JP2001081805A - Endless chain of excavator for underground continuous wall construction and construction method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of constructing an underground continuous wall using an endless chain which is circulated freely around an outer periphery of a cutter post and has a cutter bit protruding on an outer peripheral surface thereof, wherein a vertical wall of the cutter post is provided. Eliminates the need for correction work and greatly improves construction efficiency. SOLUTION: An axis of a cutter bit 7 is inclined in a direction of circulation of an endless chain 1 from a root side to a tip side thereof. The ground is excavated (down excavation) on the side where the endless chain 1 is pulled down with respect to the cutter post 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless chain of an excavator used for constructing an underground continuous wall, and a construction method using the same.

[0002]

2. Description of the Related Art An endless chain is circulated around the outer periphery of a cutter post so as to be freely circulated by using a digging device as disclosed in JP-A-7-180154 and JP-A-11-81368. The method of constructing an underground continuous wall is to construct a soil cement continuous wall by injecting solidified material such as cement milk while continuously excavating the ground, and stirring and mixing the excavated site soil and the solidified material. There is a method and a method in which the ground is discharged while excavating the ground continuously, a continuous groove is formed, and cement milk is injected into the groove to form a continuous wall.

[0003] As shown in Fig. 13- (a) and a partially enlarged view of Fig. 13 (a), the excavator is composed of a cutter post vertically built in the ground and an endless chain on the outer periphery thereof, and excavates the ground. The cutter bit is formed by welding or the like on a bit plate fixed to the outer peripheral surface of the endless chain by a bolt or the like.

In the conventional excavator shown in FIG. 13, the cutter bit has a truncated cone shape regardless of the direction of circulation of the endless chain, that is, in order to cope with both excavation on the raising side and excavation on the lowering side of the endless chain. It has a vertically symmetrical shape with tips attached to two places at the tip of the main body, and its axis protrudes in a direction perpendicular to the plane of the bit plate.

[0005] As shown in Fig. 14- (a), the cutter post is vertically built from a base machine on the ground to several meters to several tens of meters below the ground, and a pressing force for pressing an excavated ground surface from a hydraulic jack mounted on the base machine. F _P is given, and it moves in parallel while maintaining verticality by receiving the reaction force from the base machine.

However, since the pressing force F _P is applied on the ground, the drilling depth is deep, in accordance with the cutter post is long, the deflection increases occur at the lower end of the cutter post as shown in FIG. 14- (b) Since the lower pressing force F _P ′ acting on the ground from the lower portion of the cutter post decreases toward the lower end, the lower portion of the cutter post lags behind the upper portion,
It becomes difficult to excavate while maintaining the vertical state.

In order to eliminate the delay at the lower portion of the cutter post, as shown in FIG.
As shown in (d), while digging while pulling down the endless chain, the work of lowering the cutter post is alternately repeated to excavate the lower part of the cutter post at the time of descent and correct the verticality, A work process that shifts to normal excavation work is required, resulting in a significant decrease in construction efficiency.

When constructing an underground continuous wall, as described above,
Since the work of mixing and mixing the excavated earth and sand and the cement milk, or the operation of discharging (carrying out) the earth and sand is required at the same time as excavation, from the viewpoint of improving work efficiency, basically pulling up the endless chain as shown in Fig. 15 Uplift excavation, where excavation is performed on the side, is adopted.

In this case, the lower pressing force acting on the ground wall surface from the lower portion of the cutter post when the endless chain passes through the return roller at the lower end of the cutter post during the lifting excavation operation and the cutter bit bites into the bottom surface of the ground immediately below the return roller. Since the opposite biting resistance force f _R acts on F _P ′, the lower pressing force F _P ″ of the cutter post during the lifting excavation becomes F _P ″ = F _P ′ −f _R , and the lower pressing force F _{Since P} ′ further decreases (F _P ″),
The deflection on the lower side of the cutter post is further increased, which results in delay of the lower portion of the cutter post.

Further dropping speed in the pulling excavation excavated soil during operation of the circulation rate V ₁ and sediment out velocity V _U and the endless chain carried by endless chain water (in a stable solution) as shown in FIG. 16 V ₂ is V _U
= V ₁ −V ₂ , the average unloading speed of excavated earth and sand is lower than the circulation speed V ₁ of the endless chain.

