Underground wall pile structure

Abstract

To provide an underground wall pile structure whose bottom part of a wall-like body is widened in a wall thickness direction which can improve friction strength between the ground and the underground wall pile structure.SOLUTION: An underground wall pile structure whose bottom part of a wall-like body is widened in a wall thickness direction, includes a wall-like body having a fixed wall thickness in the wall thickness direction, and a widened bottom part whose bottom part is widened in the wall thickness direction, wherein the widened bottom part has an arch-shaped bottom in the wall thickness direction, the side face of the widened bottom part is formed in a widened wing finger having an arcuate shape, and the one or more widened wing fingers are continuously provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an underground wall pile structure, and more particularly to an underground wall pile structure used for wall piles that function as foundation piles for building structures. [Background technology]

[0002] Conventional underground wall piles had the same wall thickness in the depth direction. Later, underground wall piles with different excavation cross-sectional shapes (wall thickness) in the depth direction were constructed to ensure the bearing capacity at the tip of the foundation, or to increase the overall rigidity and reduce the amount of deformation, etc., and underground wall piles with different wall thicknesses in the depth direction were developed. Since water pressure and earth pressure change depending on the depth direction, walls with different wall thicknesses are used in the earth retaining diaphragm walls. The following proposals have been made as conventional examples of providing a widened bottom section or a widened section along the way. Patent Document 1 (JP Patent Publication No. 9-228398) discloses that the bearing capacity of a building is increased by using enlarged base piles, the pile diameter of which is enlarged at the tip, as foundation piles for the building. Patent Document 2 (JP Patent Publication 6-336725A) discloses an underground wall pile having an expanded bottom. A horizontally arranged rotary cutter is used as an excavator, and in the expanded bottom portion, the number of rotary cutters is increased in the lower part to excavate the expanded bottom portion. has been disclosed. Patent Document 3 (JP Patent Publication 2009-2156 A) discloses a wall pile with a widened bottom and a widened part in the middle. It also discloses the use of an excavator equipped with a Kelly bar that can rotate around a vertical axis and a bucket that is attached to the lower end of the Kelly bar. The present applicant proposed an underground wall pile equipped with an expanded bottom portion having an arched bottom surface in Patent Document 4 (JP 2019-100124 A). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-228398 [Patent Document 2] Japanese Patent Application Publication No. 06-336725 [Patent Document 3] JP 2009-002156 A [Patent Document 4] JP 2019-100124 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to develop an underground wall pile structure in which the bottom of a wall-like body is expanded in the wall thickness direction, which can improve friction strength with the ground. [Means for solving the problem]

[0005] 1. An underground wall pile structure in which the bottom of the wall body is expanded in the wall thickness direction, A wall-like body having a constant wall thickness in a wall thickness direction; The bottom portion is expanded in the wall thickness direction, The bottom of the expanded bottom portion is arch-shaped in the wall thickness direction, and the side of the expanded bottom portion is formed into an expanded finger having an arc shape, This underground wall pile structure is characterized in that the expansion fingers are provided singly or in succession. 2. An underground wall pile structure as described in 1., characterized in that the bottom surface of the expansion finger is formed into a convex curved surface. 3. An underground wall pile structure as described in 1. or 2., characterized in that the expanded bottom portion is formed partially, intermittently or over the entire length of the wall-like body in the longitudinal direction. 4. An underground wall pile structure described in any one of 1. to 3., characterized in that the enlarged bottom portion is formed on both sides or one side of the wall-like body. 5. An underground wall pile structure as described in any one of 1. to 4., characterized in that a bulging portion having a curved circumferential surface is formed in the middle of the side surface of the wall-like body. 6. An underground wall pile structure described in any one of 1. to 5., characterized in that the enlarged bottom portion has a protruding shaft portion downward. 7. A drilling device for drilling in the shape of an enlarged bottom of an underground wall pile structure, The excavator is provided with a frame body and a rotary swing excavator body provided below the frame body. The frame body is equipped with an upper stabilizer at the top that presses against the ground, and a lower stabilizer at the bottom that presses against the ground. A rotary swing drilling body is a wing-expansion drilling device for forming an expanded bottom portion of an underground wall pile structure, characterized in that a shaft with a bit attached to its circumferential surface is attached so as to be rotatable and swingable to a mounting axis arranged horizontally on a frame. 8. The fan-wing drilling device according to claim 7, further comprising an inclinometer for measuring the inclination caused by the swinging of the shaft. 9. A wing-expanding drilling device as described in 7. or 8., characterized in that a mud discharge pipe is attached to the frame body, the shaft is formed of a hollow pipe with an open tip, and the rear end of the shaft is connected to the mud discharge pipe to provide a mud discharge function. 10. The rotary swing drilling body is provided with a plurality of shafts, The fan-wing drilling device according to any one of 7. to 9., wherein the shafts are arranged so that adjacent rotation trajectories do not overlap. 11. A wing-expansion drilling device as described in any one of 7. to 10., characterized in that a bit that narrows in diameter toward the tip is provided at the tip of the rotating shaft. Effect of the Invention

