Method for constructing earth retaining structures using steel shell elements
By penetrating and connecting steel shell elements with pre-drilled joints and filling with concrete, the method addresses stability issues in conventional earth retaining methods, creating a rigid and high-quality structure that minimizes ground deformation and collapse.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TODA CORP
- Filing Date
- 2022-04-28
- Publication Date
- 2026-05-11
AI Technical Summary
Conventional earth retaining methods, such as the diaphragm wall method, face challenges in maintaining the stability of the groove wall, particularly in soft or permeable grounds, leading to ground deformation and collapse, and require high-quality structures near important infrastructure like subway lines.
The method involves sequentially penetrating multiple steel shell elements into the ground, connecting them with pre-drilled joints, using earth anchors for reaction force, and filling with concrete to form a rigid retaining structure, with stress members and grout material to enhance rigidity and watertightness.
This approach suppresses ground deformation, prevents collapse of the excavation wall, and constructs a high-quality, rigid earth retaining structure suitable for proximity to important structures.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an earth retaining structure using steel shell elements formed by sequentially penetrating steel shell elements while connecting them downward to the ground with the penetrated steel shell elements, and a construction method thereof.
Background Art
[0002] Conventionally, as one of the earth retaining (mountain retaining) methods for constructing an open-cut tunnel, a shaft, or the underground part of a building, the diaphragm wall method is known. In the case of large-scale excavation, the diaphragm wall method involves excavating in a groove shape (trench excavation) while maintaining the stability of the groove wall using a stabilizing fluid such as bentonite, and after the excavation is completed, building a core material such as a steel cage or H-shaped steel into the groove and placing concrete while replacing the stabilizing fluid to construct a continuous reinforced concrete wall (RC diaphragm wall) in the ground (for example, Patent Documents 1 and 2 below).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Patent Document 2
Patent Document 3
Summary of the Invention
Problems to be Solved by the Invention
[0004] However, in the above-described diaphragm wall method, after the trench excavation is performed first, the groove wall of this excavation trench is left in the excavated state until the excavation trench is filled with concrete. Therefore, in a ground where it is difficult to maintain the stability of the groove wall, such as a soft ground, a ground with a small uniformity coefficient, or a gravel-mixed ground, there is a risk of ground deformation such as the collapse of the groove wall surface.
[0005] Furthermore, in the aforementioned continuous underground wall construction method, in highly permeable ground such as sandy or gravelly soil, the stabilizing fluid tends to leak out, making it difficult to maintain the water level of the stabilizing fluid. As a result, the water pressure decreases due to the drop in the water level of the stabilizing fluid, which makes the trench wall prone to collapse.
[0006] When constructing underground structures in close proximity to important structures such as subway lines and stations, a higher-quality earth retention structure than the aforementioned continuous underground wall was desired.
[0007] Incidentally, in the above-mentioned Patent Document 3, the applicant proposed a joint structure for steel shell elements used when constructing an underground structure by sequentially penetrating steel shell elements while connecting them with pre-penetrated steel shell elements.
[0008] Patent Document 3, mentioned above, describes a joint structure suitable for steel shell elements used in a rectangular steel pipe jacking method, which constructs an underground structure by closing multiple steel shell elements in a rectangular, circular, or irregular shape in cross-section in the ground beneath road lines, railway lines, etc., without excavation, and then constructs an underpass tunnel by excavating the soil inside. The present invention applies this technology to construct an earth retaining structure.
