Chain-type cutter for underground diaphragm wall construction and construction device equipped with same

Abstract

To provide a construction machine allowing inexpensive construction of widened underground continuous walls, without largely improving the conventional construction machines.SOLUTION: A chain type cutter 2 for constructing underground continuous wall has an endless chain 11 fitted with multiple bit plates 13 having cutter bits 12. In the chain type cutter 2, a support frame 16 provided to a base machine 3 side is supported at least movably in the ground insertion direction, an intermediate part of the bit plate 13 is fixed to the endless chain 11, and both sides thereof protrude to the frame side and an extending side opposite thereto, respectively. The bit plate 13 has a longer protrusion length in the extending side than in the frame side, to thereby extend excavation width. A shape of the bit plate 13 is determined considering the balance between an area of the laterally protruding part from the endless chain 11 and excavation resistance moment.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a chain cutter that enables construction of a widening type underground diaphragm wall without requiring major modifications to conventional construction machines, and to a construction device equipped with the same. [Background technology]

[0002] Conventionally, one method for constructing continuous walls underground has been known to involve, for example, the TRD method, in which a chain cutter equipped with an endless chain to which multiple bit plates having cutter bits are attached is moved laterally to mix and stir the in-situ soil and solidification liquid, thereby constructing a constant-thickness soil-cement continuous wall underground.

[0003] In a conventional chain-type cutter 50, as shown in Figures 8 and 9, the center of a bit plate 51 is fixed to an endless chain 52 with a bolt 53, and in order to maintain left-right balance during excavation, the bit plate 51 is formed in a symmetrical shape that protrudes the same length on both sides of the endless chain 52.

[0004] The width of the bit plate 51 (thickness of the underground continuous wall) is limited to a certain width to prevent excessive torque from acting on the bit plate 51 during excavation, and to prevent the chain cutter 50 from coming into contact with the frame 54 of the base machine, which is equipped with a sprocket (rotating shaft) that drives the endless chain 52, a reducer, etc., when passing through the above-ground part. Until now, a maximum width of 850 mm was generally used.

[0005] In recent years, with the trend towards deeper earth retaining walls, especially in urban areas, there has been an increasing need for wide earth retaining walls with high wall rigidity. Various developments have been made in the past to build wide-type diaphragm walls. For example, the following Patent Document 1 describes a method for building a diaphragm wall with improved ground by circulating an endless chain having cutting blades around a cutter post, moving the cutter post while it is inserted in the ground, and supplying a solidification material liquid into the ground, in which the cutter post cuts a portion of the ground on one side of the center line of the cutter post from the shallowest part of the ground to be improved to the lower end of the cutter post, with a width greater than the inside dimension in the thickness direction of the cover placed on the top of the cutter post. A method for constructing an expandable underground continuous wall is disclosed, in which an expandable endless chain with cutting blades is attached to the remaining section, and a standard endless chain with cutting blades for cutting ground with a width equal to or less than the inside dimension of the cover is attached to the remaining section, and while supplying solidification material liquid, the cutter post is moved laterally, and the direction of circulation of the endless chain is repeatedly reversed each time the endless chain is circulated until the part of the expandable endless chain located at the lower end of the cutter post moves to the part located at the shallowest part of the ground, thereby constructing an underground continuous wall with a width greater than the inside dimension of the cover deeper than the shallowest part of the ground. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2003-96765 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the method described in Patent Document 1 above, an expandable endless chain is attached to the section from the shallowest part of the ground to be improved to the lower end of the cutter post, and a standard endless chain is attached to the remaining section.The direction of circulation of the endless chain is reversed so that the expandable endless chain moves back and forth over the part of the ground to be improved so as not to interfere with the frame on the ground, which has the disadvantage that excavation efficiency is poor and excavation takes a long time.

[0008] Another recent method for constructing wide underground continuous walls is the use of wide-type construction machines that can handle wall thicknesses of up to 1.2 m. However, this poses the problem of the large size of the construction machines, and there was a demand for a structure that would allow the excavation width to be expanded using existing construction machines.

[0009] It might be possible to modify a conventional construction machine with a maximum digging width of 850 mm so that a wider bit plate could be attached, but with a structure in which the centre of the bit plate is fixed to the endless chain, the distance between the frame and the depth of the sprocket would need to be extended to increase the digging width, and there was a problem that making such a major modification to the structure of the drive unit would be very costly.

