台灣西部麓山帶多軟弱岩石邊坡，在地震時常造成邊坡破壞，為進一步了解此軟弱岩石邊坡在受振時的動態力學特性，本研究初步以出露於台南縣龍崎鄉一帶的多孔隙軟弱砂岩進行壓密不排水靜態三軸試驗，並以非均向壓密不排水動態三軸試驗模擬飽和軟弱砂岩邊坡的受振情形。藉由試驗所得之應力-應變關係、超額孔隙水壓變化的量測，以探討飽和狀態下多孔隙軟弱砂岩在靜態與動態三軸試驗中的應力路徑、動態參數的變化等力學行為。
壓密不排水靜態三軸試驗結果顯示，在0.2-2MPa的圍壓下，透過超額孔隙水壓的變化，知道軟弱砂岩初始階段呈壓縮現象，爾後當超額孔隙水壓達尖峰值後，軟弱砂岩開始轉為剪脹現象，當軸差應力達尖峰值時、負超額孔隙水壓接近最大值，軟弱砂岩剪脹量達最大。藉由不同破壞準則的分析，求得靜態三軸的脆延性轉換壓力約為3.6MPa，且其剪力強度參數 、 ； 、 。
非均向壓密不排水動態三軸試驗結果顯示，試體在破壞前超額孔隙水壓力將有明顯的累積，致使試體的有效應力降低，導致軸向應變量逐漸增加，當其應變量約達1%，試體進而迅速產生破壞，最後形成破壞面與水平向夾約45~60°。在動態參數剪力模數G及阻尼比D方面，發現剪力模數在接近破壞時迅速下降，另外阻尼比隨剪應變及反覆次數的增加而下降，在接近試體破壞時，則反向迅速增加。 在不同壓密應力比Kc下所累積的超額孔隙水壓力隨Kc的增加而減少。當初始正向應力po’相同時，初始剪應力q0越大，達破壞所需應變量隨之增加，反之當相同q0的情況下達破壞的應變量隨po’增加而減少。此外，透過粒徑分析結果發現，破壞面上的顆粒在受剪後，明顯的產生破碎，並且細粒料含量隨反覆剪應力增加而增加。
綜合以上所述，可知在非均向壓密下，軟弱砂岩並沒初始液化的現象產生，試體破壞由顆粒間結構性的破壞所造成，當應變量達一定程度時，試體即產生快速且大變形的破壞。

Lushan western Taiwan with more soft rock slope is easy to damage by the earthquake, in order to understand of soft rock slope in the mechanical properties of the dynamics, this study initially exposed to the Tainan County Longci Township related to the rural area of porous soft sandstone of consolidated undrained triaxial test and use anisotropy consolidated undrained cyclic triaxial shear tests to simulate saturation of soft sandstone slope by shake. By tests of the stress - strain relations, the excess pore water pressure changes over the measure, to explore soft porous sandstone in the static and cyclic triaxial test of stress path, dynamic parameters such as changes in mechanical behavior.
The results in the consolidated undrained triaxial test under confining pressure 0.2-2 MPa showed that soft sandstone was compressed at the initial stage by excess pore water pressure changes and excess pore water pressure after the peak value, the soft sandstone phenomenon began to dilatancy, and when deviator stress to reach peak value and negative excess pore water pressure close to the maximum, the dilation to reach peak value of soft sandstone. By different failure criterion to analysis can obtain brittle-to-ductile transition pressure is 3.6MPa of triaxial test, the shear strength parameters is 、 ； 、 .
In the consolidated undrained cyclic triaxial test result shows specimens of the destruction before excess pore water pressure there will be significant cumulative, result of lower effective stress and axial strain should be increased gradually, when axial strain to reach 1%, specimens of further destabilizing rapidly, with the final form of damage to the folder level of about 45° ~ 60 °. In the dynamic parameters of shear modulus G and damping ratio D, found in the shear modulus close to destruction at the rapid decline. Also damping ratio decreased with the increment of shear strain and cyclic number, as approach of failure, and then reverses the rapid increase. In different consolidated stress ratio Kc, increasing of Kc decreased the excess pore water pressures accumulate value. When the initial normal stress p0’ at the same time, the greater the initial shear stress q0, should be required to destroy variables increases, instead when the same q0 increase of the failure strain decreased the p0’. In addition, through the particle size analysis found that the particles in the destruction of surface shear, and increase of cyclic shear stress increased the fine-grained content.
Based on the above mentioned shows are in anisotropy consolidated of soft sandstone is not the initial liquefaction phenomenon to occur and specimens to cause damage to particles structure was destroyed, When strain amounted to a certain extent, specimens were occurred the rapid destruction of large deformation.

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