許多工程的進行，常會對土體施予定量之擠壓變形量。對黏性土 壤而言，受到㆒定量擠壓變形後，會激發超額孔隙水壓，造成側向土 壓力㆖升，在擠壓變形量不在增加之條件㆘，超額孔隙水壓逐漸消 散，側向土壓力隨之減少。在此㆒過程㆗，土壤之力學性質則隨之改 本研究以方形應力試驗儀進行側向擠壓試驗，對單向度壓密後土 體施加定量之側向擠壓變形後，量測擠壓方向與未受擠壓方向土壓力 之歷時變化。另外進行㆔軸軸向擠壓試驗，對徑向壓密後土體受定量 之軸向擠壓變形後，量測軸向應力σz 與超額孔隙水壓uw 隨時間的變 由試驗結果可知，土體受到定量擠壓變形後，其力學行為會由原 本以趨向被動之狀態逐漸回復至另㆒平衡之靜止土壓力狀態，側向土 壓力則趨於㆒穩定值，且此值會大於原先靜止土壓力狀態㆘之側向土 壓力；當定量擠壓變形量愈大，最終穩定狀態時擠壓方向之應力愈 大，且㆓水平應力間差距愈大。最後並以理論公式進㆒步建立穩定狀 態時，側向擠壓試驗主應力比與㆔軸軸向擠壓試驗主應力比之關係 Soils in ground may suffer a constant deformation in construction progress. For saturated cohesive soils, excess pore water pressure and lateral earth pressure may increase after the deformation occured. With no deformation occurred continuously, the lateral earth pressure decreased gradually as excess pore water pressure dissipated. During this process, the mechanical properties of soils are changed. In this research, the lateral compression tests of one-dimensional consolidation soils with a specially designed square box were carried out to measure the elasped variation of the horizontal earth pressures. Besides, axially compressed triaxial tests were carried out to measure the elasped variation of the axial pressure and the excess pore water pressure . According to the results of the tests, the mechanical properties of soils tended to passive state after the deformation occurred, and then varied to another new equilibrium state. Finally, the lateral earth pressures tended to some stable values, which were larger than the lateral earth pressure in original condition. Besides, larger deformation caused larger variation in horizontal earth pressures. Finally, an equation was proposed for estimating the relationships between the principal stress ratio which were obtained from the both tests.
