EFFECTS OF AIR BUBBLES ON B-VALUE AND P-WAVE VELOCITY OF A PARTLY SATURATED SAND

Shuji Tamura, Kohji Tokimatsu, Akio Abe
and Masayoshi Sato

ABSTRACT: The effects of the size and solubility of air bubble on B-value and P-wave velocity of a partly saturated sand are discussed. The relations between B-value and P-wave velocity are determined for large triaxial specimens with Dr=64% and 84%. Theoretical formulas have been derived for determining P-wave velocity of a partly saturated sand containing air bubbles. It is shown that: (1) The solubility of air bubbles in the pore-water affects the relations between B-value and P-wave velocity, significantly; (2) The practical coefficient of solubility of air bubble pressured in the pore-water is about 0.002; (3) The B-value and P-wave velocity increase with a decrease in the air bubble size. This tendency is significant, when the diameter of the air bubble is less than about 0.005mm.

Key words: air bubble, B-value, coefficient of solubility, degree of saturation, P-wave velocity (IGC: D7/E8)