[0009] Therefore, the main objective of the present invention is to suppress ground deformation and to provide a highly rigid and high-quality earth retaining structure. construction The objective is to provide a method for construction. [Means for solving the problem]
[0010] To solve the aforementioned problems, the present invention according to claim 1 involves sequentially penetrating multiple steel shell elements downward into the ground, connecting them with already penetrated steel shell elements, thereby enabling multiple steel shell elements Penetration direction Multiple rows of steel shell elements connected to each other are arranged in parallel. A method for constructing an earth retaining structure using the aforementioned steel shell element, Earth anchoring work involves installing earth anchors near the area where the earth retaining structure is planned to be constructed, The steel shell elements are provided with joints to sequentially connect the steel shell elements that have already been penetrated, and by pre-drilling the planned penetration area of the joints, the in-situ ground in the planned penetration area is loosened and relaxed without completely removing the in-situ soil, and The system is equipped with a thruster that excavates the tip when the steel shell element is penetrated, and a push jack that secures reaction force with the earth anchor is installed on the launching side, and the steel shell element is sequentially driven into the thruster at the tip in a standard element construction process, A push jack with a reaction force secured by the aforementioned earth anchor is installed on the launching side, and the subsequent element installation is carried out by sequentially attaching the steel shell elements to the thrusting machine at the tip, connecting them with the already-attached steel shell elements as they penetrate, An element-inter-element soil removal work for removing soil between the aforementioned steel shell elements, A stress member installation method is used to install stress members within the steel shell element, at a location that bears the stress of the earth retaining structure, and along one side and the other side of the earth retaining structure, extending a portion or the entire length of the penetration direction of the steel shell element. A concrete filling process for filling the inside of the steel shell element and the spaces between the steel shell elements with concrete, A method for constructing an earth retaining structure using a steel shell element, characterized by including the element. is provided.
[0011] In the invention according to claim 1 above, since a plurality of steel shell elements are penetrated into the ground to construct a retaining structure, when penetrating into the ground, if the steel shell element is penetrated following the propulsion machine at the tip, unlike the conventional diaphragm wall method, the grooved wall is not left in the excavated state, ground deformation can be suppressed, and collapse of the grooved wall does not occur. Further, by filling the penetrated steel shell element with concrete and integrating them, a retaining structure with high rigidity and high quality can be obtained.
[0012] In the invention according to the above claim 1 before penetrating the steel shell element, by previously drilling the planned penetration area of the joint part, the earth and sand in the planned penetration area of the joint part are loosened, and the penetration resistance of the joint part when the steel shell element is penetrated is suppressed.
[0013] In the invention according to the above claim 1 by building a stress member inside the steel shell element and then filling it with concrete, a retaining structure with even higher rigidity and higher quality can be obtained.
[0014] As the invention according to claim 2 a retaining structure using the steel shell element according to claim 1, in which the joints between the steel shell elements adjacent in the penetration direction in the adjacent steel shell element rows are provided at different positions with respect to the penetration direction The aforementioned is provided. How to build it is provided.
[0015] In the invention according to the above claim 2 for further increasing the rigidity and improving the quality of the retaining structure, in the adjacent steel shell element rows, the joints of the steel shell elements are provided at different positions with respect to the penetration direction.
[0016] Claim 3As the invention according to the above, after the earth and sand removal work between the elements, a grout material filling work inside the joint part for filling the grout material into the joint part is provided, the construction method of the earth retaining structure using the steel shell element described in claim 1 is provided.
[0017] In the invention described in the above claim 3 by filling the grout material into the joint part, the strength and water stop property of the joint part are ensured.
[0018] As the invention according to claim 4 the propulsion machine, after the completion of excavation, at least leaves the skin plate at the lower end of the earth retaining structure and Other than the aforementioned skin plate inside reclaims it, the construction method of the earth retaining structure using the steel shell element described in claim as much as possible is provided. 1 In the invention described in the above claim
[0019] In the invention described in the above claim 4 after the completion of excavation of the propulsion machine, the skin plate of the propulsion machine is left at the lower end of the earth retaining structure and at least reclaimed, so the reclaimed Other than the aforementioned skin plate inside can be reused for the propulsion machine in subsequent excavations. as much as possible Other than skin plates
Effect of the Invention
[0020] As described in detail above, according to the present invention, ground deformation can be suppressed, and a construction method for a high-rigidity and high-quality earth retaining structure construction can be provided.
