JP2005145616A - Distortion absorbing mechanism for lining of high pressure gas storage underground space - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress to a minimum the effect on a metal lining of the difference in behavior between a rock stratum and a plug in a structure discontinuity part. <P>SOLUTION: The inside of an underground space 1 formed in the rock stratum 4 is lined with the metal lining 5 provided with resilient buffer material 18 on the outer side. Concrete 7 is inserted in the gap 6 between the metal lining 5 and the rock stratum 4. Further, in a high pressure gas storage underground space where a construction tunnel 2 communicated with the space 1 is sealed with a concrete plug 3, a distortion absorbing part 12 is provided on the metal lining opposing to the structure discontinuity part 10 which is the boundary surface between the rock stratum 4 and the plug 3, the distortion absorbing part having a convex shaped cross section and protruding into the space 1 . In addition, a metallic structural member 14 supporting the structure discontinuity part and having a shape substantially identical to the distortion absorbing part 12 is provided on the back side of the distortion absorbing part 12. Likewise, an elastic distortion absorbing material 16 is provided on the back side of the metallic structural member 14 supporting the structure discontinuity part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a strain absorption mechanism that absorbs strain of a lining of a cavity when storing natural gas, compressed air, or the like in a cavity provided in an underground rock at a high pressure of, for example, 50 to 200 atmospheres. is there.

When gas such as natural gas or compressed air is stored at high pressure in a cavity provided in the underground rock mass, the rubber or plastic system is used on the inner surface of the reinforced concrete that forms the outer lining in order to store this gas in an airtight manner. A non-metal sheet, a metal sheet such as a thin stainless steel sheet, or an airtight lining such as a membrane is bonded with an adhesive or welded. At that time, a method is conceivable in which the joint portion of the airtight sheet itself is welded in the case of a metal system and welded in the case of a rubber system or a plastic system (for example, Patent Document 1).
JP 2001-233425 A (page 3-4, FIG. 1)

  In the case of a conventional airtight lining, for example, in the case of an LNG storage tank or the like, it is only necessary to absorb a relatively small deformation of the lining due to the influence of hydraulic pressure and temperature, and the reliability of the joint portion of the airtight lining itself is fixed to the outer lining, It is secured to some extent.

  However, since the present invention is in a very high pressure state, the lining is used in a plastic region, and when the storage pressure changes every day due to the discharge and reception of the storage gas, the internal pressure changes, that is, due to repeated load. Stress concentration occurs in the fixing portion of the outer lining and the joint portion of the hermetic lining itself, which may cause gas leakage due to fatigue in the same portion.

  On the other hand, as shown in FIG. 6, the end of the construction tunnel 2 used when forming the underground cavity 1 is sealed with a concrete plug 3 after the construction is completed. Since there is a difference in displacement under the same pressure, the boundary between the rock mass 4 and the plug 3 (hereinafter referred to as a structural discontinuity) is caused by the difference in behavior between the rock mass 4 and the plug 3. As shown in (a) and (b), shearing and opening displacement occur in the discontinuous displacement portion indicated by the symbol a. For this reason, strain concentration occurs in the metal lining 5, and when considering the use for 50 years, the occurrence of gas leakage due to fatigue in the same part is very high compared to the general part of the lining.

  The present invention has been made to solve such a problem, and the object of the present invention is to determine the interface between the rock mass and the plug, that is, the difference in behavior between the rock mass and the plug at the structural discontinuity. It is an object of the present invention to provide a strain absorption mechanism for a metal lining that minimizes the influence on the resulting metal lining.

  In order to solve the above problems, the strain absorption mechanism of the lining of the high pressure gas storage underground cavity according to the present invention is lined by a metal lining provided with an elastic buffer material on the inside of the cavity formed in the rock. In addition, in the high pressure gas storage underground cavity, concrete is backed into the gap between the metal lining and the rock, and the tip of the construction tunnel communicating with the cavity is sealed with a concrete plug. A strain absorbing portion having a convex cross-section projecting into the cavity portion is provided in the metal lining portion facing the structural discontinuity that is the interface between the plug and the plug, and the strain absorbing portion is substantially the same as the strain absorbing portion on the back side of the strain absorbing portion. A structural discontinuous portion supporting structural member made of the same metal is provided, and a strain absorbing material having elasticity is provided on the back side of the structural discontinuous portion supporting structural member. It is intended to.

  In the structural discontinuous portion supporting structural member and the strain absorbing material of the present invention, the structural discontinuous portion supporting structural member and the strain absorbing material are fitted in a groove provided inside the rock and the plug.

  As described above, in the high-pressure gas storage underground cavity, the present invention provides a strain absorbing portion having a convex cross section that protrudes toward the inside of the cavity in the metal lining that faces the structural discontinuity that is the interface between the rock and the plug. Further, a structural discontinuity support member made of metal substantially the same shape as the strain absorption part is provided on the back side of the strain absorption part, and the elastic strain is provided on the back side of the structural discontinuity part support structure member. Since the absorber is provided, if there is a difference in the behavior of the rock and the plug at the boundary between the rock and the plug, that is, the structural discontinuity, the strain absorbing part of the metal lining with a convex cross section, The structural discontinuity supporting structural member and the elastic strain absorber deformed to influence the influence on the metal lining due to the interface between the rock mass and the plug, that is, the difference in the behavior of the rock mass and the plug at the structural discontinuity. Most It can be suppressed to the limit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a high-pressure gas storage underground cavity. In FIG. 1, reference numeral 1 denotes an underground cavity formed in the rock mass 4, and the inside thereof is lined with a metal lining 5 made of non-rust steel. In addition, the gap 7 between the metal lining 5 and the rock mass 4 is backed with concrete 7. In addition, the buffer material 18 made from a synthetic resin is provided in layers outside the metal lining 5 (see FIG. 3). As a method of providing the cushioning material 18, there are a spraying method, a pasting method, and the like.

