JP2018168562A - Method for constructing crushed stone structure and crushed stone structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form a structure having a desired shape and size having strength as a structure and water permeability by using a crushed stone column. A method for manufacturing a crushed stone structure is to manufacture a crushed stone structure in the ground. In this method, a first crushed stone pillar is formed by throwing crushed stone into the first space formed by the first excavation step S12 forming the first space in the ground and pressing the crushed stone into the first space formed by the first excavation step S12. The crushed stone is put into the crushed stone pillar forming step S14, the second excavation step S16 that forms the second space at the position connected to the first crushed stone pillar in the ground, and the second space formed by the second excavation step S16. The crushed stone pillar forming step S18 for forming the second crushed stone pillar connected to the first crushed stone pillar is provided. [Selection diagram] FIG. 5

Description

  The technology disclosed in the present specification relates to a method for constructing a crushed stone structure and a crushed stone structure.

  For example, in the field of large-scale infrastructure construction such as high-rise houses and highways, a method of forming crushed stone columns in the ground (for example, Patent Document 1) or concrete in the ground for ground improvement such as ground strengthening and liquefaction countermeasures. A method for forming an underground structure such as a pile has been developed. The ground that requires ground improvement has different geology and surface properties (for example, inclined surfaces) for each ground, and it is necessary to improve the ground according to the properties of the ground. For example, for ground with an inclined surface, it may be necessary to improve the ground to prevent landslide. In such a case, a flat surface in the middle of the inclined surface or above the inclined surface The underground structure may be formed in the ground. Thus, since it is necessary to perform ground improvement suitable for the ground for each ground, the size and shape of the underground structure for ground improvement are different for each ground. For example, Patent Document 2 discloses an underground structure in which a concrete pile row is constructed along a slope and the concrete pile is formed in a wall shape.

JP 2010-248885 A JP 7-238554 A

  The underground structure of Patent Document 2 suppresses landslides on inclined surfaces by placing concrete pile rows in a wall shape. However, since the underground structure of Patent Document 2 is formed of concrete, there are problems such as that it takes time and labor for construction, and that it becomes difficult to treat the solidified concrete in the ground when removing it. there were. This specification discloses the technique which uses a crushed stone pillar, and has the intensity | strength as a structure, and also forms the structure of the desired shape and magnitude | size which has water permeability easily in the ground.

  The construction method of the crushed stone structure disclosed in the present specification constructs the crushed stone structure in the ground. In this method, a first excavation step for forming a first space in the ground, and a first crushed stone column that forms a first crushed stone column by pressing and pressing the crushed stone into the first space formed by the first excavation step. A crushed stone formation process, a second excavation process in which a second space is formed in the ground and connected to the first crushed stone pillar, and the second space formed by the second excavation process is loaded with crushed stone and pressed. And a second crushed stone column forming step of forming a second crushed stone column connected to the first crushed stone column.

  In the construction method of the crushed stone structure, the second crushed stone column connected to the first crushed stone column can be formed by forming the second space at a position connected to the first crushed stone column. For this reason, a crushed stone structure in which a plurality of crushed stone pillars are continuous can be constructed in the ground. Since crushed stone is used instead of concrete, a structure having appropriate water permeability and strength can be easily formed in the ground. In other words, the method for constructing a crushed stone structure corresponds to a production method and a production method for a crushed stone structure, and can also be referred to as a production method and a production method for a crushed stone structure.

  Moreover, the crushed stone structure disclosed in the present specification is formed in a space formed in the ground. The crushed stone structure is provided with a plurality of crushed stone columns constituted by crushed stone. At least one of the crushed stone columns is connected to another crushed stone column adjacent to the crushed stone column. At least one of the crushed stone columns and the other crushed stone column continuously form one structure.

  In the above-mentioned crushed stone structure, a plurality of crushed stone pillars continuously form one structure. For this reason, the crushed stone structure which adjusted desired shape and size, water permeability, and intensity | strength in the ground can be formed easily.

The perspective view which shows an example of the crushed stone structure which concerns on an Example. The top view which shows a part of crushed stone structure which concerns on an Example. The figure which shows schematic structure of the crushed stone pillar formation apparatus. Sectional drawing which shows the structure of the cylindrical part and spiral part of an attachment. The flowchart which shows the manufacturing method of the crushed stone structure which concerns on an Example. It is a figure which shows the manufacturing method of the crushed stone structure which concerns on an Example, Comprising: The state which formed 1st space is shown. It is a figure which shows the manufacturing method of the crushed stone structure which concerns on an Example, Comprising: The state which formed the crushed stone pillar in 1st space is shown. It is a figure which shows the manufacturing method of the crushed stone structure which concerns on an Example, Comprising: The state which formed 2nd space is shown. The figure which shows another example of the crushed stone structure which concerns on an Example. The figure which shows the state in which the crushed stone structure, the drain pipe, and the stand pipe were installed in the inclined surface. The figure which shows another example of the crushed stone structure which concerns on an Example.

  The main features of the embodiments described below are listed. The technical elements described below are independent technical elements and exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Absent.

