Effect of artificial cementation on cone tip resistance and small strain shear modulus of sand

摘要

A series of cone penetration and bender element tests were performed on sands artificially cemented with gypsum in a calibration chamber to investigate the effect of cementation on the cone tip resistance (q_c) and small strain shear modulus (G_(max)) of sand. It was found that both the q_c and G_(max) of cemented sand are significantly affected by the degree of cementation while the effects of stress and density are reduced due to the cementation bonds. As the degree of cementation increases, the relationship between the q_c--G_(max)-σ'_v of cemented sand is observed to be similar to that of quartz sand with low compressibility. As the density and stress level affect q_c more significantly than G_(max), the G_(max)/q_c of cemented sand decreases with increasing q_c. However, as the cementation causes a larger increase in G_(max) than q_c, the G_(max)/q_c ratio of cemented sand increases as the gypsum content increases. It was also observed from the G_(max)/q_c - (q_c/p_a)(p_a<σ'_v)~(0.5) relation that the G_(max)/q_c ratio of cemented sand locates above the upper bound suggested by previous studies.