Reinforcement structure and method for masonry retaining walls, and tubular reinforcing members

Abstract

To provide a reinforcement structure and a reinforcement method of a masonry retaining wall as well as tubular reinforcement members excellent in workability and quality capable of improving earthquake performance by enhancing anchorage in the natural ground as holding drainage function of ground water and rain water by realizing a configuration to make perforated tubular reinforcement members fixed on the natural ground in an upward oblique posture.SOLUTION: A reinforcement structure of a masonry retaining wall 20 is provided with a ground layer 23 through a cobble stone layer 22 behind a constructed stone layer 21. A tubular reinforcement member 10, which is a perforated pipe 1 provided with a check valve mechanism 5 and on which a packer member 6 is installed at a side of the ground layer 23, is located in a water dischargeable oblique state oblique upward from the constructed stone layer 21 to the ground layer 23 as well as anchoring material discharged from a perforated hole 2a is filled inside of the packer member 6 through the check valve mechanism 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention belongs to the technical field of reinforcement structures and reinforcement methods for stone retaining walls that have a ground layer (also called an anchoring layer) behind a backfill cobblestone layer (hereinafter referred to as the "cobblestone layer"), as well as tubular reinforcing members. [Background technology]

[0002] In reinforcement techniques for stone retaining walls using tubular (rod-shaped) reinforcing members, it is common to cast the tubular reinforcing members perpendicular to the wall slope, as disclosed in Patent Document 1, for example. In this case, the tubular reinforcing member faces downward from the surface of the stone retaining wall (stone layer) toward the natural ground layer, which creates the problem that it is unable to provide drainage function against the inflow of groundwater from the back side of the stone retaining wall or rainwater from the top side of the stone retaining wall.

[0003] Patent Document 2 discloses a method of reinforcing a retaining wall in which drainage pipes (perforated tubular reinforcing members) 7 are inserted and cast into each of the drainage holes 3 of a masonry retaining wall 1, with the ends penetrating into the ground (natural bedrock layer) 6 (see paragraph

[0023] and Figures 1 and 2 of the same document 2). This method of reinforcing a retaining wall involves casting the perforated tubular reinforcing members 7 upward in accordance with the gradient of the drainage holes 3, and so as long as this configuration can be maintained, the reinforcing members 7 can be expected to have a drainage function. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-9209 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-150821 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the means for fixing the drainage pipe (perforated tubular reinforcing member) 7 to the ground (ground layer) 6 was simply to penetrate its tip into the ground 6, and it had no choice but to rely on friction with the ground 6. Therefore, it was highly questionable whether the drainage pipe 7 could be maintained in an upwardly inclined position to maintain stable continuity of its drainage function, and above all, it was difficult to expect the original purpose of reinforcing the retaining wall (especially the seismic reinforcement effect). As a means of fixing the drainage pipe 7, it is possible to consider injecting grout (fixing material) from the surface of the retaining wall toward the ground layer, but because the drainage pipe 7 in Patent Document 2 is positioned in an upwardly inclined position, the grout will flow back, and it is therefore not possible to expect the drainage pipe 7 to be fixed to the ground 6 by injecting the grout.

[0006] Therefore, the present invention has been devised in consideration of the problems of the background art described above, and its object is to provide a reinforcement structure and reinforcement method for masonry retaining walls, as well as a tubular reinforcing member, which is easy to construct and of high quality, and which can improve seismic performance by realizing a configuration in which perforated tubular reinforcing members are fixed to the ground layer in an upwardly inclined position, thereby improving anchorage to the ground layer while maintaining the drainage function of groundwater and rainwater. [Means for solving the problem]

[0007] As a means for solving the above problems, the reinforcement structure of a masonry retaining wall according to the invention described in claim 1 is a reinforcement structure of a masonry retaining wall having a natural ground layer behind a stone layer with a pebbles layer interposed therebetween, A perforated pipe equipped with a check valve mechanism and a tubular reinforcing member with a packer member attached to the natural ground layer side is positioned in a state in which it can be drained by inclining obliquely upward from the masonry layer toward the natural ground layer, and the inside of the packer member is Perforated pipe The fixing material is discharged from the hole and filled in.