[0006] 1. In an underground wall pile structure equipped with an expanded base with an arch-shaped bottom, the ground reaction acts along the curved surface of the arch-shaped expanded base. Therefore, compared to a flat expanded base, the ground reaction is not unevenly distributed. This makes it possible to form an underground wall pile with high bearing capacity in which damage such as cracks is suppressed. Furthermore, since expansion fingers with arcuate curved surfaces are provided on the sides of the expansion section, friction between the unevenness formed on the sides of the expansion section and the ground increases. Underground wall piles with enlarged bases are formed directly below areas where high axial forces act, such as the columns of the upper structure. By providing an expanded bottom section, it is possible to improve resistance to uprooting and shear forces caused by earthquakes. 2. By providing a convex curved surface at the bottom of the expansion finger, the convex curved surface protrudes into the supporting ground and is fixed to the supporting ground, and the underground wall pile structure can be firmly supported by the supporting ground. Furthermore, by providing a protruding shaft part below the expansion part, the underground wall pile structure can be firmly supported by the supporting ground. 3. The expanded bottom can be formed over the entire length, partially, or intermittently in the longitudinal direction of the wall-like body. The expanded bottom can also be formed on both sides or one side of the wall-like body. Furthermore, expanded bottoms of different sizes can be provided. In this way, by setting the location and size of the expanded bottom, it is possible to design an underground wall section that can bear the supporting force according to the part of the structure. Alternatively, underground wall piles can be designed according to the strength of the ground. Furthermore, if outward projection is restricted in relation to adjacent land or buildings, the outer expanded bottom can be made smaller, or it can be omitted and only provided on the inside. For example, it can be used as an earth retaining wall during underground excavation. Furthermore, by providing a bulge in the middle of the wall surface of the wall-like body, the bearing capacity of the ground and friction with the ground can be improved. 4. Underground wall piles with a protruding shaft below the enlarged base ensure verticality, enabling the realization of a wall pile structure with improved shear resistance. 5. The angle of the expanded bottom can be set between 0° and 90° depending on the required supporting force. Preferably, it is formed within 40°. 6.These expanded bottom sections can be manufactured with high precision by using an expanding drilling machine equipped with a rotating and oscillating drilling body whose axis rotates and whose shaft oscillates. Stabilizers that can press against the drilling wall in the ground are provided on the upper and lower parts of the main frame of the excavator, so the excavator body can be stably fixed, improving the braking accuracy of the lower rotating and swinging excavation body, and improving the accuracy of the excavation wall. An inclinometer is provided to measure the angle at which the shaft swings, allowing the amount of projection of the enlarged bottom to be controlled. As a result, the accuracy of the projection angle of the flared wing and the curved shape of the flared wing finger was improved, making it possible to carry out construction according to the design. When the test-constructed underground wall pile was excavated and inspected, it was confirmed that the underground wall pile equipped with the expanded base of the present invention fully satisfied the design accuracy. [Brief description of the drawings]

