JP2023163538A - Earth retaining structure using steel shell element and construction method thereof - Google Patents

Abstract

[Problem] To provide a highly rigid and high quality earth retaining structure that suppresses ground deformation. [Solution] The earth retaining structure 1 connects a plurality of steel shell elements 2 in tandem by sequentially penetrating the steel shell elements 2 downward into the ground while connecting them with the steel shell elements 2 that have already penetrated. It has a structure in which a plurality of steel shell element rows 3 are arranged in parallel. A main push jack 5 whose reaction force is secured by an earth anchor 4 or an adjacent steel shell element 2 that has already been penetrated is installed on the starting side, and the steel shell elements 2 are successively penetrated into the propulsion device 6 at the tip. [Selection diagram] Figure 2

Description

The present invention relates to an earth retaining structure using steel shell elements formed by sequentially penetrating steel shell elements downward into the ground while connecting them with steel shell elements that have already penetrated, and a method for constructing the same.

BACKGROUND ART The underground continuous wall construction method has been known as a type of earth retaining method for constructing cut-and-cover tunnels, shafts, and underground parts of buildings. The above-mentioned continuous underground wall construction method when performing large-scale excavation involves excavating in the shape of a trench (trench excavation) while stabilizing the trench wall using a stabilizing liquid such as bentonite. The procedure is to build a reinforced concrete wall (RC underground wall) that is continuous underground by erecting a core material such as or H-beam steel, and pouring concrete while replacing it with a stabilizing liquid (for example, Patent Documents 1, 2).

Japanese Patent Application Publication No. 2001-303553 Japanese Patent Application Publication No. 2003-155742 Japanese Patent Application Publication No. 2015-71904

However, in the above-mentioned continuous underground wall construction method, after the trench is excavated in advance, the trench wall of the excavated trench is left in an excavated state until the trench is filled with concrete, so In ground where it is difficult to maintain the stability of trench walls, such as ground with a small coefficient of uniformity or gravel, there is a risk of ground deformation such as collapse of the trench wall.

In addition, with the above-mentioned underground continuous wall construction method, there may be cases where the wall stays at a high level due to the resistance when installing the reinforcing bar cage or core material in the trench, and water leakage from the joints with adjacent elements. There was an issue in which it was not possible to ensure that.

Furthermore, in the above-mentioned continuous underground wall construction method, the stabilizing liquid tends to leak in sandy and gravelly ground with good permeability, and it is difficult to maintain the stable liquid level, so the water pressure decreases due to the lowering of the stabilizing liquid level. However, there was a problem that the groove walls were prone to collapse.

When constructing an underground structure close to an important structure such as a subway line or station, a higher quality earth retaining structure than the above-mentioned underground continuous wall is desired.

By the way, the applicant has proposed in Patent Document 3 a joint structure of steel shell elements used when constructing underground structures by sequentially penetrating steel shell elements while connecting them with steel shell elements that have already been penetrated. .

In Patent Document 3, an underground structure is constructed in which a plurality of steel shell elements are closed in a rectangular, circular, irregular shape, etc. in cross-sectional view in the ground under a route such as a road line or a railway line without excavation. describes a joint structure suitable for a steel shell element used in a rectangular steel pipe propulsion method for constructing an underpass tunnel by excavating internal earth and sand. The present invention applies this technology to construct an earth retaining structure.

Therefore, the main object of the present invention is to provide a highly rigid and high quality earth retaining structure that suppresses ground deformation, and a method for constructing the same.

In order to solve the above problem, the present invention according to claim 1 is characterized in that a plurality of steel shell elements are inserted in tandem by sequentially penetrating the steel shell elements downward into the ground while connecting with the steel shell elements that have already been penetrated. An earth retaining structure using steel shell elements is provided, which is characterized by having a plurality of rows of steel shell elements connected in parallel.

In the invention described in claim 1, since the earth retaining structure is constructed by penetrating a plurality of steel shell elements into the ground, when penetrating into the ground, the steel shell elements are By penetrating, there is no need to leave the trench walls in an excavated state as in the conventional underground continuous wall construction method, and ground deformation can be suppressed, preventing collapse of the trench walls. Furthermore, by filling the penetrated steel shell elements with concrete and integrating them, a highly rigid and high quality earth retaining structure can be obtained.

