JP2012117326A - Water cut-off structure of grout hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a cut-off performance by preventing opening of a closing lid or damages of cut-off packing.SOLUTION: A water cut-off structure 1 includes a grout hole 10 formed passing through a segment in the thickness direction thereof and a closing lid 20 attached to a pit side opening of the grout hole 10. On the grout hole 10, a hole side flat part 11 in a smooth surface shape along an inner peripheral surface on the pit side in the axial direction is formed, and a female screw part 12 is formed closer to a natural ground side than the hole side flat part 11. The closing lid 20 comprises a head part 21 in a disk shape and a cylindrical part 22 extended from one end face of the head part 21, a male screw part 23 which can be screwed to the female screw part 12 is formed on the distal end outer peripheral surface of the cylindrical part 22, and cut-off packing 25 is provided along a circumferential direction on the proximal end side of the cylindrical part 22. In the state of screwing the male screw part 23 to the female screw part 12 and attaching the closing lid 20 to the grout hole 10, the cut-off packing 25 is brought into liquid tight contact with the hole side flat part 11.

Description

  The present invention relates to a water stop structure of a grout hole in a segment used in a shield method.

  Conventionally, in the shield method, cement is built in the shield tunnel, and after assembling the segments during the shield construction, backfilling material is filled between the segments and the ground to integrate the ground and the segments. It has been broken. The grout hole used at the time of injecting the backfilling material is provided, for example, in the RC segment by penetrating in the thickness direction at a substantially central portion of the segment in advance at the segment manufacturing stage.

As an example of such a water stop structure of a grout hole, there are those disclosed in Patent Documents 1 and 2, for example.
That is, the grout hole has a structure in which a cylindrical steel pipe is integrally provided in a through-hole penetrating the thickness direction of the segment, and a closing lid is detachably provided on the inner peripheral surface side of the segment in the steel pipe. . Generally, a female screw is formed on the inner surface of the grout hole (steel pipe), and a male screw is formed on the closing lid so as to be screwed into the female screw. And the hole side taper surface in which a grout hole becomes a large diameter is formed in the inner surface near the segment inner peripheral surface of a grout hole in the axial center direction of a grout hole from the natural ground side toward a tunnel inner side. On the other hand, a lid side taper surface that coincides with the hole side taper surface is also formed in the male screw portion of the closing lid. When attaching the closing lid to the grout hole, a water-stopping packing is disposed between the hole-side tapered surface and the lid-side tapered surface, and the male screw portion of the closing lid is screwed into the female screw portion of the grout hole. The water-stopping packing is pressed between the hole-side taper surface and the lid-side taper surface to compress and deform to stop water.

Japanese Patent No. 3309096 Japanese Patent No. 2953949

However, in the conventional water stop structure of the grout hole, the male screw part of the closing lid is screwed into the female screw part of the grout hole and tightened so that the water stop packing is grouting between the hole side taper surface and the lid side taper surface. It is in a state where it is pressed in the substantially axial direction of the hole. Therefore, the amount of compressive deformation of the water-stopping packing varies depending on the degree of tightening of the closing lid (tightening strength). That is, when the closing lid is tightened too much, there is a possibility that the water-stopping packing may be crushed and damaged by the pressing force, and at that time, there is a problem that the water-stopping property is lowered and water leaks into the mine.
In addition, since the waterstop packing in a state compressed between the hole side taper surface and the lid side taper surface has a repulsive force due to elasticity, a force acts in the direction in which the closure lid opens, and the closure lid loosens, Due to insufficient tightening of the closing lid, the water-stopping effect of the water-stopping packing is not surely exhibited, and there is a problem that the water-stopping performance is deteriorated.

  The present invention has been made in view of the above-described problems, and provides a water stop structure for a grout hole that is intended to improve water stop by preventing the closure lid from being opened and the water stop packing from being damaged. The purpose is to do.