[0007] [Figure 1] A diagram showing an example of an underground wall pile with an enlarged bottom. [Diagram 2] A diagram showing the three basic sides of an underground wall pile with an enlarged basement section. [Diagram 3] FIG. 13 shows an example of a convex bottom surface of a spreader finger. [Figure 4] Diagrams showing the protruding forms of the flared base. (a) Both sides of the flared base are equally protruding, (b) Both sides are asymmetrically protruding, and (c) One-sided flared base. [Diagram 5] Figures showing the state in which a bulge has been formed in the middle of the wall. (a) Both sides of the base are equally expanded, (b) Both sides are unevenly expanded, and (c) One side is expanded. [Figure 6] Diagrams showing examples of planar arrangement of the basement wall pile enlargement. (a) Enlargement on both sides of the entire length, (b) Enlargement on one side of the entire length, (c) Partial enlargement. [Figure 7] Diagrams showing examples of basement wall layout and enlarged bottom formation. (a) Example of basement wall layout in a square shape, (b) Example of T-shaped section layout, (c) Example of L-shaped section layout, (d) Example of cross-shaped section layout. [Figure 8] A diagram showing examples of wall pile arrangements (grid pattern, multiple enclosures). [Figure 9] Diagram showing an example of an underground wall pile with an enlarged base. (a) The lower half of the enlarged base, (b) The upper half of the enlarged base. [Figure 10] Diagrams showing examples of bottom expansion drilling equipment: (a) expansion drilling machine, (b) top view, (c) bottom view, (d) side view, (e) example of tip bit. [Figure 11] A diagram showing the excavation process. (a) Excavation process of the underground wall axis, (b) Rough excavation process of the bottom enlargement, (c) Bottom excavation surplus soil discharge process, (d) Bottom enlargement finish excavation process, (e) Bottom excavation surplus soil discharge process.

[0008] The present invention is an underground wall pile structure having an expanded bottom part with an arch-shaped bottom surface, and an expanded finger with an arc-shaped curved surface formed on the side of the expanded bottom part. The arch-shaped bottom surface of the expanded bottom part is subjected to ground reaction force acting along the arch-shaped curved surface, so there is no uneven distribution of ground reaction force that occurs in a flat expanded bottom part, and the underground diaphragm wall has high bearing capacity with suppressed damage such as cracks. Furthermore, the unevenness formed by the arc-shaped curved surface on the side of the expanded bottom part firmly adheres to the ground, increasing frictional resistance and improving stability. The underground wall pile with the expanded bottom part of the present invention can obtain large bearing capacity and pull-out resistance. The setting of the expanded bottom portion can be continuous, one-sided, partial, or intermittent on the left and right sides of the wall-like body. The size of the expanded bottom portion, i.e. the projection, can be symmetrical or asymmetrical. A bulge can also be provided on the side of the wall-like body midway. By combining the installation location, installation length, size, and mid-height bulge of the expanded base section, a wide variety of underground wall piles can be designed. The underground wall piles of the present invention are cast-in-place piles, and by developing a drilling device capable of accurately drilling boreholes to construct these various underground wall piles, we have developed a construction method that can be put to practical use in architectural design, and have completed the present invention to a level where it can be put to practical use.

[0009] The underground wall pile of the present invention is used as a foundation support structure such as a wall pile of an architectural structure such as a building, or as an earth retaining structure. It can be used for continuous walls for installation. The cast-in-place continuous underground wall pile construction method with an expanded base developed in this invention is a method in which an expanded base with an arch-shaped bottom surface is provided at the tip of the continuous underground wall in order to obtain large bearing capacity and pull-out resistance, and finger-shaped projections and recesses with arc-shaped curved surfaces are provided on the sides of the expanded base. Since the basement wall pile of the present invention exerts a continuous wall-like pile function, it can ensure a high ground bearing capacity compared to the case of placing a single pile. In particular, in high-rise buildings, the weight of the building also increases, so a pile structure using basement wall piles is suitable. In addition, since the building is supported on a continuous surface, stability is improved. Since the bottom surface of the expanded base is curved in an arch shape, the support area of ​​the supporting ground is increased by providing an expanded base at the tip of the wall pile without uniformly increasing the building thickness of the wall pile body, and the load-bearing capacity of the basement wall pile is improved. And, even if the expanded base is unreinforced, the load is distributed along the arch-shaped arch surface, but in the case of a wall pile equipped with an expanded base having a flat surface, the load is unevenly distributed over the surface, so there is a risk of damage such as cracks, and the set load-bearing capacity is limited compared to the bottom area. And, the arc-shaped unevenness of the side of the expanded base can increase the friction resistance with the ground. In the present invention, the shaft with the drilling bit swings like a pendulum, so that the bottom surface of the expanded bottom part is arched, and the area of ​​the wall pile is increased. The side of the partition wall excavation part by the rotating shaft with the bit is finished in an arc shape. In the present invention, the fixation of the excavator is improved, and the swing angle of the shaft is measured to improve the shape control accuracy of the excavation hole, so that the underground wall structure with the expanded bottom part of the special shape of the present invention can be realized. In addition, the excavation device of the expanded bottom part has a mud discharge function, so that the excavated soil can be quickly discharged, and the risk of the excavated soil scattering and destroying the excavation wall surface can be reduced, and the shape accuracy of the expanded bottom part can be further improved.

