JP6197135B1 - Ground improvement device and improved wall construction method - Google Patents

Abstract

An object of the present invention is to provide a ground improvement device for increasing the digging force and the digging speed of a mixing agitation head supported by a base machine. A ground improvement device for constructing an improved wall body by penetrating a mixing and stirring head (6) attached to a base machine (1) into the ground. While keeping the crawler belt 2 of the base machine 1 substantially parallel to the plane center line C1 of the improved wall B, the angle formed by the plane center line C1 and the plane center line C2 of the boom 4 is an acute angle. When the mixing stirring head 6 is dug in the direction of the plane center line C1, the component force P1 in the direction of the plane center line C1 based on the force P in the swinging operation direction of the boom 4 is used as the digging vector in the direction of the plane center line C1. The mixing stirring head 6 is advanced. [Selection] Figure 5

Description

  The present invention relates to a ground improvement device for building a continuous improved wall in the ground as part of ground improvement, and a method for building an improved wall using the same.

  As a method for constructing this type of improved wall body, for example, Patent Document 1 and Patent Document 2 disclose a construction method using an excavator excavator represented by a backhoe as a base machine. In the construction methods disclosed in Patent Document 1 and Patent Document 2, a mixing stirring head including a chain-type mixing stirring blade that moves around in the vertical direction is attached as an attachment to the tip of an arm of a base machine such as a backhoe, After this mixing stirring head penetrates into the ground to a predetermined depth, the ground moving surface of the mixing stirring blade is moved to the excavation surface in the horizontal direction while mixing and stirring the original soil and the solidified material. It is based on constructing a continuous improved wall body corresponding to the width dimension of the orbiting moving surface of the mixing stirring blade.

  In addition, in the former method disclosed in Patent Document 1, (a) the direction in which the improved wall is to be constructed and the traveling direction of the base machine are set so as to be substantially parallel, A non-traveling excavation process for excavating and moving the mixing stirring head in the ground in the direction of construction of the improved wall body using the degree of freedom of arm turning in the traveling state; and (b) the mixing stirring head using the degree of freedom of arm turning. A non-digging traveling step in which the base machine itself travels in the digging movement direction of the mixing and stirring head substantially parallel to the construction direction of the improved wall body, instead of the digging movement of (a). The process and the non-digging travel process of (b) are repeated alternately.

  In the latter method disclosed in Patent Document 2, a polygonal cylindrical structure is constructed in the ground after the mixing and stirring head has a degree of freedom of swinging with respect to the arm of the base machine. In this case, (a) one side of the polygon in parallel with the penetration and extraction of the mixing and stirring head into the ground while the base machine is stationary at a portion corresponding to the center position of the area to be the cylindrical structure. The process of constructing the vertical wall at a position corresponding to one side of the cylindrical structure by using both the movement in the longitudinal direction and the swinging motion of the tube, and (b) the work of the vertical wall construction process And a step of constructing a polygonal cylindrical structure by sequentially performing the construction of the vertical wall portion continuous to the existing vertical wall portion by repeating a plurality of times.

JP 2005-307675 A JP 2004-108136 A

  However, the excavation process in both methods disclosed in Patent Documents 1 and 2 is that the mixing agitating blade facing the front side in the construction direction of the improved wall body among the mixing agitating heads penetrating into the ground is in situ. Since the mixing agitation head is digged and moved by the excavation force for excavating the soil (reaction force accompanying excavation and excavation of the mixing agitation head itself) and the revolving force of the swivel base of the base machine, the swirl base swivel is originally Since the capacity is not intended to turn while excavating underground, it was not always sufficient as its digging force.

  Therefore, depending on the ground strength (hardness of the original ground) of the improved wall region to be constructed, a so-called surging phenomenon occurs that the fluctuating speed of the mixing stirrer head becomes slower or faster, thereby improving Difficulty in wall quality. Moreover, since the fluctuation of the excavation speed means that the improved wall cannot be constructed at an economical speed, the construction time and construction period are long.

  In addition, both methods are basically constructed in such a posture that the improved wall to be constructed in plan view and the boom and arm axes of the base machine are almost perpendicular to each other. ) Due to the increased separation to the mixing and stirring head, the construction may be difficult in a narrow site.

  The present invention has been made paying attention to such problems, and the base machine inherently has the boom and arm forces and the digging force of the digging bucket as the digging force or the digging force of the mixing agitation head. By making limited use, it is possible to increase the digging force and digging speed of the mixing agitation head, and to provide a ground improvement device that can be constructed even in a narrow field and a construction method of an improved wall suitable for its construction. Is.

  According to the present invention, an excavator of excavator system is used as a base machine, and a mixing agitation head having a chain-type mixing agitation blade that moves around in the vertical direction is attached to the tip of an arm of the base machine. A continuous vertical improvement wall corresponding to the width dimension of the orbiting moving surface of the mixed stirring blade in the ground while excavating the original soil with the mixed stirring blade and mixing and stirring the original soil and the solidified material. It is a ground improvement device that builds.

In addition, when the improved wall body is constructed, the crawler belt of the base machine is kept substantially parallel to the plane center line that bisects the thickness dimension of the improved wall body to be constructed in plan view, The boom is configured such that the orbiting plane and the plane center line are substantially perpendicular to each other, and the boom and arm axial directions in the plan view of the base machine obliquely intersect the plane center line. And improvement of the ground used in the construction method in which the mixing stirring head is dug in the plane center line direction by using the component force in the plane center line direction based on the force in the swing motion direction of the arm as a dug vector in the plane center line direction It is assumed that it is a device.

