Corner connectors for earth retaining beams

Abstract

To provide a corner connector A for an earth retaining beam material that can withstand stronger earth pressure by suppressing deflection of a beam material B when earth pressure acts on the earth retaining beam material arranged along the inner surface of a rectangular erected sheet pile panel wall E. [Solution] Provided is a corner connector A for earth retaining beams B, which are arranged along the inner surface of a sheet pile panel wall E erected in a square shape in an excavated hole D and which connects the earth retaining beams B at the four corners of the sheet pile panel wall to form a square framework, the corner connector A comprising: left and right beam connecting arms 2, 2 connected in a substantially L-shape in a state in which they can rotate via a pivot 1 at their base ends 2a; and an arm interior angle setting part 3 which restricts the rotation of the beam connecting arms 2, 2 in the interior angle direction so that the interior angle formed by these beam connecting arms 2, 2 can be set to exceed 90 degrees.

Description

[Technical Field]

[0001] The present invention relates to a corner connector that connects at the four corners earth retaining beams (waling members) that are assembled to form a square frame along the inner surface of a square-shaped sheet pile panel wall in earth retaining construction work to prevent the side walls of an excavated hole formed in the ground from collapsing. [Background technology]

[0002] Generally, when burying pipes, septic tanks, etc. underground, sheet pile panels are driven into the ground to surround the planned excavation site in a square shape to form a panel wall, and the soil on the ground surface surrounded by the sheet pile panel wall is excavated to form a square excavation hole. Then, beams (wale members) are assembled in a square shape along the inner surface of the exposed sheet pile panel wall to reinforce the sheet pile panel wall and perform an earth retaining construction method to prevent the side walls from collapsing (see Patent Documents 1 and 2).

[0003] The beams used in the earth retaining construction method are steel square pipes or H-shaped steel beams, and as shown in Figure 8, a square frame (rectangular frame) is formed by connecting the four beams B at each corner via pivots C. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Utility Model Registration No. 3183635 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-49666 Summary of the Invention [Problem to be solved by the invention]

[0005] The sheet pile panel walls surrounding the side walls of the excavation hole are subjected to a large earth pressure. As a result, as shown in Figure 8, the four beams B supporting the sheet pile panel walls E are subjected to a bending moment toward the central space as shown by the imaginary lines, causing them to bend. If the bending moment of beams B becomes too great, the risk of the side walls collapsing increases, so it is necessary to keep the amount of bending to a minimum.

[0006] To prevent beam B from bending, it is effective to install a tension beam (strut) that presses the middle part of opposing beam B against the wall, but since the beam is arranged across the excavation space, it is likely to get in the way of excavation work. Also, if a large beam that can withstand earth pressure is used, it will be heavy, making it difficult to transport, set up, and dismantle, and the total cost including material costs will increase.

[0007] Therefore, the present invention aims to provide a reinforcing device that can suppress the deflection of beam materials toward the central space due to earth pressure even when using beam materials (belly-raising materials) similar to those used conventionally, and that can be used at sites where greater earth pressure is applied. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention employs the following technical means: The reinforcement device of the present invention is a corner connector for earth retaining beams that form a square framework by connecting the four corners of the sheet pile panel wall, which is to be placed along the inner surface of a square sheet pile panel wall erected in an excavated hole, and is configured to include left and right beam connecting arms that are rotatably connected in an L-shape via a pivot at their base ends, and an arm interior angle setting part that sets the angle α between the left and right beam connecting arms (hereinafter also referred to as arm interior angle α) to a value exceeding 90 degrees.

[0009] With the corner connector of the present invention, the interior angle α between the left and right beam connecting arms is set to exceed 90 degrees, and the beams are assembled into a square frame (rectangular frame).This causes a bending moment to be applied to the beams toward the outside (towards the sheet pile panel wall), forming a square frame in which the middle parts of each beam are curved in an arch shape toward the outside (towards the sheet pile panel wall). When the square frame formed by the outwardly curved beams is attached to the inner side of the sheet pile panel wall, the inward bending moment applied to the beams from the sheet pile panel wall due to earth pressure can be offset by the outward bending moment applied to the outwardly curved beams, thereby making it possible to suppress the amount of inward deflection of beam B. This makes it possible to suppress the amount of deflection of the beams even when a square frame is formed using beams similar to those used in the past, and allows the frame to be used with greater earth pressure than before.

