Day 10 - Thursday 17 May - A detailed look at the drainpipe layer
Work continues throughout the day to lay the first 11 lateral drains at 10m intervals. Tomorrow work will start to lay another 11 lateral drains mid-way between those laid today.
So we take a detailed look at the special purpose piece of equipment, designed and built in the Mabbott workshops, to dig and lay 100mm diameter drains.
The device has a coil of pipe on the front of a tractor. The pipe is fed through a tube over the cab of the tractor, A large circular grinding wheel (like a heavy-duty circular saw) digs out the trench. The soil that’s been dug out is fed via an elevator into a waiting tractor-drawn trailer or dumper truck. The drainage pipe is fed from the top of the tractor into the trench. At the back of the device is a hopper filled with gravel which dispenses gravel into the trench covering the drainage pipe. From tine to time the hopper is re-filled with gravel. The three tractors move forward at a slow walking pace. Perfect synchronism of the three tractors is essential. The minimum team to carry out this operation is three. However, additional tractors and trailers removing the soil and filling the hopper speeds up the operation significantly.