JP4299207B2 - Drilling method of dam body - Google Patents

Description

  The present invention relates to a drilling method for forming a flow path by drilling a through hole in a dam dam body.

  In recent years, redevelopment of existing dams has been promoted by adding or improving intake facilities and discharge facilities to existing dams. In such redevelopment, the water area around the dam dam body work area must be temporarily closed. However, because the water depth of the dam is extremely deep, the conventional method of building a sheet pile wall by driving steel sheet piles into the bottom of the bottom of the dam could not withstand a large water pressure.

Therefore, for example, a semi-cylindrical double sheet pile wall is constructed by continuously driving an H-shaped sheet pile into the bottom of the ground, and a temporary cutoff structure is formed by placing concrete in the double sheet pile wall to make a water stop wall. It is considered (for example, refer to Patent Document 1).
Japanese Patent No. 3054851 (Page 2-3, Figure 1-3)

  However, since the water depth of the dam is extremely deep, the method of Patent Document 1 requires a large amount of steel and concrete to provide a huge water barrier that extends from the bottom of the ground to the surface of the water. There was a problem that disposal costs were high because the water barrier was removed.

  In addition, in order to start work, it is necessary to drain the inside of the water blocking wall, and when sediment is accumulated at the planned position of the opening upstream of the through hole, the steel sheet pile is deeper than the sediment. There was a problem that the construction period was long because it was necessary to remove the sediment inside the water blocking wall.

  The subject of this invention is providing the drilling method of a dam dam body which can form the cheap temporary deadline and can reduce the cost concerning the drilling of a dam dam body.

  In order to solve the above problems, the invention described in claim 1 is a method of drilling a dam dam body 10, wherein a step of improving the ground of the portion of the sediment 2 in contact with the upstream side surface of the dam dam body 10; A process of filling the grouting material between the upstream side surface of the dam body 10 and the ground improvement portion 3 of the sediment, and drilling and penetrating the dam body 10 from the downstream side toward the ground improvement portion 3 of the sediment 2 And forming a hole.

  According to invention of Claim 1, while improving the ground of the sediment 2 of the part which touches the upstream side surface of the dam body 10, between the ground improvement part 3 of the sediment 2 and the upstream side surface of the dam body 10 By filling the grouting material into the ground, it is possible to stop water between the ground improvement portion 3 and the upstream side surface of the dam dam body 10, and the dam dam body 10 from the downstream side toward the ground improvement portion 3 of the sediment 2. It is possible to prevent the water of the dam lake 1 from flowing into the through hole when the hole is drilled.

  The invention according to claim 2 is the method for drilling the dam dam body 10 according to claim 1, wherein the grouting material is provided between the upstream side surface of the dam dam body 10 and the ground improvement portion 3 of the sediment 2. The dam dam body 10 is drilled halfway toward the ground improvement portion 3 of the sediment 2 from the downstream side, and the grout material is connected to the upstream side surface of the dam dam body 10 from the tip portion in the drill hole 12. It is characterized by being injected between the ground improvement portion 3 of the sediment 2.

  According to the invention described in claim 2, the dam dam body 10 is drilled halfway toward the ground improvement portion 3 of the sediment 2 from the downstream side, and the grout material is dam dam body from the tip portion in the drill hole 12. Since it inject | pours between the upstream side surface of 10 and the ground improvement part 3 of the sediment 2, the outer peripheral part of the predetermined position of the opening of the upstream of a through-hole can be stopped more reliably.

  According to the present invention, the sedimentation in the portion contacting the upstream side of the dam dam body is improved, and the grout material is filled between the ground improvement portion of the sediment and the upstream side surface of the dam dam body. Since the same effect as the formation of a water wall can be obtained, the cost of providing a water blocking wall when drilling a dam dam body and forming a through hole from the downstream side toward the ground improvement part of the sediment is reduced. The cost required for drilling a dam dam body can be reduced.

  FIG. 1 is a vertical sectional view showing a dam. In the dam lake 1 upstream of the dam body 10, sediment 2 is deposited. A through hole is provided in the dam dam body 10 at a position indicated by a broken line in order to add water intake facilities, discharge facilities, and the like. Hereinafter, a method of drilling a through hole in the dam dam body 10 will be described.

