The trenchless method is an alternative to open trench excavation where there is a need to minimise surface level disruption and surface restoration cost.
This method is advantageous for the installation of cables or pipelines along routes that could be obstructed by manmade elements (such as pavements, monsoon drains or building structures) or natural elements (such as rivers and forests), or in areas that are difficult to access.
There are generally 2 types of trenchless methods, namely Horizontal Directional Drilling (HDD) and Pipe Jacking.
HORIZONTAL DIRECTIONAL DRILLING (HDD)
We used specialised HDD machines and drilling procedures to install underground cables or pipelines, which can avoid natural and man-made objects such as roadways, rivers and etc.
After establishing the routing, an “entry site” and “exit site” will be identify and we will pilot drill small diameter hole along the established route. A reamer will be used to enlarge the diameter hole.
Fused/Joint ipelines then will be inserted and pulled back from the “exit site” to the “entry site”.
PIPE JACKING METHOD
This method is for installation of prefabricated pipes by thrusting pipes through the ground.
We use hydraulic jacks to push pipes through the ground behind a shield, while at the same time horizontal excavation is taking place within the shield.
This minimises surface disturbance such as traffic disruption and disturbance to public with regards to the noise, dust and vibration.
We adopt 2 techniques of pipe jacking in our operations, which are Microtunneling (slurry) technique and Manshield technique.