  And a turning mechanism capable of adjusting an angle between the center line of the plane and the center line of the boom and the arm in a plan view of the base machine between the tip of the arm of the base machine and the mixing and stirring head. Is provided.

The swivel mechanism is configured to allow relative rotation between a non-turning portion connected to a tip portion of an arm of the base machine, a turning portion connected to an upper end portion of the mixing and stirring head, and the non-turning portion and the turning portion. The connecting shaft member, the fastening and fixing means for fastening and fixing the non-turning part and the turning part at a relative rotation position, and the turning from the non-turning part without depending on the fastening and fixing means And a drop-off prevention mechanism for preventing the drop-out of the part.

  As a preferred aspect, as described in claim 2, the swiveling mechanism has a non-swiveling portion that is detachable with respect to a distal end portion of an arm of a base machine, and the swiveling portion is spaced from an upper end portion of a mixing and stirring head. It is formed as an intermediate bracket type that can be attached and detached.

  As another preferred aspect, as described in claim 3, the turning mechanism has a non-turning portion that can be attached to and detached from the tip of the arm of the base machine, and the turning portion of the mixing agitation head. It is assumed that the upper end portion is integrally connected.

Furthermore, in the invention according to claim 4, wherein the ground improvement device is regarded as a method for constructing an improved wall body, the excavator of excavator system is used as a base machine, and it moves around the tip of the arm of the base machine in the vertical direction. A mixing type stirring head equipped with a chain type mixing stirring blade is installed, and after the mixing stirring head penetrates into the ground to a predetermined depth, in addition to discharging the solidified material, excavation of in-situ soil by the mixing stirring blade and A method for constructing a continuous vertical improved wall body corresponding to the width dimension of the orbiting moving surface of the mixing and stirring blade in the ground while mixing and stirring the original soil and the solidified material.
In this case, the plane center line that bisects the thickness dimension of the improved wall body to be constructed in plan view between the tip of the arm of the base machine and the mixing and stirring head and the plan view of the base machine. A turning mechanism capable of adjusting an angle between the boom and the center line of the arm is provided.
And while keeping the crawler belt of the base machine substantially parallel to the plane center line, the orbiting moving surface of the mixing agitating blade and the plane center line are substantially perpendicular, and the mixing agitation head is moved to the center of the plane. upon thereby excavating a linear direction, wherein the function of the turning mechanism, in terms of the axial direction of the boom and the arm in plan view of the base machine with respect to the planar center line has a posture crossing diagonally, the mixture stirred head And generating a force in the swing direction on the boom and arm of the base machine while rotating the mixing agitating blade of the base agitator, and applying the component force in the plane center line direction based on the force in the swing operation direction of the boom and arm. As the digging vector in the plane center line direction, the mixed stirring head is dug in the plane center line direction to construct a vertical improved wall body.

In addition, the mixing stirring head is dug in the plane center line direction with the component force in the plane center line direction based on the force in the swing operation direction of the boom and the arm as the dug vector in the plane center line direction. The mixing agitation head is excavated with the sum of the advancing vector and the advancing force generated by the orbital movement of the mixing agitation blade of the mixing agitation head.

  According to the present invention, it is possible to increase the digging force and digging speed of the mixing agitation head as compared with the conventional construction method, and contribute to improving the quality of the improved wall body to be constructed. Will also be excellent. In addition, it is possible to work without difficulty in a narrow site.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic explanatory drawing which shows 1st Embodiment of the ground improvement apparatus which concerns on this invention. FIG. 3 is an enlarged explanatory view showing details of the mixing and stirring head shown in FIG. 1. Side surface explanatory drawing of the mixing stirring head shown in FIG. Plane explanatory drawing of FIG. 1 corresponded to the conventional construction method. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the construction method of the improved wall body which concerns on this invention, (a) Plane explanatory drawing at the time of construction by the backward movement of a base machine, (b) Construction by the forward movement of a base machine FIG. It is a figure which shows 2nd Embodiment of the construction method of the improved wall body which concerns on this invention, (a) is plane explanatory drawing, (b) is explanatory drawing which looked at the base machine of the figure (a) from the back side. . FIG. 2 is an enlarged explanatory view showing details of a turning mechanism interposed in a connecting portion between an arm tip of the base machine shown in FIG. 1 and a mixing and stirring head. Plane explanatory drawing of the turning mechanism in FIG. Plane explanatory drawing at the time of angle change of the turning mechanism in FIG. FIG. 8 is an enlarged explanatory view showing another example of the turning mechanism shown in FIG. 7. The figure which shows 3rd Embodiment of the construction method of the improved wall body which concerns on this invention, and is plane explanatory drawing at the time of construction of what is called a honeycomb-shaped improved wall body.

  FIGS. 1-6 shows the 1st more concrete form for implementing the ground improvement apparatus which concerns on this invention, and the construction method of the improvement wall body using the same, Especially FIGS. 1-3 are the basics of a ground improvement apparatus. The structure is shown. Hereinafter, the details of the present embodiment will be described in comparison with the prior art.

  In FIG. 1, reference numeral 1 denotes an endless track (crawler) type or crawler excavator excavating machine which is one of general-purpose construction machines, for example, a hydraulic excavator having a crawler 2 or a base machine (base machine) such as a backhoe. Similarly, a swingable arm 5 is connected to the tip of a swinging (undulation or tilting) boom 4 mounted on a swing base 3 as an upper swing body of the base machine 1. At the tip of the arm 5 in the base machine 1, a so-called trencher type mixing agitation head 6 for excavating the original soil as an attachment and mixing agitation with the solidified material (ground improvement material) is an intermediate bracket type which will be described later. It is detachably mounted via the turning mechanism 7. Reference numeral 8 is a boom cylinder for swinging the boom 4, 9 is an arm cylinder for swinging the arm 5, and 10 is an attachment cylinder (bucket) for swinging the mixing and stirring head 6, which is an attachment. Cylinder).

