Abstract
Applicability of tube sampling for Niigata sand deposits is discussed through bender element and cyclic triaxial tests for samples obtained from two-chambered hydraulic piston samplers (Shogaki, 1997) with inner diameters of 48 mm and 50 mm, a one-chambered 70 mm diameter sampler, a 125-mm rotary triple-tube sampler and the frozen (FS) sampling method (Yoshimi et al., 1989). The relationship between the relative density (Dr) and normalized SPT N-value (N1) obtained from small diameter samplers with inner diameters of 45 mm and 50 mm samplers was close to that of the FS and the N1 coefficient was greater than those of the 70-mm and other tube samplers. The stress ratio at 20 cycles (RL20) and the initial modulus of rigidity (GCTX) of samples obtained from the 45-mm and 50-mm samplers were greater than those of the 70-mm, 125-mm rotary triple-tube and other tube samplers. However, the RL20 values obtained from the 45-mm and 50-mm samplers were smaller than those of the FS sampler in the area of N1>24. The GBE and GCTX values obtained from the 45-mm and 50-mm samplers were close to those of the FS sampling. Therefore, the 45-mm and 50-mm samplers can take equally high quality samples for Niigata sand deposits.
