JP5841852B2 - Construction method of water passage hole in underground wall - Google Patents

Description

  The present invention mainly relates to an underground wall that retains soil and blocks underground water flow at the construction site during construction of the underground structure, and is formed on the underground wall to secure the underground water flow after the construction of the underground structure. The present invention relates to a water passage hole and its construction method.

  During the construction of underground structures, underground walls such as retaining walls for blocking the construction site and blocking the underground water flow are used. After building the underground structure, this underground wall functions as an underground dam by blocking the groundwater flow. The groundwater level rises on the upstream side of the groundwater and the water level falls on the downstream side. As a result, the structure on the upstream side of the groundwater may be affected by floating or inundation, and the well may wither or subsidize on the downstream side. Therefore, conventionally, the above-mentioned problem has been addressed by forming a water passage hole in the underground wall and providing a function of allowing groundwater to pass (see, for example, Patent Documents 1 to 3).

  For example, in the technique disclosed in Patent Document 1, a guide hole (or a protection cylinder) connected to the ground is provided in the underground wall, high pressure water is ejected from a nozzle inserted into the guide hole, and the interior of the underground wall is By cutting it open, a through space is formed in the outer wall surface of the underground wall that opens greatly in the vertical and horizontal directions, and communicates with the upstream side and the downstream side of the groundwater. Thereafter, a water-permeable material introduced from the ground using the guide hole is filled into the through space to form a water-permeable hole.

  In addition, in the method for constructing a water passage portion in the underground wall of Patent Document 3 proposed by the present inventors, a nozzle is inserted into an insertion hole that communicates with the underground wall, and the nozzle is inserted while jetting high-pressure water from the nozzle. By rotating around a predetermined axis along the hole, a water passage portion comprising a plurality of slit holes cut straight so as to linearly penetrate the outer wall surface from the inside of the insertion hole to the outer wall surface. It is to form.

JP 2000-328561 A Japanese Patent Laid-Open No. 10-30228 JP 2008-81942 A

  By the way, when a water passage hole having a predetermined width is formed in the underground wall, if the wall thickness of the underground wall is somewhat thick (for example, about 0.5 to 1 meter), high-pressure water is jetted from the nozzle of Patent Document 1 described above. This method requires a great deal of time. Moreover, in the method of Patent Document 3 proposed by the present inventors, it is necessary to make many rotations while ejecting the nozzle, and this also takes a lot of time. For this reason, development of the technique which can form the water flow hole of a predetermined width efficiently in a short time was calculated | required.

  The present invention has been made in view of the above, and it is an object of the present invention to provide a water passage hole in the underground wall and a method for constructing it, which can efficiently form a water hole having a predetermined width in a shorter time. And

In order to solve the above-described problems and achieve the object, the method for constructing a water passage hole in the underground wall according to the present invention is configured to communicate with the upstream side and the downstream side of groundwater separated by the underground wall. A method for constructing a water passage hole formed in a wall, wherein a slurry containing an abrasive is sprayed at high pressure toward an outer wall surface from a nozzle disposed in an insertion hole provided inside the underground wall. When cutting the inner wall, the nozzle is rotated by a predetermined angle around a predetermined axis along the insertion hole while spraying the slurry, and then the injection direction from the nozzle is fixed for a predetermined time. cutting the underground wall by performing an operation that state for a plurality of rotational positions, thereby saw including a slit forming step of forming a slit communicating with the outer wall surface from said insertion hole, said slit hole forming step Jet from the nozzle After fixing a direction for a predetermined time and drilling one point of the outer wall surface, the nozzle is rotated by a predetermined angle while continuing the injection, and the rotation is stopped after changing the injection direction, and the injection direction from the nozzle is changed. By fixing for a predetermined time and drilling another point in the vicinity of the one point, cutting is performed so as to blow away a region sandwiched between the one point and the other one point .

Moreover, the construction method of water passage holes of underground walls according to the onset bright is the invention described above, was then cut the outer wall surface of one side of the underground wall to form the slit by the slit hole forming step Thereafter, the nozzle is rotated around a predetermined axis along the insertion hole while spraying the slurry, and the slit hole is formed by cutting the outer wall surface on the opposite side of the underground wall by the slit hole forming step. It is characterized by forming.