(Feature 1) In the second excavation process, the method for constructing a crushed stone structure disclosed in the present specification excavates a part of the formed first crushed stone column and the land adjacent to the first crushed stone column into the ground. A second space may be formed. In the second crushed stone column forming step, the second crushed stone column is formed so that a part of the diameter of the first crushed stone column and the diameter of the second crushed stone column overlap each other when viewed in plan. Also good. According to such a structure, by constructing the second crushed stone column so that the diameter of the first crushed stone column and a part of the diameter of the second crushed stone column overlap each other, a more reliable underground structure can be constructed. Can do. For this reason, a crushed stone structure in which a desired shape, size, water permeability, and strength are adaptively adjusted to the geology can be constructed in the ground.

(Feature 2) In the method for constructing a crushed stone structure disclosed in the present specification, the first excavation step, the first crushed stone column forming step, the second excavation step, and the second crushed stone column forming step are performed using a crushed stone column forming device. It may be done. The crushed stone pillar forming device may include an attachment including a cylindrical portion and a spiral portion that is rotatably disposed in the cylindrical portion and is connected to a driving device to excavate the underground. In the first excavation step and the second excavation step, the underground may be excavated while inserting the attachment into the ground by rotating the spiral portion and the cylindrical portion integrally with a driving device. In the first crushed stone column forming step and the second crushed stone column forming step, the crushed stone column may be formed by putting crushed stone into the cylindrical portion and throwing the attachment into the cylindrical portion while raising the attachment from the underground. According to such a structure, 2nd space is formed so that a 1st crushed stone pillar and a 2nd crushed stone pillar may be connected by forming a crushed stone structure using the crushed stone pillar forming apparatus provided with said attachment. The first crushed stone pillar and the second crushed stone pillar can be connected by inserting and pressing the crushed stone into the second space. For this reason, a continuous crushed stone structure can be suitably constructed, and a crushed stone structure having a desired shape can be constructed.

(Characteristic 3) In the crushed stone structure disclosed in the present specification, when viewed in plan, the diameter of at least one crushed stone column among the plurality of crushed stone columns may overlap with the diameter of other crushed stone columns. Good. According to such a structure, a crushed stone structure can be made into a continuous underground structure more reliably. For this reason, the shape of a crushed stone structure can be made into a desired shape.

(Feature 4) In the crushed stone structure disclosed in the present specification, the plurality of crushed stone columns may be arranged in a straight line, or each of the plurality of crushed stone columns may be connected to another adjacent crushed stone column. Good. According to such a structure, the crushed stone structure becomes a wall shape by arranging the crushed stone columns in a straight line. For this reason, for example, it can use suitably for the ground improvement for suppressing the landslide of ground, such as an inclined surface.

(Feature 5) The crushed stone structure disclosed in the present specification may further include a drain pipe having one end connected to the crushed stone structure in the ground and the other end positioned on the ground surface. According to such a configuration, for example, by passing the other end of the drain pipe at a position lower than or equal to the one end connected to the crushed stone structure, it passes between the crushed stones constituting the crushed stone structure. The water permeation can be suitably drained through the drain pipe. For this reason, ground water can be drained suitably, the water level in the ground can be lowered, and ground collapse due to ground liquefaction or ground softening can be prevented.

  Hereinafter, the crushed stone structure 50 according to the embodiment will be described. The crushed stone structure 50 is formed by press-fitting crushed stone into a space formed in the ground. The crushed stone structure 50 includes a plurality of crushed stone columns 52. Each of the crushed stone pillars 52a to 52h has a cylindrical shape extending in the z direction. For this reason, when the crushed stone column 52 is viewed along the z direction (that is, when the crushed stone column 52 is viewed from above), the shape is circular. In the present specification, a circular diameter when viewed along the z direction is referred to as a diameter of the crushed stone column 52. As will be apparent from the description below, the z direction in which the crushed stone column 52 extends is a direction for excavating the ground to form a space in the ground. For this reason, when excavating perpendicularly | vertically with respect to the ground and forming space, the crushed stone pillar 52 is extended in the direction orthogonal to the ground. When a space is formed by inclining with respect to the ground, the crushed stone pillar 52 extends with inclining with respect to the ground. As shown in FIG. 1, the crushed stone structure 50 includes eight crushed stone columns 52 a to 52 h. The eight crushed stone columns 52a to 52h are arranged on a straight line and extend in one row in the x direction. That is, the crushed stone structure 50 has a wall shape. The dimensions in the y direction of the eight crushed stone columns 52a to 52h (that is, the radial dimensions of the crushed stone columns 52a to 52h) are the same. Moreover, the dimension (namely, dimension of the depth direction of each crushed stone pillar 52a-52h) of the eight crushed stone pillars 52a-52h is the same. In addition, in the following specification, when it is necessary to distinguish the crushed stone column 52, it describes using the alphabetical letters like the crushed stone columns 52a to 52h, and when it is not necessary to distinguish, it is simply described as the crushed stone column 52. There is a case.