The present invention according to claim 2 provides an earth retaining structure using the steel shell element according to claim 1, wherein a stress member is disposed inside the steel shell element over a part or the entire length of the steel shell element in the penetrating direction. is provided.

In the invention according to claim 2, in order to further increase the rigidity and improve the quality of the earth retaining structure, a stress member is disposed inside the steel shell element over a part or the entire length of the steel shell element in the penetrating direction. There is.

The present invention according to claim 3 is the steel shell according to claim 1, wherein in the adjacent rows of steel shell elements, joints between adjacent steel shell elements in the penetration direction are provided at different positions with respect to the penetration direction. An earth retaining structure using elements is provided.

In the invention according to claim 3, in order to further increase the rigidity and improve the quality of the earth retaining structure, in the adjacent rows of steel shell elements, the joints of the steel shell elements are provided at different positions with respect to the penetration direction. There is.

The present invention according to claim 4 uses the steel shell element according to claim 1, wherein at least a skin plate of a propulsion device that excavates the tip when the steel shell element penetrates is arranged at the lower end of the earth retaining structure. An earth retaining structure is provided.

In the fourth aspect of the invention, at least the skin plate of the propulsion device is disposed at the lower end of the earth retaining structure by penetrating the steel shell element following the tip propulsion device. After penetrating the steel shell element following the tip propulsion device, the tip propulsion device leaves the skin plate and the internal drive section is recovered, and the recovered drive section is used as the excavator for subsequent excavation. Reused.

The present invention according to claim 5 is a method for constructing an earth retaining structure according to any one of claims 1 to 4, comprising:
Earth anchor work for constructing an earth anchor near the area where the earth retaining structure is planned to be constructed;
Installing a base jack with reaction force secured by the earth anchor on the starting side, and constructing a standard element in which the propulsion machine at the tip is successively followed by steel shell elements;
A main push jack with a reaction force secured by the earth anchor or the adjacent penetrated steel shell element is installed on the starting side, and the steel shell elements are successively followed by the propulsion device at the tip and connected to the penetrated steel shell element. Construction of the trailing element that penetrates while
Inter-element earth and sand removal work to remove earth and sand between steel shell elements;
a concrete filling work that fills concrete inside the steel shell element and between the steel shell elements;
A method for constructing an earth retaining structure using a steel shell element is provided.

In the invention described in claim 5, since the steel shell element is penetrated after the propulsion device at the tip, the trench wall is not left in an excavated state as in the conventional underground continuous wall construction method, and the ground Deformation can be suppressed and collapse of the groove walls will not occur. In addition, since concrete is filled inside the penetrated steel shell elements and between the steel shell elements, a highly rigid and high quality earth retaining structure can be obtained.

As the present invention according to claim 6, the steel shell element is provided with a joint portion that connects the steel shell elements,
6. The method for constructing an earth retaining structure using a steel shell element according to claim 5, wherein a joint advance drilling machine is provided to drill a hole in a planned penetration area of the joint part in advance before the reference element construction. is provided.

In the invention according to claim 6, before penetrating the steel shell element, by drilling holes in the planned penetration area of the joint part in advance, earth and sand in the planned penetration area of the joint part are loosened, and the steel shell This suppresses the penetration resistance of the joint part when the element penetrates.

As the present invention according to claim 7, the steel shell element is provided with a joint portion that connects the steel shell elements,
There is provided a method for constructing an earth retaining structure using steel shell elements according to claim 5, wherein an in-joint grout filling work for filling grout into the joint part is provided after the inter-element earth removal work. .

In the seventh aspect of the invention, the strength and water-stopping properties of the joint are ensured by filling the joint with grout.

As the present invention according to claim 8, before the concrete filling work, a stress member construction work is provided inside the steel shell element in which a stress member is installed over a part or the entire length of the steel shell element in the penetration direction. There is provided a method for constructing an earth retaining structure using the steel shell element according to claim 5.