As a result, the endless chain rises while the excavated soil accumulates above the cutter bit.
The earth and sand existing between the excavated ground wall surface and the bit plate and the endless chain serves as a cushion, and a phenomenon occurs in which the moving speed of the cutter post is reduced. This phenomenon is remarkable in the soft ground layer.

Further, in the case of FIG. 16, the power consumption increases due to the necessity of pulling power of excavated earth and water in water, so that the operating cost increases. In addition, the tension of the chain also increases, thereby promoting the fatigue of the endless chain and shortening the service life thereof, thereby increasing the maintenance cost of the endless chain.

As shown in FIG. 17, when the endless chain encounters the hard ground during the excavation work, the cutter bit is vertically protruded from the bit plate, so that the cutter bit is also perpendicular to the ground wall surface. Therefore, surface contact with the ground wall also increases the pressing force F _P of the cutter post, or the tip of the cutter bit that point contact can not be bite into the ground.

[0014] Also by circulating endless chain in this state, the cutter bit tip slips, the tip of each cutter bit, multiplied by μ friction coefficient between the cutter bit tip and the ground wall in the pressing force F _P Friction resistance (μ
The resistance force f _b (= μ · F _P / n) obtained by dividing F _P ) by the number of cutter bits in contact with the ground wall surface acts. Since this resistance force f _b is made to the running resistance of the endless chain is not substantially excavation work performed, occurs a phenomenon that oil pressure drop in the hydraulic motor for the endless chain drive.

[0015] Under this phenomenon, only the excavation speed corresponding to the shaved amount of the ground surface can be obtained corresponding to the frictional force generated between the cutter bit and the ground wall surface, and the construction efficiency is significantly reduced. Further, if the slip cutter bit, the tension f _C of the chain only acts as a force for moving the chain can not be used as a drilling force to bite into the cutter bit tip to ground.

When a cutter bit being excavated encounters a rock layer, a boulder, or an underground structure (hereinafter referred to as a boulder) even in a relatively soft ground, the tip of the cutter bit is shown in FIG. As shown, the resistance f _S
Receiving, moments to the cutter bits is the length of the arm the distance L from the cutter bit tip to the inner peripheral surface of the chain M (= f _S · L) is generated by the resistance force f _S.

When a collision occurs with a boulder, etc., a maximum load (maximum moment) acts instantaneously on the tip of the cutter bit,
Since the cutter bit falls with the chain in the direction opposite to the endless chain circulation direction due to the maximum moment, the cutter bit cannot bite into the boulders, etc. The same result is obtained. The overturning of the cutter bit also causes uneven wear between the chains of the endless chain, which may cause breakage of the endless chain.

From the above, the excavator of the type shown in FIG. 13 in which the cutter bit protrudes perpendicularly to the bit plate is intended for relatively soft ground, and is not applicable to hard ground. It will not be possible to cope with the presence of boulders or the like inside.

The present invention proposes an endless chain and a construction method having a structure for solving the above-mentioned various problems of the excavator shown in FIG.

[0020]

According to the first aspect of the present invention, the tip of the cutter bit is grounded even on hard ground by inclining the axis of the cutter bit from the base side to the tip side in the direction of circulation of the endless chain. In addition to preventing the cutter bit from slipping or tipping over on hard ground, the cutter bit is used for construction by pulling down excavation in claim 3 to avoid lowering of the lower pressing force F _P ′ of the cutter post, Prevent delays at the bottom of the post.

The cutter bit is inclined in the direction of circulation of the endless chain from the root side to the tip side, and as shown in FIGS. 1 and 2, the cutter bit pulls down the ground wall surface with respect to the cutter post and excavates from the root side. By inclining downward toward the tip side, the cutter bit is directed in a direction to bite into the excavated ground as the endless chain advances.

For example, when digging the ground on the side where the endless chain is pulled down with respect to the cutter post (downward digging) as in claim 3, when the endless chain circulates while the cutter post moves horizontally in parallel, FIG. pressing force F _P from the cutter post against the wall surface of the ground acts as shown, the tension F _C in the chain acts on the endless chain.

As shown in FIG. 3, both the pressing force F _P and the tension F _C are divided into axial components F _Pb and F _Cb of the cutter bit and components F _Pm and F _Cm perpendicular thereto. Axial component F _Pb cutter bit, F _Cb acts on the wall surface of the ground as a biting force F _B to the ground, the vertical component F _Pm, the F _Cm acts as a moment F _M to try to overturn the cutter bit .