[0010] <Underground wall pile> FIG. 1 shows an example of a wall pile, which is an underground wall pile structure of the present invention. The wall pile 10 has a wall-like body 2 that extends long along the foundation of a building or the like, and an expanded base 3 below it, the bottom surface of which is an arched bottom surface 34, and several surfaces of the side surface 32 of the expanded base are connected in an arc shape to form finger-like expanded fingers 31. A protruding shaft 4 is provided at the bottom of the wall pile 10. This protruding shaft 4 may not be provided in some cases. The expanded bottom portion 3 has a sector-shaped cross section with an expansion angle θ relative to the vertical direction of the wall pile 10, and is provided on both sides or one side of the wall-like body 2. In the figure, a right expanded bottom portion 3a and a left expanded bottom portion 3b are provided, and three (31a, 31b, 31c) with an expansion finger 31 and an arc-shaped side surface 32 are formed continuously. Because the bottom surface of the expanded base is arched, it can stably support the load of the superstructure (vertical load, especially compressive axial force), and can withstand a larger vertical load than a flat bottom surface, providing high bearing capacity. It also allows the wall pressure to be reduced. The arc-shaped side increases friction with the ground, increasing the shear resistance in the longitudinal direction of the wall piles. In addition, the pull-out resistance acting diagonally in the longitudinal direction of the wall piles also increases, providing resistance to earthquake loads that tend to twist the building. In addition, since it is difficult to reinforce the part of the expanded base that is wider than the wall-like part, if it is left unreinforced, it will be prone to cracks and damage when a large load is applied due to an earthquake, etc., making it difficult to make the expanded base larger. In the present invention, by making the bottom surface of the expanded base arch-shaped, the expanded base is stabilized and its load-bearing capacity is improved. The reinforcing bars are inserted into holes excavated in the ground to form the shape of the underground pile wall structure, along the thickness of the wall. It is difficult to place reinforcing bars in the areas that extend beyond the wall, so they are often left unreinforced. This underground wall pile structure is suitable for wall piles that also serve as wall-like foundation structures for buildings and as retaining walls.

[0011] A basic example of the shape of an underground wall pile structure is shown in Figure 2. Figure 2 shows the three basic sides of an underground wall pile 11 with an enlarged base and a protruding shaft as shown in Figure 1: the side (a), top (b), and front (c). The symbols are the same as those in FIG. 1, so their explanation will be omitted. The underground wall pile structure shown in Figure 2(a) has an expanded base 3 whose lower side protrudes to the left and right from the side of the wall-like body 2. The expanded base width L1 is the sum of the wall thickness L2, which is the thickness of the wall, and the protruding length L3. In this figure, the pile protrudes to the left and right, so L1 = L2 + 2L3. Note that the protruding length does not include the curved arc-shaped portion 32.

[0012] The main sizes and strengths of the underground wall piles of the present invention are as follows. Reinforcement bars such as cage bars are inserted into the wall-like body, and the enlarged base is a cast-in-place continuous underground wall pile with an enlarged base that is unreinforced, providing great bearing capacity and pull-out resistance. Wall thickness is about 120~240cm, base width is 130~480cm, base angle is within 45 degrees, and concrete design strength Fc is maximum 60N / mm 2 It can be used up to 100m, so it can be applied to a wide variety of ground. The width of the expanded base is shown as the same amount of overhang on both sides of the wall, and the amount of overhang on one side can be set from 5cm. The amount of widening depends on the performance of the equipment used to excavate the widened section, but in terms of the equipment, it is technically possible to widen the excavation angle to a horizontal angle of up to 90 degrees, and an overhang amount of the length of the excavation shaft minus half the wall thickness can be secured, but in practice it is preferable to keep it at around 45 degrees, or even 30 degrees.

[0013] FIG. 3 is a diagram showing an example of a convex bottom surface of a spreader finger. This shows an example in which a convex curved surface 36 is formed on the bottom side of the expansion finger 31. By forming the convex curved surface 36 on the bottom surface of the expansion finger 31, unevenness is also formed on the bottom surface of the expansion portion 3, which increases friction with the ground.

