a vertically downward-facing cutting edge 40 is installed on the earth retaining panel 20 along the lower end width direction.

Description

Technical Field

[0001] The present invention relates to an open shield machine used in an open shield method for constructing underground structures such as sewers and underpasses in urban areas, and a method for assembling the same.

Background Art

[0002] The open shield method is a rational method that combines the advantages of the excavation method (open cut method) and the shield method. In the construction of pipe laying works such as sewers, stormwater channels, and agricultural waterways, in soft and water-bearing ground, curved construction, and near houses, etc., where conventional methods are difficult to construct or costly, it minimizes the impact on the surrounding environment and enables safe and economical construction.

[0003] Although the outline is also described in the following patent documents, first, the open shield machine used in the open shield method will be described. As shown in FIG. 25, in the figure, 1 is an open shield machine, which consists of a front part 5 and a tail part 6 that fits to the rear end thereof. These are connected with the left and right side wall plates 1a as the main components by a bottom plate 1b made of a steel plate and beam members made of steel materials between them, opening the front, rear, and upper surfaces, forming the tip as a cutting edge 2, and arranging a plurality of propulsion jacks 3 side by side vertically backward from the front end of the tail part. A slidable slide type earth retaining plate 1c is provided at the tip of the side wall plate 1a.

Patent Document 1

[0004] In addition, these left and right side wall plates 1a, bottom plate 1b, and beam members made of steel materials are joined by welding or the like to assemble the open shield machine, and they are not simple and decomposable for assembly.

[0005] In the figure, 9 is a press bar that is appropriately suspended from above and arranged at the rear end of the propulsion jack 3, and is composed of a frame body using box steel or section steel. Also, in the figure, 8 is a partition wall that divides the front excavation part and the rear part inside the open shield machine 1.

[0006] The open shield machine 1 consists of a front section 5 and a tail section 6 in the longitudinal direction, with the front end of the tail section 6 fitted to the rear end of the front section 5.

[0007] In the diagram, 11 is a folding jack, and multiple units are arranged vertically on both the left and right sides to bend the front section 5 and the tail section 6 at the folding section 10.

[0008] The open shield construction method using the open shield machine 1 is a method for constructing underground structures between the launching shaft 12 and the receiving shaft. As shown in Figure 24, the open shield machine 1 is divided into several blocks and assembled inside the launching shaft 12.

[0009] Then, the ground in front of the launch shaft 12 is excavated with a shovel-type excavator 18 installed on the surface, the propulsion jacks 3 of the open shield machine 1 are extended to take reaction force from the reaction wall 13 inside the launch shaft 12 and the open shield machine 1 is advanced, the first concrete box body 4 that will form the underground structure is lowered from above and set behind the retracted propulsion jacks 3 inside the tail section of the open shield machine 1.

[0010] Although not shown in the diagram, struts are installed between the propulsion jack 3 and the reaction wall to adjust the spacing as needed.

[0011] Furthermore, the launch shaft 12 is composed of retaining sheet piles 14 such as sheet piles and shoring, and in order to launch the open shield machine 1, a portion of the retaining sheet piles 14 in front of the launch shaft 12 is cut, but if necessary, ground improvement may be carried out in the front part of the launch shaft 12 by grout injection or the like.

[0012] Next, the excavator 18 similarly excavates and removes soil from the front or top of the open shield machine 1, moves the open shield machine 1 forward, and lowers the second concrete box 4 into the tail section of the open shield machine 1 in front of the first concrete box 4.

[0013] When lowering the concrete box 4 into the tail section of the open shield machine 1, height adjustment materials such as concrete blocks are placed below the concrete box 4, and backfill grout 15 is injected as a primary filler into the gaps on the left, right, and bottom of the concrete box 4 within this tail section.

[0014] The same excavation and concrete box body 4 setting process is repeated, and the concrete box bodies 4 are sequentially buried in the ground in a vertical line. The concrete box bodies 4 are fastened together with PC steel bars 19, and then backfill grout material 15 is injected into the outer circumference of both side walls and the bottom slab of the concrete box bodies 4 through grout holes that have been pre-installed in the concrete box bodies 4.

