Abstract: Based on assumed pendular state of isolated pore water, general thermodynamics theory, numerical and statistical methods, the former analytical procedure proposed in literatures is employed to study diverse suctions in state B, compact accumulation model composed of ball-shaped particles with discontinuous water and continuous air (DWCA) in its void. Development law of the three types of suctions as well as corresponding equivalent suctions with increasing saturation degree, and expression for suction ratio with contact angle and saturation degree or saturation radius as the two parameters are derived for unsaturated material in state B. The results of numerical method show that suction ratio is less than 1 in state B; and that is very different from that in state A, the incompact accumulation model composed of ball-shaped particles with DWCA. Therefore, it can be concluded that effect of tension suction on shear strength and deformation of unsaturated granular materials, usually unsaturated soils, will fall down to a certain extent comparing with that of matric suction with increase of compactness. With change of saturation degree, variation trend of the three types of suctions, especially the three equivalent suctions in state B is basically coincident with that in state A. Both in state B and in state A, logarithmic suction ratio is distinctly linear to saturation radius. Furthermore, relationship between suction ration and saturation degree in state B is linear too; but this is very different from that in state A.

Key words: unsaturated soil, compact accumulation, state of discontinuous water with continuous air, suction, suction ratio