METHOD FOR MANUFACTURING A SYSTEM FOR THE STORAGE OF LIQUID OR GAS AND A STORAGE SYSTEM MANUFACTURED ACCORDING TO THE METHOD

Abstract: The invention relates to a method for the construction of a system for storing liquid or gas in a storage space (1) in rock (2) or earth, lined with thin sheet (11), comprising a layer of a particle shaped drainage material (18), e.g. sand, gravel, or the like, in a space (16) between rock or earth and the thin sheet lining. An intermediate wall of corrugated sheet (15) is disposed at a distance from the rock or earth wall (17) and is anchored in the rock or earth wall. The space between the intermediate wall of corrugated sheet and the rock or earth wall is at least partly filled with said particle shaped drainage material, so that said material forms at least a layer between the intermediate wall of corrugated sheet and the rock or earth wall, the thin sheet (11), which shall form the lining, being fastened to the side of the corrugated thin sheet facing the interior of the storage space. The invention also relates to a storage system constructed according to the method.

Description: Method for manufacturing a system for the storage of liquid or gas and a storage system manufactured according to the method TECHNICAL FIELD This invention relates to a method for the construction of a system for storing liquid or gas in a thin sheet lined storage space in rock or earth, comprising a layer of a particle shaped drainage material, e.g. sand, gravel, or similar material, in a space between the rock or earth and the thin sheet lining. In the concept of storage space is included also tunnel shaped spaces having vertical walls and arched roofs. The invention also relates to the storing system mad.e according to the method, comprising the thin sheet lined storage space. BACKGROUND ART A storage system of the above mentioned type is .known τhrough WO/00151. As a result of the construction which is described in the said published international patent application, the pressure from the stored product can be taken up by the surrounding rock or earth volumes, which makes it possible to store e.g. gas at an over-pressure at depths which need not be as large as are necessary for unlined rock store where the water-pressure in rock or earth shall exceed the gas or liquid-pressure from the stored product in the storage space. The lining can also resist the pressure, when the water-pressure in the surrounding rock or earth volume exceeds the pressure in the storage space, such as when storing petroleum beneath the ground-water level, or in the case of an emptied store for storing gas. In the construction according to said WO 87/00151, the thin sheet lining is sealingly provided against a concrete wall, which in turn is disposed at a distance from the rock or earth wall, so that a space is formed which is filled with sand, gravel or similar drainage material. This construction involved a substantial technical achievement at its time as compared to older technology, but the concrete lining of the walls of the storage space was a complication and a considerable cost factor. SUBSTITUTE SHEET BRIEF DESCRIPTION OF THE INVENTION It is a purpose of the invention to provide a system of the type men¬ tioned in the preamble having the same general advantages and possi¬ bilities as are offered through the system which is described in WO 87/00151 but which does not require a concrete layer on the back of the thin sheet sealing lining in the area of the side walls of the storage space. By eliminating the inner wall of concrete it is also possible to eliminate the need of any particular sheet-metal strips or the like fastened by molding or by other means in the concrete for securing the leak-proof thin sheet against the concrete wall. These and other advantages can be achieved therein that the invention is characterized by what is stated in the appending claims. Further characteristic features and aspects of the invention will be apparent from the following description of a preferred embodiment. BRIEF DESCRIPTION OF THE DRAWINGS In the following description of a preferred embodiment, reference will be made to the accompanying drawings, in which Fig. 1 shows a vertical section through a storage space according to the invention, Fig. 2 is a side-view in the direction of arrow II in Fig. 1 and illustrates, for the sake of simplicity in the form of a plan-view, the different steps of the production of the wall according to the invention, Fig. 3 shows at a larger scale a section III-III in Fig. 1 and illu¬ strates the wall construction according to the preferred embodiment of the invention more in detail, Fig. 4 shows the same detail as Fig. 3 and illustrates schematically the changes of the shape of the wall because of pressure against