[0015] Then, using bulldozers and shovels, backfill soil 16 is applied to the pre-laid concrete box structure 4 at the rear, and compacted with a vibratory roller or similar tool. Once the open shield machine 1 reaches the arrival shaft, it is disassembled and removed to complete the construction.

[0016] Furthermore, Patent Document 1 describes an open shield machine assembly method in which the open shield machine is divided vertically and assembled, the lower section of the open shield machine is assembled on the ground surface, steel panels are attached to the sides of the assembled lower section of the open shield machine, and with the lower section of the open shield machine supported by fastening brackets attached to the steel panels, the sides of the steel panels and the bottom of the lower section of the open shield machine are excavated to lower the lower section of the open shield machine together with the steel panels, the upper section of the open shield machine is assembled on the lower section of the open shield machine, and the steel panels are added on top and the lowering is repeated to complete the assembly of the open shield machine.

[0017] According to the aforementioned Patent Document 1, in locations where it is difficult or impossible to construct a launching shaft for assembling an open shield machine, it is possible to smoothly assemble and install it at a predetermined depth underground without constructing a launching shaft. [Overview of the project] [Problems that the invention aims to solve]

[0018] As mentioned above, even if the open shield machine is divided into multiple blocks, these blocks are assembled within the launch shaft.

[0019] Furthermore, while Patent Document 1 eliminates the need to construct a launching shaft for assembling the open shield machine, making it possible to implement the open shield method even in narrow spaces where a launching shaft cannot be constructed, the open shield machine is assembled by welding or the like, and is not suitable for disassembly and reuse.

[0020] The object of the present invention is to eliminate the disadvantages of the conventional example and to provide an open shield machine and its assembly method that is cheaper than conventional open shield machines because it uses temporary materials for earth retention, has good assembly workability, and does not require the construction of a launching shaft, so can be assembled and launched even in confined spaces. [Means for solving the problem]

[0021] To achieve the above objective, the present invention provides, firstly, as an open shield machine, The main features of this open shield machine are: firstly, the main body is formed of an earth retaining structure consisting of upper and lower tiers of support materials made of bracing and waling members assembled with bolts, support members vertically connected and fixed to the bracing members by bolt assembly, and earth retaining panels installed on the outer surface of the bracing members via attachments with multiple tapped holes, and the earth retaining panels are provided with vertically downward-facing cutting edges along the width direction of the lower end. Secondly, the earth retaining structure consists of a front section and a tail section connected thereto, with the connection between the front section and the tail section being a bendable section, with a bendable jack placed inside the front section to allow bending at the bendable section, and a propulsion jack placed inside the tail section. Thirdly, plates to prevent soil intrusion are installed on both sides of the bendable section and at both rear ends of the tail section. Fourthly, a bottom plate formed from the earth retaining panel and connecting plate is fixed with giraffe jacks connected to the sides of the lower bracing members of the front and tail sections of the open shield machine and corner pieces.

[0022] As an assembly method of an open shield machine, first, on the ground surface, a strut material is bolted vertically to the belly-up material of the upper and lower stage bolt-fastened support work composed of a belly-up material and a crossbeam material for each of the front part and the tail part, and is fixed by bolt fastening to the upper and lower stage belly-up materials of each of the front part and the tail part through a connecting material to a soil retaining panel having a cutting edge material installed at the lower end. While excavating the inside of the front part and the tail part with an excavator, the front part and the tail part are buried underground to a predetermined depth. A middle folding jack is disposed at the inner rear part of the front part, and a propulsion jack is disposed at the tail part. Second, when installing a bottom plate, a giraffe jack is fixed to the side part of the crossbeam material installed at the lower end parts of the front part and the tail part so as to be able to expand and contract in the vertical direction. A bottom plate member is attached to the lower ends of these giraffe jacks. The gist is to extend each of the giraffe jacks downward so that the plurality of bottom plate materials are in the same plane at a predetermined height position and to fix them with a corner piece installed beside the giraffe jack and the crossbeam material.

[0023] According to the present invention described in claim 1, the belly-up material, crossbeam material, strut material, soil retaining panel, and corner piece used for the front part and the tail part of the open shield machine are temporary materials, and a soil retaining structure is formed using leased items, so an open shield machine cheaper than the conventional open shield machine shown in the prior art can be made.