[0014] Figure 4 shows the shape of the flared bottom portion 3. The flared bottom portions can be formed on both sides of the wall body 2 with the same size, or with different sizes, or can be formed on only one side. Furthermore, the flared bottom portions on the left and right sides can be provided at different heights. (a) shows an example with large overhangs 3a on both the left and right, (b) shows a large overhang 3a on the left side and a small overhang 3b on the right side, and (c) shows an example with a large overhang 3a on the left side and no overhang on the right side. The amount of overhang of the expanded base will be adjusted depending on the situation on the left and right of the basement wall piles. For example, (b) and (c) can be used to form the basement wall pile structure as a diaphragm wall for retaining earth, and are applicable when there is an adjacent boundary on the right side. The same applies when there is a building nearby.

[0015] Figure 5 shows a state in which a bulge 5 has been formed in the middle of the wall. A widened bottom portion 3 is formed at the bottom of the wall-like body 2, and the bulge 5 is formed in the middle. The bottom surface of the bulge 5 is also arch-shaped. The position of the bulge and the shape on the left and right can be formed as desired, as required. (a) shows an example in which a large left bulge 51, a large right bulge 52, and a small bulge 53 are provided above a bottom 3 with large protrusions 3a on both the left and right sides, (b) shows an example in which a bottom 3 with a large protrusion 3a on the left side and a small protrusion 3b on the right side, a large left bulge 51 on the left side, and a small bulge 53 on the right side, and (c) shows an example in which a widened bottom 3 with a large protrusion 3a on the left side, a large left bulge 51 on the left side, and no protrusion or bulge on the right side. By providing a bulge in the middle of the wall body 2, the bearing capacity of the underground wall structure can be further improved and friction with the ground can be increased. By increasing the bearing capacity of the bulge, the earth wall structure can be made smaller. The bulge can be set to a size ranging from that of the expanded bottom to a small size. The bulge shown in FIG. 5 is an example of a bulge excavated using an expanded-wing drilling machine. Therefore, in the example shown, a bulge is formed with an arc-shaped bottom (arch-shaped bottom) at the angle of the swinging rotary rotor. The side circumferential surface of the bulge is formed in an arc-shaped shape like the core of the expanded bottom. However, the bulge When the main function expected of the surface is friction, the main function will be to form projections and recesses, so there is no need to require the curved peripheral surface to be as precise as a circular arc. The number of bulges, which correspond to the finger-like portions of the fan-shaped fingers, may be one, or two, three or more in a row. They may also be provided on a part of the underground wall, and may be provided in any suitable location, such as continuously, intermittently, or partially.

[0016] Figure 6 shows an example of the planar arrangement of the enlarged basement wall piles. The expanded bottom can be provided on the left and right sides, on one side, or partially over the entire length of the wall pile. (a) shows an example in which expanded bottom 30a and expanded bottom 30b are provided on both sides of the wall pile 2 over the entire length, (b) shows an example in which expanded bottom 30a is provided on one side of the wall pile 2 over the entire length, and (c) shows an example in which partial expanded bottom 30p1 and partial expanded bottom 30p2 are provided intermittently at intervals on both sides of the wall pile 2.

[0017] Figure 7 shows an example of underground wall placement and base enlargement formation using an example of underground wall piles arranged in a square pattern. (a) is an example of an underground wall arranged in a square pattern. (b) is an example where an expanded bottom is allocated to a T-shaped section, T1 is an example where an expanded bottom is provided on both sides while avoiding the vicinity of the T-shaped section, T2 is an example where an expanded bottom is formed continuously on the outside and is provided on the inside while avoiding the vicinity of the T-shaped section, and T3 is an example where an expanded bottom is not provided on the outside but is provided on the inside while avoiding the vicinity of the T-shaped section. (c) is an example where an expanded bottom portion is allocated to an L-shaped portion, L1 is an example where an expanded bottom portion is provided on both sides to avoid the corners, L2 is an example where an expanded bottom portion is provided along the entire length of the outside of one piece, an expanded bottom portion is provided on the inside to avoid the corners, and an expanded bottom portion is also provided on the outside of the other piece, and L3 is an example where an expanded bottom portion is not provided on the outside, and an expanded bottom portion is provided on the inside to avoid the corners. (d) is an example in which an enlarged bottom portion is allocated to the cross section, and shows an example in which an enlarged bottom portion is provided on both sides except near the intersection.

[0018] Figure 8 shows an example of wall pile arrangement. (a) shows an example of wall piles arranged in a single layer, (b) shows an example of wall piles arranged in a double layer, (c) shows an example of wall piles arranged in a grid pattern, and (d) shows an example of wall piles arranged in a single layer around the perimeter and wall piles arranged partially on the inside. This figure shows wall piles arranged in a circular pattern, but it can also be applied to wall piles of a certain length that are not circular, but are straight, L-shaped, L-shaped, etc. The distribution of the strata on which the building is to be constructed also affects the design of the building support structure.

