Consolidation Model for Gassy Soils Considering the Compression Coefficient of Air-Water Mixture
The gassy soil or quasi-saturated soil which containing entrapped gas bubbles is a special type of unsaturated soils. Gassy soils could exist in many situations such as offshore geotechnical engineering and water infiltration under heavy rains. For this type of soil, the deformations due to the air compression cannot be ignored, which is usually described as the compressibility of the air-water mixture. This paper aims to calculate the compression coefficient of air-water mixture and propose the consolidation equation of gassy soils. Based on the conceptual model of small bubbles, deformation characteristics of entrapped gas bubbles, Bolye’s law of ideal gas and surface tension effects, the compression coefficient of air-water mixture in gassy soils is derived. The presence of gas could influence the process of soil consolidation, and the entrapped gas bubbles are considered to be drained off along with pore water in the process of consolidation. The deformation of the soil during consolidation could be divided into two parts: one part is the compression deformation due to draining of air-water mixture, and the other part is the compression of the air-water mixture. The derived compression coefficient equation of air-water mixture is used to establish the consolidation equation of gassy soils. Calculation results using our model are compared with the experimental data from literatures, and the results show that the proposed model could properly reflect the consolidation behavior of gassy soils.
KeywordsGassy soils Air-water mixture Compression coefficient Consolidation equation
The authors acknowledge the support received from Dr. Jianfeng Xue and related organizations.
This work is supported by the National Natural Science Foundation of China under Grant No. 41572258.
- 3.Wei, H., Zhan, L., Chen, Y.: Compressibility and consolidation of unsaturated soils with high degree of saturation and its application. Chin. J. Geotech. Eng. 28(2), 264–269 (2006)Google Scholar
- 4.Xu, H.: Studies on the consolidation theory for unsaturated soft soils containing biogas [Ph.D. thesis]. Zhejiang University, Hangzhou (2011)Google Scholar
- 6.Nageswaran S.: Effect of gas bubbles on the sea bed behavior [Ph.D. thesis]. The University of Oxford, Oxford (1983)Google Scholar
- 7.Thomas S. D: The consolidation behaviour of gassy soil [Ph.D. thesis]. The University of Oxford, Oxford (1987)Google Scholar
- 11.Dorsey, N.E.: Properties of Ordinary Water-Substance. Reinhold, New York (1940)Google Scholar