In order to achieve the above object, in the water stop structure for a grout hole according to the present invention, a grout hole provided with a grout hole that penetrates the thickness direction of the segment and a closing lid that is attached to the inside opening of the grout hole. In the grout hole, a smooth surface hole side flat portion is formed in the grouting hole along the inner peripheral surface of the inner side of the shaft in the axial direction, and a female screw is formed on the ground side from the hole side flat portion. The closure lid is composed of a disc-shaped lid body and a cylindrical portion extended from one end surface of the lid body, and a male threaded portion that can be screwed into the female threaded portion is formed on the outer peripheral surface of the cylindrical portion. In addition, a waterproof seal is provided along the circumferential direction on the base end side of the cylindrical portion, and the waterproof seal is attached in a state where the male screw portion is screwed to the female screw portion and the closing lid is attached to the grout hole. Is in liquid-tight contact with the hole side flat part. It is characterized in that there.
In the present invention, the male screw portion of the closing lid is screwed into the female screw portion of the grout hole and tightened, so that the water-stopping packing comes into liquid-tight contact with the hole side flat portion of the grout hole, and the cylindrical portion of the closing lid and Water is stopped between the hole side flat portion. The water-stopping packing compressed and deformed in this manner has a constant gap between the cylindrical portion and the hole-side flat portion, and the size of the gap does not change depending on the degree of tightening. The water stop effect can be demonstrated. That is, since the direction in which the water blocking packing is compressed is the radial direction of the grout hole, the closing lid does not act in the direction in which the closing lid opens (extracts) due to the repulsive force due to the elasticity of the water blocking packing. It is possible to prevent problems such as rotating and loosening. Moreover, since the amount of compressive deformation of the water-stopping packing is constant at any position as long as the water-stopping packing is located in a range in contact with the hole side flat portion, the degree of tightening of the closing lid (tightening force Even if the (strength) is not constant, a predetermined water-stopping property can be reliably ensured.

Moreover, in the water stop structure of the grout hole according to the present invention, a smooth surface-like lid-side flat portion along the outer peripheral surface is formed on the proximal end side of the cylindrical portion, and the lid-side flat portion has a circumferential direction. It is preferable that a circumferential groove is formed, and a water stop packing is attached to the circumferential groove.
In the present invention, since the water-stopping packing is attached to the circumferential groove, the water-stopping packing does not shift when the closure lid is attached to the grout hole. Can be made.

  According to the water stop structure of the grout hole of the present invention, the water stop packing is compressed and deformed in the radial direction of the grout hole, and the hole side flat part of the grout hole and the cylindrical part of the closing lid are in fluid-tight contact. The water can be stopped in a state. Therefore, it is not a water-stop structure that is compressed and deformed by being pressed in the substantially axial direction of the grout hole (insertion direction of the closure lid) as in the prior art, so that the closure lid opens in the direction of repulsion due to the elasticity of the water-stopping packing. It can prevent problems such as loosening of the closure lid due to action, damage to the water-stopping packing due to overtightening of the closure lid, or failure to secure the water-stopping performance of the water-stopping packing due to insufficient tightening of the closure lid. Can be improved.

It is a figure which shows the water stop structure of the grout hole by embodiment of this invention, Comprising: It is a vertical side view which shows the state which attached the obstruction | occlusion lid to the grout hole. It is a vertical side view of the grout hole shown in FIG. It is a vertical side view of the obstruction | occlusion lid | cover shown in FIG.

Hereinafter, a water stop structure of a grout hole according to an embodiment of the present invention will be described with reference to FIGS.
1 is a view showing a water stop structure of a grout hole according to an embodiment of the present invention, and is a longitudinal side view showing a state in which a closing lid is attached to the grout hole. FIG. 2 is a longitudinal side view of the grout hole shown in FIG. FIG. 3 and FIG. 3 are longitudinal side views of the closing lid shown in FIG.

As shown in FIG. 1, the water stop structure 1 for a grout hole according to the present embodiment includes a grout hole 10 that penetrates in the thickness direction substantially at the center in a plan view of the segment, and one of the grout holes 10 It is composed of a closing lid 20 for closing (a pit inner side opening). The grout hole 10 is for filling a backfill material such as mortar between the ground of the excavation surface and the segment.
In the following description, the outer side in the tunnel radial direction is referred to as the “natural mountain side”, and the inner side is referred to as “inner side”.