The axial components F _Pb and F _{Cb of the} cutter bit
Orientation the same, since that faces the distal end side from the root side of the cutter bit, biting force F _B is the resultant force of each component F _Pb + F
_Cb, and the acts as a force that the tension F _C of the pressing force F _P and the chain of the cutter post together cutting the ground.

As a result, since the axis of the cutter bit is inclined in the direction of circulation of the endless chain from the root side to the tip side, the excavating ability is greatly improved. If the cutter bits are perpendicular 13 to the bit plate, the pressing force F _P is for facing the axial same direction of the cutter bit, does not act as a force for cutting the ground.

[0026] Since the vertical component F _Pm, F _Cm faces each other are opposite, the moment F _M to try to overturn the cutter bit | F _Pm -F _Cm | next, each component F _Pm, F _Cm is canceled , it serves to moment F _M is reduced. As a result, the moment that the cutter bit and the chain fall over is reduced, so that the cutter bit remains in the ground, without uneven wear between the chains, preventing breakage of the endless chain due to uneven wear. Is done.

[0027] and the biting force F _B from the tip of the cutter bit F _Pb + F _Cb acts, the moment from the ground F
_By reducing _{M, the} cutter bit can be prevented from slipping and overturning even on hard ground or soft ground where there are boulders, etc., so the hydraulic pressure of the endless chain drive hydraulic motor drops and the construction speed decreases. A decrease in efficiency is avoided.

According to a second aspect of the present invention, the axis of the cutter bit in the first aspect is inclined in any direction in the width direction of the endless chain with respect to the surface including the circulation direction of the endless chain (the surface including the moving direction of the cutter post). At the same time, the cutter bit is rotatably rotated around its axis and held on a bit plate fixed to the outer peripheral surface of the endless chain, so that the cutter bit excavates, and crushed earth and sand is scattered around the cutter bit, and excavation is performed. This prevents the endless chain from rising while the earth and sand is deposited above the cutter bit, and prevents the endless chain from being deposited between the excavated ground wall surface and the bit plate and the endless chain.

Since the axis of the cutter bit is inclined with respect to the plane including the circulation direction of the endless chain as shown in FIG.
Even if the cutter bit is not forcibly rotated, a rotational force is generated due to the difference in resistance in the cutter bit, and the cutter bit constantly excavates the ground while rotating, disperses the excavated soil by rotation, and promotes deviation from the cutter bit. .

The scatter of the earth and sand prevents a phenomenon in which the earth and sand once excavated at the tip of the cutter bit is compression-secondarily crushed by the body of the cutter bit, and the excavation resistance due to the secondary compression crush is reduced. The ability is significantly increased.

The self-sharpening effect of the rotary excavation prevents uneven wear of the cutter bit and increases the sustaining effect of the excavating ability. Therefore, the life of the cutter bit, bit plate, or endless chain is extended, and the necessity of replacement is increased. As a result, the cost of maintaining the function of the endless chain is reduced.

In claim 3, claim 1 or claim 2
While moving the cutter post on which the endless chain described in the above is stretched horizontally, excavating the ground on the side where the cutter post is lowered (downward excavation), the delay of the lower portion of the cutter post is prevented, and the endless chain is moved. This eliminates the need for a vertical correction operation that alternates between raising the cutter post while excavating and raising the cutter post and lowering the endless chain and lowering the cutter post while excavating, thereby improving excavation efficiency.

In this case, the endless chain circulates along with the movement of the cutter post as shown in FIG.
When the cutter bit tilted forward in the direction of the endless chain passes through the return roller, it bites into the ground underneath and kicks the ground bottom in the direction opposite to the direction of movement of the cutter post. received a kick force f _K to try to advance the cutter post, free-running effect of the reverse can be obtained in the case of FIG. 15.

Further, as shown in FIG. 6, the excavated earth and sand is sent below the cutter post by circulation of the endless chain, and then carried through the return roller to the excavated space on the opposite side of the direction of travel of the cutter post. When the cutter bit digs into the ground, the lower part of the cutter post forms the deposited sediment because the sediment discharged to the opposite side of the direction of travel of the cutter post is lifted to some extent by the rising endless chain and then deposits behind the cutter post. receive the pressing reaction force f _T toward the ground wall from.

