In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hy...In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hydraulic fractures in layered porous reservoirs with modulus contrast.The coupled hydromechanical model is first verified against an analytical solution and a laboratory experiment.Then,the fracture geometry(e.g.height,aperture,and area)and fluid pressure evolutions of multiple hydraulic fractures placed in a porous reservoir interbedded with alternating stiff and soft layers are investigated using the model.The stress and pore pressure distributions within the layered reservoir during fluid injection are also presented.The simulation results reveal that stress umbrellas are easily to form among multiple hydraulic fractures’tips when propagating in soft layers,which impedes the simultaneous height growth.It is also observed that the impediment effect of soft layer is much more significant in the fractures suppressed by the preferential growth of adjoining fractures.After that,the combined effect of in situ stress ratio and fracturing spacing on the multi-fracture height growth is presented,and the results elucidate the influence of in situ stress ratio on the height growth behavior depending on the fracture spacing.Finally,it is found that the inclusion of soft layers changes the aperture distribution of outmost and interior hydraulic fractures.The results obtained from this study may provide some insights on the understanding of hydraulic fracture height containment observed in filed.展开更多
In light of the paramount considerations of environmental sustainability and the protection of both life and property,a significant number of existing reinforced concrete(RC)buildings fall short of meeting contemporar...In light of the paramount considerations of environmental sustainability and the protection of both life and property,a significant number of existing reinforced concrete(RC)buildings fall short of meeting contemporary standards in terms of their structural and energy performances.In response to these pressing concerns,there is an imperative need for comprehensive building retrofitting processes that integrate both structural and energy considerations.One such approach,the addition of RC walls,is commonly employed as a structural retrofitting technique.However,its potential to enhance overall building efficiency has been relatively underexplored in previous research.In this study,we focus on a representative RC building and utilize two key performance indices:structural residual life and energy consumption,to comprehensively evaluate the impact of RC wall retrofitting on both structural and energy performance.Our investigation considers retrofitting on both the exterior and interior sides of the building.It is observed that the structural performance exhibits notable improvement with the addition of RC walls on either side,and this improvement becomes even more pronounced when complemented by local retrofits to adjacent beams.While the RC walls added on the interior side have negligible impact on the building energy efficiency,those installed on the exterior side could obviously reduce the energy consumption of the HVAC system by 7.9%.Hence,the outcomes of this study indicate that employing the RC wall retrofitting on the exterior side of the existing building is an efficient way to reach structural and energy performance targets simultaneously.展开更多
文摘In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hydraulic fractures in layered porous reservoirs with modulus contrast.The coupled hydromechanical model is first verified against an analytical solution and a laboratory experiment.Then,the fracture geometry(e.g.height,aperture,and area)and fluid pressure evolutions of multiple hydraulic fractures placed in a porous reservoir interbedded with alternating stiff and soft layers are investigated using the model.The stress and pore pressure distributions within the layered reservoir during fluid injection are also presented.The simulation results reveal that stress umbrellas are easily to form among multiple hydraulic fractures’tips when propagating in soft layers,which impedes the simultaneous height growth.It is also observed that the impediment effect of soft layer is much more significant in the fractures suppressed by the preferential growth of adjoining fractures.After that,the combined effect of in situ stress ratio and fracturing spacing on the multi-fracture height growth is presented,and the results elucidate the influence of in situ stress ratio on the height growth behavior depending on the fracture spacing.Finally,it is found that the inclusion of soft layers changes the aperture distribution of outmost and interior hydraulic fractures.The results obtained from this study may provide some insights on the understanding of hydraulic fracture height containment observed in filed.
文摘In light of the paramount considerations of environmental sustainability and the protection of both life and property,a significant number of existing reinforced concrete(RC)buildings fall short of meeting contemporary standards in terms of their structural and energy performances.In response to these pressing concerns,there is an imperative need for comprehensive building retrofitting processes that integrate both structural and energy considerations.One such approach,the addition of RC walls,is commonly employed as a structural retrofitting technique.However,its potential to enhance overall building efficiency has been relatively underexplored in previous research.In this study,we focus on a representative RC building and utilize two key performance indices:structural residual life and energy consumption,to comprehensively evaluate the impact of RC wall retrofitting on both structural and energy performance.Our investigation considers retrofitting on both the exterior and interior sides of the building.It is observed that the structural performance exhibits notable improvement with the addition of RC walls on either side,and this improvement becomes even more pronounced when complemented by local retrofits to adjacent beams.While the RC walls added on the interior side have negligible impact on the building energy efficiency,those installed on the exterior side could obviously reduce the energy consumption of the HVAC system by 7.9%.Hence,the outcomes of this study indicate that employing the RC wall retrofitting on the exterior side of the existing building is an efficient way to reach structural and energy performance targets simultaneously.