[0010] Therefore, the main object of the present invention is to provide a chain cutter and a construction device equipped with the same that enable construction of wide-type underground continuous walls at low cost without significantly modifying conventional construction machines. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention according to claim 1 provides a chain cutter for constructing underground diaphragm walls, the chain cutter comprising an endless chain to which a plurality of bit plates having cutter bits are attached, The chain cutter is supported by a frame provided on the base machine side so as to be freely movable at least in the direction of insertion into the ground, and the middle part of the bit plate is fixed to the endless chain, and both sides of the bit plate protrude toward the frame side and the extension side, which is the opposite side, respectively. A chain-type cutter for constructing underground continuous wall is provided, characterized in that the bit plate has a longer protruding length on the extension side than the protruding length on the frame side, thereby increasing the excavation width.

[0012] In the invention described in claim 1, the middle part of the bit plate is fixed to the endless chain, and both sides of the bit plate protrude to the frame side and the opposite extended side, respectively, and the protruding length at this time is made longer on the extended side than on the frame side, thereby expanding the excavation width. In other words, the protruding length on the frame side is kept the same as that used in conventional construction machines, and the bit plate is made not to interfere with the frame, and the expanded excavation width is ensured by extending the protruding length on the opposite side to the frame. Therefore, conventional construction machines can be used without significantly modifying the drive structure, etc., and the excavation width can be expanded at low cost.

[0013] As the present invention related to claim 2, there is provided a chain-type cutter for constructing underground continuous wall as described in claim 1, in which the shape of the bit plate is determined taking into consideration the balance between the area of ​​the part protruding to the left and right from the endless chain and the excavation resistance moment.

[0014] In the invention described in claim 2 above, the left and right protruding lengths from the endless chain are different and the shape of the bit plate is asymmetrical, which causes the left and right excavation resistance to be different during excavation, which in turn generates a moment on the bit plate and prevents a rotational force from acting on the endless chain.In order to prevent this, the shape of the bit plate is determined taking into consideration the balance between the area of ​​the parts protruding to the left and right from the endless chain and the excavation resistance moment.

[0015] As the present invention related to claim 3, there is provided a chain type cutter for constructing underground continuous wall as described in either claim 1 or 2, in which, when the total width of the bit plate is A, the protruding length of the bit plate on the frame side is B, and the width of the protruding portion of the bit plate on the frame side is C, the width D of the protruding portion of the bit plate on the extended side is obtained from the following formula. D=B*C*(B / 2+W / 2) / [(ABW)*{(ABW) / 2+W / 2}] Here, W: width of the endless chain.

[0016] In the invention described in claim 3 above, the left and right protruding lengths from the endless chain are different and the shape of the bit plate is asymmetrical, which causes the left and right excavation resistance to be different during excavation, which in turn generates a moment on the bit plate and prevents a rotational force from acting on the endless chain. In order to prevent this, an equation is defined for determining the width D of the protruding portion on the extended side of the bit plate from the balance between the area of ​​the portion protruding to the left and right from the endless chain and the excavation resistance moment.

[0017] The present invention relates to claim 4, and there is provided a chain-type cutter for constructing underground continuous walls as described in any of claims 1 to 3, in which a clamping plate is arranged on the back side of the bit plate, and the endless chain is interposed between the clamping plate and the bit plate, and a reinforcing bolt inserted from the front side of the bit plate is tightened to the clamping plate to reinforce the connection between the bit plate and the endless chain.

[0018] In the invention described in claim 4 above, as the bit plate is widened, the rotational moment due to the drilling resistance increases, which increases the shear force acting on the fixing bolts of the bit plate, and there is a risk of the bolts breaking or the bit plate coming off. Therefore, in addition to the existing fixing bolts, a clamping plate that clamps the endless chain and a reinforcing bolt are placed to reinforce the connection between the bit plate and the endless chain, thereby countering the shear force associated with the rotational moment.

[0019] The present invention as claimed in claim 5 provides a construction device equipped with a chain cutter for constructing underground diaphragm walls, characterized in that it comprises a chain cutter for constructing underground diaphragm walls as described in any one of claims 1 to 4 above, and a base machine that supports the chain cutter so that it can be inserted into the ground. Effect of the Invention

[0020] As explained above in detail, according to the present invention, it becomes possible to construct a widening type diaphragm wall inexpensively without making major modifications to conventional construction machines. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a side view showing a construction device 1 equipped with a chain-type cutter 2 for constructing diaphragm walls according to the present invention. [Diagram 2] This is a front view. [Diagram 3] FIG. 2 is a top view of FIG. [Figure 4] FIG. 2 is an enlarged side view of a main portion of the chain cutter 2. [Diagram 5] 1 shows a bit plate 13, (A) being a plan view and (B) being a side view. [Figure 6] 1A shows a connection reinforcement structure between a bit plate 13 and an endless chain 11, in which (A) is a back view, (B) is a side view, and (C) is an end view. [Figure 7] FIG. 2 is a top view of the steel continuous underground wall core material 30. [Figure 8] FIG. 2 is an enlarged side view of a main portion showing a conventional chain cutter 50. [Figure 9] 1A and 1B show a conventional bit plate 51, in which (A) is a plan view and (B) is a side view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0023] As shown in Figs. 1 to 3, a construction device 1 according to the present invention is composed of a chain cutter 2 for constructing diaphragm walls, and a base machine 3 that supports the chain cutter 2 so that it can be inserted into the ground.

