Shunzo Kawajiri

STRENGTH CHARACTERISTICS OF COMPACTED SOIL WITH PARTICULAR REFERENCE TO SOIL STRUCTURE AND ANISOTROPY

In this paper, the effects of compaction method on deformation and strength properties of a sandy soil were examined by means of triaxial and unconfined compression tests and bender element test. A X-ray CT scan was also employed for providing us with image of structure of two sandy soils (n.b., sample A and B). The undrained shear strength and dilatancy characteristics were seemingly affected by the compaction method employed, and also the aspect depended on the soil type. The Ghh/Gvh -value of sample A was larger than that of sample B. The result would mean that the Ghh/Gvh -value reflecting soil anisotropy is strongly related to the shear strength and dilatancy characteristics. In addition, the variation of d and Dc of the statically compacted specimens is more significant than that of the dynamically compacted specimens. These variations in terms of d and Dc may also affect the deformation and strength characteristics.

EFFECTS OF MOULDING WATER CONTENT AND COMPACTION METHOD ON DEFORMATON AND STRENGHT CHARACTERISTICS OF COMPACTED SOIL

締固めた細粒分質礫質砂の変形・強度特性に及ぼす締固め時の含水比および締固め方法の影響を圧密非排水三軸圧縮試験とベンダーエレメント試験を実施して検討した．最適含水比よりやや乾燥側で締固めた供試体では，圧縮性が小さく，非排水せん断時の偏差応力が大きい結果となった．締固め方法の影響は，圧縮性が静的よりも動的に締固めた供試体の方が小さく，偏差応力は静的供試体の方が大きくなった．これらの圧密非排水三軸圧縮試験の結果は，ベンダーエレメント試験より得られた土構造の配向性を反映する弾性係数の異方性と強い相関があった．このことから，締固め時の密度や含水比，締固め方法によって生じる変形・強度特性の違いは，締固めに必要とされるエネルギーや締固めによって生じる土構造の変化と密接な関係にあることが示唆された．