[0024] Moreover, since all assembly can be performed by bolt fastening without using welding, the workability of assembly is good, and it can be assembled simply and quickly.

[0025] Also, since they are temporary materials, they can be easily disassembled and reused after use. Since the belly-up material and the like are slender members, they are easy to transport and light in weight, so the workability during assembly or disassembly is also good.

[0026] Furthermore, an attachment provided with a plurality of tap holes at the upper and lower ends of the earth retaining panel is inserted, and a connecting plate provided with tap holes at a plurality of holes at the upper and lower ends and at locations abutting against the belly-up member at the lower stage is sandwiched between the earth retaining panels. Then, in accordance with the hole positions provided in advance in the belly-up members at the upper and lower parts of the front part and the tail part, bolts are inserted through the holes of the belly-up and screwed into the respective tap holes for fastening. Therefore, the earth retaining panel can be firmly fixed to the belly-up member.

[0027] According to the present invention described in claim 2, the belly-up member, the cross beam member, the support member, and the earth retaining panel form an open shield machine composed of the front part and the tail part as an earth retaining structure using leased items. Then, the folding jack and the propulsion jack are installed, and the open shield machine advances while taking reaction force from the rear laying casing to lay the casing. Therefore, the amount of use of members such as the belly-up member is only equivalent to the length of the open shield machine, and the amount of their use is small and economical.

[0028] According to the present invention described in claim 3, since the middle folding parts on both sides of the open shield machine are covered with earth and sand intrusion prevention plates, even when the open shield machine is advancing in a curve in addition to straight propulsion, earth and sand will not enter through the middle folding parts even if the middle folding parts open. Also, since an earth and sand intrusion prevention plate is installed at the rear end of the tail part, there is no risk of earth and sand entering through the gap between the rear end of the tail part and the nearest laid concrete casing.

[0029] According to the present invention described in claim 4, since the bottom plate composed of the earth retaining panel and the connecting plate is installed and fixed to the open shield machine with a plurality of jacks and corner pieces to which the cross beam member is connected, even if the construction site is soft ground, the weight of the open shield machine can be received by the entire bottom plate. Therefore, settlement that may occur due to the weight of the open shield machine can be suppressed.

[0030] According to the present invention as described in claim 5, the parts of the open shield machine, excluding the propulsion jacks, folding jacks, and bottom plate, are assembled on the ground surface, and then the open shield machine is sunk to a predetermined depth while excavating the inside of the open shield machine with an excavator. Therefore, there is no need to construct a launching shaft for assembling the conventional open shield machine as shown in the prior art.

[0031] Therefore, open shield machines can be assembled even in narrow spaces where houses and other structures are close together, and where it is not possible to construct a launching shaft.

[0032] According to the present invention as described in claim 6, when installing the base plate, multiple base plate materials can be easily installed by using a giraffe jack so that they are on the same plane at a predetermined height. [Effects of the Invention]

[0033] As described above, the open shield machine and its assembly method of the present invention use temporary materials for earth retention, making them less expensive than conventional open shield machines, improving assembly workability, and eliminating the need to construct a launching shaft, thus enabling assembly and launching even in confined spaces. [Brief explanation of the drawing]

