JP2008115617A - Quality confirmation method for improved ground and quality confirmation instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quality confirmation method for improved ground and quality confirmation instrument, accurately and simply confirming the mixture condition of soil and solidifying material in a construction site of a surface layer ground improvement. <P>SOLUTION: First, soil 11 is removed from a scheduled area 60 for forming improved ground 17. A quality confirming instrument 10 is disposed in the scheduled area 60 so that the axial direction of the instrument body 20 is substantially vertical and also an opening 21 is directed toward the center of the scheduled area 60. In this state, back filling of mixed soil 13 obtained by mixing and stirring the soil 11 and the solidifying material 12 is performed for the scheduled area 60, and the mixed soil is contained in an inner void of the instrument body 20. Thus, in the scheduled area 60, the improved ground 17 is formed. The quality confirmation instrument 10 is provided with an earth retaining member 30, whereby the mixed soil 13 is extracted from the scheduled area 60 without dropping to confirm the mixing condition of the mixed soil 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a quality confirmation method for improved ground formed by surface ground improvement, and a quality confirmation device used for confirming the quality of the improved ground.

  Conventionally, surface ground improvement has been known as a construction method for preventing the uneven settlement of buildings by increasing the strength of the ground. Surface soil improvement is a method of forming a hard stable layer (improved ground) by mixing and stirring the soil of the ground to be improved and cement-based solidified material, and rolling and solidifying the obtained mixed soil. (For example, refer to Patent Document 1 and Patent Document 2.)

  In the surface ground improvement method described in Patent Document 1, white cement or a mixture of pigments that can be distinguished from soil is used as a cement-based solidifying material. Thereby, the mixed state of the soil and the solidified material can be easily grasped by visual recognition from the outside.

  In the surface layer ground improvement method described in Patent Document 2, mixed soil is used by mixing and stirring soil, a solidified material such as cement, and coal ash. In Patent Document 2, it is described that the uniaxial compressive strength of mixed soil is measured in order to evaluate numerically the degree of mixing of soil, solidified material, and coal ash.

JP 2003-184072 A Japanese Patent Laid-Open No. 2003-3460

  By the way, in the construction method described in Patent Document 1, although the superficial mixing condition of the soil and the solidified material being stirred can be easily confirmed, the mixing condition inside the mixed soil cannot be confirmed and improved. It was not enough as a method to check the quality of the ground.

  Moreover, although the construction method described in Patent Document 2 can evaluate the strength of the mixed soil numerically by measuring the uniaxial compressive strength of the mixed soil, it requires solidification with the soil because a dedicated testing machine is required. There is a problem that it is not possible to easily check the mixing condition with the material at the construction site.

  The present invention has been made in view of such circumstances, the quality confirmation method of improved ground, which can accurately and easily confirm the mixing condition of soil and solidified material at the construction site of surface ground improvement, and An object is to provide a quality confirmation device.

  (1) The quality check method for improved ground according to the present invention includes a first step of removing soil from a planned area where the improved ground is formed, a substantially tubular instrument body having an axially extending opening formed on a side surface, And a quality confirmation device comprising a retaining member that prevents the soil contained in the device body from falling off, the axial direction of the device body is substantially vertical, and the opening is directed toward the center of the planned area. The second step of arranging in the planned area as described above, the third step of backfilling the mixed soil formed by mixing and stirring at least the soil and the solidified material into the planned area and accommodating in the inner space of the instrument body, and A fourth step of pulling out the quality confirmation device and confirming the mixing condition of the mixed soil.

  The improved ground is formed by solidifying the mixed soil formed by mixing and stirring at least the soil and the solidifying material. In order to check the quality of the improved ground, a quality checking device is used. The instrument body of the quality confirmation instrument has a substantially tubular shape, and an opening extending in the axial direction is formed on the side surface. This opening is for accommodating the soil in the interior of the instrument body. The mixed soil enters the interior of the instrument body from the opening and is accommodated in the instrument body.

  In the first step, the soil is removed from the planned area. Here, the planned area means a range where the improved ground is planned to be formed. In the case where so-called surplus excavation is performed in the first step, the surplus excavation area is also included in this scheduled area. This first step is performed using, for example, a backhoe. In the second step, the quality confirmation instrument is placed in the planned area. The quality confirmation device is arranged such that the axial direction of the device body is substantially vertical and the opening is directed toward the center of the planned area. The number of quality confirmation devices to be arranged is not particularly limited, and is appropriately set according to the size and shape of the planned area. In the third step, the mixed soil is backfilled in the planned area and accommodated in the interior of the instrument body. At that time, since the opening of the instrument body is directed toward the center of the planned area, the mixed soil easily enters the inner space of the instrument body from the opening. In addition, the mixing and stirring for obtaining the mixed soil may be performed in the planned area or may be performed outside the planned area. In the fourth step, the quality confirmation device is pulled out from the planned area. At that time, the soil retaining member prevents the mixed soil from falling from the main body. For this reason, the quality confirmation instrument is pulled out without the mixed soil accommodated in the inner space of the instrument body falling out of the instrument body. Since the mixed soil accommodated in the instrument body is exposed from the opening, the mixing condition of the mixed soil can be easily confirmed. This confirmation is performed, for example, by an operator touching the mixed soil or by visually attaching an indicator that changes the color of the solidified material to the mixed soil.

  (2) In the second step, it is preferable that the quality confirmation device is disposed in an overexcavation area.

  As a result, when the mixed soil is rolled in the third step, it is prevented that the quality confirmation device arranged in the planned area becomes an obstacle such as a ramma that rolls the mixed soil, resulting in insufficient rolling pressure of the mixed soil. The

  (3) Even if the quality confirmation instrument has a projecting piece projecting downward from the instrument body, and the quality confirmation instrument is disposed in the second step by allowing the projecting piece to penetrate the ground. Good.