  First, the ground improvement is performed on the sediment 2 accumulated at the predetermined position of the opening on the upstream side of the through hole provided in the dam body 10. First, the scaffold 20 for installing the ground improvement device 30 is assembled on the upper part of the dam body 10 so as to overhang the dam lake 1.

The scaffold 20 is formed as follows, for example. First, as shown in FIG. 1, when there is a rail 11 at the upper part of the dam body 10, a base material 21 such as wood is stacked between the rails 11 to the height of the rail 11, and then the rail 11 and the base material 21 are stacked. A scaffolding material 22 such as H steel is placed on the top. Then, the scaffold material 22 is fixed to the dam body 10 with a chemical anchor 23 or the like.
When the scaffold 20 is completed, the ground improvement device 30 is placed on the portion of the scaffold 22 that extends over the dam lake 1. The ground improvement device 30 includes a formation pipe 31 described below, and includes a pump that sends high-pressure water, compressed air, a curing agent, and the like to the formation pipe 31, a drive device that rotates the formation pipe 31, and the like.

  As shown in FIG. 2, a drilling device 32, a lower nozzle 33, a suppression blade 34, an upper nozzle 35, and a lifting mud blade 36 are provided at the lower portion of the forming pipe 31. The hole drilling device 32 is provided at the lower end of the forming pipe 31 and drills the sediment 2 while rotating. The diameter of the drilling device 32 is larger than that of the forming tube 31, and a gap is formed between the drilling hole 3 formed by the drilling device 32 and the forming tube 31.

A lower nozzle 33 is provided on the outer peripheral surface of the forming pipe 31 above the drilling device 32. A curing agent is ejected from the lower nozzle 33. The hardener is mixed and stirred with the surrounding gravel.
On the outer peripheral surface above the lower nozzle 33 of the forming tube 31, suppression blades 34 are provided. The suppression blade 34 is a face material provided in a spiral shape in the left-handed screw direction. When the forming pipe 31 is rotated clockwise as viewed from above, the suppression blade 34 presses the surrounding gravel downward and suppresses the gravel from rolling up.

An upper nozzle 35 is provided on the outer peripheral surface of the forming pipe 31 at a position spaced upward from the suppression blade 34. From the upper nozzle 35, cutting water of 35 to 40 MPa is jetted from 80 to 150 L / min and compressed air of 0.7 MPa is jetted from 2 to ³ m ^{3 /} min, and the surrounding sediment 2 is cut and stirred. The coarse gravel of particles in the stirred sediment 2 settles downward, and the fine mud of particles stays upward.

  On the outer peripheral surface above the upper nozzle 35 of the forming pipe 31, a lifting mud blade 36 is provided. The lifting mud blade 36 is a face material provided in a spiral shape in the right-hand screw direction. When the forming pipe 31 is rotated clockwise as viewed from above, the mud blade 36 discharges the staying mud upward from the gap between the drilling hole 3 and the forming pipe 31.

  Hereinafter, the ground improvement method by the ground improvement apparatus 30 will be described. First, as shown in FIG. 1 and FIG. 2, the formation pipe 31 is lowered from the scaffold 20 while rotating the forming pipe 31 clockwise to approximately the center position of the planned improvement range of the sediment 2.

  When the forming pipe 31 is lowered until the position of the upper nozzle 35 reaches the lower part of the planned improvement range, the cutting water and the compressed air are ejected from the upper nozzle 35 while the forming pipe 31 is continuously rotated. The sediment 2 is cut and stirred. By gradually pulling up the forming pipe 31, the sediment 2 in the range to be improved can be cut and stirred upward.

  The stirred sediment 2 is classified, the gravel sediments downward, and the mud stays upward. The mud is discharged upward along with the cutting water and the compressed air from the gap between the hole 3 and the forming pipe 31 by the lifting blade 36. A mud pit 4 is provided in the upper part of the sediment 2 in advance, and the discharged mud is discharged onto the dam lake 1 by a sand pump.

