June 18, 2024
Global Tunnel Boring Machine

Global Innovations in Tunnel Boring Machine Technology

The Rise of Tunnel Boring Machine Industry

Over the past few decades, Global Tunnel Boring Machine have revolutionized the field of underground construction. Where tunnels were once built through conventional drilling and blasting methods, TBMs now efficiently bore tunnels deep underground with minimal disturbance at the surface. The first TBMs emerged in the mid-20th century, pioneered in soft ground by engineers in America and Japan. Early machines were slow and prone to breakdowns, but design improvements steadily increased reliability and speeds. By the 1970s, hard rock TBMs able to bore through granite and basalt became commercially viable. The innovation of TBM tunneling transformed major infrastructure projects worldwide and opened new possibilities for transportation and utility networks.

Advancing Cutting Head Technology

A key factor driving increased Global Tunnel Boring Machine performance is advances in cutting head design. Modern hard rock TBMs utilize cutting heads mounted with heavily-toothed cutting tools that efficiently crush rock into muck as the cutter face rotates. Early models relied on simpler disc cutters that proved inefficient for harder rock types. The development of impregnated and superabrasive cutters utilizing polycrystalline diamond compact (PDC) and tungsten carbide formulations greatly boosted cutting rates. Meanwhile, roadheader-style cutting heads with articulated disc cutters facilitated tunneling through variable geology. Improved hydraulics and heavier cutter profiles also enable application in harder and more abrasive rock conditions. Contemporary TBM cutterheads feature modular design and sensors that precisely monitor cutter wear for replacement.

Greasing the Gears of Mechanized Tunnel Boring Machine Industry

Effective muck removal lies at the core of efficient Global Tunnel Boring Machine. Initial designs conveyed muck out of the cutterhead face via screw conveyors, but these created bottlenecks. The widespread adoption of slurry shield TBMs in the 1970s revolutionized muck removal. By mixing muck into a slurry using pressurized water, slurry shields maintain a continuous removal circuit without impeding the cutting process. Further enhancements like dualscrew muck cars and high-pressure slurry pumps boost removal rates. Modern hard rock TBMs pair multi-chambered muck presses with impermeable tail shields to optimize the slurry circuit. Remote process control now monitors pressures and flows throughout the removal system. Combined with advances in cutting and reinforcement, optimized slurry technology underpins record boring speeds achieved by contemporary TBMs.

Guiding Tunneling Accuracy with Sensors

Ensuring Global Tunnel Boring Machine accuracy during long distance drives remains crucial. Early mechanical guidance relying on plumb bobs and optical alignment proved insufficiently precise for deep bore tunnels. The integration of advanced electronic sensors starting in the 1980s revolutionized tunneling guidance and control. Modern TBMs now feature integrated systems fusing data frommultiple sensors. Propulsion is precisely vectored by feedback from laser rangefinders, inclination meters, gyroscopes and multi-arm caliper gantries that monitor face position in 3D. Distributed sensor networks installed ahead of the TBM further map tunnel line and grade. Onboard computers process real-time data to automatically steer the cutting head within millimeter tolerances using hydraulic thrust cylinders. This closed-loop guidance enables boring large diameter tunnels over many kilometers with alignment maintained within design specifications.

Global Tunneling Projects Push the Limits

Spurred by technical innovations, tunneling projects have expanded in scope and complexity. Among the most ambitious is the 57.5km Gotthard Base Tunnel connecting Switzerland and Italy, completed in 2016 using five giant up to 18m in diameter. In Asia, China has undertaken a new era of “megatunneling” with the completion of the 102km Taihang Mountain Tunnel on the Beijing-Hong Kong high-speed rail line in 2011.

North America too is seeing a resurgence in major tunnel projects like the 28km Site C hydroelectric project in Canada and the ongoing expansion of Washington D.C.’s Metrorail system. As TBM technology matures, the possible applications for underground infrastructure seem limitless whether constructing high-speed rail lines, transportation hubs or water supply networks. With continued innovation, tunnel boring machines will remain at the forefront of constructing an increasingly interconnected global subterranean realm.

1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it