[0024] First, an example of the base machine 3 will be described. The base machine 3 is composed of a vehicle body 4 and a running body 5 that supports the vehicle body 4 so that it can run. A guide frame 6 that functions as a guide when moving the chain cutter 2 in the lateral direction is provided on one side of the vehicle body 4, and this guide frame 6 is provided with a leader 7 that functions as a guide when raising and lowering the chain cutter 2. The guide frame 6 is provided with a lateral movement cylinder 8 that moves the leader 7 in the lateral direction, and the leader 7 is provided with a longitudinal movement cylinder 9 that moves the chain cutter 2 in the direction of insertion into the ground.

[0025] Next, the chain cutter 2 will be explained with reference to Figures 1 to 4. The chain cutter 2 is composed of a cutter post 10 which is inserted into the ground except for the upper part exposed above ground, an endless chain 11 which runs around the cutter post 10 and has a number of bit plates 13... each having a number of cutter bits 12... attached to it, a sprocket 14 and an idler 15 which are provided at the upper and lower ends of the cutter post 10, respectively, and between which the endless chain 11 is stretched, a support frame 16 which is provided on the base machine 3 side and supported so as to be freely movable at least in the direction of insertion into the ground, and a reducer (not shown) which outputs the power obtained from the output shaft of an electric motor to the sprocket 14 by reducing the rotational speed of the gear.

[0026] As shown in FIG. 2, inside the cutter post 10, there are provided a plurality of pipes 18, 18 . . . which discharge ground improvement materials such as cement milk into the ground from discharge ports provided at the lower ends as required.

[0027] As shown in Figure 1, the chain cutter 2 has a support frame 16 provided on the upper part of the cutter post 10, and this support frame 16 is supported by the leader 7 so as to be capable of moving vertically. The support frame 16 houses the reducer and the like, and supports the sprocket 14 that outputs power. The endless chain 11 is disposed at a predetermined distance from the support frame 16 so that the bit plate 13 attached to the endless chain 11 does not interfere with the support frame 16.

[0028] The upper part of the chain cutter 2 including the support frame 16 is exposed to the ground, and this part exposed to the ground is covered with a cover 17. This cover 17 is formed to a size that allows the endless chain 11 to which the bit plate 13 is attached to pass through.

[0029] The bit plates 13 are arranged at substantially equal intervals along the endless chain 11, and as shown in Figures 4 and 5, their widthwise middle parts are fixed to the endless chain 11 by four fixing bolts 20, 20..., with both sides protruding toward the support frame 16 side (hereinafter referred to as the "frame side") and the opposite side (hereinafter referred to as the "extension side"). Each of these laterally protruding parts is provided with a cutter bit 12 at least at its tip, in the illustrated example, at two locations, the tip and the middle. The width dimension of the bit plate 13 corresponds to the excavation width of the underground diaphragm wall constructed by the chain cutter 2.

[0030] In the chain cutter 2 according to the present invention, the excavation width is increased by using the bit plate 13 in which the protruding length on the extension side on the opposite side is longer than the protruding length on the frame side. That is, the protruding length on the frame side is the same as that of a conventional construction machine equipped with a symmetrical bit plate with the same protruding length on the left and right, and the frame side of the bit plate 13 does not interfere with the support frame 16, and the increased excavation width is ensured by extending the protruding length on the extension side on the opposite side to the support frame 16. In other words, the bit plate 13 is formed in an asymmetric shape with respect to the fixed part of the endless chain 11, and the center line L of the endless chain 11 in the rotational direction is set to 1 / 2. C The center line L in the rotation direction passes through the center of the width of the bit plate 13. B It is eccentric towards the frame side.

[0031] In this way, by using a bit plate 13 with a longer protruding length on the extension side than on the frame side, there is no need to significantly modify the drive structure, such as changing the relative positional relationship between the sprocket 14 that drives the endless chain 11 and the reducer.By simply making a simple modification to extend the cover 17 on the extension side, a conventional construction machine can be used, and the excavation width can be expanded at low cost.