Moreover, the construction method of water passage holes of underground walls according to the onset bright is the invention described above, after forming the slit by the slit hole forming step, is moved along the nozzle into the insertion hole, The slit hole forming step is further performed at a position adjacent to the slit hole to increase an opening area of the slit hole on the outer wall surface.

Moreover, the construction method of water passage holes of underground walls according to the onset bright is the invention described above, and wherein filling the permeability between packed material to the slit formed by the slit hole forming step To do.

  According to the water passage hole of the underground wall according to the present invention, the water hole formed in the underground wall so as to communicate with the upstream side and the downstream side of the groundwater separated by the underground wall, When the slurry including the abrasive is sprayed at high pressure toward the outer wall surface from the nozzle disposed in the insertion hole provided in the interior of the wall to cut the underground wall, the direction of the nozzle while spraying the slurry Is rotated at a predetermined angle around a predetermined axis along the insertion hole and stopped, and then the operation is performed for a plurality of rotational positions by fixing the injection direction from the nozzle for a predetermined time. The internal shape of the slit hole formed by cutting and thereby leading from the insertion hole to the outer wall surface has the axis as a vertex when viewed in a predetermined axial direction along the insertion hole, and the outer wall surface is the opposite side or It has a substantially triangular shape or a substantially fan shape as an arc. Here, after fixing the nozzle injection direction for a predetermined time and drilling one point on the outer wall, the nozzle is rotated by a predetermined angle while continuing injection to change the injection direction and drilling one other point in the vicinity Then, the region sandwiched between the two points along with the injection is cut so as to be blown away. By performing this series of operations for a plurality of rotational positions, slit holes as water passage holes are formed on the outer wall surface. For this reason, compared with said conventional method, there exists an effect that the water flow hole of predetermined width can be formed efficiently in a short time. The present invention is particularly suitable for underground walls having a relatively thick wall thickness.

  Moreover, according to the construction method of the water passage hole of the underground wall according to the present invention, the construction of the water hole formed in the underground wall so as to communicate with the upstream side and the downstream side of the groundwater separated by the underground wall. In the method, the slurry containing the abrasive is sprayed at high pressure toward an outer wall surface from a nozzle disposed in an insertion hole provided in the underground wall, and the slurry is cut. The operation of setting the direction of the nozzle to rotate around a predetermined axis along the insertion hole by a predetermined angle and then fixing the injection direction from the nozzle for a predetermined time is performed at a plurality of rotational positions. It includes a slit hole forming step of cutting the underground wall to form a slit hole that leads from the insertion hole to the outer wall surface. Here, after fixing the nozzle injection direction for a predetermined time and drilling one point on the outer wall, the nozzle is rotated by a predetermined angle while continuing injection to change the injection direction and drilling one other point in the vicinity Then, the region sandwiched between the two points along with the injection is cut so as to be blown away. By performing this series of operations for a plurality of rotational positions, slit holes as water passage holes are formed on the outer wall surface. For this reason, compared with said conventional method, there exists an effect that the water flow hole of predetermined width can be formed efficiently in a short time. The present invention is particularly suitable for underground walls having a relatively thick wall thickness.

FIG. 1 is a schematic view showing a water passage hole in the underground wall and the underground wall in the construction method according to the present invention. 2 is a plan sectional view of the underground wall shown in FIG. FIG. 3 is a longitudinal sectional view of the underground wall shown in FIG. 4 is a longitudinal sectional view of the underground wall shown in FIG. FIG. 5 is a schematic view showing a high-pressure water supply apparatus. FIG. 6 is a schematic view showing a water passage forming device. FIG. 7 is an operation diagram for forming a water passage hole. FIG. 8 is an operation diagram for forming a water passage hole. FIG. 9 is an operation diagram for forming a water passage hole. FIG. 10 is an operation diagram for forming a water passage hole. FIG. 11 is an operation diagram for forming a water passage hole. FIG. 12A is another operation diagram for forming a water passage hole. FIG. 12-2 is another operation diagram for forming a water passage hole. FIG. 13 is a view in which the screen tube is inserted after the water passage hole is formed. FIG. 14 is a view in which a water filling hole is filled with a filling material. FIG. 15 is a diagram when the clogging of the screen tube is eliminated. FIG. 16 is a conceptual diagram in the case of forming a water passage hole in a conventional underground wall.

