Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D17/00—Excavations; Bordering of excavations; Making embankments
  • E02D17/06—Foundation trenches ditches or narrow shafts
  • E02D17/08—Bordering or stiffening the sides of ditches trenches or narrow shafts for foundations
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
  • E02D5/02—Sheet piles or sheet pile bulkheads
  • E02D5/03—Prefabricated parts, e.g. composite sheet piles
  • E02D5/04—Prefabricated parts, e.g. composite sheet piles made of steel

Definitions

• the present invention relates to a retaining screen which is intended to retain soil and debris dug from the ground when excavating a shaft into which pipes, cables or the like are to be laid, and also to retain said soil and debris subsequent to said excavation.
• the method is of the kind set forth in the preamble of the following main claim.
• Soil retaining screens of the kind intended comprise two mutually opposing and essentially parallel support walls which are driven into the ground to a depth which is greater than the depth of the shaft to be excavated and which are guided at their upper-end parts in a res ⁇ pective side-piece, wherewith both side-pieces are joined together by means of adjustable spacer devices, such as screw devices, and the walls are constructed from a plurality of profiled metal sections which overlap at their respective edges.
• profiled metal sections are made of steel. They may have different widths and lengths, depending on the size of the shaft to be excavated.
• An example of a conventional metal profiled section of this kind is one which has a width of about 40 cm, is corrugated and has a thickness across its front and back surfaces of about 6 cm. The length is about 3 m.
• the meter-weight of this metal section is about 20 kg and the combined weight is thus about 60 kg. -The total weight of thicker and longer profiled metal sections is much greater.
• Mechanical auxiliaries are required to transport and to manipulate profiled metal sections of such heavy weights. Normally, it is necessary to use some form of mobile crane to this end.
• the crane is used to lift the sections, transport said sections to the shaft site and to fit the sections into the side-piece gui ⁇ des, and then to bring the sections to an upstanding position.
• the crane must then be driven to one side, so as to make room for the digger, which is normally used to drive the sections into the ground, by hammering on the upper ends of the sections with a digger-bucket.
• a separate pile driver must be used in the case of larger sections.
• the object of the invention is to provide a method which will greatly facilitate the work of transporting profiled metal sections to the aforesaid side-pieces and raising said sections to an upstanding position in respective guides, such as to bring the sections into a starting position in which they can be driven into the ground.
• profiled metal sections used hither ⁇ to and having a total weight of about 60 kg or more are thus replaced, in accordance with the invention, with profiled sections made of an aluminium alloy which renders the sections approximately three times lighter in weight and enables the sections to be handled manu ⁇ ally by one single workman with no difficulty.
• the profiled section is so configured that when possessing the same width, height and length as a corresponding profiled steel section will have essentially the same ability as the aforesaid steel section in resisting those loads which occur.
• the invention removes all the serious drawbacks that have been encountered over many years with the use of profiled steel sections without suggestions as to how these drawbacks could be readily overcome.
• the only drawback-with the novel lightmetal profiled sections is that they are several times more expensive to manufac ⁇ ture, although this additional cost is counteracted significantly by the relatively high repurchase price for scrap sections.
• the increase in cost is also compensated to a great extent by the fact that the work involved can be carried out quickly and without the aid of a crane.
• the inventive method will greatly reduce the reluctance of contractors to construct a retaining screen, so that such a screen will probably be erected in practically all instances where the risk of hazardous soil slips prevail.
• Figure 1 is a schematic, perspective view of a known retaining screen which comprises two mutually opposing support walls constructed with the aid of profiled steel sections, of which support walls only one is shown.
• Figure 2 illustrates two known profiled steel sections arranged adjacent one another in the support wall shown in Figure 1.
• Figure 3 illustrates part of the known support wall comprising profiled steel sections in larger scale
• Figure 4 illustrates part of a support wall incorpora ⁇ ted in the retaining screen constructed in accordance with the invention with the aid of lightmetal profiled sections of particular configuration according to the invention.
• the construction illustrated in Figure 1 includes a guide frame 10 comprising two mutually parallel side- pieces 12, 14 which are connected adjustably to one another by means of spacing devices in the form of shore-spacing screws 16, such that the walls are held at a predetermined distance apart.
• the frame corres ⁇ ponds to the size of the shaft to be excavated from the ground between the walls, for pipe or cable-laying purposes.
• the frame is buried some meters in the ground.
• the known profiled steel sections are fitted to the side- pieces of the frame with the aid of a mobile crane, not shown.
• the sections are then driven to desired depths in the ground, with the aid of a digger, not shown.
• the known steel profiled sections normally weigh at least about 60 kg and are so heavy that one workman is unable to carry and manipulate the sections on his own.
• Figure 3 is a sectional view of the known wall shown in Figure 1, in which a number of steel sections overlap one another.
• the joins 24 between the sections face in towards the shaft, which means that the joins can be damaged by the bucket of the digger used to excavate the earth 26 located between the supporting walls.
• the steel section ' s 18 form relatively wide channels 27 or troughs which are mutually separated by relatively narrow ridges located at the joins 26.
• Figure 4 is a sectional view of a supporting wall 28 forming part of the inventive retaining screen and constructed, in accordance with the invention, with the aid of aluminium profiled sections 30 of particular profile configuration in accordance with the invention.
• the profiled sections engage one another at the mutual- ly overlapping side parts 32.
• the wall-building profiled sections 30 are manufactured by the extrusion of an aluminium alloy.
• the weight of the inventive profiled sections is about one third the weight of a corresponding profiled steel section.
• a study of the lightmetal profiled sectionS / 30 illu ⁇ strated reveals that the section has a substantially corrugated configuration, with three relatively wide ridges 34 and intermediate channels or troughs 36 having relatively narrow bottoms 38.
• the planar upper surfaces of the ridges 34 and the planar bottom sur ⁇ faces 38 of the troughs are connected by sloping side- walls 40.
• the distance between the planar upper sides of the ridges and the outside of the trough bottoms constitutes at least one fifth of the width of the sections between the side-edges 32, 34 of respective sections.
• the planar upper surfaces of the ridges and the planar bottoms of the troughs also have approxi- mately the same wall thickness, which is approximately twice the thickness of the side-walls.
• the inventive aluminium profiled section 30 has essen ⁇ tially the same properties as a corresponding profiled steel section with respect to resisting the loads which occur on the supporting walls of the retaining screen.
• the profiled section is configured in a manner to achieve desired mechanical strength with the least possible material consumption, so as to maintain material costs at a low level.
• the broad upper sides of the ridges 34 face in towards the shaft, so that the inner surface of the shaft will only be broken by the relatively narrow intermediate troughs 36, and conse ⁇ quently soil and debris material 26 will obtain a good anchorage in the relatively broad troughs or channels formed on the insides of the ridges 34.

Landscapes

• Engineering & Computer Science (AREA)
• Structural Engineering (AREA)
• Mining & Mineral Resources (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Paleontology (AREA)
• Civil Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Composite Materials (AREA)
• Pit Excavations, Shoring, Fill Or Stabilisation Of Slopes (AREA)
• Bulkheads Adapted To Foundation Construction (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20374018

Family Applications (1)

Country Status (3)

Cited By (2)

Citations (2)

• 1988
  • 1988-11-21 SE SE8804210A patent/SE464819B/sv not_active IP Right Cessation
• 1989
  • 1989-11-20 WO PCT/SE1989/000673 patent/WO1990005810A1/en not_active Application Discontinuation
  • 1989-11-20 EP EP19890912685 patent/EP0494136A1/en not_active Withdrawn

Patent Citations (2)

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