the wall from the fluid which is stored in the storage space, Fig. 5 is a view V-V in Fig. 3, and Fig. 6 shows at a larger scale how adjacent strips are connected to each other and how the thin sheet is secured to the backing construction. DESCRIPTION OF PREFERRED EMBODIMENT With reference first to Fig. 1, the storage space is designated 1, and the rock or earth is designated 2. In the following is presupposed that the storage space is located in rock. Therefore the word "rock" will be used consequently. The rock 2 defines the pressure vessel for the storage space 1. According to the embodiment, this has the shape of a circular cylinder having a circumferential vertical wall 3, a flat floor 4 and conical top 5. The floor 4 is suitably constructed in the manner which is known per se through the previously mentioned WO 87/00151 and comprises a concrete plate 6 molded on a sand bed 7, and on the concrete plate 6 there is a sealing layer 8 of stainless thin sheet. In the transition between side wall 3 and floor 4, there is a circumferential recess 9 in the rock 2 containing a drainage conduit 10 for discharging drainage water. Innermost, the. side wall 3 exhibits a sealing lining 11 of thin stain¬ less sheet. Suitably, the stainless, sealing thin sheet consists of austenitic stainless steel. A characteristic feature of this group of steels, which includes a great number of steel grades having varying composition, is that the steels, besides good corrosion features, also have mechanical features which are suitable for the present field of use, namely very good toughness (even in the cryogenic region), very good ductility, generally good working features and also good welda- bility. The mechanical features can also be expressed such, that the austenitic stainless steels are characterized by a comparatively low yield strength and a high rupture strength, which means that the material can be considerably deformed without rupturing. A suitable thickness of the sealing lining sheet 11 is 0.4 mm. The thin sheet used for the lining preferably consists of broad strips 12. Adjacent strips 12 are joined to each other in the side wall 3 by vertical, upright, edge folding seams 13, which can be designed according to any known construction or as will be described with reference to Fig. 6. The sealing, interior thin sheet 11 is fastened to an intermediate * wall 15 of corrugated sheet. Outside the corrugated sheet 15, in the space 16 between the corrugated sheet 15 and the rock wall 17, there is disposed a drainage layer 18 consisting of sand or gravel. The top portion 5 in principal may be designed in the same way as the side wall 3. Possibly, however, the sand or corresponding in the space between the rock wall and the corrugated sheet may be omitted in the top portion 5. How side wall 3 is designed and how it suitably can be built will now be explained more in detail with reference also to Fig. 2-6. The side wall 3 is prepared after the bottom plate 6 has been molded on the sand bed 7 and is suitably also prepared prior to the top por¬ tion 5. On the working place the corrugated sheet 15 is prepared in sections 20 with a width which may be for example 3 m and a length which may be for example 4 m. Also other widths and lengths of course may be contemplated, but suitably the width should be between 1 m and 3 m, and the length between 2 m and 6 m from i. a. transportation technical reasons and also in order that the section shall be easy to handle at the assembly. The corrugated sheet 15 may as well as the sealing thin sheet 11 consist?of a stainless austenitic steel, which from corrosion point of view is advantageos. Also other materials, however, are conceivable, for example plastic-coated thin, sheet. The thickness of the corrugated plate 15 can be chosen within broad limits. Through the corrugation the sheet is strenghtened against buckling in a direction transverse to the longitudinal direction of the corrugation. The selection of thickness of the corrugated sheet 15 depends i. a. on the design of the corrugation. If there for example is chosen a trapezoidal corrugation, as is shown in drawings, and if the folds for example have a height of about 7 cm and a breadth of about 13 cm, a sheet thickness of about 0.8 mm may be suitable. The folds, however, need not be trapezoidal. Also rounded (wave-shaped) corrugations are conceivable as well as combinations of various fold designs. While the corrugated sheet sections 20 due to the corrugation have a good stiffness against buckling in a direction transverse to the longitudinal direction of the corrugation, they have a bad stiffness in the other direction. In order to improve this, stiffening members are disposed on that side of the sections 20 which shall form the rear side of sections 20. These