In the invention as set forth in claim 8, by building the stress member inside the steel shell element and then filling it with concrete, an earth retaining structure with even higher rigidity and higher quality can be obtained.

As the present invention according to claim 9, the earth retaining structure using steel shell elements according to claim 5, wherein the propulsion device leaves the skin plate at the lower end of the earth retaining structure and recovers the driving part after the completion of excavation. A construction method is provided.

In the invention according to claim 9, after the propulsion device completes excavation, the drive section is recovered with the skin plate of the propulsion device left at the lower end of the earth retaining structure, so that the recovered drive section can be used in subsequent excavation. It can be reused for propulsion equipment.

As described in detail above, according to the present invention, it is possible to provide a highly rigid and high-quality earth retaining structure that can suppress ground deformation, and a method for constructing the same.

FIG. 1 is a plan view of an earth retaining structure 1 according to the present invention. FIG. It is a sectional view at the time of propulsion construction. FIG. 2 is a perspective view showing a steel shell element 2. FIG. It is a sectional view of joint part J. FIG. 2 is a cross-sectional view of a recessed joint 23; It is a top view showing earth anchor work. FIG. 7 is a sectional view (view taken along the line VIII-VIII in FIG. 7) showing the earth anchor work. FIG. 3 is a plan view showing a joint part advance drilling process. FIG. 9 is a cross-sectional view (view taken along the line X--X in FIG. 9) showing the preliminary drilling of the joint portion. It is a top view showing standard element construction. FIG. 12 is a cross-sectional view (view taken along the line XII-XII in FIG. 11) showing the construction of the reference element. It is a top view which shows trailing element construction. FIG. 14 is a cross-sectional view (view taken along the line XIV-XIV in FIG. 13) showing construction of the trailing element. It is a plan view showing earth and sand removal work between elements. FIG. 16 is a cross-sectional view (view taken along the line XVI-XVI in FIG. 15) showing the inter-element earth and sand removal work. It is a top view which shows the grout material filling work in a joint part. It is an enlarged sectional view of joint part J. It is a top view showing a concrete filling work. FIG. 19 is a cross-sectional view (view taken along the line XX-XX in FIG. 19) showing the concrete filling work.

Embodiments of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, the earth retaining structure 1 according to the present invention minimizes the amount of displacement of the ground when constructing an underground structure close to an important underground structure such as a subway line or station. This is an earth retaining wall constructed by interconnecting a plurality of steel shell elements 2 from the ground surface to a predetermined depth underground in a location close to an important structure.

As shown in FIGS. 1 to 3, the earth retaining structure 1 is constructed by sequentially penetrating the steel shell elements 2 downward into the ground while connecting them with the steel shell elements 2 that have already penetrated. It has a structure in which a plurality of steel shell element rows 3 in which shell elements 2 are connected in tandem are arranged in parallel. That is, a plurality of steel shell elements 2 are connected in tandem from the ground surface downward into the ground to form a steel shell element row 3 extending to a predetermined depth, and the steel shell element rows 3 are interconnected. However, a wall body is formed by arranging a plurality of them in parallel in the horizontal direction.

In order to penetrate the steel shell element 2 into the ground, as shown in FIG. This is done by installing a jack 5 on the starting side and having the steel shell element 2 follow the propulsion device 6 at the tip. In this way, the excavated wall surface is covered by the following steel shell element 2 immediately after excavation by the propulsion device 6, so the excavated wall surface is not left in the excavated state, and ground deformation can be suppressed, preventing collapse of the trench wall. will no longer occur.

In addition, since the inside of the penetrated steel shell element 2 and between the adjacent steel shell elements 2 are filled with concrete and integrated, a high-rigidity and high-quality earth retaining structure can be obtained.

As the steel shell element 2, the one described in the above-mentioned Patent Document 3 (Japanese Unexamined Patent Publication No. 2015-71904) can be suitably used. Specifically, the steel shell element 2 is an element with a rectangular cross section that is constituted by an upper plate 20, a lower plate 21, and side plates 22, 22, as shown in FIG. This steel shell element 2 is arranged so that the upper plate 20 or the lower plate 21 faces the important structure side or the opposite side. Further, 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 tip of one side, and a convex joint 24 is provided at the tip of the other side. There is. Further, on the inner surface of the steel shell element 2, a plurality of annular ribs 38 having a predetermined height and extending in the circumferential direction are provided at appropriate intervals in the axial direction of the steel shell element 2.