  2 is an enlarged explanatory view of the mixing and stirring head 6 shown in FIG. 1, and FIG. 3 is an explanatory side view of FIG. As shown in FIGS. 2 and 3, the mixing and agitation head 6 has a rigid frame 11 as a base body. The frame 11 has a wide and substantially bifurcated yoke portion 12 and a lower portion of the yoke portion 12. The frame body 13 is connected to a straight and substantially prismatic frame body 13. The bracket portion 14 at the upper end of the yoke portion 12 is detachably connected to the tip of the arm 5 in FIG. 1 via a turning mechanism 7 as shown in FIG.

  An endless (endless) drive chain 18 is provided between a drive wheel 16 of, for example, a chain sprocket type driven by a hydraulic motor 15 provided at the upper part of the frame body 13 and a driven wheel 17 provided at the lower part of the frame body 13. It is wrapped around. A plurality of mixing and stirring blades 19 shown in FIG. 2 are attached to the drive chain 18 at substantially equal pitches so as to be substantially orthogonal to the longitudinal direction of the drive chain 18. Together with the chain 18, it is driven to rotate in the vertical direction. The mixing agitating blade 19 is provided with a plurality of cutter bits 20 as excavating blades along the longitudinal direction thereof.

  Further, a discharge nozzle 21 is provided at the front end (lower end) of the frame body 13, and the discharge nozzle 21 is a solidified slurry in which water and powdered cement as a solidifying material are mixed in advance. The material is pumped through a pumping pump and a pipe 22 (not shown). Thereby, it is possible to discharge and inject the slurry-like solidified material from the discharge nozzle 21 toward the ground.

  The drive chain 18 is guided and supported in a state where a predetermined tension is applied to a plurality of guide rollers 23 provided on the frame body 13. The mixing / stirring head 6 having such a structure has a structure known in Japanese Patent Application Laid-Open No. 2005-307675 disclosed above.

  When construction is performed using the mixing and stirring head 6 having such a structure, generally, the plurality of mixing and stirring blades 19 are driven to rotate in the vertical direction together with the drive chain 18 by forward or reverse driving of the hydraulic motor 15. On the other hand, as shown in FIG. 1, the entire mixing and agitation head 6 penetrates into the ground in an upright posture using, for example, the swinging force (force in the swinging operation direction) of the boom 4 and the arm 5, and from the discharge nozzle 21. While discharging the slurry-like solidified material, the mixing agitation head 6 is digged with the digging vector described later as the advancing force of the mixing agitation head 6, thereby gradually digging in the construction direction of the improved wall body so as to move in a transverse manner. It will be. As a result, the in-situ soil excavated by the plurality of mixing agitating blades 19 is also mixed and agitated with the slurry-like solidified material by the plurality of mixing agitating blades 19 and is continuously improved on the rear side in the digging direction of the mixing agitating head 6. The body will be built. The wall thickness of the improved wall constructed in the ground is substantially equivalent to the length W of the mixing and stirring blade 19 (see FIG. 2).

  In this case, the portion corresponding to the tight side and the loose side of the drive chain 18 in the mixing and stirring head 6 and the portion that is involved in excavation and mixing and stirring by the plurality of mixing and stirring blades 19, that is, the vertical direction of the mixing and stirring blade 19. The orbiting moving surface (the orbiting moving surface facing the front side in the construction direction of the improved wall body and the orbiting moving surface facing the rear side in the construction direction) is orthogonal to the construction direction of the improved wall body. And it is determined according to the hardness and soil property of a ground whether the surrounding movement surface which faces the construction direction front side of an improved wall body is made upward or downward.

  In the conventional general construction method of an improved wall body, as shown in FIG. 4 which is a plan view of FIG. 1, a plane that bisects the thickness dimension of the improved wall body B or the improved wall body B to be constructed in plan view. Center line (hereinafter referred to as the plane center line of the improved wall body B or the improved wall body B to be constructed) C1 and the plane center line of the boom 4 and the arm 5 in the plan view of the base machine 1 (hereinafter referred to as the boom 4 etc.) It is set so that C2 is substantially orthogonal, that is, the angle θ2 between the two plane centerlines C1 and C2 is 90 °.

  Then, the mixing and stirring head 6 penetrates into the ground in a vertical posture, and the mixing and stirring blade 19 is on the circumferentially moving surface of the mixing and stirring blade 19 that faces the front side in the construction direction of the improved wall B. For example, the mixing stirring blade 19 is positively driven on the rotating surface side of the mixing stirring blade 19 that faces the front side in the construction direction of the improved wall body B by being rotationally driven so as to go around from the top to the bottom. The in-situ soil is excavated, and the mixing agitation head 6 is subjected to the reaction force of the excavated in-situ soil being mixed and agitated with the solidified material and fed to the circumferentially moving surface side of the mixing agitating blade 19 on the opposite side. It will dig itself in the direction of construction of the improved wall B.

  In such a construction method of the improved wall B, the digging force of the mixing and agitating head 6 is digging due to the reaction force during the mixing and agitation itself and the turning force of the turning base 3 of the base machine 1, and the digging force is large. As mentioned above, it cannot be a digging force.