[0034] [Figure 1] This is a front perspective view showing a first embodiment of the open shield machine of the present invention. [Figure 2] This is a rearward perspective view showing a first embodiment of the open shield machine of the present invention. [Figure 3] This is a diagram showing the construction process as viewed from the front using the open shield machine of the present invention. [Figure 4] This is a diagram showing the construction process using the open shield machine of the present invention, viewed from the rear. [Figure 5] This is an explanatory diagram showing the first step of the assembly method for the open shield machine of the present invention. [Figure 6] This is an explanatory diagram showing the second step of the assembly method for the open shield machine of the present invention. [Figure 7] This is a detailed diagram showing the upper mounting of the earth retaining panel for the open shield machine of the present invention. [Figure 8] This is a detailed diagram showing the lower part of the simple earth retaining panel for the open shield machine of the present invention. [Figure 9] This is a detailed diagram showing the installation of the soil and sand intrusion prevention plate in the folded section of the open shield machine of the present invention. [Figure 10] This is an explanatory diagram showing the third step in the assembly method of the open shield machine according to the present invention. [Figure 11] This is an explanatory diagram showing the fourth step in the assembly method of the open shield machine according to the present invention. [Figure 12] This is an enlarged rear perspective view of the open shield machine of the present invention. [Figure 13] This is a front perspective view showing a second embodiment of the open shield machine of the present invention. [Figure 14] This is a rearward perspective view of the open shield machine of the present invention, showing a second embodiment of the open shield machine of the present invention. [Figure 15] This is a diagram showing the construction process using the open shield machine of the present invention, viewed from the front. [Figure 16] This is a diagram showing the construction process as viewed from the rear using the open shield machine of the present invention. [Figure 17] This is an explanatory diagram showing the first step of the assembly method for the open shield machine of the present invention. [Figure 18] This is an explanatory diagram showing the second step of the assembly method for the open shield machine of the present invention. [Figure 19] This is an explanatory diagram showing the third step in the assembly method of the open shield machine according to the present invention. [Figure 20] This is an explanatory diagram showing the fourth step in the assembly method of the open shield machine according to the present invention. [Figure 21] This is an explanatory diagram showing the overall situation of the fourth step in the assembly method of the open shield machine of the present invention. [Figure 22] This is an explanatory diagram showing the fifth step in the assembly method of the open shield machine according to the present invention. [Figure 23]This is an explanatory diagram showing the sixth step in the assembly method of the open shield machine according to the present invention. [Figure 24] This is a diagram showing the construction process using a conventional open shield machine. [Figure 25] This is a perspective view of a conventional open shield machine. [Modes for carrying out the invention]

[0035] The embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is a front perspective view showing a first embodiment of the open shield machine of the present invention, and Figure 2 is a rear perspective view of the same, where 1 is the open shield machine.

[0036] Each open shield unit consists of a front section 5 and a tail section 6, with the front end of the tail section 6 connected to the rear end of the front section 5.

[0037] Inside the front section 5 and the tail section 6, there are two levels of support structures, upper and lower, made of bracing members 21 and cross bracing members 22, respectively. Support members 24 are connected to the upper and lower bracing members 21, and each connection point is firmly fixed with corner pieces 23.

[0038] These bracing members 21, cross bracing members 22, support members 24, and corner pieces 23 are temporary materials for retaining the earthworks, and are provided with through holes for inserting bolts and nuts. Although not shown in the illustration, they are joined together by fastening bolts and nuts.

[0039] A retaining wall structure is formed by installing connecting plates 31 and retaining panels 20 on the outer surfaces of the upper and lower waling members 21 for leasing. Note that the waling members 21, bracing members 22, support members 24, corner pieces 23, and retaining panels 20 can all be leased components.

[0040] The connection between the front section 5 and the tail section 6 is a folding section 10, and folding jacks 11 are arranged in vertical rows extending from near the left and right rear ends of the front section 5 toward the rear. By selecting several of these folding jacks 11 from the left and right sides and contacting the member at the front end of the tail section with a difference in the extension of the left and right folding jacks 11, the folding section 10 bends, and the front section 5 can be turned in either the left or right direction. Therefore, by operating these folding jacks, the open shield machine can be propelled in a curved path.

[0041] Propulsion jacks 3 are arranged in vertical vertical columns on the left and right sides, extending from the front end of the tail section 6 towards the rear.

[0042] Although not shown in the diagram, concrete box bodies 4 are laid behind the tail section 6. By selecting and extending multiple propulsion jacks 3 and contacting the leading edge concrete box body 4 of the laid concrete box bodies 4, the open shield machine 1 can be propelled forward by obtaining a propulsion reaction force from the concrete box bodies 4.

[0043] A sand and debris intrusion prevention plate 25 is installed in the bent section 10, and a sand and debris intrusion prevention plate 26 is also installed at the rear end of the tail section 6. The sand and debris intrusion prevention plate 26 installed at the rear end of the tail 6 is usually made of a flexible, rigid rubber sheet.

[0044] In the construction of the open shield tunneling method using the open shield machine 1, as shown in Figures 3 and 4, an excavator 18 is placed in front of the open shield machine 1, a dump truck 35 for removing excavated soil is placed behind it, a lifting machine 17 such as a rough terrain crane is placed behind the shield machine, and a concrete box transport truck 34 is placed behind that.