[0019] <Construction method> The construction method of the present invention employs a cast-in-place continuous underground wall pile construction method in which concrete is poured into a ground void excavated in the shape of an underground wall pile structure with an enlarged bottom. The basic construction method conforms to the method proposed in the previously filed Patent Application No. 2017-234125. A method can be adopted in which a leading wall structure and a trailing wall structure are alternately created to construct a continuous underground wall pile structure. The first step involves excavating a vertical area of ​​equal width and removing the soil and sand. In the second step, a drilling machine for widening the bottom is inserted into the vertical borehole. In the third step, the rotary oscillating rotor attached to the bottom-widening excavator is rotated laterally to perform widening excavation. In the fourth process, the soil and sand excavated in the previous process is removed. The fourth process may be carried out simultaneously with the third process. The fifth step involves excavating the opposite side to widen the area. In the sixth step, the soil and sand produced in the fifth step is removed in the same manner as in the fourth step. In the seventh step, the soil is removed from the hole for the protruding shaft formed below the enlarged bottom. This step can be carried out consecutively to the sixth step. In the eighth step, a reinforcement bar (reinforcement cage) is inserted into the space for the underground wall pile structure, and concrete is poured. After that, it is cured to manufacture the preceding or following underground wall pile structure.

[0020] <Bottom expansion drilling equipment> An example of a bottom expansion drilling device is shown in Fig. 10. (a) is a perspective view of the bottom expansion drilling device, (b) is a plan view, (c) is a bottom view, and (d) is a side view. (e) shows an example of a tip bit. The excavation of the bottom expansion is basically similar to the device proposed in the previous application, in that it is carried out using a rotating oscillating rotor that can rotate and swing into a hole excavated vertically. However, new features have been added to increase the degree of fixation of the main body, a device for removing soil and sand associated with the expansion excavation, and an instrument for measuring the expansion excavation angle, allowing for excavation control.

[0021] The bottom expansion drilling device is shown as an expansion drilling machine 60 having a rotating oscillating rotor 6 attached below a frame 7. The frame 7 is provided with an upper stabilizer 71 at its upper part, a lower stabilizer 72 at its lower part, and side stabilizers 73 at its sides. A horizontal mounting shaft 64 is provided at the lower part of the frame 7, and the rotary oscillating rotor 6 is attached to the mounting shaft 64. A hanging part is provided at the upper part of the frame 7 so that the frame 7 can be suspended from the ground. An inclinometer 66 is attached to the mounting shaft 64 to measure the swing angle of the rotary swing rotor 6 . A drive mechanism for the rotary oscillating rotor and a mud discharge mechanism are provided inside the frame 7. The sludge discharge mechanism has a sludge discharge pipe 75 that extends to the ground and into the frame from above, and is connected to a flexible sludge discharge pipe 76. A sludge discharge pump 74 is provided in the middle. The tip of the flexible sludge discharge pipe 76 is connected to the hollow pipe of the rotary oscillating rotor 6.

[0022] The rotary oscillating rotor 6 has a rotating shaft 61 with a drilling bit 62 attached to its periphery attached so as to be able to oscillate about a mounting axis 64. In the illustrated example, the rotary oscillating rotor 6 is formed by three rotors, a first rotor 6a, a second rotor 6b, and a third rotor 6c. The rotation trajectories of the respective rotary rotors are provided adjacent to each other so as not to overlap. The shaft forming the central second rotor is a hollow pipe shaft 63 , the front and rear ends of which are open, and the rear end is connected to a flexible sludge discharge pipe 76 . In the drawings (a) to (d), the tip bit provided is flat. This tip bit can be replaced with a pointed tip bit 65 shown in (e). By using the pointed tip bit 65, it is possible to excavate a convex trajectory. This makes it possible to form the convex curved surface 36 shown in FIG. 3.