  Adjacent crushed stone columns 52 are connected to each other, and the crushed stone structure 50 forms one structure. As shown in FIG. 2, when the crushed stone structure 50 is viewed in plan from above (that is, when viewed along the z direction), a part of the crushed stone column 52a and a part of the crushed stone column 52b are overlapped, and the crushed stone column 52b is overlapped. And a portion of the crushed stone column 52c overlap. Specifically, the diameter R1 of the crushed stone column 52a and the diameter R2 of the crushed stone column 52b overlap each other by a length L1. The length L1 can be, for example, 0% or more and 50% or less of the diameter R1 of the crushed stone column 52a and the diameter R2 of the crushed stone column 52b. Preferably, by setting the length L1 to 0% or more of the diameters R1 and R2, the crushed stone columns 52a and 52b can be connected to form a continuous structure. Moreover, it can suppress that the number of the crushed stone pillars 52 which comprise the crushed stone structure 50 increases by making length L1 into 50% or less of diameter R1, R2. More preferably, the length L1 may be 5% or more and 25% or less of the diameters R1 and R2. Similarly, the diameter R2 of the crushed stone column 52b and the diameter R3 of the crushed stone column 52c are overlapped by the length L2, and the length L2 is 0% or more of the diameter R2 of the crushed stone column 52b and the diameter R3 of the crushed stone column 52c, and 50% or less. Thus, all the eight crushed stone columns 52 constituting the crushed stone structure 50 overlap with the adjacent crushed stone columns 52 when viewed in plan.

  In addition, although the diameter of each crushed stone pillar 52 of a present Example is the same, it is not limited to such a structure. The plurality of crushed stone columns 52 constituting the crushed stone structure 50 may be connected to each other, and the diameters of the crushed stone columns may be different. When the diameter of each crushed stone column is different, it is preferable that the crushed stone column having the smaller diameter among the adjacent crushed stone columns overlaps with the adjacent crushed stone column in the above range. Further, in this embodiment, the size in the depth direction of each crushed stone column 52 is the same in all the crushed stone columns 52, but the size in the depth direction of each crushed stone column 52 is different for each crushed stone column 52. It may be a dimension. This makes it possible to keep the distance from the ground surface to the top of the crushed stone pillar constant by changing the depth dimension of each crushed stone pillar, even when there are restrictions when forming the crushed stone pillar with hard rock, etc. It can flexibly handle the construction of crushed stone structures kept in

  Each crushed stone column 52 constituting the crushed stone structure 50 is formed using the crushed stone column forming apparatus 100. Here, the crushed stone pillar forming apparatus 100 will be described. As shown in FIG. 3, the crushed stone pillar forming apparatus 100 includes a ground improvement machine 40 as a construction machine and an attachment 10 attached to the ground improvement machine 40. As shown in FIG. 3, the ground improvement machine 40 includes a ground improvement machine body structure 1, a cabin 7 as a driver's seat, a crawler 6 that is an endless track that can move on rough terrain with low ground pressure, And an outrigger 5 that suppresses the swing of the ground improvement machine 40.

  The ground improvement machine 40 further includes, as a configuration for operating the attachment 10, a driving device 11 that supplies a rotational driving force to the attachment 10 via the motor output shaft 27, a leader 4 having the lifting guide rail 9, and a leader 4, a leader mounting base 2 for supporting 4, a hydraulic cylinder 3 for operating the inclination of the leader 4, and an extension pedestal 8 formed integrally with the leader 4 at the lower end of the leader 4. .

  The attachment 10 includes a cylindrical portion 12 provided with fins 13, a spiral portion 14, a surrounding frame 30 for stabilizing the cylindrical portion 12, a hanger stay 18 having a bifurcated fork shape, and a cam protrusion 17. A top cover case 16, a crushed stone throwing device 32, a mounting plate 37 that supports the surrounding frame 30, a support arm 39 that supports the crushed stone throwing device 32, and a construction management device 41 that manages the construction state of the attachment 10. I have.

  A crushed stone throwing hole 15 is formed in the cylindrical portion 12, and the crushed stone throwing hole 15 is closed by an opening / closing lid 20. The crushed stone throwing device 32 includes a hopper portion 33 and a chute portion 34 disposed below the hopper portion 33. The crushed stone introduction hole 15 is closed by an opening / closing lid 20 when the attachment 10 excavates the ground. Thereby, it is possible to prevent the earth and sand from entering from the crushed stone introduction hole 15. Further, when throwing crushed stone into the cylindrical portion 12, the opening / closing lid 20 is opened. Thereby, the crushed stone thrown into the crushed stone throwing device 32 can be thrown into the cylindrical portion 12 through the crushed stone throwing hole 15. Usually used crushed stone is not a fixed shape because it is obtained by pulverizing rock, but it has a diameter of about 2 to 50 mm, but is not limited thereto. The crushed stone may contain a thing with a diameter smaller than 2 mm, and may contain a thing with a diameter larger than 50 mm. By changing the shape of the attachment, it is possible to handle a diameter larger than 50 mm.

