Earth retaining structure, steel-concrete structure, steel segment, construction method of structure, maintenance and management method of structure, measurement method of concrete parameter, and monitoring method of structure

Abstract

To provide an earth retaining structure that enables long-term maintenance and management of functionality after construction, with steel-concrete structures used underground such as foundation structures as an object.SOLUTION: A retaining structure (10) used when constructing a structure (1) used underground comprises measuring devices (71, 82, 91) that measure parameters necessary for long-term maintenance and management of functionality after construction of the structure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an earth retaining structure, a steel-concrete structure, a steel segment, a method for constructing a structure, a method for maintaining and managing a structure, a method for measuring parameters of a structure, and a method for monitoring a structure. [Background technology]

[0002] One example of an earth retaining member is a steel segment, and a segment press-in method is known in which a plurality of steel segments are used to construct an earth retaining structure such as a vertical shaft. In this method, the segments are connected circumferentially at the press-in point to assemble a ring body, and the ring body is pressed into the ground using a press-in device. After the ring body is pressed in, the inside of the ring body is excavated and soil is removed, and additional ring bodies are installed on top of it. This work process is repeated up to a predetermined depth to construct an earth retaining structure such as a vertical shaft underground (see, for example, Patent Document 1). The structure constructed by the above construction method can be used as a retaining structure that creates an underground space for constructing a steel-concrete structure such as a foundation, or as part of a steel-concrete structure such as a foundation. The foundation is constructed by placing rebar as needed inside the ring-shaped structure and pouring concrete. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-214722 Summary of the Invention [Problem to be solved by the invention]

[0004] However, steel-concrete structures used underground, such as foundation structures, are often required to maintain their functionality for a long period of time even after construction, as they are often used as the foundations for bridge piers and other structures built above them, and it is therefore necessary to regularly check the condition of the structures. However, steel-concrete structures used underground, such as foundation structures, are difficult to inspect directly due to the superstructure and surrounding ground, making it difficult to maintain their functionality over the long term after construction.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an earth retaining structure that enables long-term maintenance and management of its functionality after construction, targeting steel-concrete structures used underground such as foundation structures. [Means for solving the problem]

[0006] One aspect of the present invention is a retaining wall structure used when constructing an underground structure, characterized in that it is equipped with a measuring device that measures parameters necessary for maintaining and managing the long-term functionality of the structure after construction.

[0007] In addition, in the above aspect, it is preferable that the parameter is at least one of the axial strain of the structure, corrosion of the filled portion, verticality of the structure, the amount of opening of the members constituting the structure, the amount of material corrosion, and the load distribution rate of each member.

[0008] Furthermore, in the above aspect, the retaining structure is a segment structure in which a plurality of annular ring bodies, each formed by connecting a plurality of steel segments in the longitudinal direction, are connected in the lateral direction of the steel segments, and is integrated with a fill section provided inside the segment structure, and the steel segments have joint sections provided along the lateral direction at both longitudinal ends and connected to adjacent steel segments, and ribs provided along the lateral direction between the joint sections, and it is preferable that the measuring device is a strain measuring section provided in the joint section or the rib and measuring the strain of the joint section or the rib.

[0009] In the above aspect, it is preferable that a plurality of the strain measuring units are provided, and the strain measuring units are arranged at equal intervals along the extending direction of the ring body.

[0010] In the above aspect, it is preferable that at least one pair of the strain measuring units be provided on the steel segments that face each other across the center of the ring body.

[0011] In the above aspect, it is preferable that the strain measurement unit is provided on the steel segment in at least one of the ring bodies located at the upper end and the lower end of the segment structure.

[0012] In the above aspect, it is preferable that the steel segment has a plate that forms a wall surface of the segment structure, and that a corrosion detection unit that detects corrosion of the filler portion is provided on an inner wall surface of the plate.

[0013] In the above aspect, it is preferable that a plurality of the corrosion detectors are provided along the radial direction of the ring body.

[0014] In the above aspect, it is preferable that the corrosion detection unit is provided on a plurality of ring bodies.

[0015] In addition, in the above-mentioned aspect, it is preferable that the steel segment has a plate that forms the wall surface of the segment structure and a main girder that is erected at both short-side ends of the plate, and that the main girder has a pipe member that is provided along the axial direction of the segment structure and into which an inclinometer for inserting to measure the verticality of the segment structure is inserted.

[0016] One aspect of the present invention is a steel-concrete structure comprising the above-mentioned retaining structure and a fill section formed from concrete filled inside the retaining structure.

[0017] One aspect of the present invention is a steel segment that constitutes an earth retaining structure buried underground, comprising: a plate that forms the wall surface of the earth retaining structure; joint portions that are provided along the short side at both longitudinal ends of the plate and connect to adjacent steel segments; and ribs that are provided along the short side between the joint portions, and the joint portions or the ribs are provided with strain measuring portions that measure strain in the joint portions or ribs.

[0018] In addition, in the above aspect, it is preferable that a corrosion detection section be provided on the inner wall surface of the plate to detect corrosion of the fill section that is provided inside the retaining structure and integrated with the retaining structure.

[0019] In addition, in the above-mentioned aspect, it is preferable that the plate has a main girder erected at both ends in the short direction, and that the main girder has a pipe member into which an inclinometer for measuring the verticality of the retaining structure is inserted, arranged along the axial direction of the retaining structure.

[0020] One aspect of the present invention is a construction method for a structure using the above-mentioned retaining structure, characterized by comprising the steps of: connecting a plurality of steel segments in the longitudinal and lateral directions to construct a segment structure; pouring filler material inside the segment structure to integrate it with the segment structure; and providing the strain measurement unit at the joint portion or the rib of the steel segment before pouring the filler material inside the segment structure.

[0021] In the above aspect, it is preferable to have a step of providing a corrosion detection unit that detects corrosion of the filler portion on the inner wall surface of the plate of the steel segment that forms the wall surface of the segment structure before pouring the filler material inside the segment structure.

[0022] Furthermore, in the above-mentioned aspect, it is preferable to have a step of providing a pipe material, into which an inclinometer for measuring the verticality of the segment structure is inserted, along the axial direction of the segment structure on the main girder erected at both short-side ends of the plate of the steel segment that forms the wall surface of the segment structure before pouring the fill material inside the segment structure.

[0023] One aspect of the present invention is a method for maintaining a structure, characterized in that a measuring device installed in the above-mentioned retaining structure is used to measure parameters necessary for maintaining the long-term function of the structure after construction.

[0024] One aspect of the present invention is a method for measuring parameters of a structure, characterized in that a measuring device installed in the above-mentioned retaining structure measures parameters necessary for maintaining and managing the long-term functionality of the structure after construction.

[0025] One aspect of the present invention is a method for monitoring a structure, characterized in that a measuring device installed in the above-mentioned retaining structure measures parameters necessary for maintaining and managing the long-term function of the structure after construction, and monitors the condition of the structure. [Effects of the Invention]

[0026] According to one aspect of the present invention, it is possible to maintain and manage the long-term functionality of steel-concrete structures used underground, such as foundation structures, after construction. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic diagram showing a bridge pier and deck slab based on a foundation structure according to the present invention. [Figure 2] FIG. [Figure 3] FIG. 2 is a plan view of a steel segment. [Figure 4] FIG. 10 is a front view of the steel segment as seen from the inside. [Figure 5]FIG. 2 is a perspective view of a steel segment. [Figure 6] FIG. 2 is a perspective view illustrating the configuration of a connecting mechanism. [Figure 7] FIG. 2 is a partial cross-sectional view illustrating the configuration of a foundation structure. [Figure 8] FIG. 10 is a diagram illustrating a construction method for constructing a foundation structure after constructing a segment structure. [Figure 9] FIG. 10 is a partial cross-sectional perspective view of a foundation structure according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The foundation structure in the embodiment serves as the foundation of a building on the ground, for example, the foundation (base) of a bridge pier. The foundation structure is an example of a steel-concrete structure that is buried underground. Note that the building to which the foundation structure is applied as a foundation is not limited to a bridge pier, and may also be a high-rise building or an apartment building, and is not particularly limited.