stiffening members may consist of rails 21 of steel, for example stainless austenitic steel. In cross-section, the rails 21 for example may have an L-profile, a U-profile, or any other suitable profile. When the rails 21 are delivered, they are bent to correspond to the radius which is actual for the wall 3 of the storage space 1. The rails 21 are fastened to the rear face of sheet 15 by means of screws or, more suitably, rivets 22. Rails 21 are dis¬ posed transverse to the longitudinal direction of the corrugation at a distance from each other of for example 1 m. Rails 21 suitably are mounted in such a way that portions 23 will project beyond the longi¬ tudinal edge of sections 20 on one side, while a corresponding piece will be left empty adjacent to the other edge of sections 20, so that corresponding rail portions 23 from an adjacent section may be dis¬ posed in this .space. Possibly, the rail portions 23 may be designed . such that the rails 21 in adjacent sections 20 will grip each other in order to facilitate the assembly. ** The sheet sections 20 which are delivered to the working place have been provided with circular apertures 24 in advance, which apertures are arranged in a row in some of those folds or grooves 25 which shall be turned outwards towards to the rock wall and which in situ shall be united with the stiffening rails 21 (the other folds or ridges, which shall be turned inwards and against which the sealing thin sheet 11 shall be mounted, have been designated 26) . In front of each aperture 24 there is a bushing or washer 28 disposed coaxially with said aper¬ tures 24. The washer or bushing 28 is mounted coaxially with the aper¬ ture on the side of the corrugated sheet facing the interior of the storage space, after a hole 27 has been drilled in the rock. The open¬ ing in the washer, which afterwards is mounted by welding or in some other way, is somewhat smaller than the aperture in the corrugated sheet, which means that it is possible to use a drill steel which is thicker than the opening in the bushing or washer. Starting at the top and taking the advantage of suitable facilities, such as cranes, elevators etc., the prepared sections 20 are put in place against the rock wall 17. Through each of apertures 24 there is drilled a hole 27 in the rock wall 17. For the drilling operation there is used a drill steel which is passed through aperture 24 prior to mounting the washer 28. Thereafter, through each of the apertures 24 in the corrugated sheet 15 coaxial with the aperture 24, there is passed an anchoring means for the corrugated sheet section 20. According to the embodiment, each of these anchoring means consists of a tube 29 having substantially the same outer diameter as the inner diameter of bushing 28. The tube 29 is passed all the way to the bottom of the hole 27 in the rock wall 17. In its inner end, tube 29 may be slotted, and the material of the tube between the slots may be bent or deformed in some other way. Cement is injected through tube 29 to fill the hole 27. The cement is allowed to cure, and in this way the tube 29 is anchored in the hole 27 in the rock wall 17. Instead of anchoring the tube 29 in the hole 27 in the described way by molding, also expansion members may be used. For example, the tube 29- may be replaced by a long expansion- shell bolt, which may be conventionally designed. The tube member 29 is threaded in that end portion 30 which projects through- the aperture 24 in the corrugated sheet 15. A nut 31 is fastened by screwing in the threaded end portion 30 and is screwed so far that the corrugated sheet 15 will adopt a position at a desired distance from rock wall 17. In the above described way, one section ^ 20 of the corrugated sheet 15 will be mounted after the other starting at the top, all the way until the floor 4 has been reached. Thereafter another row of sections 20 may be mounted adjacent to the first row. Lower sections 20 are ar ¬ ranged so that they slightly overlap the adjacent section thereabove, and sections located side by side are also arranged such that they slightly overlap each other and are connected by means of screws or rivets 32, Fig. 3. Sections 20, of course also can be mounted starting from the bottom. When a sufficiently large wall surface has been covered with sections 20 of corrugated sheet 15 as above described, one can start filling sand 18 into the space 16 between the rock wall 17 and the intermedi¬ ate wall 15 of corrugated sheet, but as the sand 18 will slide side- way, a sufficiently large section of the wall has to be covered with sections 20 of corrugated sheet 15 before starting filling the space with sand. It may therefore be more suitable to cover the entire rock wall 17 with corrugated sheet 15 prior to filling the space 16 with sand. When