  Therefore, in the present embodiment, basically, an angle θ2 formed by the plane center line C1 of the improved wall B shown in FIG. 4 and the plane center line C2 of the boom 4 or the like is as shown in FIG. The mixing and stirring head 6 is held in such a posture as to be an angle larger than 0 ° and smaller than 90 ° (as described later, β is a range of angles larger than 0 ° and smaller than 90 °). By setting up, the boom force, the arm 5 and the attachment cylinder 10 which are inherently possessed by the base machine 1 are utilized to the maximum, and the mixing force of the mixing and stirring head 6 which has been a problem in the past is known. As a result of this increase, a ground improvement device that can sufficiently resist the pull-out force without losing the force of each cylinder and a method for constructing an improved wall body using the same are proposed.

  As described above, the digging force in the conventional method for constructing the improved wall body B uses the reaction force during mixing and stirring and the turning force of the upper turning base 3 in the base machine 1 as the digging force. However, the digging force is small, and the digging of hard ground or the like is slow, and digging by economic speed is difficult. In the first place, the turning force of the excavator excavator is sufficient if there is a force for turning the bucket, which is the attachment at the tip of the arm 5, in the air (in the air), and does not require a large turning force. On the other hand, the excavation force of the excavator excavator is the force in the swing operation direction of the boom 4 and the arm 5 based on the expansion / contraction operation of the boom cylinder 8 or the arm cylinder 9 (hereinafter referred to as the arm cylinder 9 or the like). It depends on the excavation force due to the expansion / contraction force of the attachment cylinder (bucket cylinder) 10 and has a large excavation force depending on the standard of the base machine 1.

  In the present embodiment, the force in the swing operation direction of the boom 4 and the arm 5 based on the expansion / contraction operation of the attachment cylinder 10 as well as the arm cylinder 9 and the like, and the excavation force due to the expansion / contraction force of the attachment cylinder 10 in the improved wall body construction direction. This is a method for constructing an improved wall body that is actively used as the digging force (digging vector) of the mixing and stirring head 6.

Specifically, as shown in FIGS. 5A and 5B, the crawler belt 2 of the base machine 1 is set so as to be substantially parallel to the construction direction of the improved wall body B, and then the base machine 1 When the base machine 1 is brought close to the construction position of the improved wall B while maintaining the distance (working radius) to the mixing and stirring head 6, the angle θ2 formed by the plane center lines C1 and C2 is an acute angle β (angle β = 1 ° to The mixing and agitation head 6 is held in a posture in a range of 89 °. Note that holding the mixing and stirring head 6 in an attitude in which the angle θ2 formed by the plane centerlines C1 and C2 is an acute angle β is a plane that is in the axial direction of the boom 4 or the like with respect to the plane centerline C1 of the improved wall B. It is also possible to hold the mixing and stirring head 6 in a posture where the center line C2 crosses obliquely. In this state, when the attachment cylinder 10 other than the arm cylinder 9 is expanded and contracted, the force P in the swinging operation direction of the boom 4 and the arm 5 based on the expansion and contraction is the component force P1 in the construction direction of the improved wall B. This component force P1 becomes the digging force in the construction direction of the improved wall B. In other words, the digging force is a vector generated from the force P in the swinging operation direction of the boom 4 and the arm 5 and becomes the digging vector P1 of the mixing and stirring head 6.

  FIG. 5A shows a vector diagram when the improved wall body B is constructed while the base machine 1 is moved backward. FIG. 5B shows a vector diagram when the improved wall body B is constructed while the base machine 1 is moved forward. In any of the digging directions, the circumferential moving surface of the mixing agitating blade 19 and the plane center line C1 of the improved wall B to be constructed are substantially perpendicular to each other, and the mixing agitating head 6 is moved to the plane of the improved wall B. Since the digging is performed in the direction of the center line C1, the digging vector P1 can be obtained as the same in any direction.

  However, the retreating force and the advancing force of the base machine 1 do not contribute to the digging force. If the improved wall body B is constructed by a predetermined amount by the digging vector P1, the base machine 1 itself is retreated by an amount corresponding to the construction. It only moves or moves forward.

  This digging vector P1 is a substantial digging force for constructing the improved wall B, and if the angle θ2 formed by the plane center line C1 of the improved wall B and the plane center line C2 of the boom 4 or the like is small, The smaller the smaller, the larger the excavation vector P1 is obtained. Incidentally, the minimum angle of the angle θ2 is the improvement wall body B or the improvement to be constructed when the crawler belt 2 of the base machine 1 is brought close to the side surface of the improvement wall body B on the base machine 1 side in a plan view. The angle formed by the plane center line C1 of the wall B and the plane center line C2 of the boom 4 etc. of the base machine 1 is approximately 15 ° (see FIG. 6). As will be described later, the digging vector P1 at this angle θ2≈15 ° is the maximum digging force.

  In the construction of the improved wall body B, the volume of the slurry-like solidified material discharged into the raw ground is increased, and the fluid treated soil in which the raw soil and the slurry-like solidified material are mixed and stirred is placed on the raw ground. It will be exciting. Therefore, it is necessary to pre-dig a place where the improved wall body B is to be constructed in advance so that the swelled soil does not flow outside (the pre-dig condition is shown in FIG. 6B). ). This pre-digging is necessary for both forward and reverse excavations of the base machine 1, and considering these pre-digs and the like, the aforementioned approximately 15 ° is the minimum angle θ2.

