GB1362978A - Dams - Google Patents

Abstract

1362978 Dams STRABAG BAU-AG 9 Dec 1971 [9 March 1971] 57338/71 Heading E1H A dam provided with coarse rock faces (5a, 5b Fig. 3 not shown), includes a core packing 1a, 22, 1b Fig. 4, preferably of interengaging mineral particles in a bituminous matrix which packing contains at least one filter bed 2, preferably of non-bitumenised interengaging mineral particles, both the core packing and the filter bed extending along the whole length of the dam and resting on a toe wall 4 provided with preferably spaced drainage compartments 6 communicating with the filter bed 2. Any water leaking through the packing is discharged through the bed 2, compartments 6 and outlet pipes 10. An inspection of the discharges through the pipes 10 indicates which portions of the dam are leaking. Alternatively as shown in Fig. 2 the drainage compartments 20a-d are grouped together at the lowermost part of the dam, water leaking into the filter bed from vertical sections k1-k4 being conducted to the compartments 20a-d and associated outlet pipes through channels 19a-19c between sealing strips 18a-18c in the filter bed 2. The strips 18a-18c may be formed of waterproof synthetic resin foil, or comprise thin sections of the core packing material interposed between the filter bed forming material (Fig. 6 not shown). Similar groups of sealing strips e.g. 14a-14c discharging to further drainage compartments 16a-d in the toe wall 4 may further subdivide the dam into groups of sections k1-k4 and k5-k8 to facilitate location of leaks in the dam. When the dam is partially submerged on its downstream side, a second filter bed 2b with corresponding drainage compartments 6' in the toe wall 4 may be provided to show if leakage is occurring through the upstream or downstream portion of the core packing. To form each layer an apparatus shown in Figs. 8 to 10 is advanced along the dam and simultaneously coarse rock for forming the outer faces is deposited from grab 36 over roof member 25 and levelled by a blade 27, bitumenised mineral material for forming the core packing is supplied through a hopper 28 and levelled by sliding gates 30 and non-bitumenised mineral material for forming the filter bed is supplied through an inner hopper 29 and levelled by sliding gate 31, the deposited materials being kept separated at this stage by partitions 23, 23' 24, 24'. The thus deposited materials are tamped by reciprocating compactors 33-35. Heat radiators 37, 37' heat the bitumenised mineral particles of the uppermost layer, as the apparatus moves over it whilst laying a fresh layer to bond the layers.