[0023] The wide-wing drilling machine 60 can be fixed by extending the upper and lower stabilizers on the frame 7 and pressing them against the inner wall of the borehole, and the attitude can be controlled by adjusting the extension of the stabilizers. This stabilizes the drilling trajectory of the rotating oscillating rotor, allowing for accurate wide-wing drilling. The three rotors 6a, 6b, 6c are attached to a mounting shaft 64 so that they can swing. Each rotor is installed so that it can swing individually or simultaneously. The rotor shaft 61 can rotate, and the bit 62 excavates the ground as a result of the rotation. Then, by swinging the shaft, widening excavation can be performed. Since the mounting shaft is the center of rotation, the tip of the rotor becomes an arc, and the bottom surface of the widening section is formed into an arch shape. The swing angle of the rotor can be measured using an inclinometer 66, and the widening angle can be controlled, allowing the shape of the widening section to be accurately formed.

[0024] A pipe shaft 63 can be used for the shaft 61, and by connecting this pipe shaft 63 to a mud discharge mechanism, the soil from the widening excavation can be quickly removed, preventing the previously excavated soil from damaging the excavation wall, and ensuring a neat finish to the borehole wall. This allows for the accuracy of the excavation shape of the expanded bottom portion, and the outer periphery of the rotation trajectory of the excavation oscillating rotor is formed in an arc shape. Therefore, when concrete is poured, an expanded wing finger having an arc-shaped side can be formed. Furthermore, by attaching a pointed bit 65 to the shaft 61, a convex swing trajectory of the rod can be formed, and the top surface of the fan finger can be formed into a convex curved surface.

[0025] Figure 11 shows the excavation process. The construction process is as described above. Figure 11 shows the excavation process of the enlarged bottom portion using the enlarged-blade excavator 60 of the present invention. Excavation will be carried out using a conventional shaft excavator to excavate the wall-like portion that will become the main body of the wall, and a widening excavator will be used to excavate the widening portion. (a) Underground wall shaft excavation process: A reverse shaft excavator is used to excavate the shaft from above ground to the tip level of the specified wall pile to form a borehole 8. During excavation, the borehole is filled with water to prevent the borehole from collapsing by utilizing water pressure. Therefore, the inside of the borehole is in a muddy state. (b) Rough excavation process for the enlarged bottom: The shaft excavator is raised, and the enlarged-wing excavator 60 proposed in this invention is inserted from the ground into the excavation hole, and at a specified depth, the upper and lower stabilizers of the enlarged-wing excavator are extended to fix the frame to the earthen wall. The rotating rotor is rotated while being flipped up to the left or right to excavate the enlarged bottom, forming an enlarged-bottom excavation hole section 81. At this stage, the swing is reduced to perform rough excavation in the shape of a slightly smaller hole. When excavating the enlarged bottom, the shaft angle (enlargement angle) is monitored with an inclinometer while the rotor of the enlarged-wing excavator is rotated, and the flip-up angle is controlled. The excavation hole 8 is formed deeper than the expanded bottom portion and serves as a hole for storing the excavated soil from the expanded bottom portion. (c) Bottom excavation residual soil discharge process: The wide-wing excavator 60 is once raised and the soil is discharged. A normal device such as a bucket is used as the discharger. A vertical excavation hole section 82 and a wide-bottom excavation hole section 81 are formed.

[0026] (d) Finishing drilling process for the flared bottom: The discharger is raised, the flared excavator 60 is introduced again, fixed by the stabilizer, and the rotor is raised to a specified flared angle to excavate the flared bottom of the designed shape. In this excavation, the angle is also monitored by an inclinometer to control the drilling angle. In this process, the hollow pipe shaft and flexible mud discharge pipe used in the rotor shaft are used to operate the mud discharge function of the flared excavator to discharge the mud. This finishing drilling can be performed intermittently in combination with the mud discharge to prevent the excavated soil from colliding with the wall of the hole and scraping it. Therefore, by providing the flared excavator with an inlet / outlet function, the borehole wall can be finished neatly. (e) Bottom excavation residual soil discharge process: The wide-wing excavator is raised and the soil discharger is introduced again to dredge up the excess soil. In this case, if a space is provided below the wide-bottom section, a protruding shaft hole 83, which is the space for the protruding shaft, can be formed. If soil is left up to the same level as the bottom of the wide-bottom section, or if soil is filled in in a later process, the protruding shaft will not be formed.

[0027] In this way, a reinforcement bar is inserted into the wall-like portion of an excavated hole with an expanded bottom at the bottom of the art type, and concrete is poured to create an underground wall structure with an expanded bottom. In addition, a construction method can be adopted in which the preceding construction section and the following construction section are constructed alternately to create a continuous underground wall structure, as proposed in the previously filed JP 2019-100124 A.