  On the other hand, as described above, the preferable range of the angle θ2 formed by the plane center line C1 of the improved wall B and the plane center line C2 of the boom 4 or the like is an angle greater than 0 ° and smaller than 90 °. When the range of angles larger than 0 ° and smaller than 90 ° is β, the range of the angle β is an acute angle. In the present embodiment, the range of the acute angle β is a range of 1 ° to 89 °. Considering the range of the angle β, the range of the angle θ2 is 15 ° ≦ θ2 ≦ 89 °.

  The above digging vector P1 can be obtained by P1 = P × cos θ2.

  Here, cos θ2 is a value that becomes a vector coefficient α of the force (excavation force) P in the swing operation direction of the boom 4 and the arm 5 based on the expansion and contraction operation of the arm cylinder 9 or the like. If the excavation vector P1 is obtained from the vector coefficient α, it can be obtained by P1 = P × cos θ2 = P × α.

[Explanation about the excavation vector]
The cylinder force of the excavator excavator is in the order of boom cylinder 8> arm cylinder 9> attachment cylinder 10, and the cylinder force of the attachment cylinder 10 is the minimum value. The details of the expansion and contraction operations of the boom cylinder 8, the arm cylinder 9, and the attachment cylinder 10 will be described later, but the excavation vector P <b> 1 is obtained based on the expansion and contraction force of the attachment cylinder 10. As an example, the excavation vector P1 of the mixing and stirring head 6 when a 1.9 m3 class power shovel is used as the base machine 1 is as follows. The excavation force of the base machine 1 described below is generated by the force in the swing operation direction of the boom 4 and the arm 5 based on the expansion / contraction operation of the attachment cylinder 10 as well as the arm cylinder 9 and the expansion force of the attachment cylinder 10. It is a drilling force.

-Propulsive force of the mixing and stirring head 6 (reaction force accompanying the excavation of the mixed stirring head 6 itself): 0.5 tons-Turning force of the base machine 1: 1.0 ton-Propulsive force of the mixing and stirring head 6 itself: 0. 5 tons ・ Drilling force of the base machine 1: 20 tons The excavation force in the prior art is the sum of the propulsive force of the mixing agitating head 6 and the turning force of the base machine 1, and 0.5 + 1.0 = 1.5 tons It becomes.

  On the other hand, the vector coefficient when the angle θ2 formed by the plane center line C1 of the improved wall B and the plane center line C2 of the boom 4 or the like is 80 °, for example, is 0.17 because cos is 80 °. And the digging vector P1 of the mixing and stirring head 6 is 20 × 0.17 = 3.4 tons. While maintaining the working radius of the mixing and stirring head 6 until the angle θ2 formed by the plane center line C1 of the improved wall B and the plane center line C2 of the boom 4 or the like is 80 °, the base machine 1 is The digging force obtained by approaching B is at least twice the digging vector P1, and if the driving force of the mixing and stirring head 6 is applied, a total digging force of 3.4 + 0.5 = 3.9 tons is obtained. It is a desirable digging force.

  Incidentally, by setting the angle θ2 to 60 ° (see FIG. 5), for example, the digging vector P1 of 20 × 0.5 = 10.0 tons is obtained, and a more desirable digging force is obtained. Further, by setting the angle θ2 to 40 °, for example, the digging vector P1 is 15.4 tons, which is about 10 times the conventional digging force, and a sufficient digging force can be obtained only by the digging vector P1.

  Although depending on the strength of the ground (hardness), by setting the angle θ2 to at least 80 ° or less, a digging force approximately twice or more that of the prior art can be obtained. It is possible to dig under a digging capacity that is significantly greater than the 6 digging. Further, by setting the angle θ2 to 60 °, 50% of the excavation force possessed by the base machine 1 (vector coefficient 0.5) is set as the excavation vector P1, and the excavation is approximately 6.6 times the conventional technology. It is also possible to obtain a force, and a more desirable digging than the conventional digging with the mixing and stirring head 6 is possible.

  The above-described excavation vector P1 has an arm cylinder 9 and the like after holding the mixing and stirring head 6 in such a posture that an angle θ2 formed by the plane center lines C1 and C2 is an angle β (range of 1 ° to 89 °). This is a vector in the direction of constructing the improved wall body caused by the excavation force generated by the force in the swing operation direction of the boom 4 and the arm 5 based on the expansion and contraction operation. The excavation vector P1 is the angle θ2 formed by the plane center line C1 of the improved wall B and the plane center line C2 of the boom 4 and the like, and the swing of the boom 4 and the arm 5 based on the expansion and contraction of the arm cylinder 9 and the like. Varies depending on the direction of movement.

  Table 1 shows the values of the vector coefficient α and the excavation vector P1 at several main angles θ2 when the 1.9m3 class excavator exemplified above is used as the base machine 1. This value is a value obtained by setting the excavation force of the base machine (the expansion / contraction force of the attachment cylinder 10) to 20 tons as in the previous case. In addition, the angle θ2 can be reduced to about 15 °, and the excavation vector in that case is 19.4 tons, and if the propulsive force (0.5 tons) of the mixing and stirring head 6 itself is applied, the base is obtained. It is possible to obtain a total digging force equivalent to the digging force of the machine 1.

[Construction examples in confined spaces]
FIG. 6A shows a plan view in the case where the improved wall body B is constructed in a narrow place where both sides are sandwiched between houses, for example. FIG. 6B shows a rear view of the base machine 1 shown in FIG.