As shown in FIG. 2, the grout hole 10 has a configuration in which a tubular body having a substantially cylindrical shape with both ends opened is embedded in a segment with its axial direction facing the thickness direction of the segment.
On the inner surface of the grout hole 10, a flat surface-like hole-side flat portion 11 is formed along the inner peripheral surface on the inner side of the shaft center direction (inner peripheral side of the segment), and deeper than the hole-side flat portion 11. A female thread portion 12 is formed on the side (the natural ground side or the outer peripheral side of the segment). And the uneven | corrugated | grooved part 13 is formed in the outer peripheral surface of the tubular body of the grout hole 10, and the outer peripheral surface is in the state adhering to the concrete of a segment.

  Further, a taper portion 10b whose inner diameter gradually increases from the ground side toward the inner side in the axial direction of the grout hole 10 is formed at the inner end of the hole-side flat portion 11. The tapered portion 10b has a wide entrance so that the cylindrical portion 22 of the closing lid 20 can be easily inserted when the closing lid 20 shown in FIG. 3 is attached to the grout hole 10.

  As shown in FIG. 3, the closing lid 20 has a bottomed cylindrical body, a disc-shaped head portion 21 (lid body), and a tubular shape that extends in a tubular shape from the back surface (one end surface) of the head portion 21. Part 22. On the outer peripheral surface of the distal end of the cylindrical portion 22, a male screw portion 23 that is screwed into the female screw portion 12 of the grout hole 10 shown in FIG. 2 is formed. Further, on the proximal end side of the cylindrical portion 22, a flat surface-like lid-side flat portion 24 is formed along the outer peripheral surface thereof. The outer diameter of the lid-side flat portion 24 is substantially the same as the inner diameter of the hole-side flat portion 11. A circumferential groove 24 a is formed at a predetermined position of the lid-side flat part 24 (position near the male screw part 23) over the entire circumference.

  And the water stop packing 25 which consists of O-rings is mounted | worn with the circumferential groove 24a. The outer diameter dimension of the water-stop packing 25 is slightly larger than the inner diameter dimension of the hole-side flat portion 11 in the state where it is mounted in the circumferential groove 24 a, and the hole is formed when the closing lid 20 is attached to the grout hole 10. The water-stopping packing 25 is compressed and deformed by a predetermined elastic force with respect to the side flat portion 11 (see FIG. 1). That is, in the state where the closing lid 20 is attached to the grout hole 10, the water-stopping packing 25 is compressed and deformed and comes into liquid-tight contact with the hole-side flat part 11 over the entire circumference, so that the lid-side flat part 24 (tubular part) 22) and the hole side flat part 11 are configured to be water-stopped.

  Further, a recess 21 a for a fastening jig is formed on the upper surface of the head 21. That is, it is possible to fasten the closing lid 20 by locking the distal end portion of the fastening jig (not shown) in the concave portion 21a (the distal end portion having a distal end shape that can be inserted into the concave portion 21a and can be locked) and rotating the jig. It can be done.

Next, the effect | action of the water stop structure 1 comprised in this way is demonstrated based on drawing.
As shown in FIG. 1, by tightening the male screw portion 23 of the closing lid 20 while being screwed into the female screw portion 12 of the grout hole 10, the edge portion 21 b of the head portion 21 of the closing lid 20 is the tube body of the grout hole 10. It will be in the state attached when it contact | abutted to the pit inner side one end part 10a. In this attached state, the waterstop packing 25 is compressed and deformed and is in close contact with the hole side flat part 11 of the grout hole 10 over the entire circumference, and the lid side flat part 24 (tubular part 22) and the hole side flat part 11 The water is stopped between the water and the intrusion of water from the grout hole 10 into the mine can be prevented.

In the water-stop packing 25 compressed and deformed in this way, the gap between the lid-side flat portion 24 (cylindrical portion 22) and the hole-side flat portion 11 is constant, and the size of the gap does not change depending on the degree of tightening. Therefore, it is possible to exert a water stop effect by compressing and deforming with a certain elastic force. That is, the direction in which the water-stopping packing 25 is compressed is the radial direction of the grout hole 10, so that the closing lid 20 acts in the direction in which the closing lid 20 opens (extracts) by the repulsive force (expansion restoring force) due to the elasticity of the water-stopping packing 25. In this case, it is possible to prevent such a problem that the closing lid 20 rotates and loosens in the opening direction.
Moreover, since the amount of compressive deformation of the water-stopping packing 25 is constant at any position as long as the water-stopping packing 25 is located in a range in contact with the hole-side flat portion 11, the degree of tightening of the closing lid 20 is constant. Even if (strength of tightening force) is not constant, a predetermined water-stopping property can be reliably ensured.

