Vacuum combined surcharge preloading is an effective method which has been used in ground treatment. This study presents the analytical solution of vertical drains with vacuum combined surcharge preloading. The surcha...Vacuum combined surcharge preloading is an effective method which has been used in ground treatment. This study presents the analytical solution of vertical drains with vacuum combined surcharge preloading. The surcharge was considered to be time-dependent preloading due to its reflection of the real situation.Moreover,the free strain,instead of equal strain hypothesis of the surface,was adopted for the mathematical rigor. Both vertical and horizontal drainages,along with the well resistance were considered.Besides,the time-dependent surcharge preloading was resolved with the impulse theorem which has been presented in the study,and the solutions for pore water pressure and degree of consolidation were derived by applying the approach of separation of variables.Furthermore,the solution is compared with previous solutions and numerical solutions,and the results verify the correctness of the proposed model.展开更多
Underground facilities are usually constructed under existing buildings,or buildings are constructed over existing underground structures.It is then imperative to account for the current overburden loads and future su...Underground facilities are usually constructed under existing buildings,or buildings are constructed over existing underground structures.It is then imperative to account for the current overburden loads and future surface loadings in the design of tunnels.In addition,tunnels are often constructed beneath the groundwater level,such as cross-river tunnels.Therefore,it is also important to consider the water pressure impact on the tunnel lining behaviour.Tunnels excavated by a conventional tunnelling method are considered in this paper.The hyperstatic reaction method(HRM)is adopted in this study to investigate the effect of surcharge loading on a horseshoe-shaped tunnel behaviour excavated in saturated soft rocks.The results obtained from the HRM and numerical modelling are in good agreement.Parametric studies were then performed to show the effects of the water pressure,surcharge loading value and its width,and groundwater level on the behaviour of the horseshoe-shaped tunnel lining,in terms of internal forces and displacements.It displays that the bending moment,normal forces and radial displacements are more sensitive to the water pressure,surcharge loading and groundwater level.展开更多
Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,t...Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,the failure mode and the earth pressure acting on the rigid retaining wall with EPS geofoam inclusions and granular backfills(henceforth referred to as EPS-wall),under limited surcharge loading are investigated through two-and three-dimensional model tests.The testing results show that different from the sliding of almost all the backfill in the EPS-wall under semi-infinite surcharge loading,only an approximately triangular backfill slides in the wall under limited surcharge loading.The distribution of the lateral earth pressure on the EPS-wall under limited surcharge loading is non-linear,and the distribution changes from the increase of the wall depth to the decrease with the increase of the limited surcharge loading.An approach based on the force equilibrium of a differential element is developed to predict the lateral earth pressure behind the EPS-wall subjected to limited surcharge loading,and its performance was fully validated by the three-dimensional model tests.展开更多
Surcharge load(e.g.embankment fill)will induce settlement and outward lateral displacement,while vacuum pressure will induce settlement and inward lateral displacement of a ground.Ideally,combination of surcharge load...Surcharge load(e.g.embankment fill)will induce settlement and outward lateral displacement,while vacuum pressure will induce settlement and inward lateral displacement of a ground.Ideally,combination of surcharge load and vacuum pressure can reduce or minimize the lateral displacement.Laboratory large scale model(length:1.50 m,width:~0.62 m,height:0.85 m)tests and finite element analyses(FEA)were conducted to investigate the main influencing factors on lateral displacement of a soft clayey ground under the combination of vacuum pressure and surcharge load.For the conditions investigated,the results indicate that the outward lateral displacement increases with the increase of the ratio of surcharge load to vacuum pressure(RL)and the loading rate of the surcharge load(LR).Also,it is shown that for a given RL and LR condition,lateral displacement reduces with the increase of the initial undrained shear strength(Su)of the ground.To predict the lateral displacement of a ground under the combination of surcharge load and vacuum pressure,the loading conditions in terms of RL and LR,and Su value of the ground have to be considered.展开更多
In this paper,the effectiveness,applicability and validity of chemical e physical combined methods(CPCMs)for treatment of marine clay(MC)slurries were evaluated.The method CPCM1 combines chemical stabilization and vac...In this paper,the effectiveness,applicability and validity of chemical e physical combined methods(CPCMs)for treatment of marine clay(MC)slurries were evaluated.The method CPCM1 combines chemical stabilization and vacuum preloading(VP),while CPCM2 is similar to CPCM1 but includes both the application of surcharge and use of geo-bags to provide con fi nement during surcharge preloading.The key advantage of CPCM2 using geo-bags is that the surcharge can be immediately applied on the chemically stabilized slurries.Two types of geo-bags were investigated under simulated land fi lling and dyke conditions,respectively.The test results show that the shear strength(c u)of treated slurry by CPCM2 is generally much higher than that by CPCM1.Besides,the use of CPCM2 can signi fi cantly reduce the treatment time due to the short drainage paths created by geo-bags.Overall,CPCM2 allows faster consolidation and higher preloading that help to achieve higher mechanical properties of the stabilized slurry.There are consistent relationships between c U and water content of slurries treated by CPCM2.Several important observations were also made based on comparisons of experimental data.展开更多
