“Geotechnical Engineering” is the academic framework solving some of the issues concerning “earth materials (ground)”, which cannot be separated from our current life unless we move to space, by utilizing mainly physics (especially mechanics), chemistry, geography and mathematics, biology, earth science and so on.
There are also similar academic frameworks to Geotechnical Engineering concerning ground and earth's surface. They are Geology in the science field and Applied geology in between Geotechnical Engineering and Geology.
地盤工学とは、宇宙空間等に移住しない限りは人間の生活から切り離すことができない足元の地盤を対象として、主に物理学（特に力学）・化学・地学・数学の知見と、場合によっては生物学・地理学等の知見も活用して、問題解決に取り組む学問体系です。
同じ地盤を対象とした学問体系として、理学分野に地質学があります。対象領域や時間スケールをおおまかに区分すると地盤工学との境界領域として応用地質学もあります。
For instance, “soil liquefaction”, which is a phenomenon of sand ground behaving like a liquid due to an earthquake and causes severe damage to structures, i.e., overturning, lateral flow and damage to the foundation. This is one of the critical issues of geotechnical engineering. Soil liquefaction has been investigated for more than 30 years by several researchers since 1964 Niigata Earthquake.
However, 2011 Great East Earthquake caused soil liquefaction followed by the unprecedented catastrophical and wide range damage on houses, thus the current situation would not be sufficient for taking measures and soil liquefaction is still a critical issue for us.
例えば、地震時などに砂地盤が液体状になる「液状化」という現象があり、各種構造物が下記に示すような被害を受けてきました。日本では1964年の新潟地震以降、30年以上も研究が進められてきましたが、2011年の東日本大震災では未曾有の範囲と規模で住宅地被害が発生するなど、十分な対策は必ずしも実施されていないのが現状です。
Geotechnical Engineering still has many unknown and unexplained phenomena of ground and earth materials like soil liquefaction.
Such situation is similar to Medical Science since there are several unknown and unexplained characteristics of the human body as well. We compare a geotechnical engineer and a doctor as
(Investigation) Medical check ⇒ Borehole survey;
(Prior measures) Injections ⇒ Ground improvement and soil reinforcement;
(Rehabilitation) Treatment ⇒ On-site measurement.
The more you study and experience these geotechnical features, the more interesting you will find it. We have put effort into the fundamental laboratory test and the establishment of theory in Geotechnical Engineering.
地盤工学の特徴は、対象とする地盤に未知・未解明な領域が多数残っていることです。その意味では、（よくわかっていない）人間の体を対象とする医学の世界と類似しています。地盤技術者の仕事を医師と対比すると下記のようになりますが、経験を多く積むほど面白さが増してきます。土質/地盤研では、下記のうち土質試験に力を入れています。
事前に調べる（健康診断）⇒ 地盤調査・土質試験
壊れたり変形しないように対策する（予防注射） ⇒地盤改良・補強
不具合が生じたら修復する（治療・手術）⇒現地計測・逆解析
We supply a test apparatus for each student and researcher, and they conduct the high-precision and complicated experiment which can be done only by our laboratory. They also collaborate with each other to carry out the shaking table test and the model test. Almost test apparatus and devices are custom-made product and especially some of them are one and only in the world.
Moreover, we have seminars not only on geotechnical engineering but also on other subjects which are required to solve geotechnical issues from various viewpoints.
土質/地盤研では、一人の学生・研究員が各1台ずつ装置の使い方を学んで、他では実施することができないような高精度で複雑な土質試験に取り組んでいます。一方で、振動台実験で模型地盤を作製する際などには、共同作業することもあります。これらの試験や実験を行うための装置や器具の多くは特注品で世界に一台しか存在しないものもあります。