[0035] As a result, the lower the pressing force acting on the ground wall from the bottom of the cutter post F _P "pressing force is applied from the hydraulic jack of the base machine F _P and the kick force f _K
And the pressing reaction force f _T (F _P = F _P + f _K + f
_T), to become larger than the pressing force F _P exerted on the top of the cutter post, FIG. 14 (bottom of delay due to the occurrence of deflection of the cutter post, as shown in b) is no longer the lower the top of the cutter post conversely It will be a more advanced look.

According to the third aspect, when the ground is pulled up and excavated, the lower pressing force F _P ″ of the cutter post is raised by receiving the kicking force f _K opposite to the biting resistance force f _R received from the ground bottom surface. Lower pressing force F _P ”when excavating
Therefore, it becomes larger by f _R + f _K + f _T.

By preventing the lower portion of the cutter post from being delayed, the work of correcting the verticality becomes unnecessary, and the excavation efficiency is greatly improved. In addition, since the lower part of the cutter post tends to precede the upper part, it is possible to construct a deep underground continuous wall exceeding the limit depth of the conventional excavator even on hard ground.

According to the third aspect of the present invention, since the excavated earth is pulled up on the opposite side of the cutter post in the traveling direction by the down excavation, no lifting power for discharging the earth and sand by the up excavation is required, and the power consumption is reduced. Operating costs are reduced. In addition, since the tension of the chain accompanying the lifting for discharging the earth and sand is reduced, the load on the chain is reduced, and the safety against breakage is improved.

Further, as shown in FIG. 7, since the direction of circulation of the endless chain coincides with the falling direction of the earth and sand, the speed of carrying out the earth and sand is increased, and the distance between the endless chain and the wall surface of the excavated ground is higher than in the case of pulling excavation. Excavation resistance and frictional resistance are reduced because sediment is no longer deposited.

At this time, the unloading speed V _D of the soil is V _D = chain speed V ₁ or the falling speed V _{2 of the} soil.
It becomes larger than V _U (V ₁ −V ₂ ) in the case of 16. The kinetic energy at the time of the falling of the earth and sand can be effectively used to supplement the power for circulating the endless chain, so that the power consumption is reduced. Also, since the chain tension is reduced,
As a result of suppressing the fatigue of the chain and extending the life, the maintenance cost of the endless chain is reduced.

According to a fourth aspect of the present invention, the endless chain is divided into a plurality of sections in the circulating direction, the inclination directions of the axes of the cutter bits in the adjacent sections are different from each other, and the cutter bits in one of the adjacent sections are different. By inclining the shaft in the direction of circulation of the endless chain from the base side to the tip side, and by inclining the axis of the cutter bit in the other section from the tip side to the base side in the direction of circulation of the endless chain. It can handle both excavation and excavation.

In order to prevent delay of the lower portion of the cutter post and to improve the excavation efficiency, it is reasonable to carry out the excavation by pulling down as described in claim 3, but it is necessary to carry out the excavation in view of ground conditions and construction management. Since there are cases where the direction of the axis of the cutter bit is changed for each section as shown in FIG. 8, two types of excavation can be performed by one type of endless chain. In this case, each cutter bit has an excavating ability in only one circulating direction due to the inclination of its axis, but the entire endless chain exerts an excavating ability in any circulating direction.

According to the fourth aspect of the present invention, the tip attached to the tip of the cutter bit only needs to be provided in one direction which exerts the excavating ability. Therefore, when the axis of the cutter bit is oriented in a direction perpendicular to the bit plate, the tip is required. Number (two)
, The cost of fabricating the cutter bit is half that of a vertical bit plate.

In the bit plate, a bolt hole for bolt connection to the endless chain is formed. According to claim 5, by arranging the bolt hole vertically symmetrically, the bit plate is turned upside down and connected to the endless chain. It can be so.

In this case, since the inclination directions of the axes of the cutter bits in the adjacent sections can be made different from each other by using the same bit plate, the excavating ability can be exhibited in any circulation direction. Above, it is not necessary to prepare a bit plate for every different inclination direction of the axis of the cutter bit, and the number of parts is reduced.

