Repair of a burst on a cold feed alkathene line:
Dig up enough ground to be able to get some flexible movement of the pipe upwards or across. Either cut the burst section out as tightly as possible and slip the alkathene coupler over both ends or cut a wide gap in the pipe and use two alkathene couplings. Be sure to lubricate the O-rings inside the fitting to ease the pipe inside and past the ring without it rolling over and twisting. Then do up tight with two pairs of pump pliers.