  DESCRIPTION OF EMBODIMENTS Embodiments of underground water passage holes and construction methods according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a schematic view showing a water passage hole in the underground wall according to the present invention and the underground wall in the construction method thereof, FIG. 2 is a plan sectional view of the underground wall shown in FIG. 1, and FIG. 3 is shown in FIG. It is the longitudinal cross-sectional view of the underground wall.

  The underground wall 1 here is one in which a plurality of column piles 2 are continuously arranged in parallel to form a column row wall. The column pile 2 penetrates the water permeable layer 101 and the impermeable layer 102 below the column pile 2. It is set up to reach. The underground wall 1 is provided opposite to the groundwater upstream side and the groundwater downstream side, respectively, and a structure K such as a vehicle tunnel is constructed in the water permeable layer 101 therebetween.

  The pillar pile 2 is formed by filling, for example, a soil cement 4 into a drilled hole 3 that has been excavated by penetrating the water permeable layer 101 from the ground surface GL to reach the impermeable layer 102 below the permeable layer 102. A core material 5 and a conduit 6 are provided inside.

  The core material 5 is made of, for example, a longitudinal steel material such as H steel, and the longitudinal direction thereof is provided so as to extend from the ground surface GL to the portion of the water permeable layer 101 in which the structure K is constructed.

  The conduit 6 is formed of a hollow pipe such as a PVC pipe or a steel pipe, and extends from the ground surface GL to the impermeable layer 102 along the longitudinal direction of the core material 5 so as to be connected between the ground and the inside of the underground wall 1. It is provided. It is preferable that the conduit 6 is disposed in the approximate center of the drilling hole 3 (soil cement 4) in plan view.

  In order to construct the underground wall 1, a plurality of drilling holes 3 are first excavated continuously. Next, a soil cement 4 is formed in the hole 3. Next, the core material 5 and the conduit 6 are inserted into the hole 3 before the soil cement 4 is solidified. Thereafter, the soil cement 4 is solidified to complete the underground wall 1. Thus, the underground wall 1 can withstand earth pressure by the core material 5 and functions as a water blocking wall between the opposing surfaces. Then, the structure K is constructed between the opposed underground walls 1.

  After the construction of the structure K is completed, a water permeable function is imparted to the underground wall 1. As shown in FIG. 4, a vertical drilling hole 17 is formed downward from the lower end of the conduit 6 using a ground boring device (not shown). In the water flow function, a nozzle is inserted into an insertion hole made up of the conduit 6 and the vertical hole 17 and high-pressure water is injected from the nozzle, and the water passage leading to the upstream side and the downstream side of the groundwater is formed into the underground wall 1. It is obtained by forming. FIG. 5 is a schematic view showing a high-pressure water supply device, FIG. 6 is a schematic view showing a water passage hole forming device, and FIGS. 7 to 11 are operation views for forming a water passage hole.

  As shown in FIG. 5, the high-pressure water supply device 10 includes a water tank 11, an abrasive material tank 12, a mixer 13, a high-pressure slurry pump 14, and a nozzle 15. The high-pressure water supply device 10 mixes the water stored in the water tank 11 and the polishing material stored in the polishing material tank 12 (for example, No. 7 silica sand with a particle size of 0.126 mm, etc.) with a mixer 13 for polishing. The material forms a slurry mixed with water. Then, the slurry is pressurized by the high-pressure slurry pump 14, and the pressurized high-pressure water is jetted from the nozzle 15 through the supply pipe 16. In this high-pressure water supply device 10, since the slurry mixed with the abrasive in advance is directly ejected from the nozzle 15, the nozzle can be reduced in size as compared with the configuration in which the abrasive is mixed with the high-pressure water ejected from the nozzle. is there.