  Further, the end of the construction tunnel 2 communicating with the cavity 1 is sealed with a concrete plug 3. The construction tunnel 2 is used to provide a gas pipe 9 having a valve 8 so that high-pressure gas such as natural gas can be taken in and out. The tip of the gas pipe 9 is fixed to the metal lining 5.

  As shown in FIG. 3, the metal lining 5 is such that the lining portion facing the structural discontinuity 10 that is the boundary surface between the rock 4 and the plug 3 protrudes in a convex shape in cross section toward the inward I of the cavity 1. The strain absorbing portion 12 is formed. Further, on the back side of the strain absorbing portion 12, a metal structural discontinuous portion supporting structural member 14 that is formed in substantially the same shape as the strain absorbing portion 12 and has flanges 13 on both sides thereof is provided. Further, on the back side of the structural discontinuous portion supporting structural member 14, it is formed of an elastic body that is formed in a convex cross section projecting inward I of the cavity portion 1 and that has flanges 15 on both sides thereof. A strain absorbing material (damper material) 16 is filled.

  Since the structural discontinuous portion support structural member 14 and the strain absorbing material (damper material) 16 are fitted in the joint groove 20 provided inside the rock mass 4 and the plug 3, friction force is applied at the time of internal pressure load. It is not necessary to fix the both ends to the rock mass 4 and the plug 3, but if necessary, it may be fixed with an anchor.

  In this case, for example, the structural discontinuity support structure member 14 and the outer flanges 13 and 15 of the strain absorbing material 16 are fixed to the rock mass 4 by the metal anchors 17, and the structural discontinuity support structure member 14 and the strain The inner flanges 13 and 15 of the absorbent material 16 are fixed to the plug 3.

  The symbol O indicates the outside of the cavity 1. In addition, the dimensions of the structural discontinuity support structural member 14, that is, the width A and the height B are set to optimum dimensions according to the relative displacement amount of the rock 4 and the plug 3.

  As shown in FIG. 2, since the structural discontinuous portion 10 is circular, the strain absorbing portion 12, the structural discontinuous portion supporting structural member 14, and the strain absorbing material 16 of the metal lining 5 are each in a ring shape in front view. Is formed.

  Here, as the material for the metal lining, the structural discontinuous portion supporting structural member, and the anchor, for example, non-rust steel or carbon steel is preferable. Moreover, as a raw material of the strain absorbing material, for example, rubber or polyurethane is preferable. Moreover, as a material of the buffer material, for example, polyurethane is preferable.

  Therefore, as shown in FIG. 4, when the plug 3 is displaced toward the inner side I of the cavity 1 as indicated by an arrow E, the strain absorbing portion 12 of the metal lining 5 is indicated by a two-dot chain line. The deformation of the metal lining 5 due to the deformation of the plug 3 is absorbed.

  On the other hand, as shown in FIG. 5, when the plug 3 is displaced to the outer side O of the cavity 1 as indicated by an arrow F, the strain absorbing portion 12 of the metal lining 5 is deformed as indicated by a two-dot chain line. Thus, the distortion of the metal lining 5 due to the behavior of the plug 3 is absorbed.

It is sectional drawing of a high pressure gas storage underground cavity. It is a partial front view of the part shown by the arrow C in FIG. It is D-D 'sectional drawing of FIG. It is operation | movement explanatory drawing of the distortion absorption part at the time of plug advance. It is operation | movement explanatory drawing of the distortion absorption part at the time of plug retraction. It is sectional drawing of the conventional high-pressure gas storage underground cavity. (A), (b) It is explanatory drawing which shows the relative behavior of a rock mass and a plug.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cavity part 2 Tunnel for construction 3 Plug 4 Rock bed 5 Metal lining 6 Crevice 7 Concrete 10 Structural discontinuity 12 Strain absorbing part 14 Structural discontinuous part support structural member 16 Strain absorbing material

Claims (2)

The inside of the cavity formed in the bedrock is lined with a metal lining provided with a cushioning material having elasticity on the outside, and concrete is backed in the gap between the metal lining and the bedrock, and further, In the high-pressure gas storage underground cavity where the tip of the communicating construction tunnel is sealed with a concrete plug,
The metal lining portion facing the structural discontinuity which is the boundary surface between the rock and the plug is provided with a strain absorbing portion having a convex cross section projecting into the cavity, and further, the strain absorbing portion on the back side of the strain absorbing portion. A high-pressure gas storage underground cavity characterized in that a structural discontinuous part supporting structural member made of a metal having substantially the same shape is provided, and a strain absorbing material having elasticity is provided on the back side of the structural discontinuous part supporting structural member Lining strain absorption mechanism. The strain absorbing mechanism for a lining of a high-pressure gas storage underground cavity according to claim 1, wherein the structural discontinuous portion supporting structural member and the strain absorbing material are fitted in a groove provided inside the rock and the plug.

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