As shown in FIG. 5, the joint portion J of the steel shell elements 2, 2 has a joint structure for sequentially connecting the steel shell elements 2 to the steel shell elements 2 that have been penetrated, It consists of a connection structure of the concave joint 23 provided on the shell element 2 and the convex joint 24 provided on the other steel shell element 2.

As shown in FIG. 6, the recessed joint 23 extends over the entire length of the steel shell element 2 in the axial direction, includes a groove 25 extending along the axial direction, and protrudes from both sides within the groove 25. The recessed joint main body 35 includes locking portions 27, 27, and a water stop portion 26 that closes a slit-shaped opening along the axial direction of the groove portion 25.

The recessed joint main body 35 is made of cast steel or hot-pressed steel and has a substantially U-shaped cross section, and the groove portion 25 is formed along the longitudinal direction of the member, and the groove portion 25 is formed on both end faces in the longitudinal direction of the member. An end opening is formed, and a slit-shaped opening of the groove portion 25 extending along the longitudinal direction of the member is formed on the end face facing the adjacent steel shell element 2. By constructing the concave joint 23 from cast metal or hot-formed steel, the yield strength of the recessed joint 23 is improved, manufacturing costs can be reduced, and manufacturability can be improved.

The water stop portion 26 is formed by leaf spring-like packings 28, 28 extending from at least both sides of the slit-shaped opening of the groove portion 25 toward the center of the opening.

In cross-sectional view, the packing 28 extends from both sides of the concave joint main body 35 toward the center of the slit-shaped opening of the groove 25, and is bent toward the inner side of the groove 25 at an intermediate position. It is composed of two bent plate-shaped bodies of about 0.3 mm, and its outer end is fixed to the concave joint main body 35 side, and its opening side is a free end, so that it acts as a leaf spring. The free ends of the packings 28, 28 are provided so as to butt each other at approximately the center position of the groove portion 25 in the groove width direction. By bending the packings 28, 28 toward the inside of the groove 25, the packings 28, 28 expand toward the inside of the groove 25 when the concave joint 23 and the convex joint 24 are fitted together. It becomes like this.

As shown in FIG. 6, on the outside of the packings 28, 28, leaf spring-shaped auxiliary packings 29, 29' extending from both sides of the slit-shaped opening of the groove 25 toward the center of the opening, respectively, are provided. As a result, the water stop portion 26 is constituted by a double packing 30 consisting of an inner packing 28 and outer auxiliary packings 29 and 29'.

As shown in FIG. 6, the inner packing 28 and the outer auxiliary packings 29, 29' are attached to the main body of the concave joint 23 using a spacer 31 disposed between each packing and the auxiliary packings 29, 29. It is fixed with a bolt 33 via a presser metal fitting 32 disposed on the outside of the frame. The spacer 31 is provided so that its inner side protrudes inward from the side wall surface on the slit-shaped opening side of the groove portion 25, and preferably extends to a bending position of the packing 28, which is bent in the middle.

The auxiliary packings 29 and 29' are two plates approximately 0.3 mm thick that extend substantially linearly from both sides of the concave joint main body 35 toward the center of the slit-shaped opening of the groove 25 when viewed in cross section. The outer end is fixed to the concave joint main body 35 side, and the opening side is a free end, so that it acts as a leaf spring. The auxiliary packings 29 and 29' are provided so as to overlap each other at the center of the slit-shaped opening of the groove portion 25. Among the auxiliary packings 29, 29', the free end of one of the auxiliary packings 29, which is disposed on the outside in the overlapping margin, is longer outwardly than the other auxiliary packing 29', which is disposed inward in the overlapping margin. The spacer 31 extends and is supported by the tip of the spacer 31 fixed to the opposing side wall via the groove 25, thereby improving pressure resistance from the outside.

