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Total engineering for underground projects

As a total engineering company for underground projects, we solve problems by mobilizing our expertise, technologies, and experience to make holistic decisions. Specifically, based on some 30 proprietary technologies such as ground improvement, earth retaining, rock processing, and contaminated soil treatment, we seek to make the most of the expertise and experience gained since our founding and establish a one-stop system that offers services ranging from design to technology development and production of core components, thereby visualizing construction work that is typically hard to envision.

Business areas

Solving ground issues


  • Earthquake

    Seismic strengthening / Liquefaction Mitigation

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  • Renovation

    Protecting Building / Important cultural properties

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  • Environment

    Soil remediation

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  • Infrastructure

    Dam / Highway / Tunnel

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  • Disaster Restoration

    Restoring for infrastructure and damaged structures

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  • Disaster Prevention

    Embankment reinforcement

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Structures continue to grow taller, bigger, and deeper. Such structures require strong grounds. In renovations of buildings and structures built soon after World War II, both the buildings and the foundation ground must be sound. These structures must also stand prepared to resist major earthquakes, like the Tokai, Tonankai, Nankai, and Tokyo Metropolitan epicentral earthquakes, which can occur at any time. In addition, plant relocations and land transactions frequently uncover soil contamination issues. We help clients solve their issues, drawing on optimal technical and cost-effective methods, including strengthening of underground foundations supporting buildings and underground structures against earthquakes, earth retaining or ground reinforcement necessary for underground construction, watertightness improvement of foundation rock for dam construction, slope stabilization to prevent earth flow and rockfall, and contaminated soil remediation.

The scope of our services

Total engineering for underground projects ranging from technological development to design and execution.


Based on our mission statement of becoming a technology-oriented company, we put emphasis on exerting originality and ingenuity through in-house development of state-of-the-art technologies, while specializing in ground improvement, contaminated soil treatment, earth retaining, and rock processing. We have been granted more than 100 major patents over the course of more than 50 years and license these patents across the world, including in Europe and in the US.


Our design division is staffed by expert engineers familiar with various types of work and execution methods for soil and foundations. These engineers offer optimal technical proposals after assessing multiple types of work and execution methods, including work done before and after the main work, in addition to the method applied to the project.


Ground varies from site to site. Before construction begins, we anticipate various potential problems. During the construction process, we seek to detect anything unusual and to take appropriate measures. When construction is completed, we add our experience to a database that informs and improves our subsequent construction.


Tailor-made system

Our tailor-made system allows the diameter and strength of columns to be set freely. With this system, we propose total and optimized engineering for specific sites.

Aseismic reinforcement and Liquefaction Mitigation

The large-scale liquefaction caused by the Great East Japan Earthquake resulted in widespread and massive damage, including toppled buildings and road surface cave-ins. In the Tokai, Tonankai, and Nankai regions, forecasts indicate the very high likelihood of an earthquake with a seismic intensity of lower 6 within the next 30 years. An earthquake of this scale could strike at any time. We achieve total cost savings for our clients through proprietary technologies that allow aseismic reinforcement and liquefaction countermeasure works to be executed even from limited spaces on the ground, leaving existing buildings unaffected.

Disaster prevention

A number of unprecedented disasters, including the Great Hanshin Earthquake, Chuetsu Earthquake, and Great East Japan Earthquake, have occurred successively in recent years. Experts state that similar major earthquakes may occur at any time in the Tokai, Tonankai, and Nankai regions. Recent recurring sediment disasters caused by torrential rains have caused serious damage and fatalities. Many locations remain keenly vulnerable to such disasters.
With our accumulated know-how, we can offer comprehensive disaster preparedness solutions.


Historic structures, valuable as cultural assets, often face numerous problems. After long periods of time, foundations may sink or buildings may age.
We handle renovations that preserve such historic structures, making the most of long-established underground construction technologies and execution skills, including Jet Grouting. Our track record includes the preservation and rebuilding of the Osaka Branch of the Bank of Japan in 1978 and the preservation and restoration of the Marunouchi station building of the Tokyo Station in more recent years.

Disaster restoration

Damage caused by natural disasters, including earthquakes, typhoons, abnormal torrential rains, and tornadoes, has grown increasingly severe in recent years.
To contribute to the fastest possible recovery in stricken areas, we work as partners in emergency restoration efforts involving the transportation infrastructure, including expressways and Shinkansen, and private industrial facilities, such as power plants, ironworks, and oil refineries, all linchpins of recovery. Following the Great East Japan Earthquake, we took part in several projects, including filling the foundations of Shinkansen power poles and rebuilding expressway slopes, while proposing optimal designs for specific sites.

Environmental conservation

Issues related to environmental contamination continue to grow more serious. Soil and groundwater pollution is an inevitable problem in redevelopment projects that involve plant relocations and land transactions.
Our capabilities make us a leading one-stop general contractor for soil remediation. We perform surveys, negotiate with government agencies, implement containment measures, including barrier construction, and mount cleanup efforts, including removing and decomposing all harmful substances.
Beyond this, civil engineering works often involve the clearing of wooded areas or the alternation of riverbeds, resulting in the loss of natural habitats. This is not only a problem of environmental degradation. It has serious implications for ecological diversity and the sustainability of the society that depends on this diversity. We are working to restore lost habitats by drawing on our technologies for slope greening and improving riparian habitats.

Infrastructure improvement

Essential to our daily lives, infrastructure represents industry’s backbone. Japan’s future depends on the soundness of its infrastructure. Drawing on proprietary technologies, we’re contributing to improvements in transport facilities, such as roads, railways, airports, and sea ports; waterworks, sewerage systems, rivers, and other facilities for daily life; energy generating facilities; and communications facilities.