土壤力學特性受有效應力狀態參數影響，非飽和土壤之有效應力較飽和土壤複雜，常用兩個獨立之應力狀態參數基質吸力與淨正向應力來描述非飽和土壤之有效應力行為。本研究以傳統三軸試驗設備加入總體積量測設備、波速量測設備以及高進氣陶瓷，並以應力軸平移方式控制基質吸力，探討不同應力狀態參數對非飽和土壤剪力波速之影響。由實驗結果發展理論公式並求出係數，係數分別為淨正向應力與基質吸力之指數，指數代入理論公式便可求得剪力波速、淨正向應力與基質吸力之關係，實驗結論可得其淨正向應力指數皆大於基質吸力指數，表示淨正向應力對非飽和土壤剪力波速之影響程度大於基質吸力，且淨正向應力之指數則與平均粒徑(D50)成反比。

Mechanical properties of soils are significantly affected by effective stress states. For unsaturated soils, the effective stresses are more complex than saturated soils and generally characterized by two independent effective stress parameters termed as net normal stress and matric suction. In this study, bender elements are integrated in an unsaturated triaxial cell to investigate the effects of stress state on shear wave velocity of unsaturated soil. Axis translate technique is implemented to control matric suction and total volume measurement device is used to confirm the balance of unsaturated state.Exponential correlation that relates the shear wave velocity with the net normal stress and matric suction are proposed. Testing data are used to find the exponential index of the correlations for different soil types. Testing results reveal that the exponential index of the net normal stress is greater than the exponential index of the matric suction, indicating that the net normal stress has more significant effects on shear wave velocity. Comparisons among different soil types reveal that the exponential index of the net normal stress is inverse proportion to the mean grain size of the soil.

林宏達，拱祥生「不飽和土壤力學性質試驗及其在邊坡工程之應用」，地工技術，83期，第39～52 頁，台灣（2001）。

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