土壤主要壓密完成時間評估方法之研究

A Study on the Methods for Evaluating End of Primary Consolidation of Soils

米艾模(Emerson Edwige Michel)

指導教授 ： 馮道偉

中原大學/工學院/土木工程研究所/碩士(2021年)

https://doi.org/10.6840/cycu202100399

摘要

關於有助於預測地盤沉降的土壤主要壓密完成(EOP)時間引起很大的關注，在文獻中可以找到各種評估 EOP 的方法，其中，廣泛使用的 Casagrande 圖形方法、Asaoka 的現地觀察方法、Sivaram 和 Swamee 的計算方法以及Mesri t95的方法。除了使用沉陷數據的這四種方法外，也許超額孔隙水壓數據也可以利用來判斷主要壓密完成，不過目前為止文獻裡還沒有提供任何相關的結論。本研究的目為使用前面提到的方法來評估壓密試驗的之 EOP，並利用獲得的EOP 時間來得到超額孔隙水壓之值。
本研究的結果顯示 Casagrande、Asaoka 和 Sivaram Swamee 的方法之間具有良好的相關性，以這三種方法對超額孔隙水壓力進行分析的結果顯示，當達到 EOP 時，超額孔隙水壓力尚未完全消散；對於黏土,當最大應力為191.8 kPa, EOP時的超額孔隙水壓力落於0.52 kPa～2.0 kPa間，而對於有機土, 當最大應力為328.8 kPa此範圍為2.0 kPa～5.0 kPa間。由於以Mesri t95的理論的方法得到了較短的時間teop，EOP時的超額孔隙水壓力會較大。

關鍵字

主要壓密 ； 主要壓密完成(EOP) ； 超額孔隙水壓 ； 二次壓縮

並列摘要

End of primary consolidation (EOP) of soils is of great interest since it helps in ground settlement prediction. Various methods for evaluating EOP are found in the literature, among them, Casagrande’s graphical method, which is widely used, Asaoka’s observational method, Sivaram and Swamee’s computational method and Mesri t95. Besides those four methods where compression data are used, another tool, which is the pore water pressure measurement, could also be used to evaluate EOP, however the literature does not provide any related tangible conclusion. This research aims to use the methods mentioned previously to estimate the EOP. Using the value of teop, the excess pore water pressure at EOP can be determined.
The results show good correlation between Casagrande, Asaoka and Sivaram and Swamee’s methods. Results from those methods show that it is not necessary that all the excess pore water pressure is dissipated when EOP is reached, in fact, at EOP, the excess pore water pressure lies within a range of 0.52 kPa to 2 kPa kPa for clayey soils, under a maximum stress of 191.8 kPa, while a range of 2 kPa to 5.2 kPa for a maximum stress of 328.8 kPa was observed for the organic soil. However, since Mesri’s theoretical t95 shows lower value for EOP in terms of time, thus the excess pore water pressure at EOP shows higher values

並列關鍵字

Primary consolidation, EOP, excess ； EOP ； Excess pore water pressure ； secondary compression

參考文獻

1. Asaoka, A. (1978), “Observational Procedure of Settlement Prediction.” Soils and Foundations Vol. 18 (4), p. 87–101

2. Barden, L. (1968), “Primary and Secondary Consolidation of Clay and Peat”, Geotechnique, Vol. 18, p. 1-24.

3. Bui, H.N, Small J.C and Hull T. (2001), “Secondary Compression of Clays”, Geotechnical Engineering, Vol. 2, p.1081-1084.

4. Burland, J.B, and Rosco, K.H (1969), “Local Strains and Pore Pressures in a Normally Consolidated Clay Layer During One-Dimensional Consolidation”, Géotechnique Vol. 19, p. 335-356.

5. Chow J.K, Wang Y.H, Lui and H.L, Huang E. (2020), “Determination of Consolidation Parameters Based on the Excess Pore Water Pressure Measurement Using a Newly Developed U-Oedometer”, Acta Geothecnica, Vol. 15, p. 2665-2680.