On the other hand, the other auxiliary packing 29' disposed on the inside in the overlapping portion is formed shorter than the one auxiliary packing 29, preferably extends to a position slightly beyond the center of the groove width, and has a convex shape. This prevents the joint 24 from interfering with the outer auxiliary packing 29 and becoming unable to expand when the joint 24 is inserted.

As shown in FIG. 6, it is desirable that a water stop seal 34 be filled between the double packing 30 consisting of the packings 28, 28 and the auxiliary packings 29, 29'. As the water-stop seal 34, it is preferable to use an oil-based water-stop seal that has high durability against high water pressure, especially to prevent underground water or backfill material from entering between the wire brushes of the shield machine. Tail Sealer (registered trademark, manufactured by Matsumura Petrochemicals Co., Ltd.) is suitable. When the concave joint 23 and the convex joint 24 are fitted together, the water stop seal 34 functions as a lubricant when the protrusion 36 of the convex joint 24 (described later) is fitted, and after the fitting is completed, the water stop seal 34 functions as a lubricant when the convex joint 24 is fitted into the concave joint 23 functions as

As shown in FIG. 5, the concave joint 23 is provided with an opening prevention bolt 38 that straddles the groove 25 and connects both side walls in order to prevent the groove 25 from opening after fitting with the convex joint 24. is provided.

On the other hand, as shown in FIG. 5, the convex joint 24 includes a flat protrusion 36 extending laterally from the side plate 22 of the steel shell element 2, and at the tip of the protrusion 36, A protrusion 37 is provided that protrudes from both sides of the protrusion 36 in the thickness direction.

As shown in FIG. 5, when the concave joint 23 and the convex joint 24 are fitted, the protrusion 36 of the convex joint 24 is inserted from the upper end opening of the groove 25, and the packing The auxiliary packings 28, 28 and the auxiliary packings 29, 29' are inserted between the packings 30 on both sides while being expanded, and the protruding portion 37 is inserted deeper than the locking portion 27 of the groove portion 25. When the protrusion 36 is inserted, as shown in FIG. 5, the packings 28, 28 and the auxiliary packings 29, 29' on both sides expand, and the free end of each packing is opened by the spring action. It is pressed against the protruding portion 36. Unlike the conventional structure in which water is stopped by contacting the tips of water stop rubber protruding from both side walls, the free ends of expanded leaf spring-shaped packings 28, 28 and auxiliary packings 29, 29' Since water is stopped by pressing the parts, the absorption of construction errors of the protruding portion 36 (convex joint 24) is increased, and water stopping performance can be ensured more reliably.

After the concave joint 23 and the convex joint 24 are fitted, grout material 15 is filled in the groove 25 of the concave joint 23 and the gap between the convex joint 24 and the concave joint 23 and the convex joint 24. It is integrated with the joint 24, ensuring watertightness. Concrete, mortar, or the like is used as the grout material 15, and it is preferable that it has good fluidity and non-shrinkage properties. This allows force to be transmitted between adjacent steel shell elements 2, 2.

Among the steel shell elements 2, the steel shell element 2 disposed in the middle part of the earth retaining structure 1 is provided with a concave joint 23 on one side and a concave joint 23 on the other side, as shown in FIG. The steel shell elements 2 disposed at both ends of the earth retaining structure 1 are provided with a concave joint 23 or a convex joint 24 only on one side, and the other side is provided with a convex joint 24. It is formed into a flat planar shape with nothing protruding outward from 22.

When constructing the earth retaining structure 1, as shown in FIG. 1, a stress member 7 may be placed inside the steel shell element 2 over the entire length of the steel shell element 2 in the penetration direction. The stress member 7 is made of a shaped steel material such as an H-shaped steel, and extends over a part or almost the entire length of the earth retaining structure 1 in the depth direction. The stress member 7 is preferably located at a position that bears the stress of the earth retaining structure 1, and in the illustrated example, it is located in an area surrounded by the upper plate 20, lower plate 21, and side plates 22, 22 of the steel shell element 2. A plurality of them are arranged at intervals along the upper plate 20 and the lower plate 21 (along one side and the other side of the earth retaining structure 1). This stress member 7 is preferably installed immediately before pouring concrete into the steel shell element 2.