People eating out at California restaurants may start to see an optional2 1% surcharge added to their bill. The money will go to a public fund that helps farmers who use practices3 that reduce carbon in the atmosphere...People eating out at California restaurants may start to see an optional2 1% surcharge added to their bill. The money will go to a public fund that helps farmers who use practices3 that reduce carbon in the atmosphere.To participate in the Restore California Renewable Restaurant program, eateries4 can choose to add a 1% fee to every diner's check5.展开更多
According to the limit equilibrium state of soils behind rigid walls and the pseudo-static approach,a general closed-form solution to seismic and static active earth pressure on the walls,which considers shear and ten...According to the limit equilibrium state of soils behind rigid walls and the pseudo-static approach,a general closed-form solution to seismic and static active earth pressure on the walls,which considers shear and tension failure of the retained soil,is put forward using a variational calculus method.The application point of the active resultant force specified in the proposed method is explained with a clear physical meaning related to possible movement modes of the walls.In respect of the derived nine dependent equations reflecting the functional characteristics of the earth pressure,the proposed method can be performed easily via an implicit strategy.There are 13 basic factors related to the retained soils,walls,and external loads to be involved in the proposed method.The tension crack segment of the slip surface is obviously influenced by these parameters,apart from vertical seismic coefficient and geometric bounds of the surcharge,but the shear slip segment maintains an approximately planar shape almost uninfluenced by these parameters.Noticeably,the proposed method quantitatively reflects that the resultant of the active earth pressure is always within a limited range under different possible movements of the same wall.展开更多
Current status and the progress of PV in China are introduced with detailed data,covering PV manufacturing,market development,cost reduction and technology innovation.Fast growing of PV industry in China is due to ser...Current status and the progress of PV in China are introduced with detailed data,covering PV manufacturing,market development,cost reduction and technology innovation.Fast growing of PV industry in China is due to series of incentive policies provided by the Chinese government,which are provided in this paper as well.To slow down the speed of PV development,the 5.31 new policy is issued on May 31,2018 by the Chinese government as a milestone.The affections of the new policy and future PV market are analyzed.The target of energy transition of China and the role of PV are provided.PV will have more broad space in development when it comes to grid parity in the future.展开更多
基金National Natural Science Foundation of China(No.51578214)
文摘Vacuum combined surcharge preloading is an effective method which has been used in ground treatment. This study presents the analytical solution of vertical drains with vacuum combined surcharge preloading. The surcharge was considered to be time-dependent preloading due to its reflection of the real situation.Moreover,the free strain,instead of equal strain hypothesis of the surface,was adopted for the mathematical rigor. Both vertical and horizontal drainages,along with the well resistance were considered.Besides,the time-dependent surcharge preloading was resolved with the impulse theorem which has been presented in the study,and the solutions for pore water pressure and degree of consolidation were derived by applying the approach of separation of variables.Furthermore,the solution is compared with previous solutions and numerical solutions,and the results verify the correctness of the proposed model.
基金The first author is supported by the Fundamental Research Funds for the Central Universities in China.The third author is supported by the Vietnam Ministry of Education and Training under grant number B2020-MDA-15.These funds are greatly appreciated.
文摘Underground facilities are usually constructed under existing buildings,or buildings are constructed over existing underground structures.It is then imperative to account for the current overburden loads and future surface loadings in the design of tunnels.In addition,tunnels are often constructed beneath the groundwater level,such as cross-river tunnels.Therefore,it is also important to consider the water pressure impact on the tunnel lining behaviour.Tunnels excavated by a conventional tunnelling method are considered in this paper.The hyperstatic reaction method(HRM)is adopted in this study to investigate the effect of surcharge loading on a horseshoe-shaped tunnel behaviour excavated in saturated soft rocks.The results obtained from the HRM and numerical modelling are in good agreement.Parametric studies were then performed to show the effects of the water pressure,surcharge loading value and its width,and groundwater level on the behaviour of the horseshoe-shaped tunnel lining,in terms of internal forces and displacements.It displays that the bending moment,normal forces and radial displacements are more sensitive to the water pressure,surcharge loading and groundwater level.
基金funding support from National Natural Science Foundation of China(Grant No.52179109)Jiangsu Provincial Natural Science Foundation(Grant No.BK20230967)Open Research Fund of State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University(Grant No.KF2022-02).
