Micro-tunneling/Pipejacking

Micro-tunneling/Pipejacking

We at GEP provide a range of Micro tunneling services. This technology is intended to install pipelines with a minimum of surface disruption. Micro tunneling is used primarily for the installation of large diameter of sewer , oil & gas and water pipelines. It is also used for culverts and subways. Usually these pipes are installed at low depths that are five meters or more.

The process may defer based on project requirements. However, the overall process consists of the following:

1. Depending on soil conditions, this method may require deepwells for dewatering purposes to be drilled at intervals along the span according to existing water level.

2. A rectangular shaft is excavated of max. 6,700 x 5,000 mm or min. 5,700 x 3,500 mm to suit site conditions. A separate drawing will be submitted for each location.

3. 200 mm thick concrete base will be provided at the bottom of each shaft.

4. Prefabricated jacking rail is lowered into the shaft.

5. A leading pipe “steel sleeve” is then lowered into the shaft and set on the rail.

6. The leading pipe is then jacked into the soil by two hydraulic jacks, 300 tones each.

7. Skilled miners then carry forward the face excavation until sufficient clearance is achieved. The jacking operation is then repeated.

8. This action of excavation and jacking continues until the leading pipe is fully buried into the ground.

9. When the leading pipe is fully buried the next section of the sleeve (each between 2,000 or 3,000 mm in length depending on the shaft size) is lowered and connected to the tail end of the leading pipe by a steel collar to give some flexibility to the directional operation.