  FIG. 4 is a cross-sectional view showing the configuration of the cylindrical portion 12 and the spiral portion 14. The spiral portion 14 is configured integrally with the rotary input shaft 26 and the core rod 22. The rotation input shaft 26 is connected to the motor output shaft 27 of the drive device 11. The rotation input shaft 26 rotates in accordance with the rotation driving force of the motor output shaft 27 and transmits the rotation driving force to the spiral portion 14 through the core rod 22 integrally coupled. A drilling blade is provided at the tip of the spiral portion 14. The excavation blade is formed in a spiral shape whose diameter increases toward the tip of the spiral portion 14. The substantially entire excavation blade is disposed in the cylindrical portion 12, and only a part of the tip of the excavation blade protrudes from the tip of the cylindrical portion 12.

  The core rod 22 is rotatably coupled to the cylindrical portion 12 by a bearing tube 23 and a radiation stay 24, and has a common rotating shaft with the cylindrical portion 12. On the other hand, the cylindrical portion 12 has a spiral fin 13 around it. The fin 13 has a spiral shape in the same direction as the spiral of the spiral portion 14 (that is, the excavating blade). That is, when excavating, the cylindrical portion 12 and the spiral portion 14 rotate in the same direction. Thereby, the excavated earth and sand generated by excavation of the spiral portion 14 is transported to the ground surface by the fins 13.

  The attachment 10 further includes a one-way clutch mechanism (not shown) between the rotation input shaft 26 and the core rod 22 inside the top cover case 16. The one-way clutch mechanism automatically enters an operating state in which the spiral portion 14 and the cylindrical portion 12 rotate as a unit in driving in the rotational direction during excavation. Thereby, the earth and sand excavated by the spiral part 14 as mentioned above can be discharged | emitted on the ground with the fin 13 which the cylindrical part 12 has. On the other hand, in rotational driving in the direction opposite to the rotational direction during excavation, the spiral portion 14 can apply pressure to the crushed stone and the cylindrical portion 12 can automatically stop rotating. Hereinafter, the direction in which the cylindrical portion 12 and the spiral portion 14 rotate in the same direction, that is, the rotation direction during excavation is referred to as “forward rotation direction”, and the direction that rotates in the direction opposite to the rotation direction during excavation, that is, the spiral portion. The rotation direction in which the pressure is applied to the crushed stone at 14 may be referred to as “inversion direction”.

  It is preferable that the crushed stone column forming apparatus 100 further includes a ruler 71 and a positioning pile 72 for positioning the attachment 10. The positioning pile 72 is attached to the ruler 71, and the ruler 71 is attached to the surrounding frame 30. The excavation position by the attachment 10 (that is, the formation position of the crushed stone column 52) can be simply and reliably positioned by the positioning pile 72. In addition, in the present Example, although the one positioning pile 72 is provided, it is not limited to such a structure. For example, two or more positioning piles 72 may be provided. By providing two or more positioning piles 72 and fixing them along the circumference of the crushed stone column 52 constructed previously, positioning accuracy can be increased, and displacement of the attachment 10 due to vibration during excavation can also be prevented. .

  With reference to FIGS. 5-8, the manufacturing method of the crushed stone structure 50 is demonstrated. The crushed stone structure 50 is constructed by forming one crushed stone column 52 constituting the crushed stone structure 50 one by one. In a present Example, the crushed stone pillar 52a is formed initially, and the crushed stone pillars 52b-52h are formed in order after that.

  As shown in FIG. 5, first, the first excavation process is executed (S12). In the first excavation step, the first space 60 for excavating the ground using the crushed stone pillar forming apparatus 100 to form the crushed stone pillar 52a is formed. The first excavation process is performed according to the following procedure. First, the attachment 10 is aligned. The alignment of the attachment 10 is performed by adjusting the position and direction of the ground improvement machine 40 by driving the crawler 6. In addition, after adjusting the position and direction of the ground improvement machine 40, the ground improvement machine 40 may be fixed by the outrigger 5. Thereby, the rocking | swiveling and position shift of the ground improvement machine 40 at the time of construction can be suppressed. After the ground improvement machine 40 is fixed, the attachment 10 is lowered while the driving device 11 is driven. The driving device 11 drives the cylindrical portion 12 and the spiral portion 14 so as to rotate in the forward rotation direction. Therefore, the attachment 10 is excavated in the ground by inserting the attachment 10 into the ground while rotating in the forward rotation direction. Sediment discharged by excavation in the ground is carried to the outer periphery of the cylindrical portion 12 and discharged to the ground surface by the fins 13. As shown in FIG. 6, when the attachment 10 reaches a predetermined depth, the drive device 11 stops driving for normal rotation and ends excavation. Then, the first space 60 is formed in the ground. As is apparent from the above description, the first space 60 has a cylindrical shape extending in the excavation direction (z direction).

  Next, a crushed stone column forming step of forming the crushed stone column 52a in the first space 60 formed in the first excavation step of step S12 is executed (S14). A crushed stone pillar formation process is performed in the following procedures. First, crushed stone is thrown into the crushed stone throwing device 32 with the open / close lid 20 open. The crushed stone thrown into the crushed stone throwing device 32 is thrown into the cylindrical portion 12 through the crushed stone throwing hole 15. Next, the driving device 11 is driven so that the spiral portion 14 rotates in the reverse direction. Then, the attachment 10 rises while rotating in the reverse direction, and discharges the crushed stone put into the cylindrical portion 12 while pressing it from the spiral portion 14. Therefore, the attachment 10 is pushed out of the first space 60 and the crushed stone pillar 52 a is formed in the first space 60. As shown in FIG. 7, when the attachment 10 is pushed out to the ground surface, the driving of the driving device 11 in the reverse rotation is stopped. Then, the crushed stone pillar 52 a is formed in the first space 60. As is clear from the above description, the crushed stone column 52a has a cylindrical shape extending in the excavation direction (z direction).