[0029] <First Embodiment> FIG. 1 is a schematic diagram showing a bridge pier 100 and a deck slab 110 based on a foundation 1. The deck slab 110 supported by the pier 100 is a portion on which vehicles such as automobiles and trains run and on which the load of the vehicles is directly applied. For ease of explanation, the center line of the foundation 1 will be referred to as axis x below. The direction in which the foundation 1 is embedded along axis x will be referred to as embedding direction A, and the direction around axis x will be referred to as circumferential direction C.

[0030] <Foundation structure> The foundation structure 1 is constructed below the pier 100. The foundation structure 1 is formed, for example, in a cylindrical shape. The foundation structure 1 includes a segment structure 10, a fill section 20, and main reinforcement 30.

[0031] The segment structure 10 is an earth retaining structure used when constructing an underground structure (for example, a foundation structure 1). The segment structure 10 is formed, for example, in a cylindrical shape and extends along an axis x that extends in an embedding direction A. The segment structure 10 is formed of a plurality of steel segments 40 that are continuously connected in the embedding direction A and in a circumferential direction C, and form an earth retaining wall when constructing the foundation structure 1, as well as a concrete formwork when constructing the fill section 20. Furthermore, since this technology uses the underground space after the construction of the retaining structure to install the measuring device, it can accommodate a variety of retaining shapes, including circular and rectangular. However, in the case of a circular structure, for example, an inner diameter of at least 1 m is required, and considering workability, an inner diameter of 3 m or more is ideal.

[0032] FIG. 2 is a plan view of the substructure 1. The segment structure 10 of the substructure 1 has a plurality of rings (annular bodies) 11 connected along an axis x in an embedding direction A. That is, the direction of the axis x of the segment structure 10 coincides with the embedding direction A. In the substructure 1, the rings 11 have a plurality of steel segments 40 connected to each other in an annular shape in the circumferential direction (the longitudinal direction of the steel segments 40) C, and can also function as tie-reinforcement substitutes that substitute for the ties of the substructure 1, as needed. That is, the rings 11 are connected in multiple units in the embedding direction (the lateral direction of the steel segments 40) A to form the substructure 1 and also substitute for the ties originally provided in each ring 11. Therefore, the rings 11 that substitute for the ties are arranged in a direction that intersects with the main reinforcement 30 (the cross-sectional direction of the substructure 1 that is perpendicular to the embedding direction A). In the ring bodies 11 adjacent to each other in the vertical direction (embedding direction A) along the axis x, the steel segments 40 of the upper ring body 11 and the steel segments 40 of the lower ring body 11 are arranged in a staggered pattern with their ends in the circumferential direction C shifted in the circumferential direction C. The number of steel segments 40 connected in the circumferential direction C is changed appropriately based on the size (outer diameter) of the foundation structure 1 to be constructed. FIG. 3 is a plan view of the steel segments 40 that make up the ring body 11. FIG. 4 is a front view of the steel segments 40 as seen from the inside. FIG. 5 is a perspective view of the steel segments 40. FIG. 6 is a perspective view illustrating the configuration of the connecting mechanism. The ring body 11, which replaces the hoops, comprises a plurality of steel segments 40 and a connecting mechanism 50.

[0033] The steel segment 40 is formed from steel material. The steel segment 40 has a plate 41, a main girder 42, a joint portion 43, and a rib (stiffener) 44. In the steel segment 40, the plate 41, the main girder 42, and the joint portion 43 define a filling space S into which concrete that forms the infill portion 20 is filled. The main girder 42, the joint portion 43, and the rib 44 may all be joined to the plate 41 by welding, or a portion thereof may be formed integrally with the plate 41.

[0034] The plate 41 forms the outer wall surface of the substructure 1, specifically the segment structure 10. The plate 41 is formed in a rectangular shape in a plan view. The plate 41 is formed to be curved in an arc shape. The curvature of the plate 41 is determined based on the size of the substructure 1 to be constructed. As shown in Figures 1 to 4, a corrosion sensor 71 is provided on the inner wall surface of the plate 41 that forms the inner wall surface of the segment structure 10 as a corrosion detection unit that detects corrosion of the fill portion 20 (concrete) poured in the filling space S. The corrosion sensor 71 is a measuring device that measures parameters (corrosion of the fill portion 20, watertightness of the segment structure 10) necessary for maintaining and managing the long-term functionality of the foundation structure 1 after construction. The corrosion sensor 71 measures the chloride ion concentration in the surrounding area and detects changes in the chloride ion concentration due to water infiltration from outside the plate 41 or other factors. For example, one corrosion sensor 71 is provided per ring body 11. The corrosion sensors 71 are provided on multiple ring bodies 11 at intervals along the embedding direction A. The corrosion sensor 71 may be provided anywhere in the filling space S as long as it is embedded in the condensate portion 20; however, since the corrosion sensor 71 is susceptible to corrosion and in consideration of ease of installation, it is preferable that it be fixed to the plate 41 in a position as close as possible to the inner wall surface of the plate 41. The corrosion sensor 71 is placed on a pedestal 72 joined to the inner wall surface of the plate 41 by welding or the like, and is fixed to the pedestal 72. The cable 73 of the corrosion sensor 71 may be embedded in the condensate portion 20 together with the corrosion sensor 71, but is preferably led to the ground, for example, through a pipe for the cable 73 passed through the hole 42c in the main girder 42. Furthermore, in order to more accurately grasp the state of the packing section 20, a plurality of corrosion sensors 71 may be provided at intervals in the circumferential direction of one ring body 11. Alternatively, a plurality of corrosion sensors 71 may be provided at intervals in the direction toward the axis x (center) along the radial direction of one ring body 11. In this case, by forming the pedestal 72 to extend along the radial direction of the ring body 11, a plurality of corrosion sensors 71 can be fixed to one pedestal 72.

[0035] The main girders 42 are erected on two end edges (short-side end edges) of the plate 41 extending along the circumferential direction C. The main girders 42 are curved along the plate 41. The main girders 42 are erected on the inner surface of the plate 41, at approximately right angles to the plate 41. When the ring bodies 11 are stacked in the vertical direction, the main girders 42 face the steel segments 40 of the ring bodies 11 in the vertical direction. One main girder 42 is provided on the edge located on the aboveground side. The other main girder 42 is provided on the edge located on the underground side.

[0036] Each main beam 42 has a plurality of holes 42a, 42b, 42c formed therein. The holes 42a are connecting holes through which connectors (not shown), such as bolts, are inserted to connect the main girder 42 to other adjacent steel segments 40 above and below. The holes 42a are formed, for example, in a circular shape and penetrate the main girder 42 in the thickness direction (direction along the axis x). The holes 42a are formed to have a diameter slightly larger than the cross section of the connector (approximately 3 to 6 mm larger than the outermost diameter of the connector), but they do not need to be formed to a size that allows the poured concrete to pass through. Of course, the holes 42a may be formed to have a size that allows aggregate contained in the concrete to pass through the gap between the holes 42a and the connector. The shape of the holes 42a is not limited to a circular shape, and they may be formed in an elliptical, oval, or rectangular shape. The shape and size of the holes 42a can be freely changed as long as the design strength of the main girder 42 is satisfied. The holes 42a are provided on the connecting side between the plate 41 and the main girder 42. The holes 42a are provided at predetermined intervals in the extension direction of the main girder 42, from one end to the other in the circumferential direction C. The holes 42a of each main girder 42 facing the axis x are provided so as to be coaxial with each other.

