A METHOD FOR CORRECTING CONSOLIDATION PARAMETERS FOR SAMPLE DISTURBANCE USING VOLUMETRIC STRAIN

抄録

Sample disturbance was investigated in terms of the volumetric strain of an oedometer specimen, ε_υο, at in-situ effective overburden pressure, σ'_υο, determined from the 24-hour e-log σ'_υ curve. Unconfined compression and oedometer tests were performed on samples of natural deposits from ten different sites in Japan. The ε_υο value has a unique correlation with the plasticity index, I_p, σ'_υο, overconsolidation ratio, OCR, and degree of sample disturbance. The ε_υο values of the in-situ sample before intentional disturbance in the laboratory were in the range of 0.85% to 7.02%, and the average was 3.80%. The ε_υο values of the completely remolded sample were in the range of 7.52% to 23.07% and the average was 15.75%. The ε_υο value, resulting from intentional sample disturbance in the laboratory, is given as a function of the ratio of unconfined compressive strength, q_u, of sample disturbed in the laboratory to that of the in-situ sample. A procedure for obtaining values of strength and consolidation parameters of an in-situ soil, and a method for estimating the preconsolidation pressure, σ'_p, compression index, C_c, e-log σ'_υ curve, and coefficient of consolidation, c_υ, values for the in-situ soil are proposed from the I_p and the measured values of ε_υο, σ'_p, C_c, and c_υ for disturbed samples in the standard oedometer test.