The velocity dispersion and attenuation in 6 kinds of water-saturated glass beads and 4 kinds of water-saturated silica sands with different grain sizes are measured in the frequency ranges of 80-140 kHz and 300-700 kHz. The measured results are compared with the calculated results by using the BIMGS model plus some acoustic models. It is shown that the velocity dispersion and attenuation is well predicted by using the BIMGS model in the range of kd < 0.5 (k : wavenumber in water, d : grain diameter) and by using the BIMGS model plus multiple scattering effects in the range of kd > 0.5 in which negative velocity dispersion appears.%水で飽和させた粒径の異なる6種のガラスビーズおよび4種の珪砂の高周波域での音速分散および減衰特性を測定した．その測定結果とBMGSモデルにいくつかの音響モデルを組み合わせたモデルを用いた計算結果との比較検討を行った．その結果，音速分散および減衰は，kd≦0.5（た：水中の波数，d：粒径）の範囲ではBIMGSモデルで，また負音速分散特性が現れるkd≧0.5の範囲ではBIMGSモデルに多重散乱モデルの効果を取り込むことで予測できることを明らかにした．
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