未飽和砂土之動態破壞特性研究

Abstract

本文採用渥太華砂與豐浦砂為試驗材料，以氣漏法製成相對密度為 50% 的重模試體，控制圍壓為0.5kfg/cm^2 ，進行飽和及未飽和狀態下之不排 水反覆三軸試驗。同時為獲得未飽和試體壓密後之飽和度，乃設計一體積 變化量測系統以量測體積變化藉以計算試體之飽和度。 試驗結果顯示 ：(1) 動態破壞強度隨飽和度的降低而增加。(2) 渥太華砂之動態破壞強 度受飽和度的影響較豐浦砂為劇。 In order to understand how degree of saturation affects the collapse resistance of sands, undrained cyclic saturated and unsaturated triaxail tests were carried out on both Ottawa and Toyoura sand with the same relative density of 50% under the confining pressure 0.5 kgf/cm^2. Due to the compressibility of the pore air of unsaturated specimens, a volumme change surveying system was developed to get the degree of saturation. The result show that : (1) The collapse resistance increased with a decrease in degree of saturation. (2) The degree of saturation affects the collapse resistance of Ottawa sand more than that of Toyoura sand.