  For example, as shown in FIG. 4, the mixing and stirring head 6 is held so that an angle θ2 formed by the plane center line C1 of the improved wall B to be constructed and the plane center line C2 of the boom 4 or the like is approximately 90 °. When trying to construct the improved wall body B, the surrounding structure becomes an obstacle and its construction becomes difficult. However, as shown in FIG. 6 (a), the crawler belt 2 of the base machine 1 is brought close enough not to interfere with the side surface of the improved wall B, and the planar center line C1 of the improved wall B and the plan view of the base machine 1 are viewed. By making the angle θ2 formed by the boom and the arm center line C2 as small as possible, the distance from the improved wall B to be constructed to the base machine 1 is reduced, and the construction thereof becomes possible. In addition, the code | symbol Q of the figure shows the boundary of a house and the improvement wall body B. FIG.

  Further, in this case, the position of the base machine 1 and the mixing and stirring head 6 is the minimum angle θ2, and the angle is approximately 15 °. The angle θ2 when the crawler belt 2 of the base machine 1 is brought close to the position of the pre-dig groove is the minimum angle of the angle θ2, and by adjusting the posture of the base machine 1 and the mixing and stirring head 6 to this position, If the width of the improved wall body B (width of the improved wall body B) and the width (work space) equivalent to the crawler belt width of the base machine 1 can be secured, the construction can be performed. Incidentally, the excavation vector P1 in that case is 19.4 tons, and becomes the maximum excavation vector in the base machine 1 concerned. From the above, the effective range of the angle θ2 is 15 ° ≦ θ2 ≦ 89 °.

[Explanation regarding the ground improvement device for setting the angle θ2 to an arbitrary angle]
Next, a ground improvement device capable of setting an angle θ2 formed by the plane center line C1 of the improved wall body B and the plane center line C2 of the boom 4 or the like of the base machine 1 to an arbitrary angle will be described.

  7 and 6, as shown in FIGS. 5 and 6, a turning mechanism capable of setting an angle θ <b> 2 formed by the plane center line C <b> 1 of the improved wall B and the plane center line C <b> 2 of the boom 4 or the like of the base machine 1 to an arbitrary angle. It is explanatory drawing of the connection part of the arm 5 which used 7 as an intermediate bracket, and the mixing stirring head 6. FIG. FIG. 8 is a plan view of the turning mechanism 7 shown in FIG. 7 alone.

  As shown in FIG. 7, the turning mechanism 7 interposed between the arm 5 of the base machine 1 and the mixing and stirring head 6 includes a link plate 26 as a non-turning portion on the arm 5 side, and the mixing and stirring head 6. A revolving plate 27 serving as a revolving part on the side is configured as a main element, and both are connected so as to be relatively rotatable as will be described later.

  The link plate 26 has a pair of side plate portions 29 erected at a predetermined distance from a substantially disc-shaped face plate portion 28, while the revolving plate 27 has a pair of side plate portions 31 erected on the face plate portion 30. The link plate 26 has substantially the same structure except that the phase is shifted by 90 ° with respect to the side plate portion 29 of the link plate 26. The face plate portions 28 and 30 of both the link plate 26 and the swivel plate 27 are coupled to each other via a cylindrical shaft member 32 penetrating through the central portion thereof. In addition, both of them are fastened and fixed via bolts and nuts (not shown) inserted into the numerous bolt holes 33 in FIG. 8 formed in the peripheral portions of both face plate portions 28 and 30. ing.

  Further, the side plate portion 29 of the link plate 26 is detachably connected to the arm 5 and the link member 5a on the arm 5 side by a connecting pin 34, and the side plate portion 31 of the turning plate 27 is connected to the mixing and stirring head 6 side. It will be connected with the bracket part 14 of an upper end part so that attachment or detachment is possible.

  The bracket portion 14 on the side of the mixing and stirring head 6 is shared with the side plate portion 29 of the link plate 26. When the turning mechanism 7 is not used, the bracket portion 14 on the side of the mixing and stirring head 6 is connected to the connecting pin 34 or It is possible to connect directly to the arm 5 side via 35.

  By using such a turning mechanism 7, if the plurality of bolts and nuts that fasten and fix the face plate portions 28, 30 are attached and the face plate portions 28, 30 are relatively rotated, each face plate portion 28. , 30, the angle formed by the link plate 26 and the swivel plate 27 in the swivel mechanism 7 and the improved wall, with the angle formed by the center of the two adjacent bolt holes 33 with the centers of the face plate portions 28, 30 as the minimum angle. An angle θ2 formed by the plane center line C1 of the body B and the plane center line C2 of the boom 4 or the like of the base machine 1 can be set to an arbitrary angle as shown in FIG.

  8 shows a state in which the angle θ2 formed by the plane center line C1 of the improved wall B and the plane center line C2 of the boom 4 of the base machine 1 is set to 90 ° using the degree of freedom of the turning mechanism 7. The construction situation is as shown in FIGS.

  9 shows a state in which the angle θ2 formed by the plane center line C1 of the improved wall B and the plane center line C2 of the boom 4 of the base machine 1 is set to 60 ° using the degree of freedom of the turning mechanism 7. The construction situation is as shown in FIGS. 5 (a) and 5 (b).

  Here, the swivel mechanism 7 shown in FIG. 7 has a structure in which a link plate 26 as a non-swiveling portion on the arm 5 side and a swiveling plate 27 as a swiveling portion on the mixing and stirring head 6 side are connected so as to be relatively rotatable. In addition to the structure in which both bolts and nuts (not shown) inserted into the large number of bolt holes 33 shown in FIG. 8 are fastened together, a drop-off prevention mechanism 50 is added.