In the earth retaining structure 1, as shown in FIG. 2, in the adjacent steel shell element rows 3, 3, there is a seam 8 between adjacent steel shell elements 2, 2 in the penetration direction (axial direction of the steel shell element 2). are preferably provided at different positions with respect to the penetration direction. That is, the seams 8 between the steel shell elements 2 in the penetration direction are staggered so that the adjacent steel shell element rows 3, 3 do not coincide with the direction perpendicular to the penetration direction (the direction in which the earth retaining structure 1 extends). has been done. As a result, the seam 8 of any steel shell element row 3 is reinforced by the steel shell elements 2 of the steel shell element rows 3 on both sides that straddle the seam 8, thereby further increasing the rigidity of the earth retaining structure 1. and improve quality.

As shown in FIG. 2, at least a skin plate 9 of a propulsion device 6, which excavates the tip when the steel shell element 2 penetrates, is arranged at the lower end of the earth retaining structure 1. When the steel shell element 2 penetrates, as shown in FIG. As shown in FIG. 2, the internal drive section of the propulsion device 6 is recovered, leaving only the outer skin plate 9, and then filled with concrete. This allows the recovered drive unit to be reused in the propulsion device 6 for the next time onward, which is economical. Furthermore, when it is difficult to recover the driving part, the lower end of the earth retaining structure 1, including the internal driving part, may be left and filled with concrete.

Next, a method for constructing the earth retaining structure 1 will be explained according to the procedure.

(Earth anchor work)
First, as shown in FIGS. 7 and 8, the earth anchor 4 is constructed near the area where the earth retaining structure is planned to be constructed. In the illustrated example, the earth anchors 4 are provided at four locations, two each at positions separated from one side and the other side of the earth retaining structure 1, for each steel shell element row 3. The construction depth can be appropriately determined depending on the size of the steel shell element 2, the depth of the earth retaining structure 1, the properties of the ground, etc., and is approximately 10 to 50 m. The earth anchor 4 can be constructed using a normal earth anchor construction method or a ground anchor construction method, and may be left in place permanently or removed after construction.

The earth anchor 4 may be installed only in the vicinity of the steel shell element row 3 (reference element) to be penetrated first, and may not be installed in other locations. The reaction force of the steel shell element row 3 (reference element) that penetrates first must be taken by the earth anchor 4, but the reaction force of the steel shell element row 3 (trailing element) that penetrates from the next time onwards is In this case, it is possible to eliminate the need for an earth anchor installed near the trailing element.

(Advance drilling at joint)
Next, as shown in FIGS. 9 and 10, holes are pre-drilled in the area 10 where the joint portion J connecting the adjacent steel shell elements 2, 2 is to be penetrated. To drill holes in this region 10, as shown in FIG. 10, it is preferable to use a multi-shaft kneading auger machine 11 used in the SMW construction method. In this joint preliminary drilling, the multi-axis kneading auger machine 11 is used to drill a hole in the ground in an area 10 with a diameter of approximately 500 to 600 mm centered on the joint J over the entire length in the direction of penetration of the steel shell element 2. The purpose is to loosen and loosen the original soil in this region 10, and the original soil is not completely removed, so there is extremely little risk of displacement of the hole wall.

(Standard element construction)
As shown in FIGS. 11 and 12, along the direction in which the earth retaining structure 1 extends (horizontal direction perpendicular to the penetration direction of the steel shell element 2), A guide wall 12 with a substantially inverted L-shaped cross section extending from the ground is installed on the starting side, and a main push jack 5 with a reaction force secured by an earth anchor 4 is installed on the starting side. (Refer to 3.), construction of the standard element is carried out, which is followed by the steel shell element 2 and penetrates into the ground.

Since the guide wall 12 is constructed in the guide wall work prior to the construction of the standard element, the guide wall 12 functions as a guide when penetrating the steel shell element 2, improving the construction accuracy of the steel shell element 2. can. The guide wall 12 may be made of precast concrete or the like.

