The mechanical responses and ultimate failure patterns of rocks are associated with the failure mechanism evolution.In this study,smoothed particle hydrodynamics(SPH)method with the mixed-mode failure model is propose...The mechanical responses and ultimate failure patterns of rocks are associated with the failure mechanism evolution.In this study,smoothed particle hydrodynamics(SPH)method with the mixed-mode failure model is proposed to probe into failure mechanism evolutions for disc specimens upon loading.The tensile damage model and the Drucker-Prager model are used to calculate the tensile failure and shear failure of the material,respectively.It is concluded that for flaw-unfilled disc specimens,the crack coalescence mechanism in the rock bridge area is affected by the flaw inclination angle and the material property.Considering disc specimens with filled flaws,the incremental rate of tensile damage grows more rapidly when the disc and filling material have a closer ratio of tensile strength to cohesion,which makes the entire specimen response greater brittleness.Furthermore,with the increasing non-uniformity of filling distribution,the incremental rate of tensile-activated damage decreases and the disc specimen performs more ductile.Besides,the influence of the fillings is greater when the flaw inclination angle is approaching 45°.It is proved that the proposed SPH method can be used to simulate the failure mechanism evolution of rocks,which lays a foundation for the study of more complex rock failure.展开更多
In the United States,more than 94%highways are paved with asphalt materials and placing crack sealant materials has been a common pavement maintenance for decades.Crack sealing treatment includes the use of a router t...In the United States,more than 94%highways are paved with asphalt materials and placing crack sealant materials has been a common pavement maintenance for decades.Crack sealing treatment includes the use of a router to create a reservoir on the intended cracks whereas crack filling is given without doing any modification to the crack wall.Although the initial cost of crack sealing is higher,it is expected to have a longer service period compared to crack filling.There is little research on comparison of short and long term cost effectiveness between these two treatments using the real field cost data analysis.In this study four test sites in Texas were treated with crack filling and sealing using the same sealant material and finishing technique.Cost effectiveness of both treatments was measured in terms of initial,annual average and life cycle cost based on the cost inputs during construction.In general,the results of this study indicated that(1)on an average approximately 45%initial cost increase was estimated with the two routing configurations of crack sealing;(2)material and labor cost is found to have the most significant effect on the higher initial cost of crack sealing compared to other associated costs;(3)annual average and life cycle costs have shown that crack sealing is more cost effective pavement maintenance compared to crack filling over a long period of time;(4)agency cost is observed to be reduced by approximately 24%with crack sealing treatment based on the35 year analysis period.展开更多
基金This work is supported in part by the National Natural Science Foundation of China(No.51779084)。
文摘The mechanical responses and ultimate failure patterns of rocks are associated with the failure mechanism evolution.In this study,smoothed particle hydrodynamics(SPH)method with the mixed-mode failure model is proposed to probe into failure mechanism evolutions for disc specimens upon loading.The tensile damage model and the Drucker-Prager model are used to calculate the tensile failure and shear failure of the material,respectively.It is concluded that for flaw-unfilled disc specimens,the crack coalescence mechanism in the rock bridge area is affected by the flaw inclination angle and the material property.Considering disc specimens with filled flaws,the incremental rate of tensile damage grows more rapidly when the disc and filling material have a closer ratio of tensile strength to cohesion,which makes the entire specimen response greater brittleness.Furthermore,with the increasing non-uniformity of filling distribution,the incremental rate of tensile-activated damage decreases and the disc specimen performs more ductile.Besides,the influence of the fillings is greater when the flaw inclination angle is approaching 45°.It is proved that the proposed SPH method can be used to simulate the failure mechanism evolution of rocks,which lays a foundation for the study of more complex rock failure.
基金TxDOTsupported by the Research Grant from KICT through the Korea Agency for Infrastructure Technology Advancement funded by the Ministry of Land,Infrastructure and Transport of the Korean government(Project No:18TBIP-C125410-02).
文摘In the United States,more than 94%highways are paved with asphalt materials and placing crack sealant materials has been a common pavement maintenance for decades.Crack sealing treatment includes the use of a router to create a reservoir on the intended cracks whereas crack filling is given without doing any modification to the crack wall.Although the initial cost of crack sealing is higher,it is expected to have a longer service period compared to crack filling.There is little research on comparison of short and long term cost effectiveness between these two treatments using the real field cost data analysis.In this study four test sites in Texas were treated with crack filling and sealing using the same sealant material and finishing technique.Cost effectiveness of both treatments was measured in terms of initial,annual average and life cycle cost based on the cost inputs during construction.In general,the results of this study indicated that(1)on an average approximately 45%initial cost increase was estimated with the two routing configurations of crack sealing;(2)material and labor cost is found to have the most significant effect on the higher initial cost of crack sealing compared to other associated costs;(3)annual average and life cycle costs have shown that crack sealing is more cost effective pavement maintenance compared to crack filling over a long period of time;(4)agency cost is observed to be reduced by approximately 24%with crack sealing treatment based on the35 year analysis period.