  More specifically, a cylindrical shaft member 32 is passed through the center of both the face plate portions 28 and 30 of the link plate 26 and the swivel plate 27 to ensure the relative rotational freedom of the two, and then the shaft member. Ring-shaped retaining members 32 a and 32 b having a diameter larger than that of the shaft member 32 are fitted to both ends of the shaft 32, and the retaining members 32 a and 32 b are fixed to the shaft member 32 by welding. Thereby, the shaft member 32 functions as a shaft body for relative rotation between the link plate 26 and the swivel plate 27, and is prevented from falling off together with the retaining members 32 a and 32 b that are welded and fixed to both ends of the shaft member 32. A mechanism 50 is formed.

  As a result, the drop prevention mechanism 50 is added, so that it is inserted into each of the large number of bolt holes 33 shown in FIG. 8, and the link plate 26 on the arm 5 side and the swivel plate 27 on the mixing and stirring head 6 side. Even if all of the bolts and nuts (not shown) that fasten and fasten are removed, the link plate 26 on the arm 5 side and the turning plate 27 on the mixing and stirring head 6 side are not separated, that is, The link plate 26 and the turning plate 27 are connected to each other by a drop-off prevention mechanism 50 so as not to be separated from each other, so that the turning-off plate 27 is prevented from dropping off from the link plate 26. Thereby, for example, the occurrence of trouble due to overload is suppressed and the safety is improved.

  In other words, the bolts inserted into the numerous bolt holes 33 shown in FIG. 8 and the nuts screwed to the bolts are relatively rotated by the link plate 26 on the arm 5 side and the swivel plate 27 on the mixing and stirring head 6 side. It has a function of positioning and fixing both while regulating the position. On the other hand, the drop-off prevention mechanism 50 ensures that the link plate 26 and the swivel plate 27 are substantially separated from each other without depending on the bolts and nuts while ensuring the relative rotational freedom between the link plate 26 and the swivel plate 27. It has a function of being integrally connected to prevent the two members from being separated (the falling of the turning plate 27 from the link plate 26).

  As the structure of the turning mechanism 7, the turning plate 27 is turned with respect to the link plate 26 at an arbitrary angle with the cylindrical shaft member 32 as the center of rotation, and then fastened and fixed with a large number of bolts and nuts. Therefore, for example, compared to the motor drive system disclosed in FIGS. 5 and 6 of Patent Document 2, the trouble of the drive unit is reduced, the structure of the turning mechanism 7 can be simplified, and the robustness and durability are also improved. It is also excellent in properties.

  FIG. 10 shows another example of the turning mechanism 7 interposed between the distal end portion of the arm 5 of the base machine 1 shown in FIG.

  As is clear from the turning mechanism 47 shown in FIG. 10, the pin detachable link plate 26 as the non-turning portion and the turning plate 40 as the turning portion are cylindrical. It is the same structure as what was shown in FIG. 7 by the point connected with the shaft member 32 so that relative rotation is possible. On the other hand, the bracket portion 14 at the upper end portion of the mixing and stirring head 6 is integrally connected to the face plate portion 30 of the swivel plate 40 directly by welding or the like without being attached or detached from the pin, as shown in FIG. It is different from the one. The other structure is the same as that shown in FIG.

  According to the turning mechanism 47 having such a structure, since the turning mechanism 47 is substantially integrated with the mixing and stirring head 6, the structure can be simplified as compared with the structure shown in FIG. The machine 1 can be easily attached to and detached from the arm 5.

[Example of honeycomb-type improved wall construction using ground improvement equipment]
If the ground improvement device as described so far is used, it is advantageous also in the case of constructing a so-called honeycomb-shaped (hexagonal) improved wall body having a planar shape as disclosed in Patent Document 2, for example.

  FIG. 11 shows a construction example of the honeycomb-shaped improved wall body B2, and shows a construction example of the vertical improved wall body at a position of an angle θ2≈15 °. The positions of the base machine 1 and the mixing and stirring head 6 in the figure are 15 ° ≦ 89 ° −0 ° ≦ 89 °, and the base machine satisfies the relationship of θ2 ≦ β−θ1 as described above. 1 and the mixing agitation head 6 are adjusted in posture. In this case, the angle θ2 can be constructed within a range of 15 ° ≦ θ2 ≦ 89 °, but in a case where the site is narrow and the work space is remarkably limited, it is desirable that θ2≈15 °. As can be seen from FIG. 11, by setting the base machine 1 outside the improved wall body B2, construction can be performed without interfering with the constructed improved wall body B2.

  In this construction example, details of the swinging motion of the boom 4 and arm 5 of the base machine 1 and the attachment cylinder 10 will be described below. The honeycomb-shaped improved wall B2 shown in FIG. 11 is constructed by expanding and contracting the boom cylinder 8 and the arm cylinder 9 to swing the boom 4 and the arm 5, and constructing the mixed stirring head 6 with the improved wall B2. It shall be performed while moving backward in the direction. When the improved wall body B2 is constructed by a predetermined amount, the swing operation of the boom 4 and the arm 5 is stopped, and the base machine 1 is moved backward by an amount corresponding to the construction amount.

  The straight portion of each side of the hexagonal honeycomb-shaped improved wall body B2 repeats the excavation (reverse movement) of the mixing and stirring head 6 and the reverse movement of the base machine 1 by this swinging motion, so The mixing agitation head 6 is advanced to the apex of the intersecting hexagons. If the mixing and stirring head 6 is dug to the apex, the base machine 1 is turned and reset (position determination) so that the next side and the crawler belt 2 of the base machine 1 are substantially parallel. In this case, the angle θ2 is set so that θ2≈15 °.