[0037] The holes 42b are air vent holes that allow air to escape from the filling space S when concrete is filled, and also allow the concrete to flow. The holes 42b are formed, for example, in a circular shape and penetrate the main girder 42 in the thickness direction (direction along the axis x). The holes 42b are formed to a size that allows not only air but also aggregate contained in the concrete to pass through. The holes 42b are not limited to a circular shape, and may be formed in an elliptical, oval, or rectangular shape, and the shape and size can be freely changed within a range that satisfies the design strength of the main girder 42. Specifically, from the viewpoint of concrete inflowability, it is preferable that the minimum diameter of the holes 42b be larger than 10 mm, which is the maximum size of fine aggregate contained in concrete, and that the maximum diameter be 1 / 3 or less of the main girder width from the viewpoint of the impact on the strength of the main girder 42. The holes 42b are provided on the connection side between the plate 41 and the main girder 42. The holes 42a and 42b are formed on the same imaginary circle centered on the axis x. The holes 42b are formed between the holes 42a and 42a in the vicinity of both sides of the rib 44, from one end to the other in the circumferential direction C of the main girder 42. That is, the holes 42b are formed in the vicinity of the connection position of the main girder 42 with the rib 44. Furthermore, the holes 42b are formed in the vicinity of both end portions of the main girder 42 in the circumferential direction C. More specifically, some of the holes 42b are formed in positions sandwiched between the connection position of the main girder 42 with the joint portion 43 and the connection position of the second joint portion 52 (described later). The holes 42b in the main girder 42 facing the axis x are provided coaxially with each other.

[0038] The holes 42c are holes for a plurality of main reinforcements, through which a plurality of main reinforcements 30 are respectively inserted, and function as locking portions for locking the main reinforcements 30. The holes 42c are formed, for example, in a circular shape and penetrate the main girder 42 in the thickness direction (direction along the axis x). The holes 42c are formed to have a diameter slightly larger than the cross section of the main reinforcements. Specifically, from the viewpoint of workability, the minimum diameter of the holes 42c is preferably equal to or greater than the outermost diameter of the main reinforcements 30 (nominal diameter + rib heights on both sides) + 1 mm (allowance) on one side, and from the viewpoint of accuracy in the positioning of the main reinforcements, the maximum diameter of the holes 42c is preferably equal to or greater than the outermost diameter of the main reinforcements 30 + 10 mm on one side (allowable tolerance for cover ±10 mm, allowable tolerance for assembly work on the center-to-center spacing of the rebars ±20 mm). Furthermore, the main reinforcement 30 was set to D19 (nominal diameter 19.1 mm) and 1300 mm long, and the hole 42c was set to the minimum diameter of 25.1 mm (maximum rib height on one side 2 mm, margin on one side 1 mm). Insertion tests were conducted within a range of up to 1200 mm, which is the maximum distance between the full-scale main girders 42, and it was confirmed that insertion could be performed without any problems. However, the holes 42c do not need to be formed to a size that allows the poured concrete to pass through. Of course, the holes 42c may be formed to a size that allows the aggregate contained in the concrete to pass through the gap between the holes 42c and the main reinforcement. The holes 42c are not limited to being circular, and may be formed to be elliptical, oval, or rectangular, and the shape and size can be freely changed as long as the design strength of the main girder 42 is satisfied. Hole 42c is provided on the side opposite to the side on which holes 42a and 42b are formed, i.e., on the edge of the main girder 42 on the side of axis x (opposite the connection portion with plate 41). Holes 42c are provided at predetermined intervals from one end to the other in the circumferential direction C of the main girder 42. The holes 42c in the main girder 42 facing the axis x are provided coaxially with one another. Hole 42c and holes 42a and 42b are formed on different imaginary circles centered on axis x. As shown in Figures 1, 2, and 5, a cylindrical pipe member 81 is inserted into one of the multiple holes 42c instead of the main reinforcement bars 30. The pipe member 81 is provided along the axis x direction of the segment structure 10. The pipe member 81 is formed to a size that allows an inclinometer 82, which measures the verticality of the segment structure 10, to be inserted therein. The inclinometer 82 is a measuring device that measures a parameter (the verticality of the segment structure 10) necessary for maintaining and managing the long-term functionality of the foundation structure 1 after construction. For example, a groove is formed in the inner peripheral wall of the pipe member 81, and the inclinometer 82 can run along this groove. Here, if the outer diameter of the pipe member 81 is larger than that of the hole 42c, the diameter of the hole 42c through which the pipe member 81 is inserted may be enlarged to match the outer diameter of the pipe member 81, or the pipe member 81 may be inserted into a hole separately formed in the main girder 42 for the pipe member 81, or may be joined to the edge of the main girder 42 by welding or the like. The inclinometer 82 measures the verticality of the foundation structure 1 in the direction of the bridge axis and in the direction perpendicular to the bridge axis, making it possible to check for the presence or absence of harmful deformation.

[0039] The joint portions 43 are provided on edges (longitudinal edges) extending along the axis x (short direction of the steel segments 40) at each end of the plate 41 in the circumferential direction C (both longitudinal ends of the steel segments 40). The joint portions 43 extend along the axis x between the main girders 42 at the ends of the main girders 42 in the circumferential direction C. The joint portions 43 come into contact with and are connected to the joint portions 43 of other steel segments 40 adjacent in the circumferential direction C. The joint portion 43 is erected on the inner surface of the plate 41 so as to extend from the plate 41 toward the axis x. One end of the joint portion 43 extending along the axis x is connected to the plate 41, and the other end extends to just before the inner edge of the main girder 42. The edges of the joint portion 43 extending toward the axis x are each connected to the main girder 42. The joint portion 43 has a plurality of holes 43a formed in two rows along the axis x at predetermined intervals along the axis x, through which the connecting portion 51 (see FIG. 2) is inserted. In addition to the hole 43a, the joint portion 43 has a plurality of holes 43b formed along the embedding direction A (longitudinal direction). The holes 43b are holes that communicate the spaces V of adjacent steel segments 40 when concrete is filled, and allow the concrete to flow into each space V. Therefore, it is preferable that the holes 43b of opposing joint portions 43 in adjacent steel segments 40 are formed concentrically. The holes 43b are formed, for example, in a circular shape and penetrate the joint portion 43 in the thickness direction. The holes 43b are formed to a size that allows aggregate contained in the concrete to pass through. Note that the shape of the holes 43b is not limited to a circle, and they may be formed in an elliptical, oval, or rectangular shape, and the shape and size can be freely changed as long as the design strength of the joint portion 43 is satisfied. Specifically, from the viewpoint of the flowability of concrete, it is preferable that the minimum diameter of hole 43b is larger than 10 mm, which is the maximum size of fine aggregate contained in concrete, and that the maximum diameter is 1 / 3 or less of the width of the joint part (perpendicular to the axis of the foundation) from the viewpoint of the impact on the strength of joint part 43. For example, six holes 43b are formed so as to sandwich the hole 43a in the longitudinal direction of the joint part 43. The number of holes 43b is not limited, and can be freely changed within a range that satisfies the design strength of the joint part 43.

