The Kajima Smart Tunnel Boring Machine from Kajima Corp. - high-precision digging for Japan’s mega projects

Reviewed: ad hoc news New Release & Launch desk. Edited and checked on 2026-06-23, 04:14. Details in the imprint.

the Kajima Smart Tunnel Boring Machine stands deep underground in a damp launch shaft, its cutterhead coated in pale grey muck and LED work lights bouncing off wet concrete. Operators in hard hats watch from a control cabin where the TBM’s data screens glow quietly.

Sensor-heavy tunnel workhorse

Kajima Smart Tunnel Boring Machine is designed for urban rail and road projects where millimetres matter and surface buildings sit almost directly above the tunnel crown. The machine combines conventional shield tunneling with dense arrays of pressure, tilt and ground-movement sensors along the shield body.

In practice, that means the machine’s guidance system constantly adjusts thrust and cutterhead rotation to hold alignment, while a ring of grout injection ports stabilises the surrounding soil. The operator feels more like a pilot than a traditional miner, steering by screen and joystick rather than raw vibration in the controls.

What sets Kajima’s TBM apart

Unlike generic tunnel boring machines hired in from global rental fleets, Kajima’s latest shield model is tailored to Japan’s soft ground and cramped job sites, with a compact back-up train and modular gantries that fit shorter launch shafts. That helps when a shaft has to be squeezed into a narrow Tokyo side street.

The cutterhead can be configured for both mixed ground and full-face rock, with replaceable cutting tools accessible from behind the head so crews do not have to enter the pressurised chamber as often. That lowers intervention time and makes the machine feel less punishing for maintenance teams on long drives.

Remote monitoring and control

Kajima’s engineers pair the hardware with cloud-linked monitoring so geotechnical teams in site offices can watch settlement trends and machine performance in near real time. That has become standard on major Japanese infrastructure sites, but Kajima’s in-house tunneling teams stress how tightly the software ties into their design models.

Project managers such as Masaki Matsumoto, who has overseen multiple shield drives, describe how the live data allows them to tweak face pressure and grouting recipes before settlement shows up at the surface. For residents above, the only sign of the machine is often a faint rumble and occasional night-time road closure.

How it feels on site

Step into the operator cabin and you first notice the hum of hydraulic pumps and the constant crunch from the cutterhead echoing through the steel shell. The floor vibrates, but the displays on the panels stay sharp, with line graphs tracking torque, thrust and face pressure in clean colours.

Operators wear thin work gloves because the joysticks and control pads respond to light inputs, more like a simulator than an old mechanical rig. When the machine advances to erect a new segment ring, the slight jolt through the seat reminds you that thousands of tonnes of soil are being pushed aside just a few metres away.

Where it fits in Kajima’s portfolio

Kajima’s TBM capability is part of a broader civil engineering toolkit that also includes bridges, high-speed rail and foundation work. The company often acts as main contractor on long tunnel projects, then redeploys its machines to new sites, spreading the capital cost across multiple jobs.

For investors, the Smart Tunnel Boring Machine itself is a tool rather than a profit centre, but it underpins orders in transport, water and energy infrastructure. Those projects typically run for years and give Kajima a steadier revenue base than pure building construction cycles.

Stock and company context

Kajima Corp. is one of Japan’s largest general contractors, listed in Tokyo under the securities code 1812 and ISIN JP3270000007. On the Tokyo Stock Exchange, the Kajima share price is a common reference point for global investors seeking exposure to Japanese infrastructure spending.

This article was AI-assisted and editorially reviewed. Product information without guarantee; prices and availability may change at short notice. No investment advice, no buy or sell recommendation. Stock-market transactions involve risks up to total loss.