Brief Description of the Drawings
[0021] <x [Figure 1] It is a plan view of the earth retaining structure 1 according to the present invention. [Figure 2] It is a front view thereof. [Figure 3] It is a cross-sectional view during propulsion construction. [Figure 4] It is a perspective view showing the steel shell element 2. [Figure 5]This is a cross-sectional view of joint J. [Figure 6] This is a cross-sectional view of the concave joint 23. [Figure 7] This is a plan view showing the earth anchor installation. [Figure 8] This is a cross-sectional view showing the earth anchoring work (viewed along the line VIII-VIII in Figure 7). [Figure 9] This is a plan view showing the pre-drilling work at the joint. [Figure 10] This is a cross-sectional view showing the pre-drilling work at the joint (viewed along line XX in Figure 9). [Figure 11] This is a plan view showing the installation of the standard element. [Figure 12] This is a cross-sectional view showing the installation of the standard element (viewed along the line XII-XII in Figure 11). [Figure 13] This is a plan view showing the construction of the subsequent elements. [Figure 14] This is a cross-sectional view showing the construction of the subsequent element (viewed along the line XIV-XIV in Figure 13). [Figure 15] This is a plan view showing the removal of sediment between elements. [Figure 16] This is a cross-sectional view showing the removal of sediment between elements (viewed along the line XVI-XVI in Figure 15). [Figure 17] This is a plan view showing the grout filling process inside the joint. [Figure 18] This is an enlarged cross-sectional view of joint J. [Figure 19] This is a plan view showing the concrete filling process. [Figure 20] This is a cross-sectional view showing the concrete filling process (viewed along the line XX-XX in Figure 19). [Modes for carrying out the invention]
[0022] Embodiments of the present invention will be described in detail below with reference to the drawings.
[0023] As shown in Figure 1, the earth retaining structure 1 according to the present invention is an earth retaining wall constructed in close proximity to important underground structures such as subway lines and stations, in order to minimize the amount of ground displacement. It is constructed by connecting multiple steel shell elements 2 to each other from the ground surface to a predetermined depth into the ground.
[0024] As shown in Figures 1 to 3, the earth retaining structure 1 is constructed by sequentially penetrating multiple steel shell elements 2 downwards into the ground, connecting them with the already penetrated steel shell elements 2, thereby creating a structure with multiple steel shell elements 2. Penetration direction Multiple rows of steel shell elements 3 connected to each other form a parallel structure. That is, multiple steel shell elements 2 are arranged downward from the ground surface into the ground. Penetration direction A wall is formed by connecting to a steel shell element row 3 extending to a predetermined depth, and arranging multiple such steel shell element rows 3 in parallel in the horizontal direction while connecting them to each other.
[0025] To penetrate the steel shell element 2 into the ground, as shown in Figure 3, a push jack 5, which has a reaction force secured by an earth anchor 4 driven deep into the ground near the planned construction area of the earth retaining structure 1, is installed on the starting side, and the steel shell element 2 is driven behind the thruster 6 at the tip. In this way, the excavation wall is covered by the following steel shell element 2 immediately after excavation by the thruster 6, so the excavation wall is not left in an excavated state, ground deformation can be suppressed, and the collapse of the trench wall will not occur.
[0026] Furthermore, since concrete is filled inside the penetrated steel shell element 2 and between adjacent steel shell elements 2, 2, and integrated, a highly rigid and high-quality earth retaining structure can be obtained.
[0027] As the steel shell element 2, the one described in Patent Document 3 (Japanese Patent Publication No. 2015-71904) can be suitably used. Specifically, as shown in Figure 4, the steel shell element 2 is a rectangular cross-section element composed of an upper plate 20, a lower plate 21, and side plates 22, 22. In this steel shell element 2, the upper plate 20 or the lower plate 21 is positioned facing either the important structure side or the opposite side. Furthermore, the upper plate 20 and the lower plate 21 each extend outward from the side plates 22 on both sides, and a concave joint 23 is provided at the end of one side, and a convex joint 24 is provided at the end of the other side. In addition, a plurality of annular ribs 38 with a predetermined height are provided on the inner surface of the steel shell element 2 at appropriate intervals along the circumferential direction.