[0032] The cutter bit 12 is provided with a blade made of a carbide tip or the like at the tip of a base protruding at a substantially right angle to the plane of the bit plate 13 or inclined outward in the width direction, and excavates the natural ground with the blade. The cutter bit 12 is disposed at least at the tip of each protruding part protruding to the left and right from the endless chain 11 in the protruding direction, and preferably also at the middle part of each protruding part in the protruding direction. In the illustrated example, the cutter bit 12 is disposed at the tip and center part in the protruding direction of each protruding part. Since the protruding lengths of the left and right protruding parts from the endless chain 11 are different, the cutter bit 12 disposed at the middle part in the protruding direction should be disposed at the same ratio to the protruding length to distribute the excavation resistance to the left and right evenly, and in the illustrated example, it is disposed at the center of the protruding direction of the left and right protruding parts.

[0033] The bit plate 13 consists of a long steel flat plate that is elongated in a direction perpendicular to the rotation direction of the endless chain 11 (the thickness direction of the underground continuous wall), and at least the planar shapes of the parts that protrude to the left and right from the endless chain 11 are each formed into a rectangular shape.

[0034] As described above, the left and right protruding lengths of the bit plate 13 are different and the shape of the bit plate 13 is asymmetrical, so that the excavation resistance on the left and right during excavation is different, which may cause a moment to be generated in the bit plate 13 and a rotational force to act on the endless chain 11. To prevent this, it is preferable to determine the shape of the bit plate 13 in consideration of the balance between the area of ​​the parts protruding to the left and right from the endless chain 11 and the excavation resistance moment.

[0035] More specifically, as shown in Figure 5, if the total width of the bit plate 13 is A, the protruding length of the bit plate 13 on the frame side is B, the width of the protruding portion of the bit plate 13 on the frame side is C, and the width of the protruding portion of the bit plate 13 on the extended side is D, the balance equation for the moment of the parts protruding to the left and right from the endless chain 11 is expressed as the product of the area of ​​the parts protruding to the left and right from the endless chain 11 and the distance from the center of gravity of each part to the center of the endless chain 11, and is given by the following equation.

[0036] (B*C)*(B / 2+W / 2)={(ABW)*D}*{(ABW) / 2+W / 2} Here, W: the width of the endless chain 11.

[0037] In addition, the overall width A of the bit plate 13 corresponds to the thickness of the underground continuous wall to be constructed, the protruding length B of the bit plate 13 on the frame side is the length in the protruding direction of the part that protrudes outward from the overall width W of the endless chain 11, and the widths C and D of the protruding parts on the frame side and extension side of the bit plate 13 are the lengths of each protruding part in the rotational direction of the chain cutter 2.

[0038] From the above formula, the width D of the protruding portion on the extension side of the bit plate 13 can be calculated as follows:

[0039] D=B*C*(B / 2+W / 2) / [(ABW)*{(ABW) / 2+W / 2}] From the above formula, for example, when A=1000 mm, B=310 mm, C=286 mm, and W=230 mm, the above D is about 151 mm.

[0040] As described above, the width D of the protruding portion can be determined from the protruding length on the extended side based on the vertical and horizontal lengths of the protruding portion on the frame side of the bit plate 13. This maintains the left and right excavation balance of the bit plate 13 during excavation, keeps the bit plate 13 perpendicular to the rotation direction of the endless chain 11, and no moment is generated on the bit plate 13, suppressing shear fracture of the fixing bolts 20, 20 ... that fix the bit plate 13, and preventing the bit plate 13 from coming off.

[0041] Next, the reinforcing structure of the fixing bolts 20 that fix the bit plate 13 to the endless chain 11 will be described with reference to Fig. 6. As the bit plate 13 is widened, the rotational moment due to excavation resistance increases, and the shear force acting on the fixing bolts 20 that fix the bit plate 13 to the endless chain 11 increases, which may cause the fixing bolts 20 to break or the bit plate 13 to break. For this reason, in addition to the existing fixing bolts 20, it is preferable to reinforce them with the reinforcing structure described below.

[0042] The reinforcement structure is a structure in which a clamping plate 21 is placed on the back side of the bit plate 13, and a reinforcing bolt 22 inserted from the front side of the bit plate 13 is fastened to the clamping plate 21 with an endless chain 11 interposed between the clamping plate 21 and the bit plate 13.

[0043] The clamping plate 21 is a long, thin steel plate, and both ends thereof are formed with female threads into which the reinforcing bolts 22 are screwed. The clamping plate 21 is arranged with respect to the endless chain 11, with the link portions of the endless chain 11 being disposed between the spaced apart reinforcing bolts 22, 22, and the link portions of the endless chain 11 are clamped between the clamping plate 21 and the bit plate 13 by fastening the reinforcing bolts 22, 22, reinforcing the connection between the bit plate 13 and the endless chain 11. It is preferable to arrange one clamping plate 21 on each of the left and right links of the endless chain 11.

