Pipeline Construction Method.
1. Open-cut Method – This is a trench construction method that shall be excavated as per surveyed route line. Open-cut method shall be applied by heavy equipment. The depth of trench shall be conformed to the specification requirement (1.5 m. top of soil minimum).
2. Horizontal Direction Drilling – This is a trenchless construction method that employs a directional drill to bore a horizontal tunnel. The tunnel is then reamed to remove the spoil and may be filled with bentonite slurry to maintain tunnel stability. The pipeline is assembled aboveground, pulled or pushed into the tunnel and anchored.
3. Pipe Jacking Method – This is a trenchless piping construction method that pushes the pipe into place (pipe jacking) behind a tunnel boring machine that is device controlled. The boring machine is connected to the head of the pipe that follows the slightly oversized tunnel as it is drilled.