[0028] As shown in Figure 5, the joint J of the steel shell elements 2, 2 is a joint structure for sequentially connecting the steel shell elements 2 to the already penetrated steel shell elements 2, and consists of a connection structure of a concave joint 23 provided on one adjacent steel shell element 2 and a convex joint 24 provided on the other steel shell element 2.
[0029] As shown in Figure 6, the recessed joint 23 consists of a recessed joint body 35 that extends along the entire axial length of the steel shell element 2 and has a groove 25 that extends along the axial direction, and locking parts 27, 27 that protrude from both sides within the groove 25, and a water-sealing part 26 that closes a slit-shaped opening along the axial direction of the groove 25.
[0030] The recessed joint body 35 is made of cast steel or hot-pressed steel and has a substantially U-shaped cross-section. The groove 25 is formed along the longitudinal direction of the member, and end openings of the groove 25 are formed on both ends in the longitudinal direction of the member. A slit-shaped opening of the groove 25 extending along the longitudinal direction of the member is formed on the end face toward the adjacent steel shell element 2. By constructing it from cast iron or hot-pressed steel, the load-bearing capacity of the recessed joint 23 can be improved, manufacturing costs can be reduced, and manufacturability can be improved.
[0031] The water-stopping portion 26 is formed by leaf spring-shaped packings 28, 28 that extend from at least both sides of the slit-shaped opening of the groove portion 25 toward the center of the opening.
[0032] The packing 28, in cross-sectional view, is composed of two bent plate-like bodies, each approximately 0.3 mm thick, that extend from both sides of the concave joint body 35 toward the center of the slit-shaped opening of the groove 25, and are bent toward the inward side of the groove 25 at an intermediate position. The outer end is fixed to the concave joint body 35 side, and the opening side is a free end, thus acting as a leaf spring. The free ends of the packings 28, 28 are arranged to abut against each other at approximately the center position in the groove width direction of the groove 25. By bending the packings 28, 28 toward the inward side of the groove 25, when the concave joint 23 and the convex joint 24 are fitted together, the packings 28, 28 expand toward the inward side of the groove 25.
[0033] As shown in Figure 6, on the outside of the packings 28, 28, there are further leaf spring-shaped auxiliary packings 29, 29' that extend from both sides of the slit-shaped opening of the groove 25 toward the center of the opening. Thus, the water-stopping portion 26 is composed of a double packing 30 consisting of the inner packing 28 and the outer auxiliary packings 29, 29'.
[0034] As shown in Figure 6, the inner packing 28 and the outer auxiliary packings 29 and 29' are fixed to the recessed joint 23 body by bolts 33 via spacers 31 disposed between each packing and retaining brackets 32 disposed on the outside of the auxiliary packings 29 and 29'. The inner side of the spacer 31 is provided so as to protrude inward from the side wall surface on the slit-shaped opening side of the groove 25, and preferably extends to the bending position of the packing 28 which is bent in the middle.
[0035] The auxiliary packings 29 and 29' are composed of two plate-like bodies, each approximately 0.3 mm thick, that extend almost linearly from both sides of the recessed joint body 35 toward the center of the slit-shaped opening of the groove 25 in a cross-sectional view. The outer ends are fixed to the recessed joint body 35, and the opening side is the free end, thus acting as a leaf spring. The auxiliary packings 29 and 29' are provided with an overlap at the center of the slit-shaped opening of the groove 25. Of the auxiliary packings 29 and 29', the free end of the auxiliary packing 29 positioned on the outside in the overlap portion extends further outward than the other auxiliary packing 29' positioned on the inside in the overlap portion, and is supported by the tip of the spacer 31 fixed to the opposing side wall via the groove 25, thereby improving resistance to external pressure.