  Thereby, it becomes possible to arrange | position the quality confirmation instrument easily, without supporting an instrument main body using another tool, and also the extraction | drawer of a quality confirmation instrument is easy.

  (4) In the third step, the mixed soil may be backfilled by mixing and stirring at least the soil and the solidified material in the predetermined area.

  Thereby, the work of the 3rd process is performed efficiently.

  (5) In the third step, the backfilled mixed soil is preferably rolled.

  Thereby, the flat improvement ground without a space | gap is formed.

  (6) In the fourth step, it is preferable to pull out the quality confirmation instrument after the mixed soil is solidified.

  As a result, the mixed soil entering from the opening is solidified inside the instrument body and is restrained by the instrument body. For this reason, when extracting the quality confirmation instrument in the fourth step, the mixed soil is prevented from spilling from the opening.

  (7) A hole is formed in the side surface of the instrument body, and in the fourth step, the quality confirmation instrument may be pulled out by pulling up the rod-shaped member inserted through the hole.

  Thereby, it becomes possible to easily pull out the quality confirmation device by hooking a string or hook on the rod-shaped member.

  (8) In the fourth step, an indicator for coloring the solidifying material may be attached to the mixed soil accommodated in the instrument body, and the mixing condition of the mixed soil may be visually confirmed.

  Thereby, it becomes possible to grasp | ascertain the mixing condition of mixed soil more easily and correctly.

  (9) Further, the quality confirmation device according to the present invention is a quality confirmation device for improved ground formed by solidifying a mixed soil formed by mixing and stirring at least soil and a solidifying material, wherein the mixed soil is It comprises a substantially tubular instrument main body formed on the side surface with an opening extending in the axial direction so as to enter the interior, and a retaining member for preventing the mixed soil accommodated in the instrument main body from falling off.

  The improved ground is formed by solidifying the mixed soil formed by mixing and stirring at least the soil and the solidifying material. In order to confirm the quality of this improved ground, the quality confirmation instrument of the present invention is used. The instrument body of the quality confirmation instrument has a substantially tubular shape, and an opening extending in the axial direction is formed on the side surface. This opening is for accommodating the mixed soil in the interior of the instrument body.

  As described above, the quality confirmation device is arranged in the planned area so that the axial direction of the tool body is substantially vertical and the opening is directed toward the center of the planned area. In the planned area, the mixed soil is backfilled and the mixed soil is accommodated from the opening into the interior of the instrument body. The quality confirmation device is pulled out from the planned area with the mixed soil contained in the device body. Since the quality confirmation instrument includes the earth retaining member, the quality confirmation instrument is pulled out without the mixed soil falling out of the instrument body. Since the mixed soil accommodated in the instrument body is exposed from the opening, the mixing condition of the mixed soil can be easily confirmed. This confirmation is performed, for example, by an operator touching the mixed soil or by visually attaching an indicator that changes the color of the solidified material to the mixed soil.

  (10) A protruding piece that can penetrate into the ground may be provided.

  With the above configuration, it is possible to easily arrange the quality confirmation device in an upright posture, and the quality confirmation device can be easily pulled out.

  (11) The instrument body preferably has a substantially C-shaped cross section in a direction orthogonal to the axial direction.

  With the above configuration, since the mixed soil is supported by the edge of the instrument body that forms the opening, the mixed soil accommodated in the instrument body is effectively prevented from spilling from the opening.

  (12) It is preferable that the axial length from the earth retaining member to the upper end of the instrument body is longer than the depth of the planned area where the improved ground is formed.

  With the above configuration, when the quality confirmation device is arranged in the planned area, a part of the device body is exposed from the ground surface. For this reason, it becomes easy to pull out the quality confirmation device.

  (13) A hole may be formed in the side surface of the instrument body.

  With the above configuration, for example, the string can be inserted into the hole to connect the string to the instrument body, or the rod-like member can be inserted into the hole as described above to hook the string or the like, thereby further pulling out the quality confirmation instrument. It becomes easy.

  (14) A protrusion projecting inward of the instrument body may be provided on the inner surface of the instrument body.

  By the said structure, compared with the case where it does not have a protrusion, the mixed soil accommodated in the inner space of an instrument main body becomes difficult to spill from opening.

  (15) It is preferable that the plurality of protrusions are arranged in a row at predetermined intervals in the axial direction.

  With the above configuration, for example, when the mixed soil is backfilled by dividing it into a plurality of layers, the protrusion can be used as a scale instead.

  According to the quality check method for improved ground and the quality check tool according to the present invention, by pulling out the quality check tool in which the mixed soil is accommodated, the mixing condition of the soil and the solidified material is improved at the construction site of the surface ground improvement. Can be confirmed accurately and easily. Thereby, it can be easily confirmed whether or not there is a poor mixing agitation due to the surface layer improvement. Moreover, since the quality confirmation instrument has a simple configuration, it can be confirmed at a low cost whether there is a poor mixing agitation due to surface ground improvement.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate. First, the configuration of the quality confirmation instrument 10 according to the embodiment of the present invention will be described.

  FIG. 1 is a perspective view of a quality confirmation device 10 according to an embodiment of the present invention. FIG. 2 is a front view of the quality confirmation device 10 as seen from the direction of arrow II in FIG. FIG. 3 is a plan view of the quality confirmation instrument 10 as seen from the direction of arrow III in FIG.

  The quality confirmation instrument 10 is an instrument used for confirming the quality of the improved ground 17 (see FIG. 12) formed by surface ground improvement. Here, the improved ground 17 is formed by solidifying the mixed soil 13 (see FIG. 11) obtained by mixing and stirring the soil 11 (see FIG. 10) and the cement-based solidified material 12 (see FIG. 10). . That is, the quality confirmation device 10 is used to confirm the mixing condition of the soil 11 and the solidified material 12.