space 16 has been filled with sand 18, the nuts 31 are further screwed or slackened, depending on the circumstances, so that the ridges 26 of the corrugated sheet 15 will coincide with the circle line with desired radius for which the storage system has been de- signed. The sand 18 in this operation also with work as a support - "backing" - for the intermediate wall of corrugated sheet and has thus two important functions in the wall .construction. An L-profile 35 with a thickness of about 0.15 mm is fastened by weld- ing on some of the ridges 26 -from top to bottom of the storage space, namely on those ridges where adjacent strips 12 of the sealing thin sheet shall be connected to each other. This operation is performed at any instance after the sections 20 of corrugated sheet 15 has been mounted from top to bottom of the storage space and prior to mounting the sealing thin sheet 11. Suitably, the operation is performed when the space 16 behind the corrugated sheet 15 has been filled with sand 18. The L-profile 35 is of the sam ϊe. type as has been described in WO 87/00151. Finally, the wall 3 is lined with the stainless thin sheet 11. The stainless sheets 11 are delivered in rolls and are unrolled like a wall paper. The edge portions are folded together in a special folding machine, as has been described in the said WO 87/00151 and is welded together through roller seam welds against the L-profile 35. The joints 13 are given the shape of upright lap joints facing the storage room 1, Fig. 6. The foldings of the seams are united with each other and with the upright leg of the L-profile 35 through roller seam welds. Between the roller seam welds and the interior of the storage space there is a channel 36 for leakage finding by means of a detec¬ tion fluid, preferably for helium leakage finding. The joints also can be given some other design than the one which has been described in this specification. Also the bottom 4 is provided with a thin sheet lining 8 which is deposited against the concrete plate 6. In the transitions between side wall 3 and top portion 5, and between side wall 3 and bottom portion 4, the sealing thin sheet lining is connected by welding, so that the storage space 1 will be completely leak-proof. When the storage space in this way has been completed, and all scaffolds and all other auxiliary means have been removed through openings which have not been shown, which openings thereupon are locked, the storage space 1 is filled with the liquid or gas which shall be stored in the space. The pressure of the fluid against the sealing stainless thin sheet 11 in the side wall 3 may effect some compression of the sand 18 in the drainage layer in space 16 and also some elastic and also plas- tic deformation of the stainless thin sheet 11 in the portions 11' in the empty space 37 in the region of the grooves 25. The first men¬ tioned effect may as a result cause the corrugated sheet .15 to move inwards against the rock wall 17, i. e. describe a movement relative to the anchoring means 29. This is shown in Fig. 4. The effect as illustrated in the figure has been somewhat exaggerated. Due to the fact that the bushing or washer 28 is firmly connected with the cor- rugated sheet on its backside it will follow the plate 15 in the move¬ ments of said plate, wether the plate moves only outwards against the rock wall 17 or in return against the nut 31, which limits the move¬ ment of the intermediate wall of corrugated sheet 15 towards the inte- rior of the storage space 1. Due to a good adaptation between the tube 29 and the bushing or busher 28 sand is substantially prevented from escaping from the drainage layer. As a result of the deformation of the stainless thin sheet 11 in por- tions 11', the thin sheet in said portions 11' will curve into the valleys 37. This curving may be considerable without jeopardizing the strength or sealing capacity of the stainless sheet 11 which is due to the feautures of the stainless austenitic steel which has been chosen as a lining material. The original level of the thin sheet 11 has been indicated by a dashed line 38 in Fig. 4. The wall 3 in other words has a considerable degree of elasticity due to its construction, which is favourable because the wall in this way can adapt itself to the pressure from the fluid which is stored in the storage space 1, as well as to the pressure which may be generated because of forces from the rock 2. The empty spaces 37 between the sealing thin sheet 11 and the grooves 25 of the intermediate wall of corrugated sheet also function as drainage conduits for water which may leak out slowly through all minor openings in the intermediate wall 15 of corrugated sheet and also function as drainage conduits for drainage water which is dis¬ charged from the top section 5.