[0028] Figure 9 shows an example of an underground wall pile with an enlarged base. Figure 9 shows an example of an excavation after driving underground wall piles with a wall length of 320 cm, wall thickness of 150 cm, basement expansion length of 245 cm, basement expansion width of 279 cm, arc bulge of 36 cm, and an expanded basement wall depth of 14 m. The piles are shown divided into two parts, top and bottom, and show the lower half of the basement wall (a) with the protruding shaft 4 and the upper part of the basement wall (b). The hole in the arc-shaped side surface 32 in (a) is This is a cored hole for testing purposes. Three expansion fingers 31a, 31b, 31c with arc-shaped sides are neatly formed on the side of the expansion section 3. The rotation trajectory of the chips created when the rotating rocker was lifted from the wall-like body 2 and excavated remains clearly visible, demonstrating the high construction capability of the expansion drilling machine. It was confirmed that there was a high degree of consistency between the design and the finished form, and that sufficient concrete strength was obtained. In addition, test construction was conducted under various ground conditions, and it was confirmed that the shape and dimensions of the enlarged base and the quality of the concrete could be secured. [Explanation of symbols]

[0029] 10 wall stakes 11 Wall pile with protruding shaft 12 Wallless pile with protruding shaft 2 Wall-like body 21 Side of wall 3. Enlarged base 3a Large overhang 3b Small overhang 30a Right expansion part 30b Left expanded bottom part 31 Spread fingers 32 Arcuate side 34 Arched bottom 36 Convex Surface 4 Protruding shaft part 5 Bulge 51 Right bulge 52 Left bulge 60 Wide-wing excavator 6-turn oscillating rotor 6a First rotor 6b Second rotor 6c 3rd rotor 61 Shaft 62-bit 63 Pipe Shaft 64 Mounting shaft 65 Pointed Bit 7 Frame 71 Upper stabilizer 72 Lower stabilizer 73 Side frame 74 Sludge pump 75 Sludge drainage pipe 8. Borehole 81 Enlarged bottom borehole section 82 Vertical drilling hole 83 Protruding shaft hole

Claims

1. An underground wall pile structure in which the bottom of a wall-like body is widened in the wall thickness direction, A wall-like body having a constant wall thickness in the wall thickness direction, It comprises a widened base portion that is widened in the direction of the wall thickness, The widened base has an arched shape at the bottom in the direction of the wall thickness, and the sides and bottom surface of the widened base are formed into curved, widened wing-like fingers. The underground wall pile structure is characterized by having one or more winged fingers provided in succession.

2. The underground wall pile structure according to claim 1, characterized in that the bottom surface of the flared fin is formed as a convex curved surface.

3. The underground wall pile structure according to claim 1 or 2, characterized in that the enlarged base portion is formed partially, intermittently, or along the entire length in the longitudinal direction of the wall-like body.

4. The enlarged base is formed on both sides or one side of the wall-like body. The underground wall pile structure according to any one of claims 1 to 3, characterized in that a bulging portion with a curved circumferential surface is formed in the middle of the side surface of the wall-like body.

5. The underground wall pile structure according to any one of claims 1 to 4, characterized in that the enlarged base portion has a protruding shaft portion at the bottom.

6. An excavation device for excavating in the shape of an enlarged base portion of an underground wall pile structure as described in any one of Claims 1 to 5, It is equipped with a frame structure and a rotating, oscillating excavator located below the frame structure. The frame structure is equipped with an upper stabilizer that presses against the ground at the top and a lower stabilizer that presses against the ground at the bottom. The rotating and oscillating drilling body is a wing-type drilling device for forming an enlarged base of an underground wall pile structure, characterized in that a shaft, with bits attached to its circumferential surface and a pointed tip bit attached to its tip, is mounted on a mounting shaft horizontally provided on a frame so as to be rotatable and oscillating.

7. An inclinometer is installed to measure the tilt caused by the swing of the shaft. The widening wing excavation device according to claim 6, characterized in that a mud discharge pipe is attached to the frame body, the shaft is formed of a hollow pipe with an open tip, and the rear end of the shaft is connected to the mud discharge pipe to provide a mud discharge function.

8. The rotating and oscillating drilling machine is equipped with multiple shafts. The wing-expanding drilling device according to claim 6 or 7, characterized in that the shafts are arranged so that adjacent rotational trajectories do not overlap.

9. The wing-expanding drilling device according to any one of 6 to 8, characterized in that a bit that decreases in diameter toward the tip is provided at the tip of the rotating shaft.

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