[0036] On the other hand, the other auxiliary packing 29' positioned on the inside in the overlapping portion is formed to be shorter than the other auxiliary packing 29, preferably extending to a position slightly beyond the center of the groove width, so as not to interfere with the outer auxiliary packing 29 and prevent the convex joint 24 from being unable to expand when it is fitted.
[0037] As shown in Figure 6, it is desirable to fill the space between the double packing 30, which consists of the packings 28, 28 and the auxiliary packings 29, 29', with a watertight seal 34. It is preferable to use an oil-based watertight seal with high durability against high water pressure as the watertight seal 34, and in particular, Tail Sealer (registered trademark, manufactured by Matsumura Petrochemical Co., Ltd.), which is used to prevent groundwater and backfill material from entering between the wire brushes of a shield machine, is suitable. The watertight seal 34 functions as a lubricant when the protruding portion 36 of the convex joint 24, which will be described later, is inserted when the concave joint 23 and the convex joint 24 are fitted together, and functions as a watertight material after fitting is complete.
[0038] As shown in Figure 5, the concave joint 23 is provided with anti-opening bolts 38 that connect both side walls across the groove 25 to prevent the groove 25 from opening after fitting with the convex joint 24.
[0039] On the other hand, as shown in Figure 5, the convex joint 24 is provided with a flat plate-shaped protrusion 36 that extends laterally from the side plate 22 of the steel shell element 2, and the tip of this protrusion 36 is provided with projections 37 that protrude on both sides in the thickness direction of the protrusion 36.
[0040] As shown in Figure 5, when the concave joint 23 and the convex joint 24 are fitted together, the protruding portion 36 of the convex joint 24 is inserted from the upper end opening of the groove 25, and the packings 28, 28 and auxiliary packings 29, 29' are each expanded and fitted between the packings 30 on both sides, and the projection 37 is inserted further inward than the locking portion 27 of the groove 25. With the projection 36 fitted, as shown in Figure 5, the packings 28, 28 and auxiliary packings 29, 29' on both sides are each expanded and the free ends of each packing are pressed against the protruding portion 36 by spring action. Unlike conventional structures where water is stopped by the tips of water-stopping rubber protruding from both side walls making contact, this structure stops water by the free ends of the expanded leaf spring-shaped packings 28, 28 and auxiliary packings 29, 29' being pressed against each other. This allows for greater absorption of construction errors in the protruding section 36 (convex joint 24), ensuring more reliable watertightness.
[0041] After the recessed joint 23 and the convex joint 24 are fitted together, grout material 15 is filled into the groove 25 of the recessed joint 23 and the gap between it and the convex joint 24, thereby integrating the recessed joint 23 and the convex joint 24 and ensuring watertightness. As the grout material 15, concrete or mortar can be used, and materials with good fluidity and no shrinkage are preferred. This enables the transmission of force between adjacent steel shell elements 2, 2.
[0042] Of the steel shell elements 2, the steel shell elements 2 positioned in the middle of the earth retaining structure 1 are provided with a concave joint 23 on one side and a convex joint 24 on the other side, as shown in Figure 4. However, the steel shell elements 2 positioned at both ends of the earth retaining structure 1 are provided with either a concave joint 23 or a convex joint 24 on only one side, and the other side is formed in a flat, planar shape with nothing protruding outward from the side plate 22.
[0043] When constructing the earth retaining structure 1, as shown in Figure 1, stress members 7 may be placed inside the steel shell element 2, extending along the entire length of the steel shell element 2 in the penetration direction. The stress members 7 are made of shaped steel such as H-beams and extend along a portion or almost the entire length of the earth retaining structure 1 in the depth direction. The stress members 7 are preferably placed in positions that bear the stress of the earth retaining structure 1. In the illustrated example, multiple stress members 7 are placed at intervals along the upper plate 20 and lower plate 21 (along one side and the other side of the earth retaining structure 1) within the area enclosed by the upper plate 20, lower plate 21 and side plates 22, 22 of the steel shell element 2. It is preferable to install these stress members 7 immediately before pouring concrete into the steel shell element 2.