[0046]

1 and 2 show a first embodiment of the present invention.
1 shows a configuration example of the endless chain 1. The endless chain 1 is held directly or indirectly by the endless chain body 3 formed by linking the chains 2, the bit plate 4 joined to the outer peripheral surface of the endless chain body 3 by bolts 5 or welding, and the bit plate 4. It is composed of a cutter bit 7. According to the fifth aspect, the bit plate 4 is joined to the endless chain main body 3 by bolts 5.

As shown in the figure, when the bit holder 6 is joined to the bit plate 4 by welding or bolts, and the bit plate 4 and the bit holder 6 are separate bodies, the cutter bit 7 is held by the bit holder 6 so as to be indirect. When the bit holder 6 is formed integrally with the bit plate 4 as a part of the bit plate 4, the bit holder 6 is directly held by the bit plate 4.

When the bit holder 6 is separate from the bit plate 4, the bit holder 6 has an insertion hole 6 a through which the shaft 7 a of the cutter bit 7 is inserted, and the cutter bit 7 connects the shaft 7 a held by the bit holder 6 and the ground. It consists of two parts, a tip part 7b to be excavated. The bit part 4 side (root side) of the shaft part 7a and the tip part 7b
Flanges 7c and 7d are formed on the sides. Tip 7b is a flange
It has a conical or frusto-conical shape with a smaller diameter from the 7d side to the tip, making it easier to penetrate the tip by point contact with the excavated ground, and intensively applying a striking force to hard ground or boulders Carbide chip 7e is embedded.

The cutter bit 7 is inserted into the insertion hole 6a of the bit holder 6 in the shaft portion 7a, and the flange 7d on the tip portion 7b side is formed.
Are held by the bit holder 6 in a state of being locked to the root side by the bit holder 6. In Fig. 1, the flange on the base side of the shaft 7a
U which is inserted between the bit 7c and the surface of the bit holder 6 on the side of the bit plate 4 and is locked to the flange 7c and the bit holder 6
The cutter bit 7 is held by the bit holder 6 by the pin 8, and the cutter bit 7 is
As long as the cutter bit 7 is not separated, the method of holding the cutter bit 7 does not matter. When the U-shaped pin 8 is used, a semicircular groove into which the U-shaped pin 8 is fitted is formed in a portion of the shaft portion 7a protruding from the surface of the bit holder 6 on the bit plate 4 side.

The diameter of the insertion hole 6a of the bit holder 6 is such that the shaft portion 7a of the cutter bit 7 can rotate freely around the axis while the cutter bit 7 is held by the bit holder 6.
Larger than the diameter of.

The axis of the cutter bit 7 is a root flange 7c.
From the side to the tip 7b side in the direction of circulation of the endless chain 1. As shown in FIGS. 1 to 7, the cutter post 9 is used when the endless chain 1 is pulled down and excavated.
The cutter bit 7 located on the side of the traveling direction of the
From the side to the tip 7b side. The shaft of the cutter bit 7 located on the traveling direction side of the cutter post 9 in the section where the ground is excavated (pull-up excavation) on the side where the endless chain 1 is lifted, of the endless chain 1 used in claim 4 as described later. Tilts upward.

FIG. 4 shows an elevational surface of the endless chain 1 of the second aspect on the excavated ground wall surface side. According to the second aspect, when the excavation is carried out, the tip 7b of the cutter bit 7 in FIG.
Causes a difference in the upward digging resistance that the shaft receives on both sides with respect to the axis, and rotates the cutter bit 7 by the difference in the resistance, so that the axis of the cutter bit 7 is circulated in the endless chain 1 (moving direction of the cutter post 9). The endless chain 1 is rotatably held around the axis by the bit holder 6 in a state of being inclined in any direction in the width direction of the endless chain 1 with respect to the plane including.

In FIG. 4, the cutter bits 7 are protruded at three positions on the center and the both sides in the length (lateral) direction of the bit plate 4, but as shown in FIG. Sometimes there are two.

Each cutter bit 7 shown in FIG. 4 rotates in the direction of the arrow due to the difference in digging resistance, and the excavated earth and sand scatters around the cutter bit 7 due to the rotation.
Deviate from

FIGS. 5 to 7 show the state of the construction method according to claim 3 during construction. As shown in FIGS. 5 and 6, while the cutter post 9 on which the endless chain 1 is stretched is horizontally moved by the hydraulic jack 11 of the base machine 10, the endless chain 1 is pulled down with respect to the cutter post 9. Is a method of excavating (pulling down) the ground.

