Air element concept and Composite Element Method (CEM) were introduced inthis paper firstly, and then an explicit drainage holes element model was developed. The mainadvantage of the new model is that it allows draina...Air element concept and Composite Element Method (CEM) were introduced inthis paper firstly, and then an explicit drainage holes element model was developed. The mainadvantage of the new model is that it allows drainage holes to be located within soil elements.Therefore the mesh generation of complicated geotechnical structures with a large number of seepagedrainage holes becomes relatively convenient and feasible. This will further facilitate the optimaldesign of seepage control system, and in this case the calculation mesh can be kept unchanged whenthe number, position and orientation of drainage holes are adjusted. The model was been implementedin software. A sluice foundation seepage control problem was studied, by which the validity and therobustness of the new model were verified.展开更多
Bio-stimulated sealing technology is an interesting and promising technology for leakage repair in geotechnical engineering.Advancing studies of this technology have shown that some nutrients can be used to activate t...Bio-stimulated sealing technology is an interesting and promising technology for leakage repair in geotechnical engineering.Advancing studies of this technology have shown that some nutrients can be used to activate the metabolic process of in-situ soil microorganisms that induce bio-mediated sealing in a relatively short time.In this paper,we injected nutrient solution into sand columns with leakage and investigated the sealing mechanism.Two sand columns,each with a 2-cm diameter hole,were set up.One was treated with nutrient solution and the other received no nutrients as a control.The results showed that 900 mL of nutrient solution per day,with a concentration of 4.4 g L-1 potato extract solution,could notably decrease the volume of groundwater seepage.Finally,the volume of the seepage in the treated column was 0.85% of the control column.Evidence of micro morphological changes to the sand samples after the bio-stimulated sealing tests is given using the ESEM observations.Chemical element composition,organic and iron compound analyses were performed for an enhanced understanding of the underlying bio-stimulated sealing mechanism.The preliminary results obtained indicate that iron compound deposits,and organics(biomass and biofilm) produced during the sealing process near the leakage enhanced the sealing effect.展开更多
文摘Air element concept and Composite Element Method (CEM) were introduced inthis paper firstly, and then an explicit drainage holes element model was developed. The mainadvantage of the new model is that it allows drainage holes to be located within soil elements.Therefore the mesh generation of complicated geotechnical structures with a large number of seepagedrainage holes becomes relatively convenient and feasible. This will further facilitate the optimaldesign of seepage control system, and in this case the calculation mesh can be kept unchanged whenthe number, position and orientation of drainage holes are adjusted. The model was been implementedin software. A sluice foundation seepage control problem was studied, by which the validity and therobustness of the new model were verified.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50908122 and 51078202)
文摘Bio-stimulated sealing technology is an interesting and promising technology for leakage repair in geotechnical engineering.Advancing studies of this technology have shown that some nutrients can be used to activate the metabolic process of in-situ soil microorganisms that induce bio-mediated sealing in a relatively short time.In this paper,we injected nutrient solution into sand columns with leakage and investigated the sealing mechanism.Two sand columns,each with a 2-cm diameter hole,were set up.One was treated with nutrient solution and the other received no nutrients as a control.The results showed that 900 mL of nutrient solution per day,with a concentration of 4.4 g L-1 potato extract solution,could notably decrease the volume of groundwater seepage.Finally,the volume of the seepage in the treated column was 0.85% of the control column.Evidence of micro morphological changes to the sand samples after the bio-stimulated sealing tests is given using the ESEM observations.Chemical element composition,organic and iron compound analyses were performed for an enhanced understanding of the underlying bio-stimulated sealing mechanism.The preliminary results obtained indicate that iron compound deposits,and organics(biomass and biofilm) produced during the sealing process near the leakage enhanced the sealing effect.