  As shown in FIG. 6, the water hole forming device 20 is a so-called boring device, and the supply rod 21 can be rotated around its central axis and can be moved up and down along the central axis, and further moved in the horizontal direction. Hold it possible. The supply rod 21 is configured as a cylindrical body having an outer diameter that can be inserted into the conduit 6 and the vertical hole 17 of the underground wall 1 and formed in a longitudinal shape in the vertical direction (center axis direction). A supply pipe 16 of the high-pressure water supply device 10 is connected to the upper end of the supply rod 21 via a swivel 22 in order to supply high-pressure water to the inside of the supply rod 21. The swivel 22 is not shown in the figure, but is provided, for example, so that the inner tube and the outer tube forming a double tube are relatively rotated around the central axis, and the gap between the inner tube and the outer tube is stopped. Further, the inner tube and the outer tube are communicated with each other. The inner tube is provided in communication with the supply rod 21 so as to coincide with the central axis, and the outer tube is provided in communication with the supply tube 16. In this way, the swivel 22 supplies high-pressure water from the supply pipe 16 to the inside of the supply rod 21 while allowing rotation around the central axis of the supply rod 21. Further, the nozzle 15 of the high-pressure water supply device 10 is attached to the lower end of the supply rod 21. That is, the water flow hole forming device 20 inserts the supply rod 21 that moves up and down in the vertical direction and rotates around its central axis into the conduit 6 and the vertical hole 17 of the underground wall 1 as shown in FIG. Then, high-pressure water is jetted from the nozzle 15 at the lower end thereof to form a water passage hole in the underground wall 1.

  The high-pressure water is sprayed linearly from the nozzle 15 in a manner (for example, in the horizontal direction) that intersects the outer wall surface 1 a of the underground wall 1. In the present embodiment, for example, the injection pressure is 40 Mpa, and the injection flow rate is 100 L / min. With this high-pressure water, the outer wall surface 1a of the underground wall 1 is penetrated.

  As shown in the plane sectional view of the underground wall in FIG. 7, the construction method of the present invention injects slurry containing abrasives from the nozzle 15 arranged in the vertical hole 17 toward the outer wall surfaces 1a and 1b at a high pressure. Then, when cutting the underground wall 1, the direction of the nozzle 15 is rotated by a predetermined angle θ around the predetermined axis along the vertical drilling hole 17 while spraying the slurry, and then the injection direction from the nozzle 15 is stopped. Is cut at a plurality of rotational positions (in the figure, three locations with respect to the outer wall surface on one side) to perform a radial cutting, and the left and right outer wall surfaces 1a and 1b have a predetermined width W. It has a slit hole forming step of forming a water passage hole 7 composed of a slit hole. Here, a cutting hole 25 that is cut by rotating while spraying slurry is formed around the vertical hole 17. According to the present invention, even if the wall thickness L of the underground wall 1 is thick (for example, L = about 0.5 to 1 m), the predetermined width W (for example, about W = 20 cm) can be efficiently achieved in a short time. A water passage hole can be formed. Further, by repeating the same cutting operation by pulling up the nozzle 15 upward, it is possible to form a water passage hole having an opening continuous in the vertical direction with a width W.

A more specific construction procedure of the slit hole forming step will be described with reference to FIG.
As shown in FIG. 8A, first, the direction of the nozzle 15 relative to the left outer wall surface 1a is rotated counterclockwise by θ, and injection is performed for a time T toward the point A while maintaining this rotational position. . Next, as shown in FIG. 8 (2), while continuing the injection, the direction of the nozzle 15 is rotated clockwise by θ so as to face the outer wall surface 1a, and the point B is maintained while maintaining this state. Is injected for a time T toward Further, as shown in FIG. 8 (3), the direction of the nozzle 15 is rotated clockwise by θ while continuing the injection, and the injection is performed for the time T toward the point C while maintaining this rotational position.

  8 (1) and 8 (2), after fixing the injection direction of the nozzle 15 for a predetermined time and drilling the point A on the outer wall surface 1a, the nozzle 15 is rotated by θ while continuing the injection. When the injection direction is changed and a nearby point B is drilled, the region R1 sandwiched between the two points A and B is cut so as to be blown away. Similarly, in FIGS. 8 (2) to (3), the region R2 sandwiched between the two points B and C is cut so as to be blown away. By performing this series of operations for a plurality of rotational positions, the water hole 7 (slit hole) is formed from the vertical hole 17 to the left outer wall surface 1a.