The earth and sand excavated by the endless chain 1 is conveyed to the opposite side of the cutter post 9 through the return roller 12 by the inclination of the cutter bit 7 and the circulation of the endless chain 1 as shown in FIGS. After being lifted up by the endless chain 1 rising on that side, it is deposited on the excavated bottom surface.

FIG. 8 shows an endless chain 1 according to a fourth aspect. Claim 4 divides the endless chain 1 into a plurality of sections in the circulation direction, makes the inclination directions of the axes of the cutter bits 7 in adjacent sections different from each other, and corresponds to both the down excavation and the up excavation. .

In the section to be excavated, the cutter post 9
The axis of the cutter bit 7 located on the side of the traveling direction is inclined downward from the root side to the tip side as in claim 1,
In the section where the excavation is performed, the axis of the cutter bit 7 located on the side of the traveling direction of the cutter post 9 is inclined upward from the root side to the tip side.

FIG. 9 shows an endless chain 1 according to a fifth aspect. A bolt hole formed in the bit plate and bolted to the endless chain body.
This is an endless chain 1 in which 4a and 4b are arranged vertically symmetrically. The bit plate 4 is turned upside down so that it can be joined to the endless chain main body 3.
The endless chain 1 according to claim 4 can be constituted only by this.

The bolt holes 4a and 4b are respectively provided when the endless chain 1 is pulled down and lifted and excavated, that is, when the cutter bit 7 is fixed downward and upward in FIG. A plurality is formed within the range of the width of the chain body 3.

In the drawing, when the cutter bit 7 is directed downward and upward in the direction of travel of the cutter post 9, there are two places near the horizontal center line of the bit plate 4, either one of the upper and lower ends. A total of eight places are formed, two places in total, each near the part, but the number of bolt holes 4a and 4b at each time is not limited to four as long as it is a sufficient number for fixing the bit plate 4 . In FIG. 9, reference numeral 4a denotes a bolt hole used when the cutter bit 7 is fixed downward in the direction of travel of the cutter post 9, and 4b denotes a bolt hole used when the cutter bit 7 is fixed upward.

FIGS. 10 to 12 show other examples of the shape of the bit plate 4, examples of projecting the cutter bit 7 from the bit plate 4 and forming bolt holes 4a and 4b. FIGS. 10 (a) and 10 (b) show the case where the axis of the center cutter bit 7 is directed in the direction of circulation of the endless chain 1 and both cutter bits 7, 7 are directed outward with respect to the center of the bit plate 4. ) ~
(d) is a case where the length of the bit plate 4 is shortened.

FIG. 10- (d) shows that the height of the bit plate 4 in (c) is increased and the projecting position of the central cutter bit 7 and the projecting positions of the cutter bits 7, 7 on both sides are shifted up and down. In this case, a large space around the bolt holes 4a and 4b is taken to improve the workability of tightening the bolt 5.

FIGS. 11A to 11C show cutter bits 7 and 7.
Are projected only at two places on both sides. Fig. 12- (a)
(C) shows the case where the height of the center of the bit plate 4 is made larger than that of both sides, and the projecting position of the cutter bit 7 at the center and the projecting position of the cutter bits 7, 7 on both sides are shifted up and down. .

[0065]

According to the first aspect, since the axis of the cutter bit is inclined in the direction of circulation of the endless chain from the root side to the tip side, the tip of the cutter bit can be cut into the ground even on hard ground. In addition, it is possible to prevent the cutter bit from slipping or falling over on hard ground.

[0066] Particularly the cutter post pressing force F _P and the endless chain tension F _C, for acting on the wall surface of the ground as a biting force F _B of the axial component of the cutter bit to both ground, drilling ability of the cutter bit Improve dramatically.

[0067] The pressing force F _P and tension F _C, for axial vertical component of the cutter bits are opposite to each other, the moment F _M to try to overturn the cutter bit is decreased, the cutter bit is in the ground The biting state is maintained, and breakage of the endless chain due to uneven wear between the chains is prevented. By preventing the cutter bit from slipping and overturning, it is possible to avoid a decrease in hydraulic pressure of the hydraulic motor for driving the endless chain and a decrease in construction efficiency due to a decrease in excavation speed.