[0040] As shown in FIGS. 1 to 4 , the joint 43 is provided with a strain gauge 91 as a strain measuring unit that measures strain at the joint 43. The strain gauge 91 is a measuring device that measures parameters (axial strain of the segment structure 10, vertical load acting on the segment structure 10) necessary for maintaining and managing the long-term functionality of the foundation 1 after construction. The strain gauge 91 measures the vertical load acting on the joint 43, thereby making it possible to check the state of load transmission to the joint 43. For example, a plurality of strain gauges 91 (for example, four as shown in FIG. 2 ) are provided per ring body 11. Specifically, as shown in FIG. 2 , the strain gauges 91 are provided at approximately equal intervals along the circumferential direction (extension direction) C of the ring body 11. Furthermore, of the plurality of strain gauges 91, at least one pair of strain gauges 91 is provided on steel segments 40 that face each other across the center (axis x) of the ring body 11. This is to measure the vertical load in the bridge axis direction and in the direction perpendicular to the bridge axis, thereby more accurately grasping the vertical load distribution in the cross section of the foundation structure 1. The strain gauges 91 are installed on multiple ring bodies 11 at intervals along the embedding direction A. Specifically, the strain gauges 91 are installed on the steel segments 40 in the ring bodies 11 located at the upper and lower ends of the segment structure 10. That is, the strain gauges 91 are installed on the uppermost ring body 11t of the segment structure 10, which is closest to the ground surface, and on the ring body 11b that constitutes the cutting edge ring buried at the deepest position. It is sufficient that the strain gauges 91 are installed on at least one of the ring bodies 11t and 11b. The cables 92 of the strain gauges 91 may be buried in the infill section 20 together with the strain gauges 91, but it is preferable to lead them to the ground through a pipe for the cables 73 that is passed through the hole 42c in the main girder 42. In order to grasp the vertical load distribution more accurately, the strain gauges 91 may be provided on ring bodies 11 other than those at the top and bottom ends of the segment structure 10. In Figure 2, of the four strain gauges 91 in one ring body 11, one strain gauge 91 is provided on the joint section 43 and the remaining three strain gauges 91 are provided on the rib 44. However, whether the strain gauges 91 are provided on the joint section 43 or the rib 44 can be freely changed depending on the size of the steel segment 40 and the arrangement of the ribs 44.

[0041] A plurality of ribs 44 are provided on the inner surface of the plate 41, extending between the two main girders 42 along the axis x. The ribs 44 are provided at predetermined intervals between the joint portions 43 provided at each end of the steel segment 40 in the circumferential direction C. The ribs 44 are erected to extend from the plate 41 toward the axis x. One end of the rib 44 extending along the axis x is connected to the plate 41, and the other end extends to just before the inner edge of the main girder 42. The edges of the ribs 44 extending toward the axis x are each connected to the main girders 42. In the main girder 42, holes 42b are formed on both sides of each rib 44 in the circumferential direction C. The holes 42b are formed near corners formed by the ribs 44 and the plates 41. The outermost hole 42b in the circumferential direction C is formed between the joint portion 43 and a second joint portion 52 (described later). The rib 44 is provided with a strain gauge 91 as a strain measuring unit that measures the strain of the rib 44. The strain gauge 91 measures the vertical load acting on the rib 44, thereby making it possible to check the state of load transmission to the rib 44. In FIG. 2, one of the four strain gauges 91 in one ring body 11 is provided in the joint portion 43, and the remaining three strain gauges 91 are provided in the rib 44.

[0042] As shown in FIG. 6, the connecting mechanism 50 includes a connecting portion 51, a second joint portion 52, a joint rib 53, and a filling portion . The connecting portion 51 is inserted through the joint portion 43 and the second joint portion 52, and connects the steel segments 40 that are adjacent in the circumferential direction (longitudinal direction). The connecting portion 51 is composed of, for example, a bolt 51a and a nut 51b. The connecting portion 51 is inserted through a hole 43a formed in the joint portion 43 and a hole 52a formed in the second joint portion 52. The second joint portions 52 are provided near both ends of the steel segment 40 in the circumferential direction C, at a predetermined interval in the circumferential direction C from each joint portion 43, and parallel to each other. The second joint portions 52 are provided on the inner surface of the plate 41 and stand so as to extend from the inner surface toward the axis x. One end of the second joint portion 52 extending along the axis x is connected to the plate 41, and the other end extends to just before the inner edge of the main girder 42. Both end edges of the second joint portion 52 extending toward the axis x are each connected to the main girder 42.

[0043] The second joint portion 52 has a plurality of holes 52a formed at predetermined intervals along the axis x, through which the bolts 51a of the connecting portion 51 are inserted. For example, six holes 52a are formed, and three holes 52a are lined up in the short direction (embedding direction A) of the steel segment 40, and the holes 52a are formed in two rows along the thickness direction of the steel segment 40. The holes 43a of the joint portion 43 and the holes 52a of the second joint portion 52 are provided in positions facing each other in the circumferential direction C. Therefore, six bolts 51a are provided to be inserted into both holes 43a, 52a, and adjacent steel segments 40 are connected by these six bolts 51a and nuts 51b. When connecting adjacent steel segments 40 in the circumferential direction C, the bolts 51a of the connecting portion 51 are inserted into the holes 43a, 52a of the four joint portions 43, 52, respectively, and nuts 51b are screwed onto the ends of the bolts 51a from the outside of the second joint portions 52. At this time, the nuts 51b abut against the second joint portions 52. In this way, the steel segments 40 are connected to each other in the circumferential direction C. When a bolt 51a having a head is used, the head of the bolt 51a abuts against one of the second joint portions 52, and the nut 51b abuts against the other of the second joint portions 52 and is screwed onto the bolt 51a. In this way, the steel segments 40 are connected to each other in the circumferential direction C.

[0044] In addition to the hole 52a, the second joint portion 52 has a plurality of holes 52b formed along the embedding direction A (longitudinal direction). The holes 52b communicate with the inside and outside of the space V when concrete is filled, allowing the concrete to flow between the inside and outside of the space V. The holes 52b are formed, for example, in a circular shape and penetrate the second joint portion 52 in the thickness direction. The holes 52b are formed to a size that allows the aggregate contained in the concrete to pass through. Note that the shape of the holes 52b is not limited to a circular shape, and they may be formed in an elliptical, oval, or rectangular shape. The shape and size of the holes 52b can be freely changed within a range that satisfies the design strength of the second joint portion 52. Specifically, from the viewpoint of concrete inflowability, the minimum diameter of the holes 52b is preferably larger than 10 mm, which is the maximum size of fine aggregate contained in concrete, and the maximum diameter is preferably ⅓ or less of the width of the second joint portion 52 (in the direction perpendicular to the axis of the foundation) from the viewpoint of the influence on the strength of the second joint portion 52. For example, six holes 52b are formed so as to sandwich the hole 52a in the longitudinal direction of the second joint part 52. The number of holes 52b is not limited and can be freely changed within a range that satisfies the design strength of the second joint part 52. Furthermore, it is preferable that the holes 52b are formed at positions facing the holes 43b in the circumferential direction C, but the positions of the holes 52b are not limited to this position.