  As shown in FIGS. 1 to 3, the quality confirmation device 10 includes a device body 20 and a retaining member 30. The instrument body 20 is formed of a metal such as iron, stainless steel, or aluminum in a substantially tubular shape. In this embodiment, the instrument main body 20 is a C-shaped steel pipe. The length of the instrument body 20 and the fixing position of the retainer member 30 so that the length in the axial direction (in the direction of the axis 19) from the earth retaining member 30 to the upper end of the instrument body 20 is longer than the depth of the planned area 60. Is set. In the present embodiment, since the ground of the planned area 60 is excavated by about 100 cm, the instrument body 20 having a length in the direction of the axis 19 of about 120 cm and the earth retaining member 30 fixed near the lower end is used. In addition, the length of the tool body 20 in the direction of the axis 19 is appropriately changed according to the depth of the ground of the planned area 60 to be excavated. The material of the instrument body 20 is not limited to metal, and the instrument body 20 may be made of wood, for example. Since the instrument body 20 is disposed on the ground where the improved ground 17 is formed, the surface is preferably plated for corrosion protection. A preferred example of plating applied to the surface of the instrument body 20 is so-called UNIQLO plating.

  As shown in FIGS. 1 and 3, the side surface 22 of the instrument body 20 includes a back surface portion 47, a side surface portion 48, and a front surface portion 49. The back surface portion 47 constitutes the back surface of the instrument body 10. As shown in FIG. 3, the side surface portion 48 is provided continuously to the back surface portion 47, and is formed to extend from the back surface portion 47 to the front surface side (right side in FIG. 3) of the instrument body 20. The front surface portion 49 is provided continuously to the side surface portion 48 and is formed to extend from the side surface portion 48 to the center side of the instrument main body 20. Thus, the instrument body 20 has a substantially C-shaped cross section (hereinafter also referred to as “horizontal cross section”) in a direction orthogonal to the axial direction (the direction of the axis 19) (see FIG. 3). ).

  The instrument main body 20 has a horizontal cross-section configured in a substantially C shape, so that an opening 21 extending in the axial direction (the direction of the axis 19) is formed in the side surface 22. The mixed soil 13 enters the inside of the instrument body 20 from the opening 21 (see FIGS. 13 to 15). The soil of the present invention includes soil 11 in addition to mixed soil 13. Moreover, although the opening 21 is formed so as to be continuous from the upper end to the lower end of the instrument body 20 in the present embodiment, it is partitioned in the axial direction if the mixed soil 13 can easily enter the interior of the instrument body 20. Also good. In other words, it may be formed so that a plurality of openings are arranged in the axial direction of the instrument body 20. The width W of the opening 21 (see FIG. 3) is not particularly limited, but the mixed soil 13 easily enters the inner space of the instrument body 20 from the opening 21 and is accommodated in the instrument body 10. It is preferable that the mixed soil 13 is set to a size that does not easily spill out of the opening 21.

  As shown in FIGS. 1 and 2, holes 23 and 24 are formed in the side surface 48 of the instrument body 20. The holes 23 and 24 are provided so as to face each other across the inner space of the instrument body 20. Since the rods 40 (corresponding to the rod-shaped members of the present invention) are inserted into the holes 23 and 24 (see FIG. 15), the holes 23 and 24 have a diameter through which the rod 40 can be inserted. The positions of the holes 23 and 24 are not particularly limited. However, since the holes 23 and 24 are used for lifting the quality confirmation device 10, as shown in FIGS. 1 and 2. Further, it is preferably formed near the upper end of the instrument body 20. The holes of the present invention are not limited to the holes 23 and 24. That is, the number of holes formed in the side surface 22 of the instrument body 20 is not limited to two, and one hole or three or more holes may be formed in the side surface 22. Moreover, the hole of this invention may be formed in the back part 47 or the front part 49. FIG.

  As shown in FIGS. 1 to 3, reinforcing bars 28 and 29 are provided on the inner surface 27 of the instrument body 20. The reinforcing bar 28 is not shown in FIG. 3 because it is disposed below the reinforcing bar 29. In the present embodiment, the reinforcing bars 28 and 29 are arranged on the inner surface 27 of the back surface portion 47 in a row at a predetermined interval in the axial direction so that the longitudinal direction thereof is substantially parallel to the axial direction of the instrument body 20 ( (See FIG. 2). The reinforcing bars 28 and 29 are fixed to the inner surface 27 by welding in this embodiment, but may be fixed by other methods. These reinforcing bars 28 and 29 correspond to the protrusions of the present invention that protrude to the inside of the instrument body 20.

  The earth retaining member 30 (see FIGS. 1 to 3) prevents the mixed soil 13 (including the soil 11) housed in the instrument body 20 from falling off. The shape of the earth retaining member 30 is not particularly limited, but the earth retaining member 30 is a flat plate having a substantially square shape in plan view (see FIG. 3). The earth retaining member 30 has substantially the same size as the inner space of the instrument body 20 in plan view, and is fixed to the inner surface 27 of the instrument body 20 by welding. Since the earth retaining member 30 prevents the mixed soil 13 accommodated in the instrument main body 20 from falling off, the earth retaining member 30 is provided near the lower end of the instrument main body 20 as shown in FIGS. Yes. As shown in FIG. 3, in this embodiment, the inner space of the instrument body 20 is almost completely sealed by the earth retaining member 30, but the inner space of the instrument body 20 is completely sealed by the earth retaining member 30. It does not have to be done. That is, the earth retaining member 30 may be, for example, a punching metal or a lath as long as the mixed soil 13 accommodated in the instrument body 20 can be prevented from falling off. If the mixed soil 13 does not fall out, a slight gap may be formed between the retaining member 30 and the inner surface 27.