  As shown in FIG. 8 (4), the shape of the interior of the water passage hole 7 is such that the center (axial center) of the nozzle 15 is the apex in a plan view (predetermined axial direction along the insertion hole), and the outer wall surface 1a. Is a substantially triangular shape or a substantially fan shape with the opposite side or arc.

  Subsequently, as shown in FIG. 8 (4), while continuing the injection, the direction of the nozzle 15 is largely rotated clockwise to inject toward the right outer wall surface 1 b toward the point D for the time T. Subsequently, as shown in FIGS. 8 (5) and (6), if the same injection is performed toward points E and F for each time T, a water passage hole 7 (slit hole) is also formed on the right outer wall surface 1b. As shown in FIG. 9, the underground wall is penetrated.

  Next, as shown in FIG. 8 (7), while continuing the injection, the direction of the nozzle 15 is largely rotated clockwise to raise the position of the nozzle 15 slightly toward the left outer wall 1a. And if a series of operation of FIG. 8 (1)-(6) is repeated, as shown in FIG. 10, the water flow hole with a large opening area which continued in the perpendicular direction by the amount (H) which pulled up the nozzle 15 upwards. 7 can be obtained. Note that the timing at which the position of the nozzle 15 is raised upward is not limited to this. For example, the nozzle 15 may be lifted upward from the state shown in FIG. Further, after the nozzle 15 is lifted upward from the state of FIG. 8 (6), the cutting is advanced from the right outer wall surface 1b to the left outer wall surface 1a by rotating the nozzle 15 in the counterclockwise direction. May be.

  Further, in addition to the procedure of FIG. 8, water passage holes can be formed by the procedure of FIGS. 12-1 (1) to (6). In this case, first, as shown in FIGS. 12-1 (1) to (3), the nozzle 15 is rotated clockwise to drill holes in the order of points A, B, and C on the outer wall surface 1a, and then the nozzle 15 is moved. Pull up slightly. Then, as shown in FIG. 12-1 (4), a point C1 immediately above the point C is drilled. Next, as shown in FIG. 12-1 (5), the nozzle 15 is rotated counterclockwise to drill the point B1, and the region R21 between the points C1 and B1 is removed. ), The nozzle 15 is further rotated counterclockwise to drill the point A1, and the region R11 between the points B1 and A1 is removed. By carrying out like this, as shown in the front view of Drawing 12-1 (7), water passage hole 7 of width W and height H can be formed in outer wall surface 1a. Then, if the nozzle 15 is pulled down and rotated 180 degrees and the same process is applied, the water passage hole 7 can be formed also on the outer wall surface 1b on the opposite side.

  Or you may form a water flow hole in the procedure of FIGS. 12-2 (1)-(4). 12-2 (1) and (2), after fixing the injection direction of the nozzle 15 for a predetermined time and drilling the point A on the outer wall surface 1a, the nozzle 15 is moved at a predetermined angle while continuing the injection. Rotate in the clockwise direction only to drill a nearby point B to remove the region R1 between points A and B. Subsequently, the nozzle 15 is slightly lifted upward to drill a point B1 above the point B as shown in FIG. 12-2 (3). Thereafter, as shown in FIG. 12-2 (4), while continuing the injection, the nozzle 15 is rotated counterclockwise by a predetermined angle to drill a point A1 immediately above the point A, and between the points A1 and B1. The region R11 is removed. By repeating this operation along the vertical drilling hole 17, as shown in the front view of FIG. 12-2 (5), the water passage hole 7 having a width W / 2 and a height H is formed in the right side portion of the outer wall surface 1a. Can be formed. By applying such a process to the left portion of the outer wall surface 1a, the water passage hole 7 having the required width W and height H can be obtained.

  Here, it will be described that the present invention has an advantageous effect as compared with the prior art (particularly, Patent Document 3 described above).

