Nice way to move a mountain
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WORK on extending Nice airport includes the construction of a new runway on land reclaimed from the sea. The amount of fill required for this project approaches 30 million tonnes of rock and earth which has to be moved from a hillside about I0km away. And the contractor has decided to use a fleet of specially adapted road vehicles in a muck-shift operation of a pattern not seen before in Europe.
The vehicle equipment selected for this mammoth task includes Saviem 6 x 6 tractive units, type 38.320, and specially built side-tipping semi-trailers.
By using an exclusive haul road closed to all other traffic restraints on operating weight were lifted to allow full advantage to be taken of the performance characteristics of the Saviem tractors.
Each of the 27 units is in fact worked as a double-bottom combination at an all-up weight of 145 tonnes. The nature of the ground traversed by the French " merry-go-round " road trains is reflected in a number of bends and gradients with a maximum of 1 in 12 at the exit of a tunnel under the existing runway. The tractors are powered by the V 10 D 2530 MF diesel engines of 15,945cum which drive through ZF 18-speed transmissions including two crawler and two reverse ratios. Reduction in low ratio bottom gear is 13.1:1.
Joint
Heavy-duty power take-offs are fitted for the hydraulic pumps supplying the tipping gear on the twin semi-trailers which are to a joint design by Marrel-Fruehauf. The transfer box for the front and bogie drive has two ratios, 1:1 and 1:1.83, and there is provision for elect ro-pneumatic selection of differential and inter-axle locks.
Final drive is through hub reduction in the 8-tonne front axle and 16-tonne bogie axles. Maximum imposed fifth-wheel load is 28 tonnes.
Tyre equipment, twinned on all drive and trailer axles, is 12.00-24 Michelin XR, and the average payload carried on each trip to the site is around 90 tonnes—about 24cum in each trailer. The second trailer in each combination is of a four-axle lay-out with the drawbar from the twin turntable semi-permanently attached to the main frame of the leading (semi) trailer. Bodywork is arranged to tip to one side only with horizontally divided sideboards operated automatically and controlled from the cab.
Compound
The working cycle involves continuous operation over a I6-hour period each day and it is estimated that the three-year project will require a total of 350,000 trips clocking up around 7,350,000km for the fleet.
To back up the full availability of each link in this "conveyor belt "operation a special service organisation, staffed by six fitters, has been established in a compound on the airport site. A purpose-built unit equipped with the most modern servicing and lubrication facilities enables the carefully planned maintenance programme to be carried out after each vehicle has completed 4,000km (after an interval of seven to 10 days). Units are washed in a bay set aside for this purpose and then inspected.
Mechanical examination and rectification of any defect is then carried out in a programme which was prepared for this unusual operation by the manufacturer. Apart from dayto-day expendable items and stocks of emergency spares held on site the local Saviem depot has also been brought into operation "Nice Airport" by allocating a section containing more than £60,000 worth of back-up parts and tools.