Claims: CLAIMS 1. Method for the construction of a system for storing liquid or gas in a thin sheet lined (11) storage space (1) in rock (2) or earth, comprising a layer of a particle shaped drainage material (18) , e. g. sand, gravel, or similar material, in a space (16) between the rock or earth and the thin sheet lining, c h a r a c t e r i z e d in that an intermediate wall of corrugated sheet (15) is provided at a distance from the wall of the rock or earth (17), said intermediate wall being anchored to said rock, or earth wall, that the space between the intermediate wall of corrugated sheet and the rock or earth wall is at least partly filled with said particle shaped drainage material, so that said particle shaped material will form at least a layer between the intermediate wall of corrugated sheet and the rock or earth wall, and that the thin sheet (11) intended to form the lining is secured to the side of the intermediate wall of corrugated sheet facing the inte¬ rior of the storage space. 2. Method according to claim 1, c h a r a c t e r i z e d in that holes (27) are drilled in the rock or earth wall (17) through aper- • tures (24) in some of the grooves of the corrugated sheet (15), that anchoring means (29) are inserted into the holes (27) through said apertures in the corrugated sheet, that the anchoring means are anchored in the holes (27) in the rock wall, that the anchoring means with a portion (30) extends into the space (37) between the corrugated sheet and the sealing thin sheet in the region of said grooves (25), and that a nut (31) or other locking means is provided on each of said end portions (30), said locking means (31) limiting the movements of the intermediate wall (15) of corrugated sheet in a direction towards the interior of the storage space. 3. Method according to claim 2, c h a r a c t e r i z e d in that the sealing thin sheet (11) is deposited against the ridges (26) which are turned against the thin sheet and is fastened to some of these ridges in the region of joints (13) between adjacent thin sheet sections (12). 4. Method according to claim 3, c h a r a c t e r i z e d in that each of the ridges (26), against which the sealing thin sheet (11) is intended to be fastened, is provided with a vertical, longitudinal fastening means (35) for said sheets. 5. Storage system for liquid or gas in rock or earth, comprising a storage space (1) lined with thin sheet (11), and a drainage layer filled with a particle shaped drainage material (18), for example sand, gravel or the like, between the rock or earth wall (17) and the thin sheet lining (11), c h a r a c t e r i z e d in that an inter¬ mediate wall of corrugated sheet (15) is disposed at a distance from the rock or earth wall (17), the grooves (25) and ridges (26) of the corrugated sheet extending vertically, that anchoring means (29) are provided, by means of which the intermediate wall of corrugated sheet is anchored at a distance from the rock or earth wall, that said drainage layer is provided in the space between .the intermediate wall of corrugated sheet and the rock or earth wall, and that the sealing thin sheet (11) is fastened to the side of the intermediate wall of corrugated sheet facing the interior of the storage space. 6. Storage system according to claim 5, c h a r a c t e r i z e d in that the sealing thin sheet (11) is fastened to the ridges (26) of the corrugated sheet. 7. Storage system according to claim 6, c h a r a c t e r i z e d in that the anchoring means (29) extends through apertures (24) in some of the grooves (25) between said ridges (26). 8. Storage system according to claim 6, c h a r a c t e r i z e d by fastening means (35) for the scaling thin sheet on some of the ridges (26) of the corrugated sheet (15). 9. Storage system according to any of claims 5-8, c h a r a c t e r ¬ i z e d in that the sealing thin sheet consists of austenitic stain- less steel. 10. Storage system according to any of claims 5-8, c h a r a c t e r i z e d in that also the corrugated sheet consists of austenitic stainless steel. 11. Storage system according to any of claims 5-8, c h a r a c t e r i z e d in that stiffening members, which extend horizontally, are provided on the rear side of the corrugated sheet.

Inventors: HAHN TORBJOERN, HAHN, TORBJOERN
Applicants: AVESTA LINING AB, AVESTA LINING AKTIEBOLAG
Application year: 1990
Main classification: E04H7
IPC codes: E04H7, F17C3