[0008] The invention described in claim 2 is characterized in that, in the reinforcement structure of a stone retaining wall described in claim 1, the check valve mechanism is arranged to be located in the ground layer of the tubular reinforcing member.

[0009] The invention described in claim 3 is characterized in that, in the reinforcement structure of a stone retaining wall described in claim 1, the check valve mechanism is arranged to be located in the ground layer behind the virtual slide line.

[0010] The invention described in claim 4 is characterized in that, in the reinforcement structure of a stone retaining wall described in any one of claims 1 to 3, the packer member is made of a material that allows the fixing material to seep out slightly.

[0011] The reinforcement method for a masonry retaining wall according to the invention described in claim 5 is a reinforcement method for a masonry retaining wall having a natural ground layer behind a stone layer with a pebbles layer interposed therebetween, A perforated pipe having a check valve mechanism and a tubular reinforcing member with a packer member attached to the ground layer side is inserted obliquely upward from the masonry layer toward the ground layer, and positioned in a state where drainage is possible. The inside of the packer member is filled with the anchoring material discharged from the hollow portion of the tubular reinforcing member through the check valve mechanism.

[0012] The tubular reinforcing member according to the invention described in claim 6 is a tubular reinforcing member used in a reinforcing structure of a masonry retaining wall having a natural ground layer behind a stone layer with a cobblestone layer interposed therebetween, It is characterized by being a perforated pipe equipped with a check valve mechanism and having a packer element attached to the ground layer side for filling with anchoring material. [Effects of the Invention]

[0013] According to the present invention, a perforated tubular reinforcing member equipped with a check valve mechanism can be fixed to the natural ground layer in an upwardly inclined position, thereby improving the fixation between the perforated tubular reinforcing member and the natural ground layer and enhancing the seismic reinforcement effect by allowing groundwater and rainwater to be efficiently drained toward the surface of the masonry layer. Therefore, a reinforcement structure and reinforcement method for a masonry retaining wall, as well as a tubular reinforcing member, that are excellent in workability and quality can be realized. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an explanatory diagram showing a schematic diagram of a reinforcement structure (reinforcement method) for a masonry retaining wall according to the present invention. [Figure 2] FIG. 2 is a left side view of FIG. 1. [Figure 3] This is an explanatory diagram showing a perforated pipe, one of the tubular reinforcing members used in the reinforcement structure (reinforcement method) of a masonry retaining wall according to the present invention, in the state before packer members are attached. The coupler portion is shown in perspective. [Figure 4] 1 is an explanatory diagram showing a tubular reinforcing member used in a reinforcement structure (reinforcement method) for a masonry retaining wall according to the present invention. [Figure 5] 5A is an enlarged view of the X portion in FIG. 4, and FIG. 5B is a longitudinal cross-sectional view of A as viewed from the axial direction. [Figure 6] 10 is an explanatory view illustrating a fastened state of the base end portion of the tubular reinforcing member according to the present invention. FIG. [Figure 7] 10A to 10C are explanatory views illustrating variations in fastening state of the base end portion of the tubular reinforcing member according to the present invention. [Figure 8] 10A to 10C are explanatory views illustrating variations in fastening state of the base end portion of the tubular reinforcing member according to the present invention. [Figure 9] 10A to 10C are explanatory views illustrating variations in fastening state of the base end portion of the tubular reinforcing member according to the present invention. [Figure 10] The tubular reinforcing member according to the present invention has been described as an example of improving drainage performance. [Figure 11] 1 is an explanatory diagram showing a variation of the reinforcement structure (reinforcement method) of a masonry retaining wall according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Next, a reinforcement structure and a reinforcement method for a masonry retaining wall, as well as a tubular reinforcement member according to the present invention, will be described with reference to the drawings. [Example]