In the present invention, the axis of the cutter bit is inclined in any direction in the width direction of the endless chain with respect to the plane including the circulation direction of the endless chain.
By holding the cutter bit rotatably around the axis on the bit plate, a difference is created in the excavation resistance on both sides with respect to the axis, and in order to rotate the cutter bit, the excavated earth and sand is scattered and dissociated from the cutter bit. Can be promoted.

By the scattering of the earth and sand, the phenomenon that the body portion of the cutter bit compresses and secondary crushes the earth and sand once excavated at the tip of the cutter bit is avoided, and the excavation resistance due to the secondary compression crushing is reduced. Significantly increase.

In addition, uneven wear of the cutter bit is prevented by the self-sharpening effect of the rotary excavation, and the effect of maintaining the excavation ability is increased. Therefore, the life of the cutter bit, the bit plate, or the endless chain is extended, and the necessity of replacement is required. The reduction reduces the cost of maintaining the functionality of the endless chain.

In claim 3, claim 1 or claim 2
Endless chain pulls on the cutter post
Excavating (downward excavation) the ground on the side to be lowered
The cutter post from the bottom of the ground to the cutter post.
Kick force f trying to move forward _KAnd from the sediment deposited
Pressing reaction force f toward the excavated ground surface_TWorks, so
There is no longer any delay at the bottom due to the deflection of the terpost.
As a result, there is no need to correct the verticality, greatly improving drilling efficiency.
improves.

Further, since the lower part of the cutter post tends to precede the upper part, it is possible to construct an underground continuous wall having a deep depth exceeding the limit of the prior art even on hard ground.

In addition, since the excavated earth is pulled up on the opposite side of the cutter post in the downward excavation due to the downward excavation, the power for lifting the excavated earth due to the upward excavation becomes unnecessary, and the operating cost is reduced by reducing the power consumption. In addition, since the tension of the chain caused by the lifting for discharging the soil is also reduced, the load on the chain is reduced, and the safety against breakage is improved.

Further, since the direction of circulation of the endless chain coincides with the falling direction of the earth and sand, the speed of discharging the earth and sand is increased, and the accumulation of earth and sand between the endless chain and the excavated ground surface is reduced as compared with the case of pulling and excavating. , Excavation resistance and friction resistance are reduced. Further, since the tension of the chain is reduced, the fatigue of the chain is suppressed, and the life is extended, so that the maintenance cost of the endless chain is reduced.

In the fourth aspect, the endless chain is divided into a plurality of sections in the circulation direction, and two types of excavation are performed by one type of endless chain so that the inclination directions of the axes of the cutter bits in the adjacent sections are different from each other. It can handle both uplifting and downhill excavation.

In this case, since the tip attached to the tip of the cutter bit needs to be provided only in one direction that exhibits the excavating ability, the cost required for manufacturing the cutter bit is half that in the case where the cutter bit is vertically protruded from the bit plate. I'm done.

According to a fifth aspect of the present invention, the bolt holes of the bit plate to be bolted to the endless chain are vertically symmetrically arranged so that the bit plate can be turned upside down and joined to the endless chain. Can be used to manufacture the endless chain according to claim 4, and it is not necessary to prepare a bit plate for every different inclination direction of the axis of the cutter bit.

[Brief description of the drawings]

FIG. 1 is an elevational view showing details of an example of protruding a cutter bit from a bit plate according to claim 1;

FIG. 2 is an elevation view showing a state of excavation of a ground wall surface by a cutter bit.

3 is an elevational view showing how the effect of the ground of the pressing force F _P and the chain tension F _C of the cutter post.

FIG. 4 is a side view of FIG. 1 showing an example in which the cutter bit of claim 2 is protruded from a bit plate.

FIG. 5 is an elevation view showing a state at the time of construction by the construction method of claim 3;

FIG. 6 is an elevational view showing the entire cutter post and the base machine in the case of FIG. 5;

FIG. 7 is an elevational view showing a state at the time of pulling down excavation using the endless chain of FIG. 4;

FIG. 8 is an elevational view showing an endless chain according to claim 4;

FIG. 9 is a side view showing an endless chain according to claim 5;

FIGS. 10A to 10D are side views showing a modification of FIG.

FIGS. 11A to 11C are side views showing a modification of FIG.

12 (a) to 12 (c) are side views showing a modification of FIG.

FIG. 13 (a) is an elevation view showing a state of construction by conventional pulling excavation, and FIG. 13 (b) is an enlarged view of an arc portion of FIG. 13 (a).