[0045] As shown in Figures 5 to 8, the first step is to lay out the support frames 33 at predetermined positions and intervals on the ground surface at the launch position of the open shield machine 1. Then, at the positions that will become the front section 5 and tail section 6 of the open shield machine 1, the bracing members 21 are placed on the support frames 33 so as to face each other in the width direction of the open shield machine 1, and the bracing members 22 are connected to the bracing members 21 at predetermined positions and intervals to assemble the lower support structure.

[0046] Next, the support members 24 are erected on the waling members 21 at the positions where the bracing members 22 are connected. Then, after assembling the upper shoring using the waling members 21 and bracing members 22, corner pieces 23 are installed at each connection point between the waling members 22, the bracing members 22, and the support members 24. The members are fastened and secured with bolts (and nuts) 30.

[0047] As the second step, as shown in Figure 6, earth retaining panels 20, which have box steel members 21-a installed at both ends, are installed vertically on both outer surfaces of the bracing members 21 of the upper and lower shoring, and the earth retaining panels 20 are installed in contact with the outer surfaces of the bracing members 21 via connecting plates 31.

[0048] Figures 7 and 8 show details of the attachment of the retaining wall panel 20 to the upper and lower parts. In the figures, 20 is the retaining wall panel, and box steel members 20-a are installed at the upper and lower ends of the retaining wall panel 20. Multiple tapped holes 28 are provided in the attachment 27.

[0049] In the figure, 31 is a connecting plate, with elongated holes 32 at its upper and lower ends, and multiple tapped holes 28 at the contact points between the connecting plate 31 and the lower bracing member 21.

[0050] The attachments 27 are pre-inserted into the box steel members 20-a at the upper and lower ends of the earth retaining panel 20. The connecting plate 31 is sandwiched between the earth retaining panel 20 and the outer surface of the waling 21, and the bolts 30 are inserted from the waling side and tightened to secure it, so that the tapped holes 28, the elongated holes 32 and the holes in the waling 21 are aligned. In this way, the earth retaining panel 20 can be firmly fixed to the waling 21.

[0051] Alternatively, instead of using tapped holes 28, the attachment material 27 may have holes provided in it, and nuts may be welded to the back of the attachment material 27 at the positions of the holes.

[0052] Figure 9 shows the installation of the soil intrusion prevention plate 25 at the folded section 10. The soil intrusion prevention plate 25 is installed by inserting an attachment 27 with tapped holes 28 into the box steel member 20-a of the retaining panel 20, inserting bolts 30 through holes in the bracing 21, and inserting them through the elongated holes 32 of the soil intrusion prevention plate 25 up to the tapped holes 28, and tightening the bolts 30 to firmly fix the soil intrusion prevention plate 25.

[0053] As shown in Figure 10, the third step involves excavating and removing soil from the inside of the open shield machine 1 with an excavator 18 while sinking the open shield machine 1 to a predetermined depth underground. Although not shown in the figure, manual excavation may also be used depending on the location of the internal excavation and the ground conditions.

[0054] As the fourth step, as shown in Figure 11, after the open shield machine was submerged to a predetermined depth, multiple folding jacks 11 were arranged in vertical columns from near the inner left and right rear ends of the front section 5 toward the rear, and multiple propulsion jacks 3 were arranged in vertical columns on the left and right sides toward the rear from the inner front end of the tail section 6.

[0055] Furthermore, a sand and debris intrusion prevention plate 26 was installed on the support member 24 at the rear end of the tail section 6.

[0056] As shown in Figure 12, the soil and sand intrusion prevention material 26 is fixed to both support members 24 at the rear end of the tail section 6 with bolts 30.

[0057] Figures 13 and 14 show a second embodiment of the present invention, in which 31 is a connecting plate which is one of the components that make up the bottom plate of the open shield machine.

[0058] Since the assembly process is the same as in the first embodiment except for the assembly of the base plate, the assembly of the base plate will be explained with reference to Figures 20 to 23.

[0059] In Figure 20, 20 is a retaining wall panel, 20-a is a box-shaped steel member installed on the retaining wall panel 20, and an attachment member 27 with tapped holes 28 is inserted into the box-shaped steel member 20-a.

