Anisotropic Consolidation Behavior of Ariake Clay from Three Different CRS Tests

摘要

Three types of constant rate of strain (CRS) consolidation tests were conducted on samples of undisturbed Ariake clay, using a newly developed consolidometer, to investigate the anisotropic consolidation behavior of the clay. CRS tests conducted using vertically cut specimens (with respect to the in situ condition) tested with vertical (or end) drainage (with respect to test condition) were designated as CRS-V-V tests. Specimens cut vertically but with radial drainage were designated CRS-V-R, whereas those cut horizontally and tested with vertical drainage were designated CRS-H-V. The test results show that the ratio of the consolidation yield stress of a horizontally cut specimen (p_(ch)) to that of a vertically cut specimen (p_(cv)) is in a range from 0.5 to 1.0. Both p_(cv)and p_(ch) increased about 15 % with a tenfold increase in strain rate, but there was no clear difference in the degree of strain-rate dependency for p_(cv) and p_(ch). Values of the coefficient of consolidation obtained from CRS-H-V (c_(hh)) and CRS-V-R (c_(hv)) test are larger than those measured in CRS-V-V (c_v) tests, and it has been identified that these differences arise mainly from the ani-sotropy of hydraulic conductivity (k). The ratio of k in the horizontal direction (k_h) measured in a CRS-V-R test to that in the vertical direction (kv) from a CRS-V-V test is about 1.65, and the ratio of c_(hv)/c_v is about 1.54. The value of k_h from a CRS-H-V test is generally smaller than that from a CRS-V-R test.