Building Foundation andGeotechnical Laboratory
Outlines
The
Building
FoundationandGeotechnical Laboratory is a facility forconducting experiments on foundation
structures and soil mechanics. In thelaboratory, we perform research anddevelopment activities to contributekeepingseismic
structuralandgeotechnicalsafetiesofbuilding
foundations from the viewpoint ofproperty preservation and functional
continuity of buildings.

Outer view of the laboratory

At the end of September 2020, we removed a shaking table with a large-scaled (10-mlong x 3.6-m wide x 5-m depth) shear box and have then constructed a 3.5-m radius
dynamic geotechnical centrifuge possessing a 1-m squares shaking table. Furthermore,
we have a large-scaled triaxial cyclic loading test equipment, that can measure strengthparameters of soils under realistic ground constrain conditions.

Research Contents
Our research topics mainly follows.
(1) Damage to pile foundations during huge earthquakes and their structuralperformances(2) Design methods of building foundations against strong ground motions(3) Design methods of ground improvement for seismic strong motions and theirapplication to the remained piles problems(4) Soil liquefaction at housing land(5) Seismic performances of housing land and retaining wall at slope

12 Building Foundation and Geotechnical Laboratory

Facilities(1) 3.5-m dynamic geotechnical centrifuge
Our 3.5-m centrifuge has been constructed to understand dynamic response
characteristics and damage procedures of building foundations including soil-structureinteraction effects during earthquakes and to develop remedial or preventive measuresagainst structural and geotechnical earthquake disasters. The 1-m squares shaking
table installed on the centrifuge can simultaneously be forced in both horizontal andvertical directions. Typical specification of the centrifuge system follows.
Loading capacity
Max. centrifugal acceleration
Max. velocity of shaking table
Max. acceleration of shaking table

100tG
50G
100cm/s horizontally 30cm/s vertically
50G horizontally
25G vertically(G is gravity acceleration = 980cm/s2)

Outer view of the centrifuge

Test pit

1-m squares shaking table

Machine pit

12 Building Foundation and Geotechnical Laboratory

Shear box for the centrifuge

Control room of the centrifuge(2) Large-scaled triaxial cyclic loading test equipment
This equipment can reproduce naturalconfining state of soil at a maximum
depth of about 20 m. Dynamic soil stresssituation during earthquakes can bemade by using the equipment, and thesoil liquefaction test can also beperformed. This apparatus is a pressurechamber in which a specimen having a
diameter of 1.5 m and a height of 3 m isconstructed. There are four tubes that
get into the upperpart of the chamber,and some kinds of ground investigation
tests can be conducted. The automaticmanagement system enables us to adjust
various test conditions such as cellpressure, axial loads, and backpressure.
Typical specification of the equipment
follows.

Max. cell pressure
Max. backpressure
Stroke0.6MN/m2
0.2MN/m2
250mm

Max. axial load
Max. loading thrustMax. loading speed

12 Building Foundation and Geotechnical Laboratory

2MN/m24MN
130mm/s