非飽和砂土、坋質壤土及黏土於固定載重下壓密行為之理論與數值研究

本研究應用孔彈性理論方程式及兩種非混合流體之應力應變本構關係，推導出含兩項非混合流體之孔隙介質的壓密理論。假設土體表面施加垂直固定壓力，我們利用拉普斯轉換求得在不同排水與不排水邊界下潤濕與非潤濕流體超額壓力及壓密沈陷量的一維解析解。為量化分析非飽和土壤其壓密行為，我們數值模擬三種不同性質的非飽和土壤（砂土、坋質壤土及黏土），其孔隙間充滿兩種不可混合之流體(空氣及水)，分別探討不同初始飽和度、邊界條件與土壤性質所造成的影響，並配合無因次孔隙水壓及土壤總沉陷量結果圖相互比較討論其壓密行為。

關鍵字

孔彈性理論；固定壓力；壓密；總沉陷量；土壤基質統體模數

並列摘要

In this study, a theoretical analysis of consolidation behaviors for an elastic porous medium containing two immiscible, compressible, viscous fluids is presented based on the theory of poroelasticity and the linear stress-strain relationship. Using Laplace transformation, we derive the analytical solution of the excess pore pressure of the wetting and nonwetting fluids as well as soil settlement for different drained and undrained boundaries under a constant external load. To quantitatively investigate the consolidation process of an unsaturated porous medium, a numerical study was carried out to determine the dimensionless pore water pressure and soil settlement for sand, silt loam and clay whose pore space is simultaneously occupied by air and water as illustrative examples. Then, the effect of fluid saturation, boundary condition, and soil texture on the dimensionless pore water pressure and soil settlement was also examined.Our numerical results show that the dimensionless pore water pressure dissipates faster as water saturation is lower, in which soil settlement also tends to achieve stable faster. In addition, it is also revealed that sand was the fastest to respond to the external load, followed by silt loam and clay. Lastly, soil settlement is found to be greatest in clay, followed by silt loam and sand, which is mainly dominated by the bulk modulus of solid matrix.

並列關鍵字

Poroelasticity theory ； Constant loading ； Consolidation ； Total settlement ； Bulk modulus of solid matrix

國際替代計量

非飽和砂土、坋質壤土及黏土於固定載重下壓密行為之理論與數值研究

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