  Generally, the cutting energy by high-pressure injection attenuates as the distance from the nozzle increases. When rotation is applied to the injection from the nozzle of Patent Document 3, the energy attenuation is further increased because the movement in the lateral direction (concentric direction) due to the rotation increases as the distance from the nozzle increases. For this reason, although it can cut in the vicinity of a nozzle for a comparatively short time, in order to cut far away (in order to make a cutting diameter large), very much time will be required. In some cases, cutting may become impossible (the cutting diameter cannot be increased). In contrast, in the present invention, the rotation is stopped at a predetermined position for cutting, and no loss of cutting energy due to the rotation occurs. Therefore, it is possible to cut farther (increase the cutting diameter) than when rotation is applied.

  Further, in the method of cutting while moving the nozzle proposed in Patent Document 3 along the insertion hole, it is necessary to reinsert the supply rod into the insertion hole. Therefore, it is difficult to reinsert, and it is necessary to drill the insertion hole again. However, according to the method of the present invention, it is not necessary to re-insert the supply rod 21 into the insertion hole (vertical drilling hole 17), so that it is not necessary to drill the insertion hole again.

  Further, the cross-sectional shape when a plurality of slit holes are provided by the method proposed in Patent Document 3 is as shown in FIG. In this case, the substantial effective width contributing to the water flow performance is the diameter W1 of the vertical hole 17. Since this part becomes a bottleneck, even if a plurality of slit holes are provided, the water passing performance is not improved. In contrast, in the present invention, the cutting hole 25 having a diameter larger than that of the vertical hole 17 is formed by rotating slowly while injecting slurry. For this reason, it becomes possible to provide a slit hole with a large effective width.

  Therefore, according to the present invention, a water passage hole having a predetermined width can be efficiently formed in a shorter time than in the conventional method of simply rotating the nozzle. In particular, it is suitable when it is desired to efficiently form a water passage hole having a predetermined width in a short time on an underground wall having a relatively thick wall thickness.

  In the example of FIG. 8 described above, the nozzle 15 is rotated clockwise from the point A. However, the present invention is not limited to this. For example, the nozzle 15 may be rotated clockwise from the point D as a starting point. Alternatively, it may be rotated counterclockwise starting from point C or point F. Moreover, although the case where the rotation position of the nozzle 15 is three places with respect to each outer wall surface 1a, 1b was shown, two places or four or more places may be sufficient, and it is good also as a different number with respect to each outer wall surface. Further, the rotation angle θ may be set to a different angle for each rotation position, and the time T may be set to a different time for each rotation position.

  These conditions include the strength of the underground wall, the cutting distance (or wall thickness) from the nozzle to the outer wall surface, the injection flow rate from the nozzle, the injection pressure, the required width and height of the water passage hole to be formed, etc. For example, it is preferable to obtain an optimum condition by conducting a field test or the like before the construction. Further, the insertion holes may be arranged at a plurality of locations in the underground wall, and the underground wall may be cut by spraying from nozzles arranged in each.

  For reference, a series of operations shown in FIGS. 8 (1) to 8 (6) will be described below using specific numerical values obtained by experiments of the present inventors.

A nozzle 15 is provided in the center of the underground wall 1 where the wall thickness is L = 0.5 m and the uniaxial compressive strength is 1 N / mm ² , and the nozzle 15 injects in one direction toward the point A for about T = 30 seconds. Cutting and then cutting in a total of 3 directions by shifting the angle θ twice by 30 degrees. Thereby, the water flow hole 7 which consists of a slit hole with a width W of about 20 cm or more is opened in the outer wall surface 1a on one side. Next, the nozzle 15 is rotated as it is toward the opposite outer wall surface 1b. Similarly, the nozzle 15 is sprayed and cut in one direction from the nozzle 15 toward the point D for about T = 30 seconds, and the angle θ is set to 30 degrees twice. Shift and cut a total of 3 directions. Thereby, the water flow hole 7 which consists of a slit hole with a width W of about 20 cm or more is opened in the outer wall surface 1b on the opposite side. Subsequently, the nozzle 15 is rotated approximately 180 degrees while being pulled up by one step (about 2.5 cm), and thereafter, the same procedure is repeated to form the water passage hole 7. The operation of pulling up the nozzle 15 is repeated until a predetermined vertical length H corresponding to the required height dimension of the water passage hole is reached. In the above description, it is possible to cut the total 7 directions by shifting the angle θ 6 times by 10 degrees, or to cut the total 4 directions by shifting the angle θ 3 times by 20 degrees.