[0010] In the above invention, the arm interior angle setting portion may include left and right clamp plates that abut against the arm interior angle side surfaces of the left and right beam connecting arms, a clamp arm that connects the left and right clamp plates and has a through hole in its middle portion, and a base portion that has a support shaft at one end that is inserted into the through hole of the clamp arm to support the clamp arm and is supported by the pivot shaft at the other end, and the base portion may be provided with an adjustment mechanism that adjusts the distance between the support position of the clamp arm on the support shaft and the pivot shaft, and the arm interior angle α may be set by this adjustment mechanism. This allows the adjustment mechanism to shorten the distance between the support position of the clamp arm and the pivot, changing the contact position of the clamp plate with the beam connecting arm, making it possible to widen the arm interior angle α and set it to an angle greater than 90 degrees. Here, the support shaft may be a threaded shaft having a thread groove, and the adjustment mechanism may be configured by the threaded shaft and an angle adjustment nut that is screwed onto the threaded shaft. This makes it possible to easily shorten the distance between the support position of the clamp arm and the pivot axis by rotating the angle adjustment nut, and the arm interior angle can be set to an angle greater than 90 degrees.

[0011] In addition, the base portion may have a columnar base body, and a pair of mounting pieces having an axial hole through which the pivot shaft is inserted may be attached to the upper and lower parts of the base body toward the pivot shaft, and the support shaft may be provided in the middle of the base body sandwiched between the pair of upper and lower mounting pieces so as to protrude in the opposite direction from the mounting pieces. This allows the vertical distance between the pair of mounting pieces to be increased, making it easier to avoid contact between the mounting pieces and the beam connecting arm.

[0012] In addition, the clamp arm may be swingably connected to the clamp plate, and the arm interior angle setting portion may be configured to allow the angle α formed by the left and right beam connecting arms to be set arbitrarily within the range of at least 90<α≦95 degrees. This allows the degree of deflection of the retaining beam material to be adjusted to suit the conditions at the site; for example, when forming a rectangular frame, the amount of deflection of the retaining beam material can be adjusted on the long and short sides. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view showing one embodiment of a corner connector according to the present invention. FIG. [Figure 2] FIG. 2 is a perspective view of the corner connector, partially disassembled, with the clamp plate and clamp arm omitted. [Figure 3] FIG. 4 is an enlarged cross-sectional view of a main portion of the arm interior angle setting portion of the corner connector. [Figure 4] FIG. [Figure 5] FIG. 10 is a plan view showing the state in which the interior angle formed by the beam connecting arms of the corner connector has been expanded to an angle exceeding 90 degrees. [Figure 6]This is a plan view showing the state in which the beams are assembled into a square shape using the above corner connectors, with the interior angles of the arms at the four corners set to an angle exceeding 90 degrees. [Figure 7] FIG. 10 is a perspective view showing another embodiment of a corner connector according to the present invention. [Figure 8] FIG. 10 is an explanatory diagram showing a conventional example of use of beams assembled in a rectangular shape. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. The corner connector A of the present invention includes a pair of beam connecting arms 2, 2 connected at their base ends 2a in a generally L-shaped configuration via a pivot 1, and an arm interior angle setting section 3 that limits rotation in the direction of the angle (arm interior angle) formed by the beam connecting arms 2, 2. In this embodiment, as shown in Figure 2, square steel pipes are used for the beam connecting arms 2, 2, and base ends 2a, 2a formed by bending thin steel plate, are connected to one end of the square steel pipe with screws, and a hole 2b is provided in the center of the base ends 2a, 2a through which the pivot 1 is inserted. Furthermore, an insertion opening 2c is opened at the other end of each beam connecting arm 2, 2, into which one end of a beam B is inserted for connection and fixation.