  Next, the second excavation process is executed (S16). In the second excavation process, the ground stone column forming device 100 is used to excavate the ground and a part of the ground stone column 52a, or to excavate the ground at a position almost in contact with the ground stone column 52a to form the stone pillar 52b. The second space 62 is formed. As described above, the crushed stone column forming apparatus 100 slightly pushes the formed space to the outer peripheral side in the crushed stone column forming step (for example, step S14). For this reason, the space for forming the crushed stone pillar 52 connected with the crushed stone pillar 52a can be formed by forming the 2nd space 62 in the position which substantially contacts with the crushed stone pillar 52a. The second excavation process is performed according to the following procedure. First, the position of the attachment 10 is moved to align the attachment 10. As shown in FIG. 2, the crushed stone column 52b is subtracted from the position of the crushed stone column 52a by R2-L1 (that is, the dimension L2 of the length in which the crushed stone columns 52a and 52b overlap from the radial dimension R2 of the crushed stone column 52b). (Dimensioned dimension) is formed at a position moved in the + x direction. For this reason, the attachment 10 is moved in the x direction by R2-L1. In addition, since the procedure of alignment of the attachment 10 is the same procedure as step S12, detailed description is abbreviate | omitted. After positioning the attachment 10, the attachment 10 is lowered while driving the driving device 11 so that the spiral portion 14 rotates in the forward rotation direction. Then, the attachment 10 excavates a part of the ground and the crushed stone column 52a while rotating in the normal rotation direction. As described above, the crushed stone column 52a simply presses and integrates the crushed stone thrown into the cylindrical portion 12. For this reason, only a part of the crushed stone column 52a can be excavated by the attachment 10 without destroying the crushed column 52a. Since the excavation procedure is the same as that in step S12, detailed description is omitted. As shown in FIG. 8, when the attachment 10 reaches a predetermined depth, a second space 62 is formed in the ground.

  Next, a crushed stone column forming step of forming the crushed stone column 52b in the second space 62 formed in the second excavation step of step S16 is executed (S18). In addition, since the procedure of the crushed stone pillar formation process of step S18 is the same as that of the crushed stone pillar formation process of step S14, detailed description is abbreviate | omitted. The second space 62 is formed by excavating the ground and a part of the crushed stone column 52a. For this reason, by forming the crushed stone pillar 52b in the second space 62, a structure in which the crushed stone pillar 52a and the crushed stone pillar 52b are connected to each other in the ground is formed.

  Next, it is determined whether or not all the crushed stone columns 52 constituting the crushed stone structure 50 have been formed (S20). That is, it is determined whether or not all the crushed stone columns 52a to 52h are formed. When there is a crushed stone column 52 that is not formed among the crushed stone columns 52a to 52h (NO in step S20), the process returns to step S16, and steps S16 and S18 are repeated. That is, a part of the crushed stone pillar 52 formed and the ground adjacent to the crushed stone pillar 52 are excavated. And the crushed stone pillar 52 is formed in the space formed by excavation. For example, if only the crushed stone column 52a and the crushed stone column 52b are formed, a part of the crushed stone column 52b in the + x direction and the ground adjacent to the crushed stone column 52b in the + x direction are excavated. And the crushed stone pillar 52c is formed in the space formed by excavation. Thus, step S16 and step S18 are repeated until all the crushed stone pillars 52a-52h which comprise the crushed stone structure 50 are formed. And if all the crushed stone pillars 52a-52h are formed (in the case of YES at Step S20), construction of the crushed stone structure 50 will be ended. In addition, when forming the crushed stone columns 52a to 52h, the crushed stone columns 52b, 52d, etc. are formed in the gap after forming the crushed stone columns by flying one by one like 52a, 52c, 52e. May be. By constructing the crushed stone structure 50 in this order, the load applied to the attachment 10 can be made closer to the left and right, and excavability with a stable set angle can be obtained.

  In this embodiment, a portion of the crushed stone column 52 and the ground adjacent to the crushed stone column 52 are excavated, and the crushed stone column 52 is formed in a space formed by excavation. For this reason, the adjacent crushed stone pillar 52 can be connected. By forming the plurality of crushed stone columns 52 in this way, the crushed stone structure 50 in which the plurality of crushed stone columns 52 are continuous can be constructed in the ground.

