Microtunnelling, a savvy method for crafting small diameter tunnels, stands out as a trenchless technique, minimizing disturbances to surface activities like traffic and business operations. This approach finds its prime application in laying pipelines beneath sensitive areas such as highways, railroads, and urban spaces.
Microtunnelling, thriving in sewerage, drinking water, and communication networks, is tailored for challenging ground conditions. The tunnels, ranging from 500mm to 4,000mm in diameter, rely on a remote-controlled microtunnel boring machine (MTBM) and the pipe jack-and-bore method for construction.
A mechanized mini boring machine with a cutter head, using a laser guidance system for real-time feedback to the operator. Steering is facilitated by a steering jack during drives.
High thrust hydraulic jacks on a frame exert force against a thrust wall, propelling pipes and shields through the ground.
Discharge pumps carry slurry through a circuit, separating coarse material in a vibrating screen. Fine material is further separated in cyclones.
A laser beam device on the jacking shaft sets the desired level, gradient, and alignment. Some machines have photosensitive cells for converting laser portions into digital data.
Operates the shield and other equipment, measuring, monitoring, and recording crucial data while displaying faults on a monitor.
Understanding ground conditions and microtunnelling equipment capabilities is vital for positioning pipelines. Analyzing past projects helps identify obstructions along the proposed tunnel route, optimizing the location of shafts and drive lengths to save costs.
Conducting numerous borings, test pits, and lab tests is essential for successful planning, bidding, and project execution. Test pits or large diameter bucket borings are recommended for sites with cobbles and boulders.
Standard index testing provides reliable information. Grain size analysis with hydrometers determines clay fraction, aiding in screen size determination, hydrocyclone quantity, and potential use of a centrifuge system.
Based on planning results, the microtunnelling system is selected for optimal productivity and minimal risk.
In conclusion, microtunnelling, with its intricate planning and streamlined construction process, emerges as a sophisticated solution for creating tunnels with minimal surface disruption.