[0045] The joint rib 53 is provided between the adjacent joint portion 43 and second joint portion 52 in the circumferential direction C. The joint rib 53 is provided parallel to the main girder 42 so as to intersect with the axis x. The joint ribs 53 are provided parallel to one another at predetermined intervals along the axis x. More specifically, the joint ribs 53 are provided between the bolts 51a of the connecting portion 51 and along the axial direction of the bolts 51a. The joint ribs 53 are provided on the inner surface of the plate 41 and stand so as to extend from the inner surface toward the axis x. One end of each joint rib 53 in the direction intersecting the axis x is connected to the joint portion 43, and the other end is connected to the second joint portion 52. As a result, each joint rib 53 divides the space V surrounded by the joint portion 43 and the second joint portion 52. A hole 53b is formed in the approximate center of the joint rib 53. The hole 53b connects the spaces partitioned by the joint rib 53 within the space V when concrete is filled, allowing the concrete to flow between the spaces. The hole 53b is formed, for example, in a circular shape and penetrates the joint rib 53 in the thickness direction. The hole 53b is formed to a size that allows the aggregate contained in the concrete to pass through. The shape of the hole 53b is not limited to a circular shape, and it may be formed in an elliptical, oval, or rectangular shape. The shape and size of the hole 53b can be freely changed within a range that satisfies the design strength of the joint rib 53. Specifically, from the viewpoint of concrete inflowability, the minimum diameter of the hole 53b is preferably larger than 10 mm, which is the maximum size of fine aggregate contained in concrete, and the maximum diameter is preferably 1 / 3 or less of the width of the joint rib 53 (in the direction perpendicular to the axis of the foundation) from the viewpoint of the influence on the strength of the joint rib 53. For example, one hole 53b is formed near the center of the joint rib 53. The number of holes 53b is not limited and can be freely changed within a range that satisfies the design strength of the joint rib 53. Furthermore, it is preferable that the holes 53b formed in each joint rib 53 are formed at positions facing each other along the embedding direction A, but the positions of the holes 53b are not limited to this position.

[0046] The filling section 54 is provided in the space V surrounded by the plate 41, the main girder 42, the joint section 43, and the second joint section 52, and is integrated with the bolt 51a of the connecting section 51. Specifically, the filling section 54 is concrete, and is integrated with the steel segment 40 and the connecting mechanism 50 by being poured into the space V and solidifying. Here, the space V is partitioned by the joint ribs 53, and the space V is divided into multiple spaces. The filling section 54 is formed by filling the space V with concrete poured when constructing the infill section 20.

[0047] The spacing between adjacent holes 43a, 52a is determined so that the pitch of the bolts 51a inserted through these holes 43a, 52a is equal to or less than the pitch required for the ties in the design. Specifically, for a general foundation, in other words, when the segment structure 10 cannot be used as part of a foundation, the spacing of the bolts 51a is determined so that it is equal to or less than the pitch of the ties wrapped around the main reinforcement, which is designed based on the size and required strength of the foundation. For example, if the designed pitch of the ties is 150 mm, the center-to-center spacing of the bolts 51a connecting the steel segments 40 must also be 150 mm or less. The diameter and number of bolts 51a are selected so that the total cross-sectional area of ​​the bolts 51a per height of the steel segment 40 is equal to or greater than the total cross-sectional area of ​​the tie bars per height. For example, if the bolts 51a are D41 (cross-sectional area 1340 mm 2 ) The total cross-sectional area of ​​the tie bars is 5360 mm 2 In this case, M33 (effective cross-sectional area 694 mm 2 When using bolts 51a conforming to the standard JIS 1001-1002, it is necessary to connect the steel segments 40 using at least eight bolts 51a.

[0048] The material of the bolt 51a is selected so that the strength of the bolt 51a (yield stress of the material) is equal to or greater than the strength of the hoop (yield stress). For example, if the hoop is D41 (yield stress 345 N / mm 2 ) is used, M33 (yield stress 480N / mm 2) standard bolt 51a is used, there is no problem in terms of strength. It is possible to reduce the number of bolts 51a used by using bolts with a larger standard than M33, but larger bolts 51a require a larger torque to tighten, which reduces workability. Therefore, a structure in which multiple bolts 51a are arranged in the thickness direction of the segment, as shown in Figure 6, is preferable. This makes it possible to determine the size and number of bolts 51a to be used by considering the balance between the effort required to tighten the bolts 51a and the required tightening torque. In addition, in parts other than the joint part 43, the thickness and material are determined so that the sum of the cross-sectional areas and strength of the plate 41 and main girder 42 are greater than or equal to the sum of the cross-sectional areas and strength of the designed tie bars.

[0049] The main reinforcement 30 is, for example, a reinforcing bar made of steel. The main reinforcement 30 is arranged on a predetermined imaginary circle centered on the axis x. The main reinforcement 30 extends along the embedding direction A and is arranged at predetermined intervals in the circumferential direction C. Note that the main reinforcement 30 arranged at the same location in the segment structure 10 may be a single reinforcing bar extending along the axis x, or may be formed by multiple reinforcing bars having a predetermined length. The main reinforcement 30 extends at least from the upper end of the segment structure 10 on the aboveground side to the other end on the underground side. The main reinforcement 30 is inserted through the holes 42c in each steel segment 40 along the axis x. The main reinforcement 30 is formed integrally with the steel segment 40 when the filled portion 20 cast inside the segment structure 10 solidifies.

[0050] The filler section 20 is provided inside the cylindrical segment structure 10 formed by connecting the ring bodies 11 in the height direction. The filler section 20 is formed when poured concrete solidifies, and in the foundation structure 1, the inside of the steel segments 40 is filled with the filler section 20 and is integrated with the segment structure 10.

[0051] <Method of constructing foundation structures> Next, we will explain how to construct the foundation 1. An embedding device (not shown) made up of, for example, a hydraulic jack or the like is installed at the location where the foundation 1 is to be constructed. The embedding device is provided at multiple locations in the circumferential direction C of the annular foundation 1.

[0052] Next, the steel segments 40 are connected in the circumferential direction C (longitudinal direction) inside the burying device to form the annular ring body 11. When forming the ring body 11, bolts 51a are inserted into the joint portion 43 and the second joint portion 52 and fastened with nuts 51b. Furthermore, another ring body 11 is formed on top of the ring body 11 to connect the two. Another ring body 11 is formed on top of this other ring body 11 to connect the two. The ground inside the ring body 11 is excavated using a clamshell (not shown). Once the excavation has been completed to the depth required to bury the ring body 11 in the ground, the excavation is stopped, and the top surface of the ring body 11 is pressed into the ground by the burying device, thereby pressing the ring body 11 into the ground.

[0053] Next, multiple other ring bodies 11 are assembled on top of the buried ring body 11. The ground inside the ring body 11 is excavated to the required depth using a clamshell, and the ring body 11 is pressed into the ground using an embedding device, burying the ring body 11 in the ground. This process is repeated to the specified depth. In this way, a cylindrical segment structure 10 is constructed in which multiple ring bodies 11 are connected in the ground along the axis x. The positions of the joint portions 43 of the steel segments 40 of adjacent ring bodies 11 on the top and bottom are offset from each other in the circumferential direction C, and the steel segments 40 are arranged in a staggered pattern.

[0054] Next, the groundwater filling the inside of the segment structure 10 is discharged to the outside using a submersible pump (not shown). Next, main reinforcement 30 is inserted along the axis x into each steel segment 40 of the ring body 11 on the aboveground side. The method of forcing the ring body 11 into the ground by press-fitting along the height direction is extremely accurate in the height direction along the axis x, and the alignment of the holes 42c of the steel segments 40 of the ring bodies 11 stacked one on top of the other is extremely high. Note that the main reinforcement 30 may be multiple reinforcing bars of a predetermined length inserted through the same hole 42c of the ring body 11 at the top of the segment structure 10 and connected along the way as appropriate.