[0015] The arm interior angle setting unit 3 is used to set the angle α (arm interior angle α) formed by the left and right beam connecting arms 2, 2 from the 90 degree state shown in Figure 4 to a value exceeding 90 degrees (for example, 90 degrees < α ≦ 100 degrees) to limit the rotation of the beam connecting arms 2, 2 in the interior angle direction, and in this embodiment is configured as shown below.

[0016] That is, the arm interior angle setting portion 3 comprises left and right clamp plates 4, 4 that abut against the side surfaces of the beam connecting arms 2, 2 on the arm interior angle side, a clamp arm 6 that swingably connects these clamp plates 4, 4 via a pin shaft 5, and a base portion 7 whose one end is inserted into a through hole 6a provided in the middle portion of the clamp arm 6 and whose other end is supported by the pivot 1.

[0017] As shown in FIGS. 2 and 3 , the base portion 7 has a cylindrical base body 12 and is provided with a screw shaft 8 (support shaft) that protrudes from the base body 12 toward the clamp arm 6, with its tip end inserted into a hole 6a formed in the middle (preferably the center) of the clamp arm 6. In this embodiment, a through hole 12a is formed in the center of the base body 12, and a bolt is inserted into the through hole 12a from the pivot 1 side so that the screw shaft 8 of the bolt protrudes toward the clamp arm 6. An angle adjustment nut 9 is threaded onto the exposed end (shaft end side) of the screw shaft 8, and by tightening this (by the clamp plates 4, 4 abutting against the beam connecting arms 2, 2), the clamp arm 6 is supported and connected to the screw shaft 8. In addition, upper and lower mounting pieces 11, 11 each having a shaft hole 10 through which the pivot 1 of the beam connecting arms 2, 2 is inserted are provided on the upper and lower parts of the base portion 7, and the mounting pieces 11, 11 are oriented opposite to the direction of the screw shaft 8. The base portion 7 is supported by the pivot 1 by inserting the pivot 1 into the shaft hole 10. The ends of the upper and lower mounting pieces 11, 11 are fastened to the base body 12 with screws 13, 13.

[0018] In the arm interior angle setting unit 3, when the arm interior angle α of the beam connecting arms 2, 2 is set to 90 degrees as shown in Fig. 4, the angle adjustment nut 9 is threaded forward, and the clamp arm 6 moves together with the clamp plate 4 in a direction approaching the pivot 1. As a result, the contact position of the clamp plate 4 with the connecting arm 2 moves closer to the pivot 1, and the beam connecting arms 2, 2 are pressed together, and the arm interior angle α can be set in the range of 90 degrees < α ≦ 100 degrees (at least in the range of 90 degrees < α ≦ 95 degrees) as shown in Fig. 5.

[0019] Figure 6 shows the state in which beams B have been assembled into a square shape, with the arm interior angle α of the corner connectors A at the four corners set to 92 degrees. Because the four beams B are connected by corner connectors A at an angle greater than a right angle, the middle portions of beams B will curve in an arch shape toward the outside (toward the sheet pile panel wall in Figure 8) (for ease of explanation, the curvature of beams B is exaggerated in this figure), making it possible to assemble a square frame in which an outward bending moment has already been applied to beams B.

[0020] Then, at a site where a sheet pile panel wall has been erected in a square shape, when a curved square frame with an outward bending moment applied to beam B as shown in Figure 6 is attached to the inner side of the sheet pile panel wall, part of the earth pressure applied to beam B from the sheet pile panel wall can be offset by the outward bending moment, and as a result, the amount of inward deflection of beam B can be reduced. This makes it possible to suppress the deflection of beam material B even when a square frame is attached to the inner surface of a sheet pile panel wall using the same beam material B as before, and also makes it possible to use it at sites where greater earth pressure is applied than before.