  The quality confirmation instrument 10 is provided with a bolt 25 (an example of the protruding piece of the present invention) that can penetrate into the ground. In this embodiment, the bolt 25 is provided on the earth retaining member 30 so as to protrude downward (downward in FIG. 2) of the instrument body 20. Although not shown in the drawing, the retaining member 30 is formed with a bolt insertion hole penetrating in the thickness direction (perpendicular to the paper surface in FIG. 3) at a position corresponding to the bolt 25 shown in FIG. . The bolt 25 is inserted into the bolt insertion hole from the upper surface side of the earth retaining member 30 with the head portion on the upper side and the screw portion on the lower side, and is screwed onto the nut 26 on the lower surface side of the earth retaining member 30 so as to be earthed. It is fixed to the fastening member 30 (see FIG. 2). The length of the bolt 25 is not particularly limited, but it is preferable that the bolt 25 has such a length that the instrument body 20 can be supported in a self-supporting posture by being penetrated into the ground. The fixing of the bolt 25 is not limited to screwing with the nut 26, and may be fixed to the earth retaining member 30 by welding, for example. Moreover, since the volt | bolt 25 penetrates the ground, the thing with the pointed tip may be sufficient. Moreover, the fixing position of the bolt 25 is not limited to the earth retaining member 30 and may be fixed to the lower end of the instrument body 20 by welding, for example. However, when the bolt 25 is fixed to the outer peripheral portion of the instrument body 20, it is difficult to pull out the quality confirmation instrument 10 from the planned area 60 (see FIG. 12), so that the bolt 25 may be fixed to the earth retaining member 30. preferable. The number of bolts 25 is not limited to one, and two or more bolts 25 may be provided.

  Hereinafter, the quality confirmation method of the improved ground 17 which concerns on embodiment of this invention is demonstrated. In this quality confirmation method, surface ground improvement is applied to form improved ground 17 (see FIG. 12), and the quality of the formed improved ground 17, in other words, the mixing condition of soil 11 and solidified material 12 is confirmed. Is.

  FIG. 4 is a plan view schematically showing the planned areas 60, 70, 80.

  As shown in FIG. 4, in the present embodiment, the ground to be improved on the surface layer is divided into three planned areas 60, 70, and 80. Here, all the planned areas 60, 70, and 80 are work areas where the improved ground 17 is to be formed, and surface layer ground improvement is performed for each planned area. In addition, since the surface layer ground improvement in the planned areas 60, 70, and 80 is performed in the same manner, in this embodiment, the surface layer ground improvement in the planned area 60 will be mainly described.

  The quality confirmation method for the improved ground 17 includes four steps from the first step to the fourth step. The first step is a step of removing the soil 11 from the planned area 60 where the improved ground 17 is formed. The second step is a step of arranging the quality confirmation device 10 in the planned area 60 so that the axial direction of the device body 20 is substantially vertical and the opening 21 is directed toward the center of the planned area 60. The third step is a step in which the mixed soil 13 formed by mixing and stirring the soil 11 and the solidifying material 12 is backfilled in the planned area 60 and accommodated in the inner space of the instrument body 20. The fourth step is a step of pulling out the quality confirmation device 10 and confirming the mixing condition of the mixed soil 13.

  First, prior to the removal of the soil 11 from the planned area 60, an arrangement location where the quality confirmation instrument 10 should be arranged is set. As shown in FIG. 4, in the present embodiment, four placement locations 61 to 64 are set for the planned area 60. These arrangement locations 61 to 64 are set as follows. That is, it is preferable to always set the arrangement locations on the sides 91 and 92 that do not contact the planned area 70 and the planned area 80 in the outer peripheral portion (sides 91 to 94) of the planned area 60. The arrangement locations 61 and 62 are set on the side 91 and the side 92 in consideration of this point. In addition, in the side 91 and the side 92 of the planned area 60, an overexcavation area 33 is set. The surplus excavation area 33 is an area where the ground is excavated to a specified dimension or more in consideration of workability and the like. When the quality confirmation device 10 is arranged near the center of the planned area 60, there is a risk that insufficient rolling of the mixed soil 13 (see FIG. 11) described later will occur. For this reason, the arrangement locations 61 and 62 are set in the overexcavation area 33.

  Further, as shown in FIG. 4, the outer periphery of the planned area 60 is taken into consideration in terms of workability such as avoiding the vicinity of the temporary storage place 35 (see FIG. 7) where the soil 11 removed from the planned area 60 is temporarily placed. Arrangements 63 and 64 are also set on the other sides 93 and 94 of the part, respectively. However, since the arrangement location 63 and the arrangement location 64 are adjacent to the planned area 70 and the planned area 80, they may be set when the planned area 70 and the planned area 80 are constructed. That is, in the present embodiment, four placement locations 61 to 64 are set for the planned area 60, but only the placement locations 61 and 62 may be set. In addition, in this embodiment, although the arrangement locations 61-64 are each set in the center part of each edge | side 91-94, the position of the arrangement locations 61-64 is not limited to this. In other words, the positions of the placement locations 61 to 64 may be changed along the sides 91 to 94 if they are not near the corners of the planned area 60. In addition to the arrangement locations 61 to 64, another arrangement location may be further set.

  FIG. 5 is a plan view showing an arrangement place 61 where the quality confirmation device 10 is arranged.