[0055] FIG. 7 is a partial cross-sectional view illustrating the configuration of the foundation structure 1. In FIG. 7, the foundation structure 1 is drawn so that the degree of completion increases from the left half to the right half. After the segment structure 10 is constructed to the designed height, a predetermined number of main reinforcements 30 (reinforcing bars) are inserted into the same holes 42c in the circumferential direction C, as shown in FIG. 8(a) (see the right side of FIG. 7). If one main reinforcement 30 is insufficient for the height of the segment structure 10, multiple main reinforcements 30 are inserted and the ends are connected together by mechanical joints, welding, etc.

[0056] After the main reinforcement bars 30 have been installed around the entire circumference, strain gauges 91 are attached to the joints 43 and ribs 44 of the steel segments 40 in the uppermost and lowermost ring bodies 11 of the segment structure 10. Four strain gauges 91 are installed at approximately equal intervals along the circumferential direction C of the ring body 11. In other words, the strain gauges 91 are placed every 90° as viewed from the center of the segment structure 10. The strain gauges 91 are fixed to the joints 43 and ribs 44 by welding or the like. The cables 92 of the strain gauges 91 are passed through pipe material and led to the ground. Furthermore, instead of the main reinforcement 30, a pipe material 81 is passed through one of the holes 42c of the steel segment 40 and fixed to the main girder 42. The pipe material 81 is arranged along the axis x direction of the segment structure 10. Depending on the inclinometer 82, the diameter of the pipe material 81 may also become large. Therefore, if the pipe material 81 cannot be passed through the hole 42c, the pipe material 81 is fixed to the edge of the main girder 42 by welding or the like. In addition, a pedestal 72 is fixed to the inner wall surface of the plate 41 of the steel segment 40 in a predetermined ring body 11 by welding or the like, and a corrosion sensor 71 is placed on the pedestal 72 and fixed thereto.

[0057] After the corrosion sensors 71, pipe material 81, and strain gauges 91 are installed, concrete that will form the filled section 20 is poured in stages inside the segment structure 10, as shown in FIG. 8(b). The poured concrete spreads toward the plate 41. The concrete that is gradually poured increases in volume toward the ground. The concrete fills the filled space S while pushing out the air inside the filled space S through the holes 42b. This reliably prevents air pockets from forming inside the foundation 1. The concrete also flows into the space V surrounded by the plates 41, main girders 42, joints 43, and second joints 52 that open to the inside of the segment structure 10, and after the concrete hardens, it becomes integrated with the bolts 51a of the connecting parts 51 as filling parts 54. This strengthens the connection between adjacent steel segments 40.

[0058] As shown in FIG. 8( c), the process of inserting the main reinforcement 30 into the hole 42c, attaching the corrosion sensor 71, the pipe material 81, and the strain gauge 91, and pouring concrete is repeated until the concrete is poured up to the top end of the segment structure 10, forming the filled section 20. As a result, the main reinforcement 30 and the steel segments 40 are integrated with each other via the filled section 20, and the foundation 1 is constructed. At this time, the main reinforcement 30 functions as the main reinforcement of the foundation 1 (reinforced concrete structure), and the ring body 11 to which the steel segments 40 are connected by the connecting mechanism 50 functions as hoop reinforcement of the foundation 1 (reinforced concrete structure). Note that this technology is not limited to the order of inserting the main reinforcement 30 into the hole 42c and attaching the corrosion sensor 71, the pipe material 81, and the strain gauge 91, and they can be arranged in any order.

[0059] The method of constructing the foundation structure 1 by press-fitting the steel segments 40 is extremely suitable, for example, for repairing bridge piers 100 on an elevated road. The vertical space under an elevated road is limited. The method of constructing the ring bodies 11 and press-fitting them into the ground is less subject to vertical space restrictions. Note that the main reinforcement 30 may be inserted each time multiple stages of the ring bodies 11 are buried in the ground. The above-mentioned measuring devices (corrosion sensor 71, strain gauge 91, inclinometer 82) are used to measure parameters necessary for maintaining and managing the long-term functionality of the foundation structure 1 after construction, and the measured parameters are checked periodically to monitor the condition of the foundation structure 1. Maintenance and management of the foundation structure 1 is carried out in this manner. This technology enables long-term maintenance of the foundation structure 1, but regular inspections are not necessarily required, and the frequency of inspections can be set as desired. For example, it is possible to operate pre-installed measuring devices to measure each parameter only if there is concern about damage or changes in condition after an earthquake.

[0060] According to the foundation structure 1 having the earth-retaining structure 10 described above, by providing strain gauges 91 at the joints 43 or ribs 44 of the steel segments 40, it is possible to measure the vertical load acting on the joints 43 or ribs 44 extending in the axial x direction of the segment structure 10. As a result, by understanding the vertical load distribution measured by the strain gauges 91 at each position, it is possible to check the state of load transmission to the foundation ground, and it becomes possible to perform maintenance and management of the foundation structure 1. Furthermore, because the measuring device is installed after the construction of the earth-retaining structure (segment structure) 10, there is no resistance or damage from the measuring device during construction of the earth-retaining structure 10, and it can be installed simply and accurately without the need for special protective materials. Furthermore, by providing multiple strain gauges 91 on one ring body 11, it is possible to grasp the vertical load distribution more accurately. Here, by providing two pairs of strain gauges 91 on steel segments 40 that face each other across the center of the ring body 11, it is possible to measure the vertical load in the direction of the bridge axis and in the direction perpendicular to the bridge axis, thereby making it possible to grasp the vertical load distribution more accurately. As the strain gauges 91 are provided at the upper and lower ends of the segment structure 10, it is possible to check the transmitted load distribution at the upper and lower ends of the segment structure 10. Furthermore, by providing corrosion sensors 71 on the inner wall surfaces of the plates 41 of the steel segments 40, it is possible to check the corrosion status of the fill section 20, and therefore the watertight performance of the segment structure 10 (the status of water seepage into the segment structure 10) can be confirmed. By providing multiple corrosion sensors 71 along the radial direction of the ring body 11 or by providing them on multiple ring bodies 11, it is possible to check the watertight performance of the segment structure 10 in more detail. In addition, by passing the pipe material 81 into which the inclinometer 82 is inserted through the hole 42c of the main girder 42 or by attaching it to the edge of the main girder 42, after the foundation structure 1 is constructed, the inclinometer 82 can be inserted into the pipe material 81 to measure the verticality of the foundation structure 1.

[0061] <Embodiment 2> A second embodiment, which is a modified example of the present invention, will be described. FIG. 9 is a partial cross-sectional perspective view of a foundation 1A. The foundation 1A comprises a cylindrical segment structure 10A and multiple main reinforcements 30A. The segment structure 10A extends along an axis x extending in an embedding direction A. The main reinforcements 30A extend along the axis x and are arranged at predetermined intervals in a circumferential direction C around the axis x, and engage with the segment structure 10A. The segment structure 10A is formed of multiple steel segments 40A that are continuously connected in the embedding direction A and the circumferential direction C to form a wall surface. The steel segments 40A include an outer piece 60 that forms the outer wall of the segment structure 10A, and an inner piece 65 that forms the inner wall of the segment structure 10A. A filler section 80 is provided between the outer piece 60 and the inner piece 65. The main reinforcements 30A, the steel segments 40A, and the filler section 80 are integrated with each other. The configuration of the foundation 1A will be described in detail below.

[0062] The foundation 1A comprises a segment structure 10A, a fill section 80, and main reinforcement bars 30A. The segment structure 10A has a plurality of ring bodies (only some of which are shown) 11A that connect a plurality of steel segments 40A in the circumferential direction C and can function as hoop substitutes that replace hoops. The steel segments 40A have an outer piece 60, an inner piece 65, and a connecting piece 70. The outer piece 60 forms the outer wall of the foundation 1A. The inner piece 65 forms the inner wall of the foundation 1A. The connecting piece 70 connects the outer piece 60 and the inner piece 65 to each other.