  As described above, as shown in FIG. 10, the water passage hole 7 that leads to the upstream side and the downstream side of the groundwater is formed in the underground wall 1. Moreover, since abrasives are mixed in the high-pressure water and the particles of the soil cement 4 are surely scraped off, large crushed pieces are hardly generated. And as shown in FIG. 9, the fine crushing piece 18 raises the inside of the conduit | pipe 6 and the vertical hole 17 with high pressure water, and is discharged | emitted on the ground, without damaging the soil cement 4. As shown in FIG.

  In addition, when changing the injection direction of the high pressure water injected from the nozzle 15, the high pressure water supply device 10 shown in FIG. A rotation motor (not shown) is driven to rotate the supply rod 21 by a predetermined angle. Accordingly, as shown in the plan view of FIG. 11A and the front view of FIG. 11B, the supply rod 21 (not shown) in which the nozzle 15 that injects high-pressure water is inserted along the vertical hole 17 is formed. Is rotated by a predetermined angle around the central axis of the nozzle, and the injection direction of the high-pressure water injected from the nozzle 15 changes.

  And after forming the slit-shaped water passage hole 7 by the radial cutting from three rotation positions, the raising / lowering mechanism (not shown) of the water passage formation apparatus 20 is driven, and the supply rod 21 is made upward. The height position of the nozzle 15 is changed, and the rotary motor (not shown) of the water passage forming device 20 is driven while the high pressure water supply device 10 again ejects the high pressure water from the nozzle 15 in a straight line. Then, the supply rod 21 is rotated by a predetermined angle to perform radiation cutting at three rotational positions. By repeating this operation, a water passage hole 7 having an opening having a width W and a height H continuous in the vertical direction along the conduit 6 is formed as shown in FIGS.

  Moreover, in order to maintain the shape of the water passage hole 7 formed as described above, it is preferable to fill the hollow portion with a water-permeable filling material (for example, No. 3 silica sand). In this case, first, as shown in FIG. 13, a small-diameter reticulated screen tube 19 is built in the conduit 6 (not shown), and the conduit 6 is pulled upward. At this time, as shown in FIG. 14, the conduit 6 (not shown) is pulled out, and at the same time, the interstitial material 23 is introduced into the outside of the screen tube 19 together with water. The filling material 23 is watered in a timely manner while being divided into small portions. By doing so, the filling material 23 can be filled in the entire interior of the water hole 7.

  Then, as shown in FIG. 15, after filling the water filling hole 7 with the filling material 23, an air hose 24 is appropriately built in the screen tube 19. The screen tube 19 can be cleaned by the air lift effect of the air blown from the lower end of the air hose 24 to eliminate clogging. The screen tube 19 may be cleaned by inserting a water jet nozzle instead of the air hose 24.

  As described above, according to the water hole of the underground wall according to the present invention, the water hole formed in the underground wall so as to communicate with the upstream side and the downstream side of the groundwater separated by the underground wall. The slurry is injected when the slurry including the abrasive is sprayed at a high pressure toward the outer wall surface from the nozzle disposed in the insertion hole provided inside the underground wall to cut the underground wall. However, after rotating and stopping the direction of the nozzle by a predetermined angle around a predetermined axis along the insertion hole, an operation for fixing the injection direction from the nozzle for a predetermined time is performed for a plurality of rotational positions. The inner wall of the slit hole formed by cutting the underground wall from the insertion hole to the outer wall surface with the axis as a vertex in a predetermined axial direction along the insertion hole, A substantially triangular shape with the outer wall as the opposite side or arc. It is a substantially fan shape. Here, after fixing the nozzle injection direction for a predetermined time and drilling one point on the outer wall, the nozzle is rotated by a predetermined angle while continuing injection to change the injection direction and drilling one other point in the vicinity Then, the region sandwiched between the two points along with the injection is cut so as to be blown away. By performing this series of operations for a plurality of rotational positions, slit holes as water passage holes are formed on the outer wall surface. For this reason, compared with said conventional method, there exists an effect that the water flow hole of predetermined width can be formed efficiently in a short time. The present invention is particularly suitable for underground walls having a relatively thick wall thickness.