  In the present embodiment, in the second excavation process, the crushed stone columns 52b to 52h are formed so that the crushed stone columns 52a to 52h are linearly arranged, but the present invention is not limited to such a configuration. What is necessary is just to form the crushed stone pillar 52 formed later so that it may connect with the crushed stone pillar 52 formed previously, and the crushed stone pillar 52 formed later is in any direction with respect to the crushed stone pillar 52 formed previously. It may be adjacent. For example, as shown in FIG. 9, in the crushed stone structure 150, the crushed stone column 52i is connected to five crushed stone columns 52j to 52n. Thus, the crushed stone structure 150 may be configured such that one crushed stone column 52 is connected to a plurality of three or more crushed stone columns 52. Moreover, the crushed stone structure 150 is provided with the part 53 in which the three crushed stone pillars 52i-52k overlap. Thus, the crushed stone structure 150 may include an overlapping portion 53 in which three or more crushed stone columns 52 overlap. By constructing in this way, the strength of the crushed stone structure 150 can be further increased. Thus, by combining a plurality of crushed stone pillars 52, a crushed stone structure of a desired shape can be constructed in the ground.

  Moreover, in the present Example, although the crushed stone pillar 52 which comprises the crushed stone structure 50 is formed so that it may reach to the earth surface vicinity, it is not limited to such a structure. For example, the crushed stone structure may be buried in the ground without reaching near the ground surface. Such a crushed stone structure forms a crushed stone column in the middle of the excavated space when the crushed stone column forming apparatus 100 forms the crushed stone column, and takes out the attachment 10 from the ground without forming a crushed stone column from the middle. Can be built. For the portion of the excavated space where the crushed stone pillars are not formed, for example, the earth and sand discharged during excavation may be input again.

  Moreover, in the crushed stone pillar forming apparatus 100 used in the present embodiment, the fins 13 are provided in the cylindrical portion 12, but the configuration is not limited thereto. For example, an attachment 10 having a cylindrical portion 12 provided with fins 13 (hereinafter, also referred to as a soil removal type attachment 10) and a cylindrical portion having no fins that are configured to discharge almost no earth and sand from excavation to the ground surface. A crushed stone structure may be constructed using both of the attachments (hereinafter, also referred to as non-soil-type attachments).

  In this case, first, a part of the crushed stone columns 52 selected from the plurality of crushed stone columns 52 constituting the crushed stone structure body 50 (specifically, independently in the ground, using a non-exhaust type attachment). The existing crushed stone column 52 (the crushed stone column 52 not adjacent to the already formed crushed stone column 52) is formed. Thereafter, the remaining crushed stone pillars 52 are formed by using the soil removal type attachment 10. For example, in the crushed stone structure 50 of FIG. 1, first, the crushed stone columns 52a, 52c, 52e, and 52g are formed using a non-discharged attachment. Thereafter, the remaining crushed stone pillars 52 b, 52 d, 52 f, 52 h are formed using the soil removal type attachment 10. When a non-soil removal type attachment is used, unnecessary earth and sand are compressed and pressed around the space formed by excavation. By using a combination of the non-discharging type attachment and the discharging type attachment 10 in the order as described above, the continuous crushed stone structure 50 can be suitably constructed even when the non-discharging type attachment is used. Thus, if the non-soil-discharging attachment is used, the amount of earth and sand discharged can be reduced. In the case where a large overlap of the diameters of the crushed stone columns 52 described so far is provided, it is desirable to use the soil removal type attachment 10 as described above. Moreover, when excavating with the soil removal type attachment 10, the crushed stone column 52 will contact | connect both sides and it is preferable also at the point from which excavation load becomes uniform. Here, it is possible to form all the crushed stone columns 52 by using a non-discharging type attachment, but there may be a case where the excavation resistance becomes large due to the compression of the ground, which is difficult. In addition, the diameter of each crushed stone column 52 is usually about 25 to 45 cm when the non-earth type attachment is used, and about 30 to 50 cm when the earth type attachment 10 is used. It is not limited to a simple configuration. The length in the depth direction of the crushed stone column 52 is determined by the dimension in the height direction (z direction) of the non-exhaust type attachment 10 or the exhaust type attachment 10 and the depth of excavation, and is about 4 to 6 m. It is not limited to such a configuration. For example, a crushed stone pillar larger than the above dimensions can be formed by changing the size and driving ability of the crushed stone pillar forming apparatus.

  Moreover, since the crushed stone structure 50 constructed | assembled using the construction method of a present Example is formed with the crushed stone, in the crushed stone structure 50, a clearance gap will arise between crushed stone and crushed stone. For this reason, the crushed stone structure 50 constructed | assembled using the construction method of a present Example can store water, such as groundwater which flows in the ground. Hereinafter, an example in which the crushed stone structure 250 constructed using the construction method of the present embodiment is used to prevent ground collapse such as an inclined surface will be described.

  As shown in FIG. 10, a crushed stone structure 250 and a drain pipe 54 are disposed in the ground in order to prevent the ground collapse of the inclined surface. The crushed stone structure 250 is constructed at a position higher than the inclined surface where the ground collapse such as landslide may occur (in FIG. 10, the + y direction of the inclined surface). The crushed stone structure 250 is a wall-like structure in which crushed stone columns 52 are continuously formed in the x direction, and the number of crushed stone columns 52 constituting the crushed stone structure 250 is the length of an inclined surface that prevents ground collapse. It can be changed to match. Therefore, the number of crushed stone columns 52 constituting the crushed stone structure 250 is different from the number of crushed stone columns 52 constituting the above-described crushed stone structure 50 (see FIG. 1) (that is, eight). The number is larger than the number of crushed stone columns 52 constituting the crushed stone structure 50. Note that the crushed stone structure 250 and the above-described crushed stone structure 50 differ only in the number of crushed stone pillars 52 that are different, and the other configurations of the crushed stone structure 250 are the same as the crushed stone structure 50. For this reason, the detailed explanation about the construction details of the crushed stone structure 250 and the construction method of the crushed stone structure 250 is omitted. By constructing the crushed stone structure 250 having water permeability along the inclined surface, water contained in the soil on the upstream side (+ y direction) of the inclined surface can be discharged appropriately. For this reason, a crushed stone structure having moderate water permeability has a markedly improved effect on the prevention of ground collapse and the maintenance effect compared to conventional methods.