[0063] The outer piece 60 has a plate 61, a main girder 62, a joint portion 63, and a rib (stiffener) 64. In the outer piece 60, the plate 61 and the main girder 62 define a filling space S1 when filling with concrete that forms a filled portion 80 (described later). The plate 61 forms the outer wall surface of the foundation structure 1A. The main girders 62 are erected along the edges of the plates 61 extending in the circumferential direction C. A plurality of holes 62a, 62b, and 62c are formed in each main girder 62. The holes 62a, 62b, and 62c have the same configuration and function as the holes 62a, 62b, and 62c of the steel segment 40A. The main girders 62, joint portions 63, and ribs 64 have the same configuration as the main girders 62, joint portions 63, and ribs 64 of the steel segment 40A. Here, strain gauges 91 are provided on the joints 63 and the ribs 64. The number and arrangement of the strain gauges 91 are the same as those of the foundation structure 1 described above, but may be changed. Furthermore, a pipe material 81 on which an inclinometer 82 runs is inserted into the hole 62c of the main girder 62. The pipe material 81 may be provided on the edge of the main girder 62 depending on the diameter. Furthermore, corrosion sensors 71 are provided on the plate 61. The number and arrangement of the corrosion sensors 71 are the same as those of the foundation structure 1 described above, but may be changed.

[0064] The inner piece 65 has a plate 66, a main girder 67, a joint 68, and a rib (stiffener) not shown in the drawing. In the inner piece 65, the plate 66 and the main girder 67 define a filling space (not shown) when filling with concrete to form the infill section 80. The plate 66 forms the inner wall surface of the foundation structure 1A. In the inner piece 65, the plate 66 is provided along the edge of the main girder 67 on the opposite side to the outer piece 60. The main girders 67 are erected along the edges of the plates 66 extending in the circumferential direction C. Each main girder 67 has a plurality of holes 67a, 67b, and 67c formed therein. The holes 67a, 67b, and 67c have the same configuration and function as the holes 67a, 62b, and 62c of the steel segment 40A. The main girders 67, joint portions 68, and ribs have the same configuration as the main girders 42, joint portions 43, and ribs 44 of the steel segment 40. The steel segments 40A are connected to each other by a connecting mechanism (not shown) in the circumferential direction C. The configuration of the connecting mechanism in the foundation 1A is the same as the configuration of the connecting mechanism 50 in the foundation 1. Similarly to the outer piece 60, the inner piece 65 may also be provided with strain gauges 91 at the joints 68 and ribs (not shown). The number and arrangement of the strain gauges 91 are the same as those of the foundation structure 1 described above, but may be changed. A pipe member 81 through which an inclinometer 82 runs may be inserted into the hole 67c of the main girder 67. The pipe member 81 may be provided at the edge of the main girder 67 depending on the diameter. A corrosion sensor 71 may also be provided on the plate 66.

[0065] The connecting pieces 70 increase the shear strength of the steel segments 40A. A plurality of connecting pieces 70 are provided between the outer piece 60 and the inner piece 65. The connecting pieces 70 are joined to the filler portion 80, thereby increasing the unity between the outer piece 60 and the inner piece 65. The connecting piece 70 is formed from a steel bar. The connecting piece 70 connects the outer piece 60 and the inner piece 65 between both ends of the outer piece 60 and the inner piece 65 in the circumferential direction C. The connecting piece 70 spans the rib 64 of the outer piece 60 and the rib of the inner piece 65. The connecting piece 70 is fixed to the upper and lower ends of the rib 64 of the outer piece 60 and the rib of the inner piece 65, respectively, in the height direction of the steel segment 40A along the axis x. The filling section 80 is provided between the outer piece 60 and the inner piece 65.

[0066] A method for constructing the foundation 1A using the steel segments 40A will be described. The method for constructing the foundation 1A is the same as the method for constructing the foundation 1. The steel segments 40A are connected in the circumferential direction C to form an annular ring body 11A. After stacking and connecting multiple ring bodies 11A in the vertical direction, the ground inside the ring body 11A is excavated using a clamshell (not shown). Once the excavation has been completed to the depth required to bury the ring body 11A in the ground, the excavation is stopped, and an embedding device is used to press the top surface of the ring body 11A toward the ground, thereby pressing the ring body 11A into the ground. This process is repeated until the segment structure 10A reaches the designed height, after which the groundwater filling the inside of the segment structure 10A is discharged to the outside using a submersible pump (not shown). After that, a predetermined number of main reinforcements 30A (reinforcing bars) are inserted into the same holes 62c in the circumferential direction C.

[0067] After the main reinforcement bars 30A have been installed around the entire circumference, strain gauges 91 are attached to the joints 63 and ribs 64 of the outer pieces 60 of the steel segments 40A in the uppermost and lowermost ring bodies 11A of the segment structure 10A. Four strain gauges 91 are installed at approximately equal intervals along the circumferential direction C of the ring body 11A. In other words, the strain gauges 91 are placed every 90° when viewed from the center of the segment structure 10A. The strain gauges 91 are fixed to the joints 63 and ribs 64 by welding or the like. Furthermore, instead of the main reinforcement 30A, a pipe material 81 is passed through one of the holes 62c of the main girder 62 and fixed to the main girder 62. The pipe material 81 is arranged along the axis x direction of the segment structure 10A. Depending on the inclinometer 82, the diameter of the pipe material 81 may also become large. Therefore, if the pipe material 81 cannot be passed through the hole 62c, the pipe material 81 is fixed to the edge of the main girder 62 by welding or the like. Furthermore, a pedestal 72 is fixed to the inner wall surface of the plate 61 of the outer piece 60 of a predetermined ring body 11A by welding or the like, and a corrosion sensor 71 is placed on the pedestal 72 and fixed thereto. The corrosion sensor 71 , the pipe material 81 , and the strain gauge 91 may be provided in the inner piece 65 .

[0068] After installing the corrosion sensors 71, pipes 81, and strain gauges 91, concrete is poured between the outer piece 60 and the inner piece 65 of the segment structure 10A. The poured concrete spreads between the outer piece 60 and the inner piece 65. This completes the construction of a foundation 1A in which multiple ring bodies 11A are connected underground along the axis x. The foundation 1A is a cylindrical structure with a hollow space inside the inner piece 65. Alternatively, the concrete may be poured in stages. Specifically, after multiple ring bodies 11A stacked to a predetermined height are pressed into the ground, the main reinforcement 30 is inserted into the holes 62c, 67c in the outer piece 60 and the inner piece 65 of the pressed-in ring bodies 11A. After the main reinforcement 30 is inserted, concrete is filled between the outer piece 60 and the inner piece 65. After the concrete has hardened, multiple other ring bodies 11A are assembled on top of the buried ring body 11A. The ground inside the ring body 11A is excavated to the required depth using a clamshell, and the ring body 11A is pressed into the ground using an embedding device, further embedding the ring body 11A in the ground. After burying the steel segments 40A, the main reinforcement 30 is inserted into the steel segments 40A, and the lower ends of the main reinforcement 30 are connected to the upper ends of the main reinforcement 30 inserted in the steel segments 40A that were previously buried in the ground. Next, concrete is filled between the outer piece 60 and the inner piece 65. This process is repeated to a predetermined depth. In this way, a foundation 1A is constructed in the ground, with multiple ring bodies 11A connected along the axis x. In addition, in this embodiment 2, as in embodiment 1, the order of inserting the main reinforcement 30 into the hole 42c, and installing the corrosion sensor 71, pipe material 81, and strain gauge 91 is not limited, and they can be arranged in any order.