[0021] The above describes typical embodiments of the present invention, but the present invention is not necessarily limited to the above embodiments, and can be modified or changed as appropriate within the scope of the claims, while achieving its objectives. For example, in the above embodiment, the bolt is inserted into the through hole 12a of the base body 12 from the pivot 1 side, but the bolt may be inserted into the through hole 6a of the clamp arm 6 and then into the through hole 12a of the base body 12, and a nut may be placed on the pivot 1 side of the base body 12 to tighten the head of the bolt and thread it forward. Also, a thread groove may be formed in the through hole 12a of the base body 12 to serve as a substitute for a nut. Also, in the above embodiment, the screw shaft 8 (support shaft side) is used to adjust the distance between the support position of the clamp arm 6 and the pivot, but instead of or in addition to this, an adjustment mechanism may be provided to change the length of the middle arm portion of the mounting piece 11. In the above embodiment, the clamp arm 6 and the clamp plate 4 are swingably connected via the pin shaft 5, so that the arm interior angle α can be set arbitrarily within the range of at least 90 degrees < α ≦ 95 degrees, but if it is desired to use only a specific arm interior angle (for example, 92 degrees), the left and right clamp plates 4, 4 can be directly connected to the clamp arm 6 without using the pin shaft 5, and the angle between the contact surfaces of the left and right clamp plates 4, 4 can be fixed to the value of the specific arm interior angle (for example, 92 degrees) that is desired, as shown in Fig. 7. In this way, when tightening the angle adjustment nuts 9, the angle adjustment nuts 9 can be tightened so that the contact surfaces of the left and right clamp plates 4, 4 are in close contact with the side surfaces of the beam connecting arms 2, 2 on the interior angle side. [Industrial Applicability]

[0022] The present invention can be used as a corner connector for beams arranged in a square frame along the inner surface of a sheet pile panel wall erected in an excavated hole. [Explanation of symbols]

[0023] A Corner Connector B Beam material D Drilling hole E Sheet pile panel wall 1. Axis 2 Beam connecting arms 2a Base end of beam connecting arm 3 Arm interior angle setting section 4 Clamp plate 6 Clamp Arm 6a through hole 7 Base 8 screw shaft 9 Angle adjustment nut 10 Shaft hole 11 Mounting piece 12 Base body 12a through hole

Claims

1. A corner connector for earth retaining beams that is arranged along the inner surface of a sheet pile panel wall erected in a square shape in an excavated hole and connects the earth retaining beams at the four corners of the sheet pile panel wall to form a square framework, Left and right beam connecting arms connected at their base ends in a substantially L-shape in a rotatable manner via a pivot; The corner connector for earth retaining beams is provided with an arm interior angle setting portion that sets the arm interior angle α between the left and right beam connecting arms to a value exceeding 90 degrees.

2. The arm interior angle setting portion includes left and right clamp plates that abut against the arm interior angle side surfaces of the left and right beam connecting arms, a clamp arm that connects the left and right clamp plates and has a through hole in the middle; a support shaft that is inserted into a through hole of the clamp arm to support the clamp arm at one end thereof, and a base portion that is supported by the pivot at the other end thereof; A corner connector for a retaining beam material as described in claim 1, wherein an adjustment mechanism is provided in the base portion to adjust the distance between the support position of the clamp arm on the support shaft and the pivot axis, and the arm interior angle α is set by the adjustment mechanism.

3. The corner connector for a retaining beam material as described in claim 2, wherein the support shaft is a threaded shaft having a threaded groove, and the adjustment mechanism is composed of the threaded shaft and an angle adjustment nut screwed onto the threaded shaft.

4. The base portion has a columnar base body, and a pair of mounting pieces, each having an axial hole through which the pivot is inserted, are attached to an upper and lower part of the base body toward the pivot, A corner connector for a retaining beam material as described in claim 2, wherein the support axis is provided in the middle of the base body sandwiched between the pair of upper and lower mounting pieces so as to protrude in the opposite direction to the mounting pieces.

5. The clamp arm is swingably connected to the clamp plate, 5. The corner connector according to claim 2, wherein the arm interior angle setting portion can set the angle α formed by the left and right beam connecting arms within a range of at least 90<α≦95 degrees.

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