To explain in more detail the method of penetrating the steel shell element 2 using the original pushing jack 5, as shown in FIG. Both ends of are fixed to earth anchors 4, respectively, and a total of four push jacks 5, two on the bottom surface of each reaction force girder 13, are installed so that they can extend downward using the reaction force girder 13 as a reaction force. A temporary penetrating device is used, which is equipped with a square ring-shaped pushing ring 14 at the lower end of the original pushing jack 5, which contacts the upper edges of the upper plate 20, lower plate 21, and side plate 22 of the steel shell element 2. be done. By extending the four main push jacks 5 evenly, pressure in the penetrating direction is transmitted to the steel shell element 2 via the push ring 14, and the thrusting device 6 at the tip and the penetration of the steel shell element 2 are prevented. It will be done.

After the construction of the reference element is completed, the propulsion device 6 at the tip leaves the skin plate 9 and recovers the internal driving section.

(Tracking element construction)
When the construction of the reference element is completed, as shown in Figs. 13 and 14, a main push jack 5 with reaction force secured by the earth anchor 4 or the adjacent penetrated steel shell element 2 is installed on the starting side, and the tip Construction of the trailing element is performed by sequentially following the steel shell elements 2 into the propulsion device 6 and penetrating the steel shell elements 2 while connecting them to the steel shell elements 2 that have already been penetrated. The penetration device used in the construction of the trailing element can be the same as that used in the construction of the reference element. However, when securing the reaction force with the adjacent steel shell element 2 that has already been penetrated, the reaction force girder 13 is used while being fixed to the adjacent steel shell element 2 that has already penetrated.

To explain the procedure for constructing the joint part J, preferably, an element provided with the concave joint 23 is used as the reference element so that the concave joint 23 is placed in advance. When penetrating through this recessed joint 23 in advance, since the recessed joint 23 is provided with the water stop portion 26 as described above, the recessed joint 23 can be penetrated without dirt or the like flowing into the groove portion 25.

Thereafter, the following steel shell element 2 is penetrated while the convex joint 24 of the following steel shell element 2 is fitted into the concave joint 23 of the steel shell element 2 that has already been penetrated. After the construction of the trailing element is completed, similarly to the construction of the reference element described above, the propulsion device at the tip leaves the skin plate 9 and recovers the internal driving section. The above-mentioned trailing element construction is repeated for the length of the earth retaining structure 1.

(Earth removal work between elements)
When all the penetration of the steel shell elements 2 is completed, as shown in FIGS. 15 and 16, inter-element earth and sand removal work is performed to remove earth and sand between the elements 16 between the steel shell elements 2 and 2. The range excavated by the propulsion device 6 is mainly the area surrounded by the upper plate 20, lower plate 21, and side plates 22, 22 of the steel shell element 2, and the area between the elements 16, that is, the area adjacent to the steel shell outside the side plate 22. The area where the joint part J between the shell element 2 and the side plate 22 is provided is an area where the propulsion device 6 does not excavate and dirt remains. The inter-element earth and sand removal work is to remove earth and sand remaining between the elements 16.

Specific removal methods include, for example, drilling a hole between the elements 16 from the ground with a hole drill to loosen the earth and sand, and then sucking it up from the ground with a vacuum, or digging it out from the ground. Another method is to similarly loosen the earth and sand in this area 16 using a drilling machine, and then remove a closing plate (not shown) that closes the opening previously provided in the side plate 22 of the steel shell element 2. Alternatively, a method may be used in which the earth and sand are scraped out from the opening.

(Filling of grout material inside the joint)
When the removal of the earth and sand between all the elements 16 is completed, as shown in FIGS. 17 and 18, grout filling work is performed to fill the joint with grout 15. In this construction procedure, after cleaning the inside of the groove 25 of the concave joint 23 into which the convex joint 24 is fitted with high-pressure washing water or the like, if necessary, the groove 25 is filled with grout material 15 such as high-strength mortar.

(Stressed member erection work)
As shown in FIGS. 19 and 20, a stress member construction in which a stress member 7 made of H-shaped steel or the like is installed inside the steel shell element 2 over the entire length of the steel shell element 2 in the penetration direction. Perform the finishing work. Preferably, the stress member 7 is fixed to the steel shell element 2 by suitable means.