  As shown in FIG. 5A, when an overexcavation area 33 having a width exceeding the depth of the instrument body 20 (the length in the left-right direction in FIG. 5) is set, the arrangement location 61 is the overexcavation. Set in area 33. In this case, the quality confirmation instrument 10 is disposed outside the improved range line indicated by the two-dot chain line in FIG. 5A (see FIG. 4). As shown in FIG. 5 (B), when the overexcavation area 33 having a width less than the depth of the instrument body 20 is set, the ground outside the overexcavation area 33 is excavated and the overexcavation area 33 is expanded. Thus, the arrangement location 61 is set (see FIG. 5B). Thereby, it can prevent that the instrument 10 for quality confirmation becomes a disorder | damage | failure at the time of rolling of the mixed soil 13, and insufficient rolling pressure of the mixed soil 13 arises. The arrangement location 62 is set in the same manner.

  FIG. 6 is a schematic diagram showing how the soil 11 is removed from the planned area 60.

  After setting the placement locations 61 to 64, the soil 11 is removed from the planned area 60 as shown in FIG. Specifically, the ground of the planned area 60 is excavated using the backhoe 45, and the soil 11 is carried out from the planned area 60 to the temporary storage place 35. Here, the depth of the ground of the planned area 60 to be excavated is set to be substantially the same as the thickness of the improved ground 17 formed in the planned area 60. In the present embodiment, the ground of the planned area 60 is excavated to a depth of about 100 cm. The backhoe 45 is a hydraulic excavator with a bucket attached to the front. The temporary storage place 35 is a place where the soil 11 carried out from the planned area 60 is temporarily placed. Thus, the soil 11 is removed from the planned area 60 where the improved ground 17 is formed. This step corresponds to the first step of the present invention.

  Since the first step is an operation for removing the soil 11 from a place lower than the ground surface, it is performed using the backhoe 45, but may be performed manually, for example, using a scoop. Since the soil 11 is backfilled to the planned area 60 in a later operation, not all the soil 11 in the planned area 60 may be removed. However, since the quality confirmation device 10 is disposed at the placement locations 61 to 64, it is necessary to remove at least the soil 11 at the placement locations 61 to 64.

  Next, the quality confirmation device 10 is placed in the planned area 60. That is, the quality confirmation device 10 is disposed at each of the placement locations 61 to 64. FIG. 7 is a perspective view schematically showing a planned area 60 in which the quality confirmation device 10 is arranged. As shown in FIG. 7, the quality confirmation tool 10 is placed at preset placement locations 61 to 64 so that the axial direction of the tool body 20 is substantially vertical. As described above, the arrangement locations 61 and 62 are set in the overexcavation area 33 (see FIG. 4). Accordingly, here, the two quality checking instruments 10 are arranged in the overburden area 33. When the quality confirmation device 10 is disposed, the quality confirmation device 10 is disposed so that the opening 21 faces the center of the planned area 60. This step corresponds to the second step of the present invention. In addition, the quality confirmation instrument 10 is arranged in the following manner.

  FIG. 8 is a perspective view showing a state in which the quality confirmation instrument 10 is arranged using the square member 15. FIG. 9 is a schematic diagram for explaining the arrangement of the quality confirmation instrument 10 when the excavation section 68 of the planned area 60 is inclined.

  As shown in FIG. 1, the quality confirmation device 10 has a bolt 25 that protrudes downward from the device body 20. The quality confirmation device 10 is disposed in the planned area 60 by causing the threaded portion of the bolt 25 to penetrate into the ground. Specifically, as shown in FIG. 8, the quality confirmation tool 10 is supported so that the tool body 20 is substantially vertical, and the bolts 25 are driven to the ground with the square members 15. Since the bolt 25 is provided so as to protrude from the earth retaining member 30, the bolt 25 penetrates into the ground, and the ground in the planned area 60 is solidified by the lower surface of the earth retaining member 30. As a result, the quality confirmation instrument 10 is supported in a posture in which the instrument body 20 is self-supporting. As shown in FIG. 8, when the excavation cross section 68 of the planned area 60 is formed substantially vertically, the quality confirmation instrument 10 is substantially configured by bringing the back surface portion 47 of the instrument body 20 into contact with the excavation cross section 68. It is supported stably in a vertically independent posture. Since the backhoe 45 is used for excavation of the ground in the planned area 60, the excavation cross section 68 of the planned area 60 may be inclined as shown in FIG. When the quality checking device 10 is arranged in such a place, as shown in FIG. 9, the soil 11 or the mixed soil 13 is filled between the back surface portion 47 of the device body 20 and the excavation cross section 68, and the device body 20 Is placed in the planned area 60 so that is substantially vertical.

  FIG. 10 is a schematic diagram showing how the mixed soil 13 is backfilled in the planned area 60. FIG. 11 is a perspective view schematically showing a planned area 60 in which the improved layer 51 is formed.

Following the second step, the mixed soil 13 is backfilled in the planned area 60 and accommodated in the inner space of the instrument body 20. The mixed soil 13 is obtained by mixing and stirring the soil 11 and the solidifying material 12. For example, cement is used as the solidifying material 12. As shown in FIG. 10, the soil 11 and the solidified material 12 temporarily placed in the temporary storage place 35 are carried into the planned area 60 using the backhoe 45. In the present embodiment, the ground of the planned area 60 is excavated to a depth of about 100 cm. When the solidified material 12 and the soil 11 of the temporary storage place 35 are carried into the planned area 60 excavated in this way, the mixed stirring of the soil 11 and the solidified material 12 becomes insufficient, or the mixed soil is mixed in a later step. There is a risk of 13 rolling shortage. For this reason, the operation of filling the mixed soil 13 back to the planned area 60 is performed four times in the present embodiment. Accordingly, here, about ¼ of the soil 11 with respect to the volume of the planned area 60 is carried into the planned area 60 from the temporary storage place 35. Then, the soil 11 and the solidified material 12 are mixed and stirred in the planned area 60. By this series of operations, the mixed soil 13 is backfilled in the planned area 60. Then, the backfilled mixed soil 13 is pressed by a vibrating roller or a ramma. As shown in FIG. 11, the mixed soil 13 spreads over the entire planned area 60 or the mixed soil 13 becomes flat. In the quality confirmation device 10 arranged at the outer peripheral portion of the planned area 60 (arrangement locations 61 to 64 in this embodiment), the opening 21 of the device main body 20 is directed toward the center side of the planned area 60. For this reason, the mixed soil 13 easily enters the inner space of the instrument body 20 from the opening 21. Note that the mixed soil 13 in the planned area 60 may be positively inserted into the inner space of the instrument body 20 so that the interior of the instrument body 20 is filled with the mixed soil 13. This step corresponds to the third step of the present invention.