[0016] 1 to 5 show an embodiment of a reinforcement method and structure for a masonry retaining wall 20 and a reinforcement member 10 according to the present invention. The reinforcing structure of this stone retaining wall 20 comprises a bedrock layer 23 behind a stone masonry layer 21, with a cobblestone layer 22 between them, and a perforated pipe 1 equipped with a check valve mechanism 5 and a tubular reinforcing member 10 with a packer member 6 attached to the bedrock layer 23 side, positioned diagonally upward from the stone masonry layer 21 towards the bedrock layer 23 so as to allow drainage, and the inside of the packer member 6 is filled with a fixing material (solidification material) discharged from the holes 2a of the perforated pipe 1 through the check valve mechanism 5.

[0017] In this embodiment, the perforated pipe 1 constituting the tubular reinforcing member 10 is implemented using two hollow pipes (a leading pipe 2 and a trailing pipe 3) connected in series at the front and rear in the axial direction via a coupler 4. The entire length of the pilot pipe 2 is long enough to be positioned in the natural ground layer 23, and multiple holes 2a are regularly drilled in the axial direction, and a check valve mechanism 5 such as a check valve (backflow prevention member) 5 is provided in the hollow portion (inside) of the rear end. The following pipe 3 has a total length extending from the rear end of the leading pipe 2 to the stone layer 21, and has a plurality of holes 3a drilled regularly in the axial direction.

[0018] Specifically, the lead pipe 2 has an outer diameter of approximately 28.5 mm, an inner diameter of approximately 13 mm, and a total length (see symbol L2) of approximately 2 m. The holes 2a, each approximately 5 mm in diameter, are drilled at a total of 19 locations with a staggered arrangement of 45 degrees upward (more specifically, two holes symmetrically arranged at 45 degrees on each side of the vertical as shown in FIG. 5B ; the same applies below) at intervals of approximately 100 mm. The holes 2a function as discharge holes 2a for discharging an anchorage material (not shown) such as grout injected into the hollow of the lead pipe 2 through an injection tube (not shown) attached to the check valve mechanism 5. The check valve mechanism 5 prevents backflow of the anchorage material toward the following pipe 3 by pressurizing and closing the valve. The following pipe 3 has, for example, an outer diameter of about 28.5 mm, an inner diameter of about 13 mm, and a total length (see symbol L3) of about 1 m. The holes 3a have, for example, a diameter of about 5 mm, and are drilled in a total of nine places at a pitch of about 100 mm in a staggered configuration facing upward at 45 degrees with the leading pipe 2 (following pipe 3) in position. The holes 3a serve as intake holes 3a for guiding excess water, such as rainwater flowing in from the top of the masonry retaining wall 20 and groundwater at the back of the masonry retaining wall 20, into the following pipe 3 and discharging (draining) it from the masonry layer 21 to the outside.

[0019] In this embodiment, the length of the leading pipe 2 is about 2 m and the length of the following pipe 3 is about 1 m, totaling about 3 m, but this is not limited to this. The design can be modified as appropriate depending on the shape of the masonry retaining wall 20 as well as the position of the virtual slide line S, as shown in Figure 11. For example, the leading pipe 2 is set to a length that fits its entire length within the area of ​​the natural ground layer 23, and the following pipe 3 is set to a length that allows it to be discharged to the masonry layer 21 side, taking into account various requirements. Furthermore, the leading pipe 2 and the following pipe 3 are not limited to a single pipe as in this embodiment, but can of course be implemented as a configuration in which multiple pipes are connected together as appropriate. The leading pipe 2 and the trailing pipe 3 in this embodiment are both made of plated steel pipes, but are not limited to this and may also be made of stainless steel or titanium. The hole diameter, pitch (arrangement interval), and number of holes 2a, 3a provided in the leading pipe 2 and the following pipe 3 can be appropriately changed depending on the structural design. However, considering the role of each hole (the discharge hole 2a, the intake hole 3a), it is preferable to provide them facing upward.