  Further, the drain pipe 54 is connected to the crushed stone structure 250. One end of the drain pipe 54 is connected to the crushed stone structure 250, and the other end of the drain pipe 54 is disposed on the ground surface. In FIG. 10, the drain pipe 54 extends with a gradient capable of draining in the direction opposite to the y direction in principle. By connecting the crushed stone structure 250 to the drain pipe 54, the water in the crushed stone structure 250 can be discharged to the ground surface. The drain pipe 54 is preferably disposed at a bottom portion of 0 cm or more and less than 50 cm of the crushed stone structure 250, and a plurality of drain pipes 54 are desirably provided at regular intervals in the x direction of the crushed stone structure 250. In addition to the bottom, it is also effective to provide a drain pipe (not shown) additionally on the surface side of the drain pipe 54 as a measure against heavy rain such as guerrilla heavy rain. By providing the drain pipe, the water level in the soil on the upper side (+ y direction) of the crushed stone structure 250 can be lowered, and the strength of the soil can be increased. Further, the stand pipe 56 may be installed in the crushed stone structure 250. One end of the stand pipe 56 is disposed in the crushed stone column 52 from the upper surface of the crushed stone column 52 constituting the crushed stone structure 250, and the other end is disposed on the ground surface above the crushed stone structure 250. The number of stand pipes 56 installed in the crushed stone structure 250 is not particularly limited. For example, the stand pipes 56 are installed for every plurality of crushed stone columns 52 constituting the crushed stone structure 250. May be. The standpipe 56 and the crushed stone structure 250 can suppress the groundwater at atmospheric pressure and reduce the water level in the soil. Therefore, ground collapse such as landslide can be suppressed by keeping the groundwater level below a certain level as described above. In addition, although the crushed stone structure 250 of a present Example is located in a position higher than an inclined surface, it is not limited to such a structure. For example, the crushed stone structure 250 may be located in the middle of the inclined surface. Moreover, although the stand pipe 56 is installed in this embodiment, the stand pipe 56 may not be installed.

  In addition, the crushed stone structures 50, 150, and 250 of the present example are all arranged in the same direction (parallel to the z direction) in the plurality of crushed stone columns 52 that constitute the crushed stone structures 50, 150, and 250. It is not limited to such a configuration. The plurality of crushed stone columns constituting the crushed stone structure may be arranged in different directions. For example, as shown in FIG. 11, the crushed stone structure 350 includes crushed stone columns 152 a to 152 d parallel to the z direction, The crushed stone pillars 153a to 153d that are disposed obliquely in the z direction (inclined in the -y direction in FIG. 11) may be connected. The crushed stone structure 350 is a structure in which the crushed stone columns 152a to 152d and the crushed stone columns 153a to 153d are completely separated in the vicinity of the ground surface and overlap in the ground. Such a structure is constructed by forming the crushed stone columns 152a to 152d in the vertical direction and forming the crushed stone columns 153a to 153d slightly inclined. With such a structure, a space is created between the crushed stone columns 152a to 152d and the crushed stone columns 153a to 153d. For example, while constructing a ground drainage channel, the surroundings of the drainage channel are surrounded by the crushed stone columns 152a to 152d. And it can protect with the crushed stone pillars 153a-153d. In the crushed stone structure 350, the crushed stone columns 152a to 152d are arranged parallel to the z direction, and the crushed stone columns 153a to 153d are arranged obliquely in the z direction, but a plurality of crushed stones constituting the crushed stone structure The columns need only be connected to each other. For example, the crushed stone columns 152a to 152d may be formed to be inclined in the z direction, and the crushed stone columns 153a to 153d may be formed to be inclined in the z direction. Moreover, when arrange | positioning a some crushed stone pillar in a mutually different direction, in the xy cross section of the part which a crushed stone pillar connects, the overlapping part of two connected crushed stone pillars may exceed 50%.

