Earthquake geo-disaster mitigation

Factors affecting liquefaction characteristics

The liquefaction characteristics of a certain soil are greatly affected not only by the soil density, but also by aging effects, pre-shearing by past earthquakes and liquefaction history.

We aim to realize a rational liquefaction assessment by studying the various effects on the liquefaction characteristics using advanced soil testing equipment.



Liquefaction strength assessment

We have proposed a method to evaluate in-situ liquefaction resistance that reflects the effects of soil fabric, previous earthquakes and liquefaction histories as based on the in-situ and laboratory-measured shear wave velocities.

The proposed method can potentially be effectively employed in engineering practice.



Damage strain of geomaterial and slope stability

The damage strain accumulated due to the earthquake motion reduces the strength of geomaterial and slope failure may be induced.

We clarify the strength-deformation characteristics of the geomaterial at a large strain level affected by the damage strain using an advanced torsional shear apparatus.

地震動により地盤に蓄積するひずみ(damage strain)によって、地盤の強度は大きく低下して斜面崩壊を誘発することがあります。

本研究では、高さ30cmの供試体に100%以上のせん断ひずみを与えることが可能な特殊な中空ねじり試験装置を用いて、damage strainの影響を受ける大ひずみレベルでの地盤の強度変形特性を明らかにします。

Liquefaction-induced road damage and hazard map

We examine the influence of thickness of road pavement and roadbed on liquefaction-induced road-subsidence through field surveys, airborne LiDAR and shaking table model tests.

A new hazard map is developed that quantitatively shows the expected liquefaction-induced damage to the road-network due to future earthquake.


Mechanism of long-distance flow-slide

We investigate the occurrence mechanism of long-distance flow-slide on very gentle slopes due to the 2018 Sulawesi Earthquake by means of field survey, model test, laboratory soil test, and numerical simulation.