[0020] The effective pipe 1 consisting of the leading pipe 2 and the following pipe 3 of the above-mentioned configuration further has a packer member 6 attached to the entire outer periphery of the leading pipe 2, thereby forming a tubular reinforcing member 10. The packer element 6 has an outer diameter of, for example, about 50 mm and is a long, narrow bag like an umbrella bag that covers from the tip of the lead pipe 2 to a position near the installation location of the check valve mechanism 5 (i.e., approximately the entire length of the lead pipe 2 in this embodiment), and is made of a material (e.g., nonwoven fabric) that allows the anchoring material filled inside to slightly seep out. By attaching the packer element 6 to the lead pipe 2, the anchoring material discharged to the outside from the discharge hole 2a not only fills the inside of the packer element 6, but also seeps out slightly and becomes integrated with the surrounding natural ground 23, thereby ensuring the adhesion of the lead pipe 2, and therefore the tubular reinforcing element 1, to the natural ground 23 over time and further improving the seismic performance of the masonry retaining wall 20. The outer diameter of the packer member 6 is not limited to 50 mm, but can be appropriately changed depending on the structural design, such as to approximately match the diameter of the hole drilled by the boring machine described below. The packer member 6 is preferably made of nonwoven fabric, but the permeability coefficient is 3×10 -2 The material is not limited to nonwoven fabric as long as it can achieve a speed of about cm / s.

[0021] Next, a method for reinforcing a masonry retaining wall 20 using the tubular reinforcing member 10 having the above-described configuration will be described. Please note that the method (including construction procedures) described below is merely an example.

[0022] The reinforcement method for the masonry retaining wall 20 begins with the preparation of assembling the tubular reinforcing member 10. Specifically, the check valve (check valve mechanism) 5 is installed at the rear end of the leading pipe 2. An injection tube (e.g., φ10 mm) for injecting an anchoring agent (cement, cement, etc.) is then detachably attached to the check valve 5. The injection tube is previously passed through the following pipe 3 and coupler 4. The following pipe 3 is then connected to the leading pipe 2 via the coupler 4. At this time, the holes 2a, 3a are aligned so that they face approximately the same direction. Meanwhile, the leading pipe 2 is covered over its entire length with the packer member 6, and the opening near the coupler 4 is closed with a cable tie (not shown) such as an insuloc lock. This completes the assembly of the tubular reinforcing member 10.

[0023] Once the preparations are complete, in order to insert and position the tubular reinforcing member 10 in a stable position, a core drill is driven into the surface of the stone layer 21 in a position facing horizontally and slightly diagonally upward to drill a hole, and the stone is bored out to form a borehole 18 (for example, a borehole diameter of about 65 mm) in an upward diagonal direction. Next, using the borehole 19, a boring machine (a drilling machine such as a drifter) is used to drill the cobblestone layer 22 and the natural ground layer 23 in that order, forming a borehole 19 (for example, a borehole diameter of about 50 mm) that is one size smaller than the borehole 18 and has a length of just under 3 m in an upward diagonal direction.

[0024] In this embodiment, the drilling work is performed to penetrate the masonry stone 21 itself so that Fig. 2 can be easily understood, but the present invention is not limited to this, and the design can be modified as appropriate according to the structural design taking into consideration the shape of the masonry retaining wall 20 to which the present invention is applied. In short, the drilling method is not particularly important as long as the tubular reinforcing member 10 can be inserted and positioned in a stable state. For example, if the positioning work for the tubular reinforcing member 10 is performed using the gaps (joints) between the masonry stones (interlocking stones) 21 or existing drainage holes, there is no need to penetrate the masonry stone 21 itself, and therefore drilling work using a core drill can be omitted. Furthermore, the combined length of the boreholes 18, 19 is not limited to about 3 m, and can be appropriately changed depending on the structural design. For example, by positioning the check valve mechanism 5 located at the boundary between the leading pipe 2 and the following pipe 3 closer to the natural ground layer 23 or in the natural ground layer 23 behind the virtual slide line S, the hole 2a provided in the leading pipe 2 can reliably function as the discharge hole 2a, and other such conditions can be taken into consideration when designing the structure.