[0044] In the earth retaining structure 1 described above, as shown in Figure 2, it is preferable that the joints 8 between adjacent steel shell elements 2, 2 in adjacent rows of steel shell elements 3, 3 are located at different positions relative to the penetration direction (axial direction of the steel shell element 2). That is, the joints 8 between steel shell elements 2 in the penetration direction are offset so that they do not coincide with the direction perpendicular to the penetration direction (the direction in which the earth retaining structure 1 extends) between adjacent rows of steel shell elements 3, 3. As a result, any joint 8 in a row of steel shell elements 3 is reinforced by the steel shell elements 2 of the adjacent rows of steel shell elements 3 that straddle the joint 8, thereby further increasing the rigidity and improving the quality of the earth retaining structure 1.
[0045] As shown in Figure 2, at least the skin plate 9 of the thruster 6, which excavates the tip when the steel shell element 2 is driven in, is positioned at the lower end of the earth retaining structure 1. When the steel shell element 2 is driven in, as shown in Figure 3, the steel shell element 2 is driven in following the thruster 6 at the tip. After the steel shell element 2 has been driven in to the desired depth, as shown in Figure 2, only the outer skin plate 9 of the thruster 6 is left, the internal drive unit is recovered, and then concrete is filled in. This allows the recovered drive unit to be reused in subsequent thrusters 6, which is economical. If it is difficult to recover the drive unit, the entire structure, including the internal drive unit, may be left at the lower end of the earth retaining structure 1 and then concrete may be filled in.
[0046] Next, the method for constructing the earth retaining structure 1 will be explained in detail according to the procedure.
[0047] (Earth anchor work) First, as shown in Figures 7 and 8, earth anchors 4 are installed near the area where the retaining wall structure is planned to be constructed. In the illustrated example, a total of four earth anchors 4 are provided for each row of steel shell elements 3, two at positions spaced apart from one side and the other side of the retaining wall structure 1. The installation depth can be appropriately determined depending on the size of the steel shell elements 2, the depth of the retaining wall structure 1, the properties of the ground, etc., and is generally between 10 and 50 m. The earth anchors 4 can be installed using the standard earth anchor method or the ground anchor method, and may be left permanently or removed after construction.
[0048] The earth anchor 4 is installed only in the vicinity of the first steel shell element row 3 (reference element) to penetrate, and does not need to be installed in other locations. The reaction force of the first steel shell element row 3 (reference element) to penetrate needs to be taken up by the earth anchor 4, but the reaction force of subsequent steel shell element rows 3 (subsequent elements) to penetrate can be secured by the adjacent already penetrated steel shell elements, so in this case, earth anchors installed near the subsequent elements are unnecessary.
[0049] (Pre-drilling work at joint sections) Next, as shown in Figures 9 and 10, the planned penetration area 10 of the joint J connecting adjacent steel shell elements 2, 2 is pre-drilled. To drill this area 10, it is preferable to use a multi-screw mixing auger machine 11 used in the SMW method, as shown in Figure 10. In this pre-drilling of the joint, the purpose is to loosen and relax the in-situ ground in the area 10, which has a diameter of approximately 500 to 600 mm centered on the joint J, by drilling along the entire length in the penetration direction of the steel shell element 2 using the multi-screw mixing auger machine 11. Since this does not completely remove the in-situ soil, the risk of displacement of the borehole wall is extremely low.
[0050] (Standard element installation) As shown in Figures 11 and 12, guide wall construction is performed on the upper ends of one and the other sides of the earth retaining structure 1, respectively, by constructing guide walls 12 with a roughly inverted L-shaped cross-section that extend in the direction in which the earth retaining structure 1 extends (the horizontal direction perpendicular to the penetration direction of the steel shell element 2). Then, a push jack 5 with reaction force secured by an earth anchor 4 is installed on the launching side, and a reference element construction is performed in which the steel shell elements 2 are sequentially driven into the ground by the thrusting machine 6 at the tip (see Figure 3).