[0044] As shown in FIG. 4, anti-slip plates 23, 23 for preventing the bit plates 13 from slipping are fixed to the endless chain 11 adjacent to the front and rear of each bit plate 13. The anti-slip plates 23 are narrower than the bit plates 13 and are formed to a size that slightly protrudes from both sides of the endless chain 11, and are fixed to the endless chain 11 with four fixing bolts 24, 24.... The anti-slip plates 23 are arranged on the front and rear sides of the fixing part of the bit plate 13 to the endless chain 11 so that the end faces face each other without any gaps. In the illustrated example, one cutter bit 25 is provided in the center of the anti-slip plate 23, but two or more cutter bits may be arranged, or may not be arranged.

[0045] As shown in Fig. 7, after constructing a soil cement wall by mixing and stirring in-situ soil and a solidification material, a steel continuous wall is constructed by inserting a plurality of core members 30, 30, such as H-shaped steel, while connecting them to each other, and when this steel continuous wall is used as the main body, a coupler 31 for connecting a reinforcing bar 32 is welded to the outer surface of the flange on the main body side at the point where the bottom plate and top plate of the main structure are connected, but in the past, the overhang of this coupler 31 sometimes became an obstacle when erecting the core member 30. With the chain-type cutter 2 according to the present invention, an underground continuous wall can be constructed that is eccentric to the extension side from the center of the endless chain 11, so that the coupler 31 can be prevented from interfering with the ground during insertion, and the core member can be smoothly inserted.

[0046] Furthermore, by using the construction device 1 of the present invention, it is possible to construct an underground continuous wall that is eccentric to the extension side of the center of the endless chain 11, which has the effect of enabling construction while ensuring distance from existing structures, etc., when building an earth retaining wall with little distance from existing structures, etc.

[0047] [Other examples] In the above embodiment, the base machine 3 is described as being a construction machine used in the TRD method as shown in Figures 1 to 3, but this is not limited to this and any construction machine equipped with a chain-type cutter mechanism can be used. [Explanation of symbols]

[0048] 1...construction device, 2...chain cutter, 3...base machine, 4...vehicle body, 5...traveling body, 6...guide frame, 7...leader, 8...transverse cylinder, 9...vertical cylinder, 10...cutter post, 11...endless chain, 12...cutter bit, 13...bit plate, 14...sprocket, 15...idler, 16...support frame, 17...cover, 18...piping, 20...fixing bolt, 21...clamping plate, 22...reinforcing bolt, 23...anti-slip plate, 24...fixing bolt, 30...core material, 31...coupler

Claims

1. A chain cutter for constructing underground diaphragm walls, comprising an endless chain to which a plurality of bit plates having cutter bits are attached, The chain cutter is supported so that a frame provided on the base machine side is movable at least in the direction of insertion into the ground, and the middle part of the bit plate is fixed to the endless chain, and both sides of the bit plate protrude toward the frame side and the extension side, which is the opposite side, respectively. A chain-type cutter for constructing underground continuous walls, characterized in that the bit plate has a protruding length on the extension side that is longer than the protruding length on the frame side, thereby increasing the excavation width.

2. 2. A chain cutter for constructing underground diaphragm walls according to claim 1, wherein the shape of said bit plate is determined in consideration of the balance between the area of ​​the portion protruding to the left and right from said endless chain and the excavation resistance moment.

3. A chain cutter for constructing underground continuous wall according to claim 1 or 2, wherein when the total width of the bit plate is A, the protruding length of the bit plate on the frame side is B, and the width of the protruding portion of the bit plate on the frame side is C, the width D of the protruding portion of the extended side of the bit plate is obtained from the following formula. D=B*C*(B / 2+W / 2) / [(ABW)*{(ABW) / 2+W / 2}] Where W is the width of the endless chain.

4. A chain-type cutter for constructing underground continuous walls as described in any one of claims 1 to 3, wherein a clamping plate is arranged on the back side of the bit plate, and the endless chain is interposed between the clamping plate and the bit plate, and a reinforcing bolt inserted from the front side of the bit plate is tightened to the clamping plate to reinforce the connection between the bit plate and the endless chain.

5. A construction device equipped with a chain cutter for underground diaphragm wall construction, characterized in that it comprises a chain cutter for underground diaphragm wall construction according to any one of claims 1 to 4, and a base machine that supports the chain cutter so that it can be inserted into the ground.

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