  However, the backward movement of the mixing and agitating head 6 by the aforementioned swinging operation is not only the operation of extending the boom cylinder 8, but at that time, the front end side of the mixing and agitating head 6 with the connecting pin between the boom 4 and the arm 5 as the rotation center. As a result, the mixing and stirring head 6 is inclined. For the tilt correction, the arm cylinder 9 is contracted and the mixing and stirring head is operated so as to be in a vertical posture.

  Thus, in order to dig the mixing and stirring head 6 in the construction direction of the improved wall B2 by swinging the boom 4 and the arm 5 while holding the mixing and stirring head 6 in the vertical posture, the boom cylinder 8 and the arm cylinder 9 and the attachment cylinder 10 are required to be appropriately expanded and contracted. And the measurement management of the direction of digging here shows the direction which should be constructed correctly, for example by adopting the laser emitter and light receiver by the technique (patent 3698704) proposed by the inventor of the present invention. Shall be performed. The inclination angle here is assumed to be operated by the operator based on an inclinometer installed in the cabin (cab).

  Furthermore, the construction form as shown in FIG. 11 is from a case in which the original ground is surrounded not only by a honeycomb shape (hexagonal shape) but also by an improved wall body such as a quadrilateral, pentagon, octagon, or circle. It is an effective means even in the case of constructing an improved wall body such as a water-impervious wall or a retaining wall in a streak shape.

DESCRIPTION OF SYMBOLS 1 ... Base machine 2 ... Crawler belt 3 ... Turning base 4 ... Boom 5 ... Arm 6 ... Mixing stirring head 7 ... Turning mechanism 18 ... Drive chain 19 ... Mixing stirring blade 26 ... Link plate (non-turning part)
27 ... Swivel plate (swivel part)
32 ... Shaft member 32a, 32b ... Retaining member 40 ... Revolving plate (revolving part)
47 ... Turning mechanism 50 ... Drop-off prevention mechanism B ... Improved wall body C1 ... Planar center line of improved body C2 ... Plane center line of boom, etc.

Claims (4)

Using a shovel excavator as a base machine, a mixing agitation head having a chain type agitation agitating blade that moves around in the vertical direction is attached to the tip of the arm of the base machine, The ground to construct a continuous vertical improved wall corresponding to the width dimension of the orbiting moving surface of the mixing stirring blade in the ground while excavating the in situ soil by mixing and mixing and stirring the in situ soil and the solidified material An improved device,
When constructing the improved wall body, while keeping the crawler belt of the base machine substantially parallel to a plane center line that bisects the thickness dimension of the improved wall body to be constructed in plan view, The boom and the arm are swung in a posture in which the plane center line is substantially perpendicular to the plane center line and the axis directions of the boom and the arm in the plan view of the base machine are obliquely intersected with the plane center line. In the ground improvement device used for the construction method in which the mixed stirring head is dug in the plane center line direction with the component force in the plane center line direction based on the force in the moving direction as the digging vector in the plane center line direction,
A swivel mechanism is provided between the tip of the arm of the base machine and the mixing and agitation head. The swivel mechanism can adjust the angle formed by the plane center line and the center line of the boom and arm in plan view of the base machine. And
The turning mechanism is
A non-rotating part connected to the tip of the arm of the base machine;
A swivel unit connected to an upper end of the mixing and stirring head;
A shaft member that connects the non-slewing part and the turning part so as to be relatively rotatable;
Fastening and fixing means for restricting and fastening the non-swirl part and the swivel part to a relatively rotated position;
A drop-off prevention mechanism that prevents the turning part from falling off the non-turning part without depending on the fastening and fixing means ,
A ground improvement device characterized by comprising:   The turning mechanism is formed as an intermediate bracket type whose non-turning part is detachable with respect to the tip part of the arm of the base machine, and whose turning part is detachable with respect to the upper end part of the mixing and stirring head. The ground improvement device according to claim 1 characterized by things.   The swivel mechanism is characterized in that a non-turning part is detachable from a tip part of an arm of a base machine, and the turning part is integrally connected to an upper end part of a mixing and stirring head. Item 1. The ground improvement device according to Item 1. Using a shovel excavator as a base machine, a mixing agitation head equipped with a chain-type mixing agitating blade that moves around in the vertical direction is attached to the tip of the arm of the base machine. After penetrating to a predetermined depth, in addition to discharging the solidified material, excavating the in-situ soil with the mixing agitating blade and mixing the agitated soil with the in-situ soil and the solidifying material, moving the mixed agitating blade into the ground a method of constructing a continuous vertical improved wall corresponding to the width of the surface,
Between the front end of the arm of the base machine and the mixing and stirring head, a plane center line that bisects the thickness dimension of the improved wall to be constructed in plan view, and the boom and arm in plan view of the base machine A swivel mechanism that can adjust the angle with the axial direction is provided,
While maintaining the crawler belt of the base machine substantially parallel to the plane center line, the circumferential moving surface of the mixing agitating blade and the plane center line are substantially perpendicular, and the mixing agitation head is moved in the plane center line direction. In order to dig into
Wherein the function of the turning mechanism, in terms of the axial direction of the boom and the arm in plan view of the base machine with respect to the planar center line has a posture crossing diagonally,
While causing the mixing and stirring blades of the mixing and stirring head to move around, generating force in the swing direction on the boom and arm of the base machine,
A vertical improvement wall obtained by digging the mixing stirring head in the plane center line direction with the component force in the plane center line direction based on the force in the swing operation direction of the boom and arm as the digging vector in the plane center line direction A method for constructing an improved wall, comprising constructing a body.

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