本文旨在探討地震荷重下，均質砂土層反應行為之模擬與分析。其中包括動力大地離心機試驗與數值模式之模擬，及傳統動態三軸剪力與中空圓柱試體扭轉剪力等基本試驗。本研究運用三軸及扭轉試驗結果之數據，藉以標定砂質土之界面擬塑性模式之參數。界面擬塑性理論指出，土體受力後，其應變率方向不僅與應力狀態相關，且須考慮其應力率之方向。因此，界面擬塑性理論能模擬地震作用下，土體主應力方向之連續性變動。在分析及比較離心機試驗與有限元素程式「SUMDES」間，對於地震荷重下土層反應行為之模擬結果顯示，藉由界面擬塑性理論，SUMDES程式成功地描述地震作用時，砂土層超額孔隙水壓之生成與消散、應變之軟化、地層之振動及沉陷等現象。

　　　　　Experimental and numerical studies of soil response in a fine uniform sand layer under earthquake loading are presented. They include dynamic geotechnical centrifuge model test results and constitutive model simulation. Several types of element tests are also presented:conventional cyclic triaxial tests and hollow cylinder torsional shear tests. A bounding surface hypoplasticity model for sand was calibrated suing triaxial and torsional shear testing data and then to simulate other "element" test results. To enable prediction of the effects of principal stress rotation in hypoplasticity theory, the strain rate direction depends on both current stress state and the stress rate direction. The hypoplasticity model was also tested by comparing predictions of finite element code "SUMDES" (Site Under Multi-Directional Earthquake Shaking) with dynamic centrifuge model tests. The computer code incorporates to the bounding surface hypoplasticity model for granular soils and provides prediction of the generation and dissipation of pore water pressures, strain softening, ground motions and permanent settlement for the soil layers.