[0051] Since the guide wall 12 is constructed in the guide wall construction prior to the construction of the reference element, the guide wall 12 functions as a guide when the steel shell element 2 is penetrated, thereby improving the construction accuracy of the steel shell element 2. The guide wall 12 can be formed from precast concrete or the like.
[0052] To further explain the method of penetrating the steel shell element 2 using the aforementioned thrust jacks 5, as shown in Figure 12, during penetration, both ends of two reaction girders 13 that straddle the steel shell element 2 are fixed to earth anchors 4, and two thrust jacks 5 are installed on the underside of each reaction girder 13, for a total of four, so as to be extendable downward using the reaction girders 13 as a reaction force. A temporary penetration device is used in which a square annular thrust ring 14 is provided at the lower end of each thrust jack 5, which contacts the upper edge of the upper plate 20, lower plate 21, and side plate 22 of the steel shell element 2. By extending the four thrust jacks 5 evenly, pressure in the penetration direction is transmitted to the steel shell element 2 via the thrust rings 14, causing the thruster 6 at the tip to excavate and the steel shell element 2 to penetrate.
[0053] After the installation of the reference element is complete, the thruster 6 at the tip is recovered, leaving the skin plate 9 in place and removing the internal drive unit.
[0054] (Later element installation) Once the construction of the reference element is complete, as shown in Figures 13 and 14, a push jack 5, which secures a reaction force with an earth anchor 4 or an adjacent already-penetrated steel shell element 2, is installed on the launching side, and subsequent element construction is performed by sequentially penetrating the steel shell elements 2 to the thruster 6 at the tip, connecting them with the already-penetrated steel shell elements 2. The penetration device used for subsequent element construction is the same penetration device used for the reference element construction described above. However, if a reaction force is secured with an adjacent already-penetrated steel shell element 2, the reaction girder 13 is fixed to the adjacent already-penetrated steel shell element 2 before use.
[0055] Regarding the construction procedure for joint J, preferably, a reference element equipped with a recessed joint 23 is used so that the recessed joint 23 is positioned first. When penetrating the recessed joint 23 first, as described above, the recessed joint 23 is equipped with a watertight portion 26, so it can be penetrated without soil or other debris flowing into the groove 25.
[0056] Subsequently, the trailing steel shell element 2 is driven in while fitting the convex joint 24 of the trailing steel shell element 2 into the concave joint 23 of the already driven steel shell element 2. After the trailing element is installed, the thruster at the tip is recovered, leaving the skin plate 9 in place, and the internal drive unit is retrieved, similar to the installation of the reference element described above. The above-described installation of trailing elements is repeated for the length of the retaining wall structure 1.
[0057] (Soil removal work between elements) Once the penetration of all steel shell elements 2 is complete, as shown in Figures 15 and 16, an inter-element soil removal operation is performed to remove the soil between the steel shell elements 2, 2, i.e., the inter-element soil removal operation. The area excavated by the thruster 6 is mainly the region enclosed by the upper plate 20, lower plate 21 and side plates 22, 22 of the steel shell elements 2. The inter-element soil removal operation is performed to remove the soil remaining in this inter-element soil removal operation.
[0058] Specific removal methods include, for example, drilling holes from the ground between the elements 16 using a drilling machine to loosen the soil, and then sucking it up from the ground with a vacuum or digging it out from the ground. Alternatively, another method may be used in which the soil in this area 16 is loosened using a drilling machine, a closing plate (not shown) that has been pre-installed in the side plate 22 of the steel shell element 2 to close the opening is removed, and the soil is scraped out through that opening.
[0059] (Grout filling work inside joints) Once the removal of soil and sediment between all elements 16 is complete, a grouting procedure is performed in which grout material 15 is filled into the joint, as shown in Figures 17 and 18. In this procedure, if necessary, the groove 25 of the concave joint 23 into which the convex joint 24 is fitted is cleaned with high-pressure cleaning water, etc., and then grout material 15 such as high-strength mortar is filled into the groove 25.
