The objective of this work is to compare the responses of geosynthetically-reinforced embankment and unreinforced embankment due to road widening by using the centrifuge model tests and a two-dimensional(2D) finite el...The objective of this work is to compare the responses of geosynthetically-reinforced embankment and unreinforced embankment due to road widening by using the centrifuge model tests and a two-dimensional(2D) finite element(FE) model. The measured and calculated responses of the embankment and foundation exposed to road widening include the settlement,horizontal displacement,pore water pressure,and shear stresses. It is found that the road widening changed the transverse slope of the original pavement surface resulting from the nonuniform settlements. The maximum horizontal movement is found to be located at the shoulder of the original embankment. Although the difference is small,it is clearly seen that the geosynthetic reinforcement reduces the nonuniform settlements and horizontal movements due to road widening. Thus the reinforcement reduces the potential of pavement cracking and increases the stability of the embankment on soft ground in road widening.展开更多
A new kind of tunnel support was put forward on the basis of the anchor spraysupport principle. The mechanics of the new three-dimensional steel bar shotcrete liningsupport was studied and the structure's internal...A new kind of tunnel support was put forward on the basis of the anchor spraysupport principle. The mechanics of the new three-dimensional steel bar shotcrete liningsupport was studied and the structure's internal forces were analyzed. The model experiment was done relying on the industrial test. The conclusion of numerical calculationsproved that the ANSYS program is reasonable and creditable. It was compared to otherkinds of support that are commonly used in soft rock tunnels. The technique and economiccontrasts of the typical tunnel with support three-dimensional steel bar were completed.展开更多
In a landfill, excessive tensile strains or failure of the liner system due to localized subsidence underneath the geosynthetic liner, is a concern in design and operation of the landfill. The localized subsidence can...In a landfill, excessive tensile strains or failure of the liner system due to localized subsidence underneath the geosynthetic liner, is a concern in design and operation of the landfill. The localized subsidence can be commonly withstood by reinforcements such as geogrids. A total of nine model tests were carried out to study the influence of soil arching in overburden sandy soil on the geosynthetics and the interaction between the soil and the geosynthetics. The localized subsidence was modeled by a strip trapdoor under the geosynthetic reinforcements. The reinforcement includes several layers of polyvinylchlorid （PVC） membrane or both PVC membrane and a compacted clay layer. Test results show that the vertical soil pressure acting on the geosynthetics within the subsidence zone is strongly related to the deflection of the geosynthefics. The soil pressure acting on the deflected geosynthetics will decrease to a minimum value with respect to its deflection if the final deflection is large enough, and this minimum value is almost independent of the overburden height. Otherwise, the deflection of geosynthetics cannot result in a full degree of soil arching, and the soil pressure within the subsidence zone increases with the increase of overburden height. Deflections and strains of the geosynthetics obviously decrease with the increase of their tensile stiffness. The presence of a compacted clay layer buffer can therefore reduce both deflections and strains of the geosynthetics. Finally, a composite liner structure is recommended for landfills to withstand the localized subsidences.展开更多
基金Project(200231800032) supported by Research on Transportation Construction in Western, China
文摘The objective of this work is to compare the responses of geosynthetically-reinforced embankment and unreinforced embankment due to road widening by using the centrifuge model tests and a two-dimensional(2D) finite element(FE) model. The measured and calculated responses of the embankment and foundation exposed to road widening include the settlement,horizontal displacement,pore water pressure,and shear stresses. It is found that the road widening changed the transverse slope of the original pavement surface resulting from the nonuniform settlements. The maximum horizontal movement is found to be located at the shoulder of the original embankment. Although the difference is small,it is clearly seen that the geosynthetic reinforcement reduces the nonuniform settlements and horizontal movements due to road widening. Thus the reinforcement reduces the potential of pavement cracking and increases the stability of the embankment on soft ground in road widening.
文摘A new kind of tunnel support was put forward on the basis of the anchor spraysupport principle. The mechanics of the new three-dimensional steel bar shotcrete liningsupport was studied and the structure's internal forces were analyzed. The model experiment was done relying on the industrial test. The conclusion of numerical calculationsproved that the ANSYS program is reasonable and creditable. It was compared to otherkinds of support that are commonly used in soft rock tunnels. The technique and economiccontrasts of the typical tunnel with support three-dimensional steel bar were completed.
基金supported by the National Basic Research Program of China(No. 2012CB719800)the National Natural Science Foundation of China (No. 51127005)the Key Innovative Team Program of Zhejiang Province (No. 2009R50050), China
文摘In a landfill, excessive tensile strains or failure of the liner system due to localized subsidence underneath the geosynthetic liner, is a concern in design and operation of the landfill. The localized subsidence can be commonly withstood by reinforcements such as geogrids. A total of nine model tests were carried out to study the influence of soil arching in overburden sandy soil on the geosynthetics and the interaction between the soil and the geosynthetics. The localized subsidence was modeled by a strip trapdoor under the geosynthetic reinforcements. The reinforcement includes several layers of polyvinylchlorid （PVC） membrane or both PVC membrane and a compacted clay layer. Test results show that the vertical soil pressure acting on the geosynthetics within the subsidence zone is strongly related to the deflection of the geosynthefics. The soil pressure acting on the deflected geosynthetics will decrease to a minimum value with respect to its deflection if the final deflection is large enough, and this minimum value is almost independent of the overburden height. Otherwise, the deflection of geosynthetics cannot result in a full degree of soil arching, and the soil pressure within the subsidence zone increases with the increase of overburden height. Deflections and strains of the geosynthetics obviously decrease with the increase of their tensile stiffness. The presence of a compacted clay layer buffer can therefore reduce both deflections and strains of the geosynthetics. Finally, a composite liner structure is recommended for landfills to withstand the localized subsidences.