  In the formation through which groundwater permeates, it is also effective to set the crushed stone particles constituting the crushed stone structure as follows. For example, a relatively small crushed stone having a diameter of about 3 cm is introduced into the lower part of the crushed stone structure (that is, a part far from the ground surface), and the diameter is about 5 cm at the upper part of the crushed stone structure (ie, a part close to the ground surface). A relatively large crushed stone can be introduced. Moreover, since the crushed stone structure of the present Example is continuous, the crushed stone structure can also be used as an underground water channel. In this case, like the above-mentioned crushed stone structures 50 and 250, the crushed stone structure is constructed continuously in a straight line. At this time, crushed stone having a particle size larger than that of the upper portion is introduced into the lower portion of the crushed stone structure. Then, in the lower part of the crushed stone structure, an underground water channel can be formed through the space between the crushed stones. For this reason, by adjusting the particle size of the crushed stone of the crushed stone structure to be built in the ground with the dimension in the depth direction, it is possible to construct a groundwater channel at a desired depth in the ground. Moreover, a crushed stone having a small particle diameter such as gravel can be mixed with a crushed stone having a relatively large particle diameter. Furthermore, you may throw in the crushed stone from which a particle size differs for every crushed stone pillar. Thus, the crushed stone structure of the present embodiment can change the particle size of the crushed stone constituting the crushed stone structure for each part in one crushed stone structure. For this reason, you may adjust the particle size of the crushed stone according to the topography and the ground which construct a crushed stone structure, or the statistical value of the drainage condition at the time of the rain of the soil. Thus, the water permeability and strength can be optimized according to the characteristics of the soil.

  Since the crushed stone structure manufactured using the manufacturing method of a present Example is constructed | assembled with the crushed stone, it can be equipped with fixed water storage and high water permeability. Even when a structure is formed using water-permeable concrete in the ground, water is stored in the structure (hereinafter also referred to as a water-permeable concrete structure). However, while the water-permeable concrete structure has higher water permeability than a normal concrete structure, the gap generated in the structure is small and the water permeability is low compared to the crushed stone structure of this example. Since the crushed stone structure of the present embodiment is formed of crushed stone, it has a certain water storage capacity and can increase water permeability, so that the groundwater level can be lowered. Moreover, the crushed stone structure 50 of a present Example can be manufactured without spending time and effort for construction by using said manufacturing method. The above-mentioned permeable concrete structure is difficult to reconstruct at the same location even if the permeability decreases due to the intrusion of earth and sand into the gaps in the structure. The crushed stone structure 50 of a present Example can be re-constructed in the same location by using said manufacturing method. For this reason, even if water storage and water permeability fall, re-construction can be easily performed at the same location, and water storage and water permeability can be secured in a good state for a long period of time.

  As mentioned above, although the specific example of the technique disclosed by this specification was demonstrated in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

DESCRIPTION OF SYMBOLS 10: Attachment 11: Drive device 12: Cylindrical part 13: Fin 14: Spiral part 15: Crushing stone insertion hole 20: Opening / closing lid 32: Crushing stone feeding device 40: Ground improvement machines 50, 150, 250: Crushed stone structure 52: Crushed stone pillar 54: Drainage pipe 60: First space 62: Second space 100: Crushed stone pile forming device

Claims (7)

A method of building a crushed stone structure in the ground,
A first excavation step of forming a first space in the ground;
A first crushed stone column forming step of forming a first crushed stone column by charging and pressing the crushed stone into the first space formed by the first excavation step;
A second excavation step of forming a second space in the ground and at a position connected to the first crushed stone pillar;
A second crushed stone column forming step of forming a second crushed stone column connected to the first crushed stone column by charging and pressing the crushed stone into the second space formed by the second excavation step, Construction method of crushed stone structure. In the second excavation step, a part of the formed first crushed stone pillar and a land adjacent to the first crushed stone pillar are excavated to form a second space in the ground,
In the second crushed stone column forming step, the second crushed stone column is arranged so that a part of the diameter of the first crushed stone column and the diameter of the second crushed stone column overlapped when viewed in plan. The method for constructing a crushed stone structure according to claim 1, wherein: The first excavation step, the first crushed stone column forming step, the second excavation step, and the second crushed stone column forming step are performed using a crushed stone column forming device,
The crushed stone pillar forming device includes an attachment including a cylindrical portion, and a spiral portion that is rotatably arranged in the cylindrical portion and connected to a driving device to excavate the ground,
In the first excavation step and the second excavation step, excavating the ground while inserting the attachment into the ground by rotating the spiral portion and the cylindrical portion integrally with the driving device,
In the first crushed stone column forming step and the second crushed stone column forming step, the crushed stone is put into the cylindrical portion, and the crushed stone column is formed by the crushed stone put into the cylindrical portion while raising the attachment from the underground. The construction method of the crushed stone structure of Claim 1 or 2. A crushed stone structure formed in the space formed in the ground,
It has a plurality of crushed stone pillars composed of crushed stone,
At least one crushed stone column among the plurality of crushed stone columns is connected to another crushed stone column adjacent to the crushed stone column,
A crushed stone structure in which at least one of the crushed stone pillars and the other crushed stone pillar continuously form one structure.   5. The crushed stone structure according to claim 4, wherein a diameter of at least one crushed stone column of the plurality of crushed stone columns partially overlaps with a diameter of the other crushed stone column when viewed in a plan view.   The crushed stone structure according to claim 4 or 5, wherein the crushed stone pillars are arranged in a straight line, and each of the crushed stone pillars is connected to another adjacent crushed stone pillar.   The crushed stone structure according to any one of claims 4 to 6, further comprising a drain pipe having one end connected to the crushed stone structure in the ground and the other end positioned on the ground surface.