[0060] In the figure, 31 is a connecting plate, which connects the earth retaining panel 20 to the plate that prevents soil and sand from entering from the bottom of the folded section. The connecting plate is also provided with tapped holes 28 so that it can be connected to the bottom of the giraffe jack 29. The bottom plate of the open shield machine 1 is made up of these components. 38 is a retaining plate that spans and connects the bottom plates.

[0061] In the diagram, 29 is a giraffe jack, of which multiple are installed horizontally on the bracing member 22. The lower end of the giraffe jack 29 is extended vertically downward to adjust each of the predetermined base plates so that they are on the same plane in height. The base plates are then fixed to the corner piece 23, which is fixed horizontally on the bracing member 22, just like the giraffe jack 29 connected horizontally on the bracing member 22.

[0062] The fifth step of the assembly method is shown in Figures 22 and 23. After the installation of the base plate is complete, the temporary bracing member 22-a and the giraffe jack 29 fixed to it, which are installed at the rear end of the tail section 6 as shown in Figure 20, are removed because they would interfere with the installation of the concrete box body 4 on the tail section 6. [Explanation of Symbols]

[0063] 1…Open shield aircraft 1a...Side wall plate 1b...Bottom plate 1c...Sliding retaining board 2...Blade opening 3...Propulsion jack 4...Concrete box 5...Front section 6...Tail section 9... Press bar 10... Folding section 11... Articulated jack 12... Launch shaft 13…Reaction wall 14…Sheet pile retaining wall 15…Backfilling injection material 16…Backfilling soil 17…Lifting machine 18…Excavator 19...PC steel bars 20...Earth retaining panels 20-a...Box steel frame 21...Walking material 22... Bracing material 22-a... Temporary bracing material 23...Corner piece 24...Support post 25…Soil and debris intrusion prevention plate (folded section) 26... Soil and debris intrusion prevention board 27...Attachment material 28...Tap hole 29... Giraffe jack 30... Bolts and nuts 31...Connecting plate 32...Slong hole 33...Support structure 34...Concrete box transport truck 35…Dump truck for transporting excavated soil 37…Grout hole 38…Retaining plate 39... Slotted holes (slotted holes in the box steel members of the earth retaining panel 20) 40...Blade tip

Claims

1. An open shield machine is characterized by forming the main body of the open shield machine with an earth retaining structure consisting of upper and lower support materials made of bracing members and cross bracing members assembled with bolts, support members that are vertically connected and fixed to the bracing members by bolt assembly, and earth retaining panels that are installed on the outer surface of the bracing members via attachments that have multiple tapped holes, and having vertically downward-facing cutting edges installed along the lower end width direction on the earth retaining panels.

2. The earth retaining structure comprises a front section and a tail section connected thereto, the connection between the front section and the tail section is a bendable section, a bendable jack is provided inside the front section to allow bending at the bendable section, and a propulsion jack is provided inside the tail section, as described in claim 1.

3. The open shield machine according to claim 2, wherein soil and sand intrusion prevention plates are installed on both sides of the folded section and on both rear ends of the tail section.

4. An open shield machine according to claim 2 or claim 3, wherein the bottom plate formed from earth retaining panels and connecting plates is fixed with giraffe jacks and corner pieces connected to the sides of the lower bracing members of the front and tail sections of the open shield machine.

5. On the ground surface, at the front and tail sections, vertical support members are bolted to the waling members of the upper and lower bolted shoring system, which consists of waling members and bracing members, and the retaining panels, which have cutting edge members installed at their lower ends, are fixed to the upper and lower waling members of the front and tail sections via connecting members and bolted to each. An assembly method for an open shield machine, characterized by excavating the interior of the front and tail sections with an excavator, sinking the front and tail sections into the ground to a predetermined depth, installing a folding jack in the inner rear part of the front section, and installing a propulsion jack in the tail section.

6. The assembly method for an open shield machine according to claim 5, wherein when installing the bottom plate, giraffe jacks are fixed to the sides of the bracing members installed at the lower ends of the front and tail sections so as to be able to extend and retract vertically, a bottom plate member is attached to the lower ends of the giraffe jacks, each of the giraffe jacks is extended downward so that the multiple bottom plate members are on the same plane at a predetermined height, and the giraffe jacks are fixed with corner pieces installed next to the bracing members.

Images