[0025] Next, the tubular reinforcing member 10 having the above-described configuration is inserted diagonally upward into the hole 19 that was drilled diagonally upward by the boring machine, and positioned. The tubular reinforcing member 10 is inserted diagonally upward into the hole 19 that was drilled diagonally upward by the boring machine. The outer diameter (approximately 28.5 mm) of the perforated pipe 1 (leading pipe 2 and trailing pipe 3) is smaller than the diameter of the drilled hole 19 (approximately 50 mm), and the packer member 6 (outer diameter approximately 50 mm) attached to the leading pipe 2 is smaller than the diameter of the drilled hole 19 (approximately 50 mm) before being expanded with the anchoring material, allowing for smooth insertion and positioning operations.

[0026] After completing the positioning work of the tubular reinforcing member 10, grout (anchoring material) is pumped by a grout pump through the injection tube into the perforated pipe 1 (pilot pipe 2 in this embodiment) on the natural ground 23 side. The pumped grout is prevented from flowing back by the check valve mechanism 5 and is discharged throughout the entire length of the pilot pipe 2 and eventually to the outside (inside the packer member 6) through the discharge hole 2a of the pilot pipe. The grout injection work is completed when the inside of the packer member 6 is filled (overflowed) with the grout, and then the injection tube is pulled out of the check valve mechanism 5 and removed from the perforated pipe 1, thereby completing the installation work of one tubular reinforcing member 10. Note that the grout filling status cannot be confirmed visually, so it is managed by the amount (volume) of grout injected, etc.

[0027] Next, the method described in the above paragraphs

[0022] to

[0026] is applied to the number of tubular reinforcing members 10 to be positioned (for example, 1 to 2 m when the masonry retaining wall 20 is viewed in plan). 2 This is repeated according to the number of columns (one for each column, see Figure 2), and thus the reinforcement method for the stone retaining wall 20 is completed.

[0028] In this embodiment, as shown in Figures 1 and 2, the base end of the tubular reinforcing member 10 is slightly protruded outward (toward the viewer), and a pressure plate (fixing plate) 11 is attached to the protruding portion using bolts, welding, or other connecting means to support the masonry retaining wall 20. Specifically, when using bolts for connection, the bolts are threaded into the female threads formed at the base end of the tubular reinforcing member 10, and the connected bolts are passed through the pressure plate 11 (through a hole formed in the center of the plate) and then fastened by threading a nut 12 (via a spacer 13, if necessary) (see Figure 6). This method can also be achieved by providing a step inside the masonry layer 21, as shown in Figure 7. Other methods, such as installing a covering net over the surface of the masonry retaining wall 20 using steel wire, wire rope, or resin material, can be used as appropriate. Furthermore, as shown in Figure 8, in order to more firmly fix the pressure plate 11, the drilled building stone 21 can be fixed to the adjacent building stone 21 using a fixing material 14 such as grout or adhesive at the joints, and the stone retaining wall 20 can be reinforced by the entire fixing material 14 around the drilled building stone 21. Furthermore, as shown in Figure 9, a structure can be implemented to reinforce a stone retaining wall 20 by providing multiple linear slits formed at approximately equal intervals around the circumferential direction of the tubular axis of the tubular reinforcing member 10, and expanding the diameter of the areas between adjacent linear slits in the circumferential direction so that they bulge radially when viewed from the axial direction of the tube to form pull-out resistance sections 15.