FIGS. 14 (a) to (d) are elevation views showing the state of construction when the excavation depth is large.

FIG. 15 is an elevational view showing a state of pulling excavation by the excavator of FIG. 13;

FIG. 16 is a partially enlarged view of FIG. 15;

FIG. 17 is an elevational view showing a state of slipping of a cutter bit when an excavation wall surface is hard ground.

FIG. 18 is an elevational view showing a state in which the cutter bit is turned over when a rolling stone is encountered.

[Explanation of symbols]

1 endless chain, 2 chain, 3 endless chain body, 4 bit plate, 4a, 4b
... bolt holes, 5 ... bolts, 6 ... bit holders, 6a
... insertion hole, 7 ... cutter bit, 7a ... shaft, 7b ...
... Front, 7c ... Flange, 7d ... Flange, 7e ... Carbide tip, 8 ... U-shaped pin, 9 ... Cutter post, 10
…… Base machine, 11… Hydraulic jack, 12 …… Return roller.

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[Procedure amendment]

[Submission date] January 17, 2000 (2000.1.1)
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 2

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

According to a second aspect of the present invention, the cutter bit is held on a bit plate fixed to the outer peripheral surface of the endless chain so as to be rotatable around its axis. By inclining with respect to the circulation direction of the endless chain when viewed in the vertical direction, the cutter bit excavates and scatters crushed earth and sand around the cutter bit,
The endless chain is prevented from rising while the excavated earth and sand accumulate above the cutter bit, and is prevented from accumulating between the excavated ground wall surface and the bit plate and the endless chain.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

As shown in FIG. 4, when the shaft is inclined with respect to the circulation direction of the endless chain when viewed in a direction perpendicular to the plane of the bit plate, a difference occurs in the excavation resistance on both sides with respect to the shaft. Even if the cutter bit is not rotated, a torque is generated due to the difference in resistance between the cutter bit and the cutter bit excavates the ground while constantly rotating, and scatters the excavated earth and sand by the rotation, thereby promoting separation from the cutter bit.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

According to a second aspect of the present invention, the cutter bit is held on the bit plate so as to be rotatable around its axis, and when the axis of the cutter bit is viewed in a direction perpendicular to the plane of the bit plate, the cutter bit extends in the circulation direction of the endless chain. By making the cutter bit inclined, a difference is generated in the excavation resistance on both sides with respect to the axis, and the cutter bit is rotated, so that the excavated earth and sand can be scattered and the deviation from the cutter bit can be promoted.

Claims (5)

[Claims] An excavation for constructing an underground continuous wall comprising a cutter post and an endless chain which is stretchably circulated around the outer periphery of the cutter post and has a cutter bit protruding from a bit plate fixed to the outer peripheral surface. In the device,
The endless chain of a drilling rig for underground continuous wall construction, in which the axis of the cutter bit is inclined from the root side to the tip side in the direction of the endless chain circulation. 2. A shaft of the cutter bit is inclined with respect to a plane including a circulation direction of the endless chain in any direction in a width direction of the endless chain, and the cutter bit is rotatably mounted on the bit plate around the axis. The endless chain of the excavator according to claim 1, which is held. 3. An endless chain which excavates the ground on the side where the endless chain is pulled down with respect to the cutter post while horizontally moving the cutter post on which the endless chain according to claim 1 or 2 is stretched. Construction method. 4. An excavation for construction of an underground continuous wall comprising a cutter post and an endless chain which is circulated around the outer periphery of the cutter post and is provided with a cutter bit protruding from a bit plate fixed to the outer peripheral surface. In the device,
The endless chain is divided into a plurality of sections in the circulation direction, and the inclination directions of the axes of the cutter bits in the adjacent sections are different from each other, and the axes of the cutter bits in one section extend from the root side to the tip side of the endless chain. An endless chain of an excavator for underground continuous wall construction, wherein the cutter bit in the other section is inclined in the direction of circulation of the endless chain from the tip side to the base side. 5. An excavation for constructing an underground continuous wall comprising a cutter post and an endless chain which is stretchably circulated around the outer periphery of the cutter post and has a cutter bit protruding from a bit plate fixed to the outer peripheral surface. In the device,
An endless chain for an excavator for constructing an underground continuous wall, wherein a bolt hole for bolt connection to an endless chain is formed in a bit plate in a vertically symmetrical manner.