(Concrete filling work)
As shown in FIGS. 19 and 20, if necessary, the inside of the steel shell element 2 and the outer surface of the side plate 22 are cleaned with high-pressure washing water, etc., and the required piping is installed. Fill concrete between the steel shell elements 2 and 2. Here, the inside of the steel shell element 2 refers to the area surrounded by the upper plate 20, lower plate 21, and side plates 22, 22 of the steel shell element 2, and the area between the steel shell elements 2 and 2 refers to the area surrounded by the upper plate 20, lower plate 21, and side plates 22, 22 of the steel shell element 2. This is between the opposing side plates 22, 22 of the steel shell element rows 3, 3. The concrete filling can be poured directly from the agitator truck.

DESCRIPTION OF SYMBOLS 1... Earth retaining structure, 2... Steel shell element, 3... Steel shell element row, 4... Earth anchor, 5... Main push jack, 6... Propulsion machine, 7... Stress member, 8... Seam, 9... Skin plate, 10 ... Planned penetration area of joint J, 11... Multi-shaft kneading auger machine, 12... Guide wall, 13... Reaction force 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...Water stop part, 27...Locking part, 28...Packing, 29/29'...Auxiliary packing, 30...Double packing, 31...Spacer , 32... Holding metal fitting, 33... Bolt, 34... Water stop seal, 35... Concave joint body, 36... Projection, 37... Projection

Claims (9)

By sequentially penetrating the steel shell elements downward into the ground while connecting them with the steel shell elements that have already been penetrated, it is possible to form multiple rows of steel shell elements in which multiple steel shell elements are connected in tandem. Earth retaining structure using distinctive steel shell elements. 2. The earth retaining structure using a steel shell element according to claim 1, wherein a stress member is disposed inside the steel shell element over a part or the entire length of the steel shell element in the penetrating direction. 2. The earth retaining structure using steel shell elements according to claim 1, wherein in the adjacent rows of steel shell elements, joints between adjacent steel shell elements in the penetration direction are provided at different positions with respect to the penetration direction. 2. The earth retaining structure using a steel shell element according to claim 1, wherein at least a skin plate of a propulsion device that excavates the tip when the steel shell element penetrates is arranged at the lower end of the earth retaining structure. A method for constructing an earth retaining structure according to any one of claims 1 to 4, comprising:
Earth anchor work for constructing an earth anchor near the area where the earth retaining structure is planned to be constructed;
Installing a base jack with reaction force secured by the earth anchor on the starting side, and constructing a standard element in which the propulsion machine at the tip is successively followed by steel shell elements;
A main push jack with a reaction force secured by the earth anchor or the adjacent penetrated steel shell element is installed on the starting side, and the steel shell elements are successively followed by the propulsion device at the tip and connected to the penetrated steel shell element. Construction of the trailing element that penetrates while
Inter-element earth and sand removal work to remove earth and sand between steel shell elements;
a concrete filling work that fills concrete inside the steel shell element and between the steel shell elements;
A method for constructing an earth retaining structure using a steel shell element. The steel shell element is provided with a joint portion that connects the steel shell elements,
6. The method for constructing an earth retaining structure using a steel shell element according to claim 5, wherein a joint advance drilling machine is provided to drill a hole in a planned penetration area of the joint part in advance before the reference element construction. . The steel shell element is provided with a joint portion that connects the steel shell elements,
6. The method for constructing an earth retaining structure using steel shell elements according to claim 5, wherein an in-joint grout filling work for filling grout into the joint part is provided after the inter-element earth removal work. 6. The steel shell according to claim 5, wherein a stress member erecting work is provided inside the steel shell element before the concrete filling work for erecting a stress member over a part or the entire length of the steel shell element in the penetrating direction. A method of constructing an earth retaining structure using elements. 6. The method of constructing an earth retaining structure using steel shell elements according to claim 5, wherein the propulsion device leaves the skin plate at the lower end of the earth retaining structure and recovers the driving part after the excavation is completed.

Images