[0029] Therefore, the reinforcement structure constructed by the above-mentioned reinforcement method for masonry retaining walls 20 is a perforated pipe 1 equipped with a check valve mechanism 5, and multiple tubular reinforcing members 10 with packer elements 6 attached on the side of the natural ground layer 23 are positioned in a drainable state, inclined obliquely upward from the masonry layer 21 through the cobblestone layer 22 toward the natural ground layer 23. At the same time, the inside of the packer elements 6 is filled with an anchoring material (grout) discharged from the holes 2a through the check valve mechanism 5. The anchoring material (grout) filled (filled) inside the packer elements 6 seeps out of the packer elements 6 into the excavation holes 19 approximately evenly over time, forming a tubular anchoring layer integrated with the surrounding natural ground layer 23. In this way, the cylindrical fixing layer not only exhibits an earthquake-resistant reinforcement effect but also exhibits a pull-out resistance effect, so that the tubular reinforcing member 10 can maintain a stable diagonally upward posture, and the holes (intake holes) 3a provided in the subsequent pipe 3 can effectively guide groundwater and rainwater into the subsequent pipe 3, thereby reliably performing its drainage function.

[0030] Although the embodiments have been described above based on the drawings, it should be noted that the present invention is not limited to the illustrated examples and includes the range of design modifications and application variations that would normally be made by a person skilled in the art, provided that they do not deviate from the technical concept of the present invention. For example, as shown in Figure 10, by fitting a steel perforated drainage pipe 16 (for example, with an outer diameter of 50 mm, the same as the excavated hole 19) over part or the entire length of the following pipe 3, it is possible to reinforce the following pipe 3 and further improve the drainage effect. Finally, although the present embodiment has been described mainly with respect to the masonry retaining wall 20, it should be noted that the present invention is also applicable to stone walls. [Explanation of symbols]

[0031] 1 Perforated pipe 2. Pilot 2a hole (discharge hole) 3 Subsequent tube 3a hole (intake hole) 4 Coupler 5. Backflow valve mechanism (backflow prevention component) 6 Packer member 10 Tubular reinforcing member 10' tubular reinforcement member 11 Pressure plate 12 nuts 13 Spacer 14 Adhesive 15 Pull-out resistance section 16 Drain pipe 18 Boreholes 19 Borehole 20 Stone retaining wall 21 Building stone layer (building stone) 22 Kuriishi Formation 23 Geological Layer L2 Total length of the pilot tube L3 Total length of the trailing tube S Virtual slip line

Claims

1. In the reinforcement structure of a masonry retaining wall with a natural ground layer behind a stone layer with a chestnut stone layer in between, A reinforcement structure for a masonry retaining wall, characterized in that a tubular reinforcing member is a perforated pipe equipped with a check valve mechanism and has a packer member attached to the ground layer side, positioned in a drainable state at an angle upward from the masonry layer toward the ground layer, and the inside of the packer member is filled with fixing material discharged from the holes in the perforated pipe through the check valve mechanism.

2. 2. The reinforcement structure for a masonry retaining wall according to claim 1, wherein the check valve mechanism is provided so as to be located in the natural ground layer of the tubular reinforcing member.

3. 2. The reinforcement structure for a masonry retaining wall according to claim 1, wherein the check valve mechanism is provided so as to be located in the natural ground layer behind the virtual slide line.

4. A reinforcement structure for a stone retaining wall described in any one of claims 1 to 3, characterized in that the packer member is made of a material that allows the fixing material to slightly seep out.

5. In a reinforcement method for a masonry retaining wall with a natural ground layer behind a stone layer with a chestnut stone layer in between, A perforated pipe having a check valve mechanism and a tubular reinforcing member with a packer member attached to the ground layer side is inserted obliquely upward from the masonry layer toward the ground layer, and positioned in a state where drainage is possible. A reinforcement method for a masonry retaining wall, characterized in that the inside of the packer member is filled with an anchoring material discharged from the hollow portion of the tubular reinforcing member through the check valve mechanism.

6. A tubular reinforcing member used in the reinforcing structure of a masonry retaining wall having a natural ground layer behind a stone layer with a pebbles layer interposed therebetween, A tubular reinforcing member characterized by being a perforated pipe equipped with a check valve mechanism and having a packer member attached to the ground layer side for filling with an anchoring material.

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