  FIG. 12 is a perspective view schematically showing the planned area 60 in which the improved ground 17 is formed. FIG. 13 is a longitudinal sectional view showing the quality confirmation device 10 in which the mixed soil 13 is accommodated. FIG. 14 is a plan view of the quality confirmation tool 10 in which the mixed soil 13 is accommodated in the tool body 20.

  In the third step in the present embodiment, the work of backfilling the mixed soil 13 into the planned area 60 and accommodating it in the inner space of the instrument body 20 is repeated four times. As a result, as shown in FIGS. 12 and 13, a flat improved ground 17 having no voids composed of the improved layers 51, 53, 55, and 57 is formed in the planned area 60. Reinforcing bars 28 and 29 are provided in the instrument body 20 that accommodates the mixed soil 13. Since the reinforcing bars 28 and 29 are arranged at predetermined intervals in the axial direction of the instrument main body 20, the reinforcing bars 28 and 29 are graduated when the mixed soil 13 is divided into a plurality of layers and backfilled as in this embodiment. It can be used as an alternative. Therefore, it becomes easy to make the layer thickness of the improvement layers 51, 53, 55, and 57 uniform. Further, as shown in FIG. 14, the mixed soil 13 that has entered the interior of the instrument body 20 is solidified so as to involve the peripheral edges of the reinforcing bars 28 and 29. For this reason, compared with the case where the reinforcing bars 28 and 29 are not provided, the mixed soil 13 accommodated in the inner space of the instrument body 20 is less likely to spill from the opening 21.

  After the third step is completed, the mixed soil 13 is cured so that the underground water enters and the mixed soil 13 is solidified. Thereafter, the quality confirmation device 10 is pulled out from the planned area 60. FIG. 15 is a perspective view showing a state in which the quality confirmation device 10 is pulled out from the planned area 60. Since the axial length from the earth retaining member 30 to the upper end of the instrument body 20 is longer than the depth of the planned area 60, the holes 23 and 24 are exposed from the ground surface as shown in FIG. The rod 40 is inserted into the holes 23 and 24 of the quality confirmation device 10, and the string 42 is hooked on both ends of the rod 40. The string 42 is hooked on the bucket of the backhoe 45 and is lifted by the backhoe 45. In this way, the quality confirmation device 10 is pulled out from the planned area 60 by pulling the bar 40 upward. Since the earth retaining member 30 is provided in the quality confirmation device 10, the quality confirmation device 10 is pulled out without the mixed soil 13 falling out of the inner space of the device body 20.

  FIG. 16 is a front view of the quality confirmation instrument 10 in which the mixed soil 13 is accommodated.

  As shown in FIG. 16, the mixing condition of the mixed soil 13 is confirmed using the quality confirmation device 10 pulled out from the planned area 60. Specifically, the quality confirmation device 10 pulled out from the planned area 60 is arranged in a substantially horizontal place so that the opening 21 faces upward. Then, the staff 37 is arranged next to the quality confirmation device 10 so that the lower end of the staff 37 and the upper surface of the earth retaining member 30 are arranged in the lateral direction. By measuring the height of the mixed soil 13 accommodated in the instrument body 20 with the staff 37, the thickness of the improved ground 17 formed in the planned area can be easily confirmed. In the present embodiment, four quality confirmation instruments 10 are used. For this reason, it is possible to easily confirm whether or not the thickness of the improved ground 17 is uniform by arranging the four quality confirmation instruments 10.

  In addition, the phenolphthalein solution 38 (an example of the indicator of the present invention) is used in addition to the staff 37 for this confirmation work. The phenolphthalein solution 38 is obtained by dissolving phenolphthalein in ethanol and diluting with water. Phenolphthalein is a PH indicator that distinguishes acids and bases. The phenolphthalein solution 38 is colorless when acidic, and is alkaline and reddish purple. The phenolphthalein solution 38 is attached to the mixed soil 13 accommodated in the instrument body 20 and the mixing condition of the mixed soil 13 is confirmed by visual observation. Specifically, the phenolphthalein solution 38 is sprayed onto the mixed soil 13 accommodated in the instrument body 20 using the spray bottle 43. In this embodiment, since cement is used for the solidifying material 12, the phenolphthalein solution 38 exhibits a reddish purple color by adhering to the solidifying material 12. Thus, the phenolphthalein solution 38 colors the solidified material 12. When the soil 11 and the solidifying material 12 are sufficiently mixed, the mixed soil 13 accommodated in the tool body 20 and exposed from the opening 21 exhibits a uniform reddish purple color as a whole. On the contrary, when the mixing of the soil 11 and the solidifying material 12 is insufficient, the mixed soil 13 includes a portion exhibiting a reddish purple color and a portion exhibiting a soil color. By adhering the phenolphthalein solution 38 to the mixed soil 13 accommodated in the instrument body 20, the mixing condition of the mixed soil 13 can be easily and accurately grasped. Thus, the operation | work which confirms the mixing condition of the mixed soil 13 using the staff 27 and the phenolphthalein solution 38 corresponds to the 4th process of this invention.

