Oedometer Study Regarding the Consolidation Behavior of Nanjing Soft Clay
Abstract
:1. Introduction
- (1)
- Extend the straight sections in the middle and end parts of the curve;
- (2)
- Determine the intersection point of the extended lines, and the horizontal coordinate of this point represents the boundary time between primary consolidation and secondary compression. Time point t1 in the figure corresponds to the end of primary consolidation, while subsequent times correspond to secondary compression deformation.
- (3)
- Calculate the slope of the line passing through points corresponding to t1 and t2, which represents the sought-after coefficient for secondary compression settlement.
- (1)
- Locate point A on the curve with the minimum radius of curvature;
- (2)
- Draw a horizontal line (I) and a tangent line (II) through this point, and determine the bisecting line (III) of these two lines;
- (3)
- Find the straight part in the high pressure range, and extend it so that line IV and line III cross each other. The pressure corresponding to the intersection (point B) of line III and line IV defines Pc.
2. Experimental Program
2.1. One-Dimensional Compression Test
2.2. Measurement Equipment
2.3. Experimental Methodology
2.4. Specimen Preparation and the Oedometer Test
3. Results and Discussions
4. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
- Jiang, J.; Li, X.; Gao, G.; Luo, G. Investigation on the correlation between physical mechanical parameters of clay subsoil and Nanjing metro foundation. China Railw. Sci. 2007, 28, 19–26. [Google Scholar]
- Tjong-Kie, T. Secondary time effects and consolidation of clays. Sci. China 1958, 7, 1060–1075. [Google Scholar]
- Mesri, G.; Choi, Y.K. The uniqueness of the end-of-primary (EOP): Void ratio-effective stress relationship. In Proceedings of the 11th International Conference on Soil Mechanics and Foundation Engineering, San Francisco, CA, USA, 11 August 1985; Volume 2. [Google Scholar]
- Mitchell, J.K.; Campanella, R.G.; Singh, A. Soil creep as a rate process. ASCE Soil Mech. Found. Div. J. 1968, 94, 231–253. [Google Scholar] [CrossRef]
- Leroueil, S.; Kabbaj, M.; Tavenas, F.; Bouchard, R. Stress-strain-strain rate relation for the compressibility of sensitive natural clay Geotechnique V35, N2, June 1985, P159–180. Int. J. Rock Mech. Min. Sci. Geomech. Abstr. 1985, 22, 187–188. [Google Scholar] [CrossRef]
- GB/T 50123-2019; The Hydrology and Water Resources Bureau of the Ministry of Water Resources, N.H.R.I. Standard for Geotechnical Testing Method. General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China: Beijing, China, 2019; p. 717.
- Taylor, D.W.; Merchant, W. A Theory of Clay Consolidation Accounting for Secondary Compression. J. Math. Phys. 1940, 19, 167–185. [Google Scholar] [CrossRef]
- Casagrande, A.; Fadum, R.E. Notes on Soil Testing for Engineering Purposes; Harvard University: Cambridge, MA, USA, 1940; p. 74. [Google Scholar]
- Mesri, G. Coefficient of Secondary Compression. ASCE Soil Mech. Found. Div. J. 1973, 99, 123–137. [Google Scholar] [CrossRef]
- Zhou, Q.J.; Chen, X.P. Experimental study on secondary consolidation characteristics of soft soil. Rock Soil Mech. 2006, 27, 5. [Google Scholar]
- Cao, Y.P. The relationship between the coefficient of secondary consolidation of saturated cohesive soil and moisture content. China Harb. Eng. 2007, 3, 21–23. [Google Scholar]
- Yu, X.; Yin, Z.; Dong, W. Experimental Study on the Influence of Load on Secondary Consolidation of Soft Soil. Chin. J. Geotech. Eng. 2007, 29, 4. [Google Scholar]
- Shuchong, W.; Minyun, H.; Yong, Z.; Bin, X.; Kailei, C. Experimental study on secondary consolidation characteristics of silty clay. J. Hydraul. Eng. 2015, 6. [Google Scholar] [CrossRef]
- Dun, Z. Experimental Study on the Secondary Consolidation Characteristics of Soft Soil in Shanghai Area. Low Temp. Archit. Technol. 2020. [Google Scholar] [CrossRef]
