Practical assessment of subgrade settlement induced by train operation requires developing suitable models capable of describing permanent deformation characteristics of subgrade filling under repeated dynamic loading...Practical assessment of subgrade settlement induced by train operation requires developing suitable models capable of describing permanent deformation characteristics of subgrade filling under repeated dynamic loading.In this paper,repeated load triaxial tests were performed on coarse-grained soil(CGS),and the axial permanent strain of CGS under different confining pressures and dynamic stress amplitudes was analysed.Permanent deformation behaviors of CGS were categorized based on the variation trend of permanent strain rate with accumulated permanent strain and the shakedown theory.A prediction model of permanent deformation considering stress state and number of load cycles was established,and the ranges of parameters for different types of dynamic behaviors were also divided.The results indicated that the variational trend of permanent strain rate with accumulated permanent strain can be used as a basis for classifying dynamic behaviors of CGS.The stress state(confining pressure and dynamic stress amplitude)has significant effects on the permanent strain rate.The accumulative characteristics of permanent deformation of CGS with the number of load cycles can be described by a power function,and the model parameters can reflect the influence of confining pressure and dynamic stress amplitude.The study’s results could help deepen understanding of the permanent deformation characteristics of CGS.展开更多
The creation of the new“Ferry-Free Coastal Highway Route E39”in southwest Norway entails the production of a remarkable quantity of crushed rocks.These resources could be beneficially employed as aggregates in the u...The creation of the new“Ferry-Free Coastal Highway Route E39”in southwest Norway entails the production of a remarkable quantity of crushed rocks.These resources could be beneficially employed as aggregates in the unbound courses of the highway itself or other road pavements present nearby.Two innovative stabilizing agents,organosilane and lignosulfonate,can significantly enhance the key properties,namely,resilient modulus and resistance against permanent deformation,of the aggregates that are excessively weak in their natural state.The beneficial effect offered by the additives was thoroughly evaluated by performing repeated load triaxial tests.The study adopted the most common numerical models to describe these two key mechanical properties.The increase in the resilient modulus and reduction in the accumulated vertical permanent deformation show the beneficial impact of the additives.Furthermore,a finite element model was created to simulate the repeated load triaxial test by implementing nonlinear elastic and plastic constitutive relationships.展开更多
The resilient modulus (RM) of hydrated cement treated crushed rock base (HCTCRB) affected by amount of hydration periods, compaction and dryback processes was presented using repeated load triaxial tests. The rela...The resilient modulus (RM) of hydrated cement treated crushed rock base (HCTCRB) affected by amount of hydration periods, compaction and dryback processes was presented using repeated load triaxial tests. The related trends of RM corresponding to the different hydration periods still cannot be concluded. Instead, It is found that the moisture content plays more major influence on the RM performance. Higher additional water during compaction of HCTCRB, even at its optimum moisture content and induced higher dry density, led to the inferior RM performance compared to the sample without water addition. The RM of damper samples can be improved through dryback process and superior to that of the sample without water addition at the same moisture content. However, the samples withut water addition during compaction deliver the comparable RM values even its dry density is lower than the other two types. These results indicate the significant influence of moisture content to the performances of HCTCRB with regardless of the dry density. Finally, the experimental results of HCT- CRB and parent material are evaluated with the K-O model and the model recommended by Austroads. These two models provide the excellent fit of the tested results with high degree of determination.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51878666 and 51678572).
文摘Practical assessment of subgrade settlement induced by train operation requires developing suitable models capable of describing permanent deformation characteristics of subgrade filling under repeated dynamic loading.In this paper,repeated load triaxial tests were performed on coarse-grained soil(CGS),and the axial permanent strain of CGS under different confining pressures and dynamic stress amplitudes was analysed.Permanent deformation behaviors of CGS were categorized based on the variation trend of permanent strain rate with accumulated permanent strain and the shakedown theory.A prediction model of permanent deformation considering stress state and number of load cycles was established,and the ranges of parameters for different types of dynamic behaviors were also divided.The results indicated that the variational trend of permanent strain rate with accumulated permanent strain can be used as a basis for classifying dynamic behaviors of CGS.The stress state(confining pressure and dynamic stress amplitude)has significant effects on the permanent strain rate.The accumulative characteristics of permanent deformation of CGS with the number of load cycles can be described by a power function,and the model parameters can reflect the influence of confining pressure and dynamic stress amplitude.The study’s results could help deepen understanding of the permanent deformation characteristics of CGS.
基金The study was financed by the Norwegian Public Roads Administration(Grant No.25134404.Sparks AS(Asker,Norway)Zydex Industries(Vadodara,India)courteously provided the polymer-based additive.Borregaard AS(Sarpsborg,Norway)courteously provided the lignin-based additive.The authors do not have any conflicts of interest with other entities or researchers.
文摘The creation of the new“Ferry-Free Coastal Highway Route E39”in southwest Norway entails the production of a remarkable quantity of crushed rocks.These resources could be beneficially employed as aggregates in the unbound courses of the highway itself or other road pavements present nearby.Two innovative stabilizing agents,organosilane and lignosulfonate,can significantly enhance the key properties,namely,resilient modulus and resistance against permanent deformation,of the aggregates that are excessively weak in their natural state.The beneficial effect offered by the additives was thoroughly evaluated by performing repeated load triaxial tests.The study adopted the most common numerical models to describe these two key mechanical properties.The increase in the resilient modulus and reduction in the accumulated vertical permanent deformation show the beneficial impact of the additives.Furthermore,a finite element model was created to simulate the repeated load triaxial test by implementing nonlinear elastic and plastic constitutive relationships.
基金the Australian Research Council(ARC) for financial support under the ARC Linkage Scheme(LP100100734)
文摘The resilient modulus (RM) of hydrated cement treated crushed rock base (HCTCRB) affected by amount of hydration periods, compaction and dryback processes was presented using repeated load triaxial tests. The related trends of RM corresponding to the different hydration periods still cannot be concluded. Instead, It is found that the moisture content plays more major influence on the RM performance. Higher additional water during compaction of HCTCRB, even at its optimum moisture content and induced higher dry density, led to the inferior RM performance compared to the sample without water addition. The RM of damper samples can be improved through dryback process and superior to that of the sample without water addition at the same moisture content. However, the samples withut water addition during compaction deliver the comparable RM values even its dry density is lower than the other two types. These results indicate the significant influence of moisture content to the performances of HCTCRB with regardless of the dry density. Finally, the experimental results of HCT- CRB and parent material are evaluated with the K-O model and the model recommended by Austroads. These two models provide the excellent fit of the tested results with high degree of determination.