  As described above, by pulling out the quality confirmation device 10 in which the mixed soil 13 is accommodated, the mixing condition of the soil 11 and the solidified material 12 can be confirmed accurately and easily at the construction site of the surface ground improvement. . Thereby, it can be easily confirmed whether or not there is a poor mixing agitation due to the surface layer improvement. Moreover, since the instrument 10 for quality confirmation is a thing of a simple structure, it can be confirmed at low cost whether there exists a poor location of mixing stirring by surface layer ground improvement.

  In addition, this invention is not limited to the said embodiment, The following forms may be sufficient.

  In this embodiment, although the form in which the quality confirmation instrument 10 is arranged in the overburden area 33 has been described, the arrangement place of the quality confirmation instrument 10 is not limited to this. That is, the quality confirmation device 10 may be arranged inside the overexcavation area 33 or may be arranged in the planned area 60 without setting the overexcavation area 33. However, in these cases, the quality confirmation instrument 10 may become an obstacle and cause insufficient rolling of the improved ground 17. Therefore, the quality confirmation instrument 10 is preferably disposed in the overexcavation area 33.

  Moreover, in this embodiment, although the case where the instrument 10 for quality confirmation had the volt | bolt 25 was demonstrated, if the instrument 10 for quality confirmation can be arrange | positioned without falling down, the instrument 10 for quality confirmation will not necessarily be a volt | bolt. 25 may not be included. FIG. 17 is a perspective view showing a quality confirmation device 90 according to another embodiment. As shown in FIG. 17, the quality confirmation device 90 has a point that it does not have the bolt 25 and the nut 26, and a point that the earth retaining member 30 is fixed closer to the upper side than the vicinity of the lower end of the device body 20. Except for this, it is the same as the quality confirmation instrument 10 (see FIG. 8). When the quality confirmation device 90 is arranged, a portion 41 protruding downward from the earth retaining member 30 in the device main body 20 is penetrated into the ground as a projecting piece of the present invention. Thereby, the instrument 90 for quality confirmation can be stably arrange | positioned with a self-supporting attitude | position. Since the quality confirmation instrument 90 does not need to form bolt insertion holes in the retaining member 30 and fix the bolts 25 unlike the quality confirmation instrument 10, the configuration is simplified compared to the quality confirmation instrument 10. be able to.

  Moreover, in this embodiment, although the form which backfills the mixed soil 13 to the planned area 60 by mixing and stirring the soil 11 and the solidification material 12 in the planned area 60 was demonstrated, the backfill of the mixed soil 13 is limited to this. It is not something. That is, the soil 11 and the solidifying material 12 may be mixed and stirred outside the planned area 60, and the mixed soil 13 obtained thereby may be backfilled in the planned area 60.

  Moreover, although this embodiment demonstrated the form in which the mixed soil 13 backfilled to the planned area 60 in the 3rd process was rolled, the mixed soil 13 does not necessarily need to be rolled. However, when the mixed soil 13 is rolled, the improved ground 17 having a uniform thickness and strength is formed. Therefore, the mixed soil 13 is preferably rolled.

  Moreover, although this embodiment demonstrated the form which pulls out the quality confirmation instrument 10 after solidifying the mixed soil 13 in the 4th process, you may pull out the quality confirmation instrument 10 before the mixed soil 13 is solidified. In this case, however, the mixed soil 13 may collapse when the quality confirmation device 10 is pulled out, and the mixed soil 13 may easily spill from the device body 20. For this reason, it is preferable that the quality confirmation instrument 10 is pulled out after the mixed soil 13 is solidified.

  Moreover, in this embodiment, although the horizontal cross section of the instrument main body 20 demonstrated the form which is substantially C shape, the shape of the horizontal cross section of the instrument main body 20 is not limited to this. That is, the instrument body 20 may have a substantially circular tube shape or a substantially U-shaped horizontal section. However, by configuring the instrument main body 20 so that the horizontal cross section is substantially C-shaped, there is an advantage that the mixed soil 13 is not easily spilled by being held by the instrument main body 20 so that the mixed soil 13 is wrapped. For this reason, it is preferable that the instrument main body 20 has a substantially C-shaped horizontal cross section.

  Moreover, in this embodiment, although the form where the holes 23 and 24 were formed in the side surface 22 of the instrument main body 20 was demonstrated, instead of forming the holes 23 and 24, a string, a hook, etc. are attached to the instrument main body 20, for example. A member for attachment may be fixed to the instrument body 20.

  In the present embodiment, the rebars 28 and 29 are arranged on the inner surface 27 at a predetermined interval. However, the rebars 28 and 29 are not necessarily used at the predetermined intervals unless they are used as marks. It is not necessary to be arranged in line, and one or three or more reinforcing bars may be arranged. Moreover, the protrusion of this invention is not limited to the reinforcing bars 28 and 29, For example, a volt | bolt may be sufficient. When fixing this bolt to the instrument body 20, for example, a bolt insertion hole is formed in the thickness direction of the back surface portion 47 (see FIG. 1) (perpendicular to the paper surface of FIG. 2), and the bolt is moved from the outside to the inside of the instrument body 20. It is inserted and screwed into the nut inside the instrument body 20. Since this bolt protrudes more inside the instrument main body 20 than the reinforcing bars 28 and 29, the mixed soil 13 is effectively prevented from spilling from the instrument main body 20. The bolt can be used as a mark by adjusting the position of the bolt insertion hole. The bolt insertion hole may be formed in the side surface portion 48 or the front surface portion 49. Further, if the mixed soil 13 is not easily spilled from the instrument body 20, the protrusion of the present invention may not be provided.