文摘Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,the failure mode and the earth pressure acting on the rigid retaining wall with EPS geofoam inclusions and granular backfills(henceforth referred to as EPS-wall),under limited surcharge loading are investigated through two-and three-dimensional model tests.The testing results show that different from the sliding of almost all the backfill in the EPS-wall under semi-infinite surcharge loading,only an approximately triangular backfill slides in the wall under limited surcharge loading.The distribution of the lateral earth pressure on the EPS-wall under limited surcharge loading is non-linear,and the distribution changes from the increase of the wall depth to the decrease with the increase of the limited surcharge loading.An approach based on the force equilibrium of a differential element is developed to predict the lateral earth pressure behind the EPS-wall subjected to limited surcharge loading,and its performance was fully validated by the three-dimensional model tests.
文摘Surcharge load(e.g.embankment fill)will induce settlement and outward lateral displacement,while vacuum pressure will induce settlement and inward lateral displacement of a ground.Ideally,combination of surcharge load and vacuum pressure can reduce or minimize the lateral displacement.Laboratory large scale model(length:1.50 m,width:~0.62 m,height:0.85 m)tests and finite element analyses(FEA)were conducted to investigate the main influencing factors on lateral displacement of a soft clayey ground under the combination of vacuum pressure and surcharge load.For the conditions investigated,the results indicate that the outward lateral displacement increases with the increase of the ratio of surcharge load to vacuum pressure(RL)and the loading rate of the surcharge load(LR).Also,it is shown that for a given RL and LR condition,lateral displacement reduces with the increase of the initial undrained shear strength(Su)of the ground.To predict the lateral displacement of a ground under the combination of surcharge load and vacuum pressure,the loading conditions in terms of RL and LR,and Su value of the ground have to be considered.
基金the R&D project, titled " Creating a Marine Clay Matrix with Incineration Bottom Ash (IBA) for Land Reclamation " (Wu et al., 2014), under the Innovation for Environmental Sustainability (IES) Fund from National Environment Agency (NEA) of Singapore (ETO/CF/3/1)
文摘In this paper,the effectiveness,applicability and validity of chemical e physical combined methods(CPCMs)for treatment of marine clay(MC)slurries were evaluated.The method CPCM1 combines chemical stabilization and vacuum preloading(VP),while CPCM2 is similar to CPCM1 but includes both the application of surcharge and use of geo-bags to provide con fi nement during surcharge preloading.The key advantage of CPCM2 using geo-bags is that the surcharge can be immediately applied on the chemically stabilized slurries.Two types of geo-bags were investigated under simulated land fi lling and dyke conditions,respectively.The test results show that the shear strength(c u)of treated slurry by CPCM2 is generally much higher than that by CPCM1.Besides,the use of CPCM2 can signi fi cantly reduce the treatment time due to the short drainage paths created by geo-bags.Overall,CPCM2 allows faster consolidation and higher preloading that help to achieve higher mechanical properties of the stabilized slurry.There are consistent relationships between c U and water content of slurries treated by CPCM2.Several important observations were also made based on comparisons of experimental data.
文摘People eating out at California restaurants may start to see an optional2 1% surcharge added to their bill. The money will go to a public fund that helps farmers who use practices3 that reduce carbon in the atmosphere.To participate in the Restore California Renewable Restaurant program, eateries4 can choose to add a 1% fee to every diner's check5.
基金supported by the National Natural Science Foundation of China(No.51578466)the Construction S&T Project of Department of Transportation of Sichuan Province,China(No.2020A01)。
文摘According to the limit equilibrium state of soils behind rigid walls and the pseudo-static approach,a general closed-form solution to seismic and static active earth pressure on the walls,which considers shear and tension failure of the retained soil,is put forward using a variational calculus method.The application point of the active resultant force specified in the proposed method is explained with a clear physical meaning related to possible movement modes of the walls.In respect of the derived nine dependent equations reflecting the functional characteristics of the earth pressure,the proposed method can be performed easily via an implicit strategy.There are 13 basic factors related to the retained soils,walls,and external loads to be involved in the proposed method.The tension crack segment of the slip surface is obviously influenced by these parameters,apart from vertical seismic coefficient and geometric bounds of the surcharge,but the shear slip segment maintains an approximately planar shape almost uninfluenced by these parameters.Noticeably,the proposed method quantitatively reflects that the resultant of the active earth pressure is always within a limited range under different possible movements of the same wall.
文摘Current status and the progress of PV in China are introduced with detailed data,covering PV manufacturing,market development,cost reduction and technology innovation.Fast growing of PV industry in China is due to series of incentive policies provided by the Chinese government,which are provided in this paper as well.To slow down the speed of PV development,the 5.31 new policy is issued on May 31,2018 by the Chinese government as a milestone.The affections of the new policy and future PV market are analyzed.The target of energy transition of China and the role of PV are provided.PV will have more broad space in development when it comes to grid parity in the future.