  On the other hand, the gravel components that have settled downward are mixed and stirred with the curing agent ejected from the lower nozzle 33. The gravel portion mixed with the curing agent is pressed downward by the restraining blades 34 and curling is suppressed. When the curing agent is cured, the ground improvement of the portion is completed. By gradually pulling up the forming pipe 31, it is possible to improve the ground of the sediment 2 in the planned improvement area upward.

  When the ground improvement is completed, the dam dam body 10 is drilled from the downstream side toward the ground improvement portion 3 of the sediment 2 as shown in FIG. The dam body 10 can be drilled using a core boring machine, a shield machine, or the like, but any other method may be used.

  Immediately before the penetration, the drilling of the dam dam body 10 is temporarily stopped, and contact grouting 13 is applied between the upstream surface of the dam dam body 10 and the ground improvement portion 3, Stop the outer periphery. The contact grouting 13 penetrates the grout material injection device from the tip of the hole 12 in the traveling direction and outward of the hole 12, and the grout is formed between the upstream surface of the dam dam body 10 and the ground improvement portion 3. Inject in between.

  As a grouting material used for the contact grouting 13, a general injecting agent can be used. For example, a urethane foam-based injecting agent, a silica resin-based injecting agent, or the like can be used.

  When the surface between the upstream side of the dam dam body 10 and the ground improvement portion 3 is stopped by the grout material, the hole drilling is resumed and the hole 12 is penetrated. At this time, since the opening on the upstream side of the through hole is blocked with the sediment-improved sediment 2, the water of the dam lake 1 and the sediment 2 do not flow into the through-hole.

  After that, the necessary equipment for the gate that opens and closes the through hole, the water intake facility, the discharge facility, etc. is installed in the through hole. Finally, the ground improvement portion 3 is crushed and removed with the gate closed. As described above, through-holes can be provided in the dam, and water intake facilities and discharge facilities can be provided.

  As described above, according to the present invention, the sedimentation 2 on the upstream side of the dam dam body 10 is improved in the ground, and the grout material is filled between the ground improvement portion 3 and the upstream surface of the dam dam body 10. Thus, since the same effect as that of forming the water blocking wall can be obtained, the cost for providing the water blocking wall can be reduced.

  In addition, when a water blocking wall is provided, water and sediment in the water blocking wall must be removed before the through hole is formed. In the present invention, the sediment is formed after the through hole is formed. The sediment can be removed while water intake facilities, discharge facilities, and the like are provided. For this reason, a construction period can be shortened.

  In the above embodiment, the drilling of the dam dam body 10 is interrupted and the grout material is injected between the upstream surface of the dam dam body 10 and the ground improvement portion 3. A grout injection device is provided at the tip of the machine, and when the tip of the drilling machine reaches the upstream side of the dam dam body 10 while drilling the dam dam body 10 with the drilling machine, the grout is started from the tip of the drilling machine. The material may be discharged to stop water between the dam bank body 10 and the ground improvement portion 3.

  Moreover, the ground improvement method of the sediment 2 is also arbitrary, and it is needless to say that the shape of the dam dam body 10 and other specific detailed structures can be appropriately changed.

It is an elevation sectional view showing the drilling method of the dam dam body of the present invention. FIG. 2 is a vertical sectional view showing the forming pipe of FIG. It is an elevation sectional view showing the drilling method of the dam dam body of the present invention.

Explanation of symbols

1 Dam lake 2 Sedimentation 3 Ground improvement part 10 Dam body 12 Drilling hole

Claims (2)

  The process of improving the ground in the part of the dam body that touches the upstream side of the dam body, the process of filling the grout material between the upstream side of the dam body and the ground improvement part of the sediment, A method for drilling a dam dam body comprising a step of drilling a dam dam body toward a ground improvement portion to form a through hole.   The step of filling the grouting material between the upstream side surface of the dam dam body and the ground improvement portion of the sediment is to drill the dam dam body halfway toward the ground improvement portion of the sediment from the downstream side. 2. The method for drilling a dam dam body according to claim 1, wherein the grouting material is injected from the front end portion between the upstream side surface of the dam dam body and the ground improvement portion of the sediment.

Images