[0060] (Stress member installation work) As shown in Figures 19 and 20, if necessary, a stress member installation process is performed in which a stress member 7 made of H-shaped steel or the like is installed inside the steel shell element 2, extending along the entire length in the penetration direction of the steel shell element 2. Preferably, the stress member 7 is fixed to the steel shell element 2 by appropriate means.
[0061] (Concrete filling work) As shown in Figures 19 and 20, the inside of the steel shell element 2 and the outer surface of the side plates 22 are cleaned with high-pressure cleaning water as needed, and after the necessary piping is installed, concrete is filled inside the steel shell element 2 and between the steel shell elements 2, 2. Here, the inside of the steel shell element 2 refers to the area enclosed by the upper plate 20, lower plate 21 and side plates 22, 22 of the steel shell element 2, and the space between the steel shell elements 2, 2 refers to the space between the opposing side plates 22, 22 of adjacent steel shell element rows 3, 3. The concrete can be poured directly from an agitator truck. [Explanation of symbols]
[0062] 1…Earth retaining structure, 2…Steel shell element, 3…Steel shell element row, 4…Earth anchor, 5…Primary thrust jack, 6…Thrusting machine, 7…Stress member, 8…Joint, 9…Skin plate, 10…Penetration area of joint J, 11…Multi-shaft mixing auger machine, 12…Guide wall, 13…Reaction girder, 14…Push ring, 15…Grout material, 20…Upper plate, 21…Lower plate, 22…Side plate, 23…Concave joint, 24…Convex joint, 25…Groove, 26…Waterproofing part, 27…Locking part, 28…Packing, 29·29'…Auxiliary packing, 30…Double packing, 31…Spacer, 32…Pressing bracket, 33…Bolt, 34…Waterproofing seal, 35…Concave joint body, 36…Protruding part, 37…Projection
Claims
1. A method for constructing an earth retaining structure using steel shell elements, wherein multiple rows of steel shell elements are arranged in parallel, with multiple steel shell elements connected in the direction of penetration, by sequentially penetrating the steel shell elements downward into the ground while connecting them to already penetrated steel shell elements, Earth anchoring work involves installing earth anchors near the area where the earth retaining structure is planned to be constructed, The steel shell elements are provided with joints to sequentially connect the steel shell elements that have already been penetrated, and by pre-drilling the planned penetration area of the joints, the in-situ ground in the planned penetration area is loosened and relaxed without completely removing the in-situ soil, and The system is equipped with a thruster that excavates the tip when the steel shell element is penetrated, and a push jack that secures reaction force with the earth anchor is installed on the launching side, and the steel shell element is sequentially driven into the thruster at the tip in a standard element construction process, A push jack with a reaction force secured by the aforementioned earth anchor is installed on the launching side, and the subsequent element installation is carried out by sequentially attaching the steel shell elements to the thrusting machine at the tip, connecting them with the already-attached steel shell elements as they penetrate, An element-inter-element soil removal work for removing soil between the aforementioned steel shell elements, A stress member installation method is used to install stress members within the steel shell element, at a location that bears the stress of the earth retaining structure, and along one side and the other side of the earth retaining structure, extending a portion or the entire length of the penetration direction of the steel shell element. A concrete filling process for filling the inside of the steel shell element and the spaces between the steel shell elements with concrete, A method for constructing an earth retaining structure using a steel shell element, characterized by including the element.
2. A method for constructing an earth retaining structure using steel shell elements according to claim 1, wherein in adjacent rows of steel shell elements, the joints between adjacent steel shell elements in the penetration direction are provided at different positions with respect to the penetration direction.
3. A method for constructing an earth retaining structure using steel shell elements according to claim 1, wherein, after the earth removal work between the elements, a joint grouting work is provided in which grout material is filled into the joint.
4. The method for constructing an earth retaining structure using a steel shell element according to claim 1, wherein, after the completion of excavation, the thrusting machine recovers as much of the material inside other than the skin plate as possible, leaving at least the skin plate at the lower end of the earth retaining structure.