Further, in the water stop structure 1, the water stop packing 25 is compressed and deformed in the radial direction of the grout hole 10 (that is, the direction substantially orthogonal to the insertion direction of the closing lid 20). Since the closing lid 20 can be pushed into the grout hole 10 by sliding the water-stopping packing 25, the pushing force pushes the water-stopping packing in the direction of the axial center of the grout hole (the insertion direction of the closing lid). It can be made smaller compared to the case of making it.
In the water stop structure 1, since the water stop packing 25 is attached to the circumferential groove 24 a formed in the lid side flat portion 24, the water stop packing 25 is displaced when the closing cover 20 is attached to the grout hole 10. The water stop packing 25 can be reliably brought into contact with the hole-side flat portion 11.

As described above, in the water stop structure of the grout hole according to the present embodiment, the water stop packing 25 is compressed and deformed in the radial direction of the grout hole 10, and the hole side flat portion 11 of the grout hole 10 and the cover side flat of the closing cover 20. The water can be stopped in a state of being in liquid-tight contact with the portion 24 (tubular portion 22).
Therefore, it is not a water-stop structure that is compressed and deformed by being pressed in the substantially axial direction of the grout hole (insertion direction of the closure lid) as in the prior art, so that the closure lid opens in the direction of repulsion due to the elasticity of the water-stopping packing. It can prevent problems such as loosening the opening / closing lid, damaging the water-stopping packing due to excessive tightening of the closing lid, or failing to ensure the water-stopping performance of the water-stopping packing due to insufficient tightening of the closing lid. Can be improved.

As mentioned above, although embodiment of the water stop structure of the grout hole by this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, in the present embodiment, a water-stop structure is provided in which the one-stage water-stopping packing 25 is provided on the cylindrical portion 22 of the closing lid 20, but the present invention is not limited to this. The flat part 24 may be provided with two or more stages.
Moreover, the range of the hole side flat part 11 and the lid side flat part 24, the position of the water stop packing 25 with respect to the lid side flat part 24, etc. are arbitrary and can be set suitably. In short, it is only necessary that the water-stopping packing 25 is pressed with a predetermined amount of compressive deformation and is in liquid-tight contact with the hole-side flat portion 11 with the closing lid 20 attached to the grout hole 10. .

DESCRIPTION OF SYMBOLS 1 Water stop structure 10 Grout hole 11 Hole side flat part 12 Female thread part 20 Closure lid 21 Head (lid body)
22 Cylindrical part 23 Male thread part 24 Lid side flat part 24a Circumferential groove 25 Water stop packing

Claims (2)

A grouting hole water-stopping structure comprising a grouting hole penetrating the thickness direction of the segment, and a closing lid attached to a pit inner opening of the grouting hole,
In the grout hole, a smooth surface-shaped hole side flat portion is formed along the inner peripheral surface on the inner side in the axial direction of the grout hole, and a female screw portion is formed on the ground side from the hole side flat portion,
The closing lid includes a disc-shaped lid body and a cylindrical portion extending from one end surface of the lid body, and a male screw portion that can be screwed to the female screw portion is formed on the outer peripheral surface of the distal end of the cylindrical portion. And a water stop packing is provided along the circumferential direction on the base end side of the cylindrical portion,
In the state where the male screw part is screwed to the female screw part and the closing lid is attached to the grout hole, the water blocking packing is configured to be in liquid-tight contact with the hole side flat part. Water stop structure of grout hole. On the base end side of the cylindrical portion, a smooth surface-like lid-side flat portion along the outer peripheral surface is formed,
A circumferential groove along the circumferential direction is formed in the lid-side flat portion,
The water stop structure of a grout hole according to claim 1, wherein the water stop packing is attached to the circumferential groove.

Images