Deformation behaviour of geotechnical materials with gas bubbles and time dependent compressible organic matter
- Liu, Kan, Xue, Jianfeng, Yang, Min
- Authors: Liu, Kan , Xue, Jianfeng , Yang, Min
- Date: 2016
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 213, no. (2016), p. 98-106
- Full Text:
- Reviewed:
- Description: Geotechnical materials may contain organic matters and gas bubbles during the process of their formation. The existence of compressible gas bubbles and organic matters may affect the excess pore water pressure distribution during compression and the deformation behaviour of the materials. Immediate settlement and creep have been observed in the early stage of consolidation curves of brown coal and peat samples, which can not be explained with Terzaghi's consolidation theory where soils are considered as fully saturated and soil particles are incompressible. A numerical model has been developed to model the consolidation behaviour of brown coal and peat considering the inclusion of gas bubbles and the time dependent compressible organic matters. In the model, the materials are assumed to contain incompressible minerals, compressible organic matters, gas bubbles and water. Consolidation of the materials is considered as a coupling process of water extrusion and volume variation of gas bubbles and organic matters. The model has been validated using the experimental results from one dimensional consolidation curves of brown coal and historical test results of peat. The gas content and the compressibility of organic matters can be obtained using the proposed model. The model can be used to analyze compression behaviour of geotechnical materials containing compressible particles and gas bubbles.
- Description: Geotechnical materials may contain organic matters and gas bubbles during the process of their formation. The existence of compressible gas bubbles and organic matters may affect the excess pore water pressure distribution during compression and the deformation behaviour of the materials. Immediate settlement and creep have been observed in the early stage of consolidation curves of brown coal and peat samples, which can not be explained with Terzaghi's consolidation theory where soils are considered as fully saturated and soil particles are incompressible. A numerical model has been developed to model the consolidation behaviour of brown coal and peat considering the inclusion of gas bubbles and the time dependent compressible organic matters. In the model, the materials are assumed to contain incompressible minerals, compressible organic matters, gas bubbles and water. Consolidation of the materials is considered as a coupling process of water extrusion and volume variation of gas bubbles and organic matters. The model has been validated using the experimental results from one dimensional consolidation curves of brown coal and historical test results of peat. The gas content and the compressibility of organic matters can be obtained using the proposed model. The model can be used to analyze compression behaviour of geotechnical materials containing compressible particles and gas bubbles. © 2016 Elsevier B.V.
- Authors: Liu, Kan , Xue, Jianfeng , Yang, Min
- Date: 2016
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 213, no. (2016), p. 98-106
- Full Text:
- Reviewed:
- Description: Geotechnical materials may contain organic matters and gas bubbles during the process of their formation. The existence of compressible gas bubbles and organic matters may affect the excess pore water pressure distribution during compression and the deformation behaviour of the materials. Immediate settlement and creep have been observed in the early stage of consolidation curves of brown coal and peat samples, which can not be explained with Terzaghi's consolidation theory where soils are considered as fully saturated and soil particles are incompressible. A numerical model has been developed to model the consolidation behaviour of brown coal and peat considering the inclusion of gas bubbles and the time dependent compressible organic matters. In the model, the materials are assumed to contain incompressible minerals, compressible organic matters, gas bubbles and water. Consolidation of the materials is considered as a coupling process of water extrusion and volume variation of gas bubbles and organic matters. The model has been validated using the experimental results from one dimensional consolidation curves of brown coal and historical test results of peat. The gas content and the compressibility of organic matters can be obtained using the proposed model. The model can be used to analyze compression behaviour of geotechnical materials containing compressible particles and gas bubbles.
- Description: Geotechnical materials may contain organic matters and gas bubbles during the process of their formation. The existence of compressible gas bubbles and organic matters may affect the excess pore water pressure distribution during compression and the deformation behaviour of the materials. Immediate settlement and creep have been observed in the early stage of consolidation curves of brown coal and peat samples, which can not be explained with Terzaghi's consolidation theory where soils are considered as fully saturated and soil particles are incompressible. A numerical model has been developed to model the consolidation behaviour of brown coal and peat considering the inclusion of gas bubbles and the time dependent compressible organic matters. In the model, the materials are assumed to contain incompressible minerals, compressible organic matters, gas bubbles and water. Consolidation of the materials is considered as a coupling process of water extrusion and volume variation of gas bubbles and organic matters. The model has been validated using the experimental results from one dimensional consolidation curves of brown coal and historical test results of peat. The gas content and the compressibility of organic matters can be obtained using the proposed model. The model can be used to analyze compression behaviour of geotechnical materials containing compressible particles and gas bubbles. © 2016 Elsevier B.V.
Experimental study of brown coal hydraulic behavior at low confining stress
- Liu, Kan, Mackay, Rae, Xue, Jianfeng, Tolooiyan, Ali
- Authors: Liu, Kan , Mackay, Rae , Xue, Jianfeng , Tolooiyan, Ali
- Date: 2014
- Type: Text , Conference paper
- Relation: 6th International Conference on Unsaturated Soils p. 1125-1130
- Full Text: false
- Reviewed:
- Description: The hydraulic behavior of Victorian brown coal has been studied under low pressure confining conditions. A triaxial constant head permeameter was constructed to carry out permeability tests under alternative confining conditions. Test results from alternative constant head test methods were found to be different indicating higher than expected internal storage due to the possible existence of gas in the coal matrix and/or compressibility of the coal grains. A conceptual model of brown coal with disconnected gas bubbles was proposed to explain the observed variation of hydraulic behavior. In this model, the compressible gas bubbles are assumed to be trapped between compressible coal particles. A numerical model was developed to gain insights into the hydraulic influence of these factors and the model was used to simulate the test process. Constant hydraulic conductivity was assumed. The results from the model and the tests are found to compare well. The model explains most but not all of the observed behavior.
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