[0069] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and includes all aspects encompassed by the concept of the present invention and the scope of the claims. Furthermore, the configurations of the above embodiments may be appropriately and selectively combined to achieve at least some of the above-described problems and effects. Furthermore, for example, the shape, material, arrangement, size, etc. of each component in the above embodiments may be appropriately modified depending on the specific use of the present invention.

[0070] The type, arrangement procedure, position, and number of measuring devices can be set arbitrarily, without being limited to the above. For example, the strain gauge (strain measurement unit) 91 only needs to be able to measure the axial strain of the foundation structure (structure) 1, and does not necessarily have to measure at the joint 43 or rib 44. The corrosion sensor (corrosion detection unit) 71 only needs to be able to detect corrosion in the filled section 20, and is not limited to the plate 41 as long as it is on the inner wall surface. The pipe material 81 into which the inclinometer 82 that measures verticality is inserted only needs to be provided along the axial direction of the foundation structure 1, and does not necessarily have to be the main girder 42. Furthermore, it is also possible to measure the condition of the retaining structure 10 itself as needed to improve the maintenance performance of the structure 1. For example, the opening size of the joints 43, the amount of corrosion of the steel material, the load sharing rate of each member, etc. can be measured using a measuring device suitable for the measurement item.

[0071] It is desirable to use a measuring device that has excellent long-term durability, such as one that uses optical fiber.

[0072] This technology is not limited to foundation structures; it can be effective on any steel-concrete structure used underground, and can be applied to any retaining structure, regardless of material, including permanent or temporary structures, joint structures, and deep foundations for landslide prevention measures. For example, it can be used not only for steel segments, but also for composite segments, RC segments, concrete segments, etc., and can also be applied to hollow concrete caissons, liner plates, steel pipe sheet piles, steel sheet piles, corrugated steel plates, etc. [Explanation of symbols]

[0073] 1. Foundation structure (steel-concrete structure) 10 Segment structure (earth retaining structure) 11 Ring body (replacement for tie bars) 20 Filling section 30 Main reinforcement 40 steel segments 41 Plate 42 Main girder 42c holes (holes through which the main reinforcement bars are inserted) 43 Joint 44 Rib (stiffener) 50 Connection mechanism 51 Connecting part 52 Second joint 53 Joint rib 54 Filling section 1A Foundation structure 10A Segment structure (earth retaining structure) 11A Ring body (replacement for tie bars) 30A main bar 40A Steel Segment 60 outer piece 61 Plate 62 Main digit 62c hole 65 Inner piece 66 Plate 67 Main digit 67c hole 70 Connecting Pieces 71 Corrosion Sensor 72 Pedestal 73 Cable 80 Inner filling section 81 Piping material 82 Inclinometer 91 Strain gauge 92 Cable A Burial direction C circumferential direction S,S1 Filling space (space) x-axis

Claims

1. An earth retaining structure used when constructing an underground structure, A retaining structure characterized by being equipped with a measuring device for measuring parameters necessary for maintaining and managing the long-term function of the structure after construction.

2. The retaining structure described in claim 1, characterized in that the parameters are at least one of the axial strain of the structure, corrosion of the filled portion, verticality of the structure, the amount of opening of the components that make up the structure, the amount of material corrosion, and the load distribution rate of each component.

3. The retaining structure is a segment structure in which a plurality of annular ring bodies, each formed by connecting a plurality of steel segments in the longitudinal direction, are connected in the lateral direction of the steel segments, and is integrated with a fill section provided inside the segment structure, The steel segments have joints provided at both longitudinal ends along the short side direction and connected to adjacent steel segments, and ribs provided between the joints along the short side direction, 3. The retaining structure according to claim 1, wherein the measuring device is a strain measuring unit provided in the joint portion or the rib and measures the strain of the joint portion or the rib.

4. The strain measuring unit is provided in plurality, The retaining structure according to claim 3, wherein the strain measuring units are arranged at equal intervals along the extension direction of the ring body.

5. 5. The retaining structure according to claim 4, wherein at least one pair of the strain measuring units is provided on the steel segments that face each other across the center of the ring body.

6. 4. The retaining wall structure according to claim 3, wherein the strain measurement unit is provided in the steel segment in at least one of the ring bodies located at the upper and lower ends of the segment structure.

7. The steel segment has a plate that forms a wall surface of the segment structure, 4. The retaining structure according to claim 3, wherein a corrosion detector for detecting corrosion of the filled portion is provided on the inner wall surface of the plate.

8. The retaining structure according to claim 7, wherein the corrosion detection section is provided in a plurality along the radial direction of the ring body.

9. The retaining structure according to claim 7, wherein the corrosion detection unit is provided on a plurality of ring bodies.

10. The steel segment has a plate that forms a wall surface of the segment structure and a main girder that is erected at both ends of the plate in the short side direction, The retaining structure described in claim 3, characterized in that a pipe material into which an inclinometer for measuring the verticality of the segment structure is inserted is provided on the main girder along the axial direction of the segment structure.

11. The earth retaining structure according to claim 1; a filling portion formed of concrete poured inside the retaining structure; A steel-concrete structure comprising:

12. A steel segment constituting an earth retaining structure buried underground, a plate forming a wall surface of the earth retaining structure; Joint portions are provided along the short direction at both ends of the plate in the longitudinal direction and are connected to adjacent steel segments; a rib provided along the short direction between the joint portions, A steel segment characterized in that the joint portion or the rib is provided with a strain measuring portion that measures strain in the joint portion or the rib.

13. The steel segment according to claim 12, characterized in that a corrosion detection section is provided on the inner wall surface of the plate to detect corrosion of a fill section that is provided inside the retaining structure and integrated with the retaining structure.

14. The plate has a main girder erected at both ends in the short side direction, A steel segment as described in claim 12 or 13, characterized in that a pipe material into which an inclinometer for measuring the verticality of the retaining structure is inserted is provided on the main girder along the axial direction of the retaining structure.

15. A construction method for a structure using the earth retaining structure according to claim 3, A step of connecting a plurality of steel segments in the longitudinal direction and the lateral direction to construct a segment structure; a step of pouring a filler material into the inside of the segment structure to integrate it with the segment structure; a step of providing the strain measuring unit at the joint portion or the rib of the steel segment before pouring a filler material inside the segment structure; A method for constructing a structure, comprising:

16. Before pouring the fill material into the inside of the segment structure, 16. The method for constructing a structure according to claim 15, further comprising the step of providing a corrosion detection unit for detecting corrosion of the fill portion on an inner wall surface of the plate of the steel segment that forms the wall surface of the segment structure.

17. Before pouring the fill material into the inside of the segment structure, The method for constructing a structure as described in claim 15, characterized in that it includes a step of providing a pipe material, into which an inclinometer for measuring the verticality of the segment structure is inserted, along the axial direction of the segment structure on the main girder erected at both short-side ends of the plate of the steel segment that forms the wall surface of the segment structure.

18. A method for maintaining a structure, characterized in that a measuring device installed in the retaining structure according to claim 1 is used to measure parameters necessary for maintaining the long-term functionality of the structure after construction.

19. A method for measuring parameters of a structure, characterized in that a measuring device installed in the retaining structure according to claim 1 is used to measure parameters necessary for maintaining and managing the long-term functionality of the structure after construction.

20. A method for monitoring a structure, characterized in that a measuring device installed in the retaining structure described in claim 1 is used to measure parameters necessary for maintaining and managing the long-term functionality of the structure after construction, and to monitor the condition of the structure.

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