- Becker, D.E.; Crooks, J.H.A.; Been, K.; Jefferies, M.G. Work as a criterion for determining in situ and yield stresses in clays. Can. Geotech. J. 1987, 24, 327–328. [Google Scholar] [CrossRef]
- Conte, O.; Rust, S.; Ge, L.; Stephenson, R. Evaluation of Pre-Consolidation Stress Determination Methods. In Proceedings of the Geohunan International Conference, Changsha, China, 9–11 June 2011; pp. 147–154. [Google Scholar]
- Casagrande, A. The determination of pre-consolidation load and its practical significance. Trans. Am. Soc. Civ. Eng. 1936, 101, 557–586. [Google Scholar]
- Zhai, Q.; Zhu, Y.; Rahardjo, H.; Satyanaga, A.; Dai, G.; Gong, W.; Zhao, X. Mathematical model for the determination of the pre-consolidation pressure using the graphical method. Arab. J. Geosci. 2023, 16, 69. [Google Scholar] [CrossRef]
- Fredlund, D.G.; Xing, A. Erratum: Equations for the soil-water characteristic curve. Can. Geotech. J. 1994, 31, 1023–1025. [Google Scholar] [CrossRef]
- Brumund, W.F.; Jonas, E.; Ladd, C.C. Estimating in situ maximum past (preconsolidation) pressure of saturated clays from results of laboratory consolidometer tests. Equipment 1976, 1, 4–12. [Google Scholar]
- Zhang, Q.X.; Chao, F.C. An experimental study on the influence of excessive consolidation ratio on subconsolidation settlement of soil. Jiangsu Agric. Res. 2000, 21, 66–68. [Google Scholar]
Depth (m) | Water Content w (%) | Unit Weight γ (kN·m−3) | Void Ratio e | Liquid Limit wl (%) | Plastic Limit wp (%) | Liquidity Index Il | Compression Coefficient α1-2 (MPa−1) |
---|---|---|---|---|---|---|---|
7.8 | 30.42 | 1.812 | 0.856 | 47.18 | 35.23 | −0.403 | 0.387 |
8.0 | 33.42 | 1.824 | 0.887 | — | — | −0.152 | 0.433 |
14.8 | 37.02 | 1.869 | 0.892 | 63.80 | 37.22 | −0.007 | 0.492 |
15.0 | 36.63 | 1.862 | 0.893 | — | — | −0.022 | 0.421 |
Sample Depth (m) | Soil Specimen Number | Loading Method | Loading Sequence |
---|---|---|---|
7.8 | a | Hierarchical loading | 25-50-100-200-400-800-1600 |
8.0 | b | ||
14.8 | c | ||
15.0 | d |
Soil Specimen Number | a | b | c | d |
---|---|---|---|---|
Pre-consolidation stress pc (kPa) | 584.514 | 529.916 | 611.243 | 499.980 |
Soil Specimen Number | a | b | c | d |
---|---|---|---|---|
Compression index Cc | 0.242 | 0.235 | 0.267 | 0.260 |
Applied Load (kPa) | Soil Specimen | |||
---|---|---|---|---|
a | b | c | d | |
25 | 0.00458 | 0.00707 | 0.00221 | 0.01476 |
50 | 0.00237 | 0.00394 | 0.00341 | 0.00442 |
100 | 0.00523 | 0.00794 | 0.00504 | 0.00504 |
200 | 0.00557 | 0.00817 | 0.00808 | 0.00942 |
400 | 0.00656 | 0.00702 | 0.00824 | 0.00767 |
800 | 0.00672 | 0.00479 | 0.00665 | 0.00661 |
1600 | 0.00672 | 0.00589 | 0.00688 | 0.00711 |
Loading Level (kPa) | Ca | |||
---|---|---|---|---|
a | b | c | d | |
25 | 35.99% | 1.19% | 69.11% | 106.29% |
50 | 32.96% | 11.46% | 3.54% | 25.04% |
100 | 10.02% | 36.60% | 13.29% | 13.29% |
200 | 28.68% | 4.61% | 3.46% | 20.61% |
400 | 11.02% | 4.78% | 11.77% | 4.04% |
800 | 8.52% | 22.65% | 7.39% | 6.74% |
1600 | 1.05% | 11.43% | 3.46% | 6.92% |
Cc | 4.67% | 5.05% | 10.14% | 9.85% |
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Liu, Y.; Ma, R.; Zhu, Y.; Yi, X.; Satyanaga, A.; Dai, G.; Gao, P.; Zhai, Q. Oedometer Study Regarding the Consolidation Behavior of Nanjing Soft Clay. Appl. Sci. 2024, 14, 7339. https://doi.org/10.3390/app14167339
Liu Y, Ma R, Zhu Y, Yi X, Satyanaga A, Dai G, Gao P, Zhai Q. Oedometer Study Regarding the Consolidation Behavior of Nanjing Soft Clay. Applied Sciences. 2024; 14(16):7339. https://doi.org/10.3390/app14167339
Chicago/Turabian StyleLiu, Yang, Ruchen Ma, Yiyao Zhu, Xianting Yi, Alfrendo Satyanaga, Guoliang Dai, Peng Gao, and Qian Zhai. 2024. "Oedometer Study Regarding the Consolidation Behavior of Nanjing Soft Clay" Applied Sciences 14, no. 16: 7339. https://doi.org/10.3390/app14167339