37
Honour Lectures /
Conférences honorifiques
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
3
7. Model-pile Calibration Chamber cyclic loading experiments.
8. Cyclic soil element tests to replicate pile loading conditions.
A common theme is that sands show strong non-linearity,
plasticity and time dependency from very small strains and have
markedly anisotropic properties. It is argued that their overall
responses can be understood within a critical state soil
mechanics framework, provided that the above features are
accommodated and the importance of particle breakage is
recognised, especially under high pressures and within abrading
shear bands. Space constraints limit the details that can be
reported for the various studies cited, or the reviews that can be
made of research by other groups. However, PhD theses and co-
authored articles are cited to cover the main omissions.
2 CHARACTERISING STRESS-STRAIN BEHAVIOUR
Bishop recognised at an early stage that geotechnical stress-
strain measurements are constrained heavily by equipment
capabilities. ISSMGE Technical Committee 29 (now TC-101)
was set up to coordinate advanced laboratory developments,
leading to a review of apparatus, sensors and testing strategies by
Tatsuoka et al 1999. The hydraulic stress path cells and Hollow
Cylinder Apparatus (HCA) advocated by Bishop and Wesley
1974 and Bishop 1981 allow in-situ stress conditions to be
imposed and studies made of shear strength anisotropy; see for
example Hight et al 1983 and Shibuya et al 2003a,b. Burland and
Symes 1982 and Jardine et al 1984 went onto show that end-
bedding, sample tilting and compliance caused very large errors
in conventional geotechnical strain measurements that often led
to completely misleading soil stiffness characteristics. Local
strain sensors or dynamic non-destructive techniques are
required to obtain representative data: see Tatsuoka et al 1999.
Laboratory research with such equipment that contributed to
the first phase of research that advanced the “Dunkerque
agenda” included the PhD studies of Porovic 1995, who worked
with a Resonant Column (RC) equipped HCA and Kuwano 1999
who developed dual-axis Bender Elements (BE) and enhanced
resolution local strain sensors for stress-path triaxial tests.
Porovic worked mainly with Ham River Sand (HRS), a silica
sand graded from Thames Valley gravels that has been tested
since Bishop’s arrival at Imperial College and is now known
generically as Thames Valley Sand (TVS); Takahashi and
Jardine 2007. Kuwano studied Dunkerque sand, spherical glass
ballotini and HRS; Connolly 1998 undertook RC and HCA
experiments on Dunkerque sand. The sands were tested saturated
after pluviation to the desired initial void ratios; Table 1 and Fig.
4 summarise their index properties. Figures 5 to 7 illustrate the
apparatus employed in this first period of ‘sand’ research. We
consider studies with the Thames Valley (TVS) and French
Fontainebleau NE34 sands later in the paper.
Table 1. Index properties of silica sands employed in laboratory studies.
Sand Specific
gravity (G
s
)
d
10
(mm)
d
50
(mm)
d
90
(mm)
C
u
e
max
e
min
Dunkerque
2.65
0.188 0.276 0.426 2.27 0.97 0.51
NE34
2.65
0.150 0.210 0.230 1.53 0.90 0.51
HRS
2.66
0.190 0.283 0.312 1.64 0.85 0.55
TVS
2.66
0.160 0.250 0.265 1.67 0.85 0.55
0.01
0.1
1
10
0
20
40
60
80
100
Percentage fine by weight (%)
Particle size (mm)
Dunkerque, Kuwano(1999)
new-HRS Kuwano (1999)
NE34, Yang et al. (2010)
TVS, Rimoy & Jardine (2011)
Fig. 4. Summary of particle size distributions for granular media
employed in reported laboratory research
Fig. 5. Automated hydraulic stress path triaxial cell for 100mm OD
specimens employed to investigate non-linear, anisotropic, pressure and
time-dependent stiffness of sands: Kuwano and Jardine 1998, 2002a
