The use of marginal backfills in GSE （geosynthetic stabilized earth） walls has not been recommended by different standards specifications. Restrictions are motivated by the poor hydraulic conductivity of fine soils ...The use of marginal backfills in GSE （geosynthetic stabilized earth） walls has not been recommended by different standards specifications. Restrictions are motivated by the poor hydraulic conductivity of fine soils that are capable of developing of water pressures. However, the use of granular materials can expend the cost of the construction. As a result, local soils, granular or not, have been increasingly used. Unsaturated conditions of fine soils may result in convenient performance even using extensible reinforcements. This paper evaluates the performance of a full scale model of a nonwoven geotextile reinforced wall constructed with fine grained soil backfill. The unsaturated condition was maintained and matric suctions, displacements and reinforcement strains were monitored during the test. Results have shown that the unsaturated condition of the backfill allowed maximum reinforcement peak strain of 0.4 %. For the case of a wrap faced wall on a firm foundation the performance and good agreement between measured strains and factors of safety from limit equilibrium analyses have shown the maintenance of unsaturated conditions as an economical alternative to the use of high quality fill.展开更多
This study defines and compares four scenarios for MSW （municipal solid waste） management： Scenario 1, unsorted waste taken to a landfill （baseline scenario）; Scenario 2, sorted waste used for home or communal co...This study defines and compares four scenarios for MSW （municipal solid waste） management： Scenario 1, unsorted waste taken to a landfill （baseline scenario）; Scenario 2, sorted waste used for home or communal composting; Scenario 3, sorted waste used for anaerobic digestion; and Scenario 4, sorted waste taken to a composting centre. The results of this study suggest that Scenario 1 would emit the highest levels of GHG （greenhouse gas） emissions, 692 x 103 tonnes CO2eq per year. Scenario 3 would have the lowest levels of GHG emissions, 195 x 103 tonnes CO2eq per year. Compared with the baseline scenario, it yields a 72% reduction of GHG emissions with a total savings of 498 ~ 103 tonnes CO2eq per year. The second-best option is Scenario 2, followed closely by Scenario 4, both yield 66.6% reductions with deviation by 0.03%. The deviation is due to transportation, which emission is negligibly small. The amounts of GHG savings for Scenario 2 and 4 are 461.3 ×10^3 tonnes CO2eq per year and 461×10^3 tonnes CO2eq per year, respectively It is evident from these results that anaerobic digestion has the highest potential for reducing GHG emissions.展开更多
文摘The use of marginal backfills in GSE （geosynthetic stabilized earth） walls has not been recommended by different standards specifications. Restrictions are motivated by the poor hydraulic conductivity of fine soils that are capable of developing of water pressures. However, the use of granular materials can expend the cost of the construction. As a result, local soils, granular or not, have been increasingly used. Unsaturated conditions of fine soils may result in convenient performance even using extensible reinforcements. This paper evaluates the performance of a full scale model of a nonwoven geotextile reinforced wall constructed with fine grained soil backfill. The unsaturated condition was maintained and matric suctions, displacements and reinforcement strains were monitored during the test. Results have shown that the unsaturated condition of the backfill allowed maximum reinforcement peak strain of 0.4 %. For the case of a wrap faced wall on a firm foundation the performance and good agreement between measured strains and factors of safety from limit equilibrium analyses have shown the maintenance of unsaturated conditions as an economical alternative to the use of high quality fill.
文摘This study defines and compares four scenarios for MSW （municipal solid waste） management： Scenario 1, unsorted waste taken to a landfill （baseline scenario）; Scenario 2, sorted waste used for home or communal composting; Scenario 3, sorted waste used for anaerobic digestion; and Scenario 4, sorted waste taken to a composting centre. The results of this study suggest that Scenario 1 would emit the highest levels of GHG （greenhouse gas） emissions, 692 x 103 tonnes CO2eq per year. Scenario 3 would have the lowest levels of GHG emissions, 195 x 103 tonnes CO2eq per year. Compared with the baseline scenario, it yields a 72% reduction of GHG emissions with a total savings of 498 ~ 103 tonnes CO2eq per year. The second-best option is Scenario 2, followed closely by Scenario 4, both yield 66.6% reductions with deviation by 0.03%. The deviation is due to transportation, which emission is negligibly small. The amounts of GHG savings for Scenario 2 and 4 are 461.3 ×10^3 tonnes CO2eq per year and 461×10^3 tonnes CO2eq per year, respectively It is evident from these results that anaerobic digestion has the highest potential for reducing GHG emissions.