  Moreover, according to the construction method of the water passage hole of the underground wall according to the present invention, the construction of the water hole formed in the underground wall so as to communicate with the upstream side and the downstream side of the groundwater separated by the underground wall. In the method, the slurry containing the abrasive is sprayed at high pressure toward an outer wall surface from a nozzle disposed in an insertion hole provided in the underground wall, and the slurry is cut. The operation of setting the direction of the nozzle to rotate around a predetermined axis along the insertion hole by a predetermined angle and then fixing the injection direction from the nozzle for a predetermined time is performed at a plurality of rotational positions. It includes a slit hole forming step of cutting the underground wall to form a slit hole that leads from the insertion hole to the outer wall surface. Here, after fixing the nozzle injection direction for a predetermined time and drilling one point on the outer wall, the nozzle is rotated by a predetermined angle while continuing injection to change the injection direction and drilling one other point in the vicinity Then, the region sandwiched between the two points along with the injection is cut so as to be blown away. By performing this series of operations for a plurality of rotational positions, slit holes as water passage holes are formed on the outer wall surface. For this reason, compared with said conventional method, there exists an effect that the water flow hole of predetermined width can be formed efficiently in a short time. The present invention is particularly suitable for underground walls having a relatively thick wall thickness.

  As described above, the underground water passage hole and the construction method thereof according to the present invention are useful for efficiently forming a predetermined width water passage hole in the underground wall in a shorter time. When the wall thickness of the middle wall is thick, it is suitable for efficiently forming a water passage hole having a predetermined width.

1 underground wall 1a outer wall 2 pillar pile 3 drilling hole 4 soil cement 5 core material 6 conduit 7 water flow hole (slit hole)
DESCRIPTION OF SYMBOLS 10 High pressure water supply apparatus 11 Water tank 12 Abrasive material tank 13 Mixer 14 High pressure slurry pump 15 Nozzle 16 Supply pipe 17 Vertical drilling 18 Fragment piece 19 Screen pipe 20 Water flow hole formation apparatus 21 Supply rod 22 Swivel 23 Filling material 24 Air hose 25 Cutting hole 101 Permeable layer 102 Impermeable layer GL Ground surface K Structure

Claims (4)

A method for constructing a water passage hole formed in the underground wall so as to communicate with an upstream side and a downstream side of groundwater separated by the underground wall,
When the slurry including abrasive is sprayed at a high pressure toward the outer wall surface from the nozzle disposed in the insertion hole provided inside the underground wall, the injection of the slurry is continued. after the orientation of the nozzle was stopped rotated by a predetermined angle about a predetermined axis along the insertion hole, carrying out the operation to a state in which the ejection direction from the nozzle to secure a predetermined time for a plurality of rotational positions at while It said diaphragm wall cutting, thereby saw including a slit forming step of forming a slit communicating with the outer wall surface from the insertion hole,
In the slit hole forming step, the injection direction from the nozzle is fixed for a predetermined time and a point on the outer wall surface is cut, and then the nozzle is rotated by a predetermined angle while continuing the injection to change the injection direction. The rotation direction is stopped, the injection direction from the nozzle is fixed for a predetermined time, and another point in the vicinity of the one point is drilled to blow away the region sandwiched between the one point and the other one point. A method of constructing a water passage hole in the underground wall, characterized by cutting . After forming the slit hole by cutting the outer wall surface on one side of the underground wall in the slit hole forming step, the nozzle is rotated around a predetermined axis along the insertion hole while spraying the slurry. The method for constructing a water passage hole in the underground wall according to claim 1 , wherein the slit hole is formed by cutting the outer wall surface on the opposite side of the underground wall in the slit hole forming step. After forming the slit hole by the slit hole forming step, the nozzle is moved along the insertion hole, and the slit hole forming step is further performed at a position adjacent to the slit hole, so that the slit on the outer wall surface The construction method of the water hole of the underground wall according to claim 1 or 2 , wherein an opening area of the hole is increased. The construction method of the water passage hole in the underground wall according to any one of claims 1 to 3 , wherein the slit hole formed by the slit hole forming step is filled with a water-permeable filling material. .

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