GB476319A - Improvements in or relating to facings or linings for underground works such as tunnels - Google Patents

Abstract

476,319. Underground structures. MORAN, T. W. June 6, 1936, No. 15866. [Class 85] [Also in Group X] Underground structures, such as tunnels, subways, tube railway stations, cellars, magazines, &c., are provided with an interior lining formed of cementitious material and inert aggregate sprayed over reinforcement by a cement gun and spaced from the inner surface of the main tunnel &c. structure to form drainage cavities continuous from the top to the bottom of the lining and provided with outlets at their lower ends. In Figs. 1 and 2, spacer strips 21, which may have inclined grooves for passage of moisture, are nailed to inserts 23 between the transverse flanges of segments 20, and backing 24 is fixed thereto ; reinforcement 26 is spaced from the backing by concrete blocks &c. 13 and tied to strips 21 by wire loops 29, and the lining is then applied. Transverse grooves 27 are formed in the lining to allow expansion, the grooves 27 being sealed by buckled copper strips 28. Preformed abutments 30 for the lining have drainage slots 31 and have extending rods 32 later covered by the lining. Auxiliary abutments 33 or 34 are provided. In inclined tunnels, thrust collars are provided coinciding with expansion joints 41, Fig. 4, and comprising concrete 42, with a step 43, applied to a transverse row of segments 36 before application of the lining and provided with projecting rods 44 for connection to the reinforcement of the lining. In Fig. 5, a flat ceiling 46 is formed before the lining 47, a bitumen strip 52 being placed between the parts which are held by rag-bolts 49. In Fig. 6, a tunnel formed of concrete 54 with transverse steel joists 55 has angle bars 59 or a ledge of concrete for support of the spaced lining 58. In another form, the lining consists of a semicircular ceiling carried by longitudinal abutments on spaced pilasters. Instead of using separate spacers, the backing may be provided with corrugations &c. 78, Fig. 20. In Fig. 12, the lining comprises walls 80 and a ceiling of twin arches 81 abutting against a joist 82 on spaced columns 83, spaced thrust pieces 84 being provided, and the backing of the arches being secured to curved ribs 86 ; drainage holes 87 are provided. The ceiling may be supported from pre-cast concrete beams which may be closely spaced. The backing may consist of reinforced bitumen felt, sheet-metal, or asbestos-cement, and the lining may be formed in one or more layers. The cavity behind the lining may be used as a ventilation duct. A raised floor may be provided, constructed similarly to the lining, to leave a cavity for drainage.