不飽和土壤壓密之數值分析

至今飽和土壤一維壓密的經典理論已有相當成熟技術發展與應用，並且成功解決關於地工結構物加載所產生的地表沈陷問題。也有些許關於不飽和壓密試驗的研究，但對於使用分析軟體來探討實際不飽和壓密問題卻不多。本研究為驗證Dakshanamurthy et al. (1984)的不飽和壓密方程，驗證後再進行前人的不飽和土壤壓密行為之K_0壓密試驗模擬。K_0壓密試驗是將常含水量試驗、壓密試驗，增加基質吸力試驗相互串連循環而成，可探討基質吸力與垂直載重交互作用下之情況以及不飽和紅土K_0壓密時之水體積、土體積變化。之後進行真空預壓密案例分析，此部分分析包括飽和及不飽和之沉陷量比較，另外針對各種不同地下水位之沉陷量比較以及各種不同土壤之沉陷量比較。分析結果顯示不飽和壓密方程式會與固體力學產生耦合效應，因此可模擬出超額孔隙水壓之消散趨勢以及土壤沉陷量之變化。在不飽和土壤K_0壓密分析中也可使用不飽和壓密方程來模擬土、水體積之變化、壓密係數等變化。

關鍵字

不飽和土壤；壓密；數值分析；真空加載

並列摘要

The classical one-dimensional consolidation theory for saturated soil has brought many successful applications in geotechnical engineering practice especially those related to consolidation settlement. The theory is not suitable for unsaturated soil application as the volume change of the soil mass and water volume are not considered. This study verifies the consolidation theory for unsaturated soil that was proposed by Fredlund and Hasan in 1979. Results from an analytical study and experimental test of one-dimensional consolidation test on unsaturated soil specimen were used for the verification study. Finally, the application of the unsaturated consolidation theory on a preloading consolidation case was also performed.

並列關鍵字

Unsaturated soil ； consolidation ； Numerical analysis ； Vacuum consolidation

參考文獻

Ashraf, S.O. (2014). “Comparison between coupled and uncoupled consolidation analysis of a rigid sphere in a porous elastic infinite space.” Journal of Engineering Mechanics – ASCE.

Biot, M. A. (1941). “General Theory of Three-Dimensional Consolidation.” J.Appl. Phys., 12(2), 155-164.

Chai, J., Carter, J. P., & Liu, M. D. (2013). “Methods of vacuum consolidation and their deformation analyses. “ICE Publishing.

Fredlund, D. G., & Rahardjo, H. (1993). “Soil mechanics for unsaturated soils .”,Wiley-Interscience.pp.441.

Fredlund, D. G, Xing, A. (1994). “Equations for the soil-water characteristic curve.” Canadian Geotechnical Journal, 31(4), 521-532.

國際替代計量

不飽和土壤壓密之數值分析

全文下載

主題瀏覽