  Moreover, in this embodiment, although the mixed soil of this invention demonstrated the form which is the mixed soil 13 which consists of the solidification material 12 and the soil 11 of the scheduled area 60, the mixed soil of this invention is not limited to this. Absent. The mixed soil of the present invention may be as follows, for example. That is, the mixed soil of the present invention may be one obtained by mixing and stirring the soil 11, the solidifying material 12, and the admixture. Moreover, the soil constituting the mixed soil of the present invention may include soil other than the soil 11 removed from the planned area 60.

FIG. 1 is a perspective view of a quality confirmation device 10 according to an embodiment of the present invention. FIG. 2 is a front view of the quality confirmation device 10 as seen from the direction of arrow II in FIG. FIG. 3 is a plan view of the quality confirmation instrument 10 as seen from the direction of arrow III in FIG. FIG. 4 is a plan view schematically showing the planned areas 60, 70, 80. FIG. 5 is a plan view showing an arrangement place 61 where the quality confirmation device 10 is arranged. FIG. 6 is a schematic diagram showing how the soil 11 is removed from the planned area 60. FIG. 7 is a perspective view schematically showing a planned area 60 in which the quality confirmation device 10 is arranged. FIG. 8 is a perspective view showing a state in which the quality confirmation instrument 10 is arranged using the square member 15. FIG. 9 is a schematic diagram for explaining the arrangement of the quality confirmation instrument 10 when the excavation section 68 of the planned area 60 is inclined. FIG. 10 is a schematic diagram showing how the mixed soil 13 is backfilled in the planned area 60. FIG. 11 is a perspective view schematically showing a planned area 60 in which the improved layer 51 is formed. FIG. 12 is a perspective view schematically showing the planned area 60 in which the improved ground 17 is formed. FIG. 13 is a longitudinal sectional view showing the quality confirmation device 10 in which the mixed soil 13 is accommodated. FIG. 14 is a plan view of the quality confirmation tool 10 in which the mixed soil 13 is accommodated in the tool body 20. FIG. 15 is a perspective view showing a state in which the quality confirmation device 10 is pulled out from the planned area 60. FIG. 16 is a front view of the quality confirmation instrument 10 in which the mixed soil 13 is accommodated. FIG. 17 is a perspective view showing a quality confirmation instrument 10 according to another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,90 ... Quality confirmation instrument 11 ... Soil 12 ... Solidified material 13 ... Mixed soil 17 ... Improved ground 20 ... Instrument main body 21 ... Opening 22 ... Side 23 , 24... Hole 25... Bolt (an example of the projecting piece of the present invention)
27 ... Inner surfaces 28, 29 ... Reinforcing bars (an example of the protrusion of the present invention)
30 ... Earth retaining member 33 ... Excavation area 38 ... Phenolphthalein solution (an example of the indicator of the present invention)
40 ... Rod (corresponding to the rod-shaped member of the present invention)
60, 70, 80 ... planned area

Claims (15)

A first step of removing soil from the area where the improved ground will be formed;
An instrument for quality confirmation comprising a substantially tubular instrument body having an axially extending opening formed on a side surface thereof, and a retaining member for preventing the soil accommodated in the instrument body from falling off. A second step of arranging in the planned area such that the direction is substantially vertical and the opening is directed toward the center of the planned area;
A third step of backfilling the mixed soil obtained by mixing and stirring at least the soil and the solidified material into the predetermined area and accommodating the mixed soil in the inner space of the instrument body;
A method for confirming the quality of the improved ground, comprising: a fourth step of pulling out the quality confirmation device and confirming the mixing condition of the mixed soil.   The quality check method for improved ground according to claim 1, wherein in the second step, the quality check tool is disposed in an overexcavation area. The quality check device has a protruding piece protruding downward from the device body;
The quality confirmation method for improved ground according to claim 1 or 2, wherein, in the second step, the protruding piece is inserted into the ground and the quality confirmation device is arranged.   The method for confirming the quality of the improved ground according to any one of claims 1 to 3, wherein, in the third step, at least the soil and the solidified material are mixed and stirred in the predetermined area to refill the mixed soil.   The quality confirmation method for improved ground according to any one of claims 1 to 4, wherein in the third step, the backfilled mixed soil is rolled.   The quality confirmation method for improved ground according to any one of claims 1 to 5, wherein in the fourth step, the quality confirmation device is pulled out after the mixed soil is solidified. The instrument body has a hole on the side,
The quality confirmation method for improved ground according to any one of claims 1 to 6, wherein, in the fourth step, the quality confirmation instrument is pulled out by pulling upward the rod-shaped member inserted through the hole.   The quality according to any one of claims 1 to 7, wherein in the fourth step, an indicator for coloring the solidifying material is attached to the mixed soil accommodated in the instrument body, and the mixing condition of the mixed soil is visually confirmed. Confirmation method. A tool for confirming the quality of the improved ground formed by solidifying a mixed soil formed by mixing and stirring at least soil and a solidifying material,
A substantially tubular instrument body having an opening formed on the side surface extending in the axial direction so that the mixed soil enters the interior;
A quality confirmation instrument comprising: a retaining member that prevents the mixed soil accommodated in the instrument body from falling off.   The quality confirmation instrument according to claim 9, wherein a protruding piece that can penetrate into the ground is provided.   The instrument for quality confirmation according to claim 9 or 10, wherein the instrument body has a substantially C-shaped cross section in a direction orthogonal to the axial direction.   The quality confirmation instrument according to any one of claims 9 to 11, wherein an axial length from the earth retaining member to an upper end of the instrument body is longer than a depth of a planned area where the improved ground is formed.   The quality confirmation instrument according to any one of claims 9 to 12, wherein a hole is formed in a side surface of the instrument body.   The quality confirmation instrument according to any one of claims 9 to 13, wherein a protrusion projecting inward of the instrument body is provided on an inner surface of the instrument body.   The quality confirmation instrument according to claim 14, wherein the plurality of protrusions are arranged in the axial direction at predetermined intervals.

Images