The pipe curtain structure method(PSM)is a novel construction method to control ground deformation strictly.Compared with the traditional pipe-roofing and pipe jacking method,the connection between pipes in large spac...The pipe curtain structure method(PSM)is a novel construction method to control ground deformation strictly.Compared with the traditional pipe-roofing and pipe jacking method,the connection between pipes in large spacings using PSM is widely acknowledged as a unique construction procedure.Further study on this connection procedure is needed to resolve similar cases in that the pipes are inevitably constructed on both sides of existing piles.Cutting the steel plate during the connection procedure is the first step,which is crucial to control the safety and stability of the surrounding environment and existing structures.The deformation mechanism and limit support pressure of the cutting steel plate during the connection between pipes in large spacings are studied in this paper,relying on the undercrossing Yifeng gate tower project of Jianning West Road River Crossing Channel in Nanjing,China.A modified 3D wedge-prism failure model is proposed using the 3D discrete element method.Combined with Terzaghi loose earth pressure theory and the limit equilibrium theory,the analytical solutions for the limit support pressure of the excavation face of the cutting steel plate are derived.The modified 3D wedge-prism failure model and corresponding analytical solutions are categorised into two cases:(a)unilateral cutting scheme,and(b)bilateral cutting scheme.The analytical solutions for the two cases are verified from the numerical simulation and in-situ data and compared with the previous solutions.The comparative analysis between the unilateral and bilateral cutting schemes indicates that the bilateral cutting scheme can be adopted as a priority.The bilateral cutting scheme saves more time and induces less ground deformation than the unilateral one due to the resistance generated from the superimposed wedge.In addition,the parametric sensitivity analysis is carried out using an orthogonal experimental design.The main influencing factors arranged from high to low are the pipe spacing,the cutting size,and the pipe burial depth.The ground deformation increases with the increased cutting size and pipe spacing.The pipe burial depth slightly affects the ground deformation if the other two factors are minor.Cutting steel plates in small sizes,excavating soil under low disturbance,and supporting pipes for high frequency can effectively reduce the ground surface subsidence.展开更多
Solar energy is one of the most extensively utilized sustainable energy resources.It can effectively reduce greenhouse gas emissions and achieve energy savings.Photovoltaic/thermal(PV/T)modules are typically used to a...Solar energy is one of the most extensively utilized sustainable energy resources.It can effectively reduce greenhouse gas emissions and achieve energy savings.Photovoltaic/thermal(PV/T)modules are typically used to achieve photo-to-electricity and photo-to-thermal energy conversions.Various nanofluids have been adopted as thermal fluids to improve the heat exchange performance of PV/T modules.Consequently,this paper reviews and investigates the latest progress in PV/T module applications integrated with different types of nanomaterials,including metal and metal oxides,non-metallic materials,magnetic fluids,and nano-reinforced phase change materials(NePCMs),and thermal pipe structures such as twisted tubes,bionic tubes,serpentine tubes,and microchannels.The influences of different parameters,including dimensions,concentration,stability,and nanomaterial base-fluid choices,on the overall energy conversion efficiency are also discussed.Furthermore,the effect of an external magnetic field on the PV/T system performance is analyzed.The results demonstrated that the entire system efficiency could be achieved in the 85%–90%range by optimizing the PV/T pipe structure arrangements and introducing various nanofluids compared with conventional PV/T modules.展开更多
基金financial support by the National Natural Science Foundation of China(Grant No.52108363)the Postdoctoral Research Foundation of China(Grant Nos.2021M700654 and 2023T160074)+2 种基金the Key Project of High-speed Rail Joint Fund of National Natural Science Foundation of China(Grant No.U1934210)the Liaoning Revitalization Talents Program(Grant No.XLYC1905015)the Key Project of Liaoning Education Department,China(Grant No.LJKZZ20220003).
文摘The pipe curtain structure method(PSM)is a novel construction method to control ground deformation strictly.Compared with the traditional pipe-roofing and pipe jacking method,the connection between pipes in large spacings using PSM is widely acknowledged as a unique construction procedure.Further study on this connection procedure is needed to resolve similar cases in that the pipes are inevitably constructed on both sides of existing piles.Cutting the steel plate during the connection procedure is the first step,which is crucial to control the safety and stability of the surrounding environment and existing structures.The deformation mechanism and limit support pressure of the cutting steel plate during the connection between pipes in large spacings are studied in this paper,relying on the undercrossing Yifeng gate tower project of Jianning West Road River Crossing Channel in Nanjing,China.A modified 3D wedge-prism failure model is proposed using the 3D discrete element method.Combined with Terzaghi loose earth pressure theory and the limit equilibrium theory,the analytical solutions for the limit support pressure of the excavation face of the cutting steel plate are derived.The modified 3D wedge-prism failure model and corresponding analytical solutions are categorised into two cases:(a)unilateral cutting scheme,and(b)bilateral cutting scheme.The analytical solutions for the two cases are verified from the numerical simulation and in-situ data and compared with the previous solutions.The comparative analysis between the unilateral and bilateral cutting schemes indicates that the bilateral cutting scheme can be adopted as a priority.The bilateral cutting scheme saves more time and induces less ground deformation than the unilateral one due to the resistance generated from the superimposed wedge.In addition,the parametric sensitivity analysis is carried out using an orthogonal experimental design.The main influencing factors arranged from high to low are the pipe spacing,the cutting size,and the pipe burial depth.The ground deformation increases with the increased cutting size and pipe spacing.The pipe burial depth slightly affects the ground deformation if the other two factors are minor.Cutting steel plates in small sizes,excavating soil under low disturbance,and supporting pipes for high frequency can effectively reduce the ground surface subsidence.
基金supported by the Natural Science Foundation Project of Shandong Province(Grant No.ZR2023ME121)Taishan’s Scholar Program of Shandong Province,China(Grant No.tsqn 202211183)the Outstanding Youth Science Foundation Project of Shandong Province(Overseas)(Grant No.2023HWYQ-076).
文摘Solar energy is one of the most extensively utilized sustainable energy resources.It can effectively reduce greenhouse gas emissions and achieve energy savings.Photovoltaic/thermal(PV/T)modules are typically used to achieve photo-to-electricity and photo-to-thermal energy conversions.Various nanofluids have been adopted as thermal fluids to improve the heat exchange performance of PV/T modules.Consequently,this paper reviews and investigates the latest progress in PV/T module applications integrated with different types of nanomaterials,including metal and metal oxides,non-metallic materials,magnetic fluids,and nano-reinforced phase change materials(NePCMs),and thermal pipe structures such as twisted tubes,bionic tubes,serpentine tubes,and microchannels.The influences of different parameters,including dimensions,concentration,stability,and nanomaterial base-fluid choices,on the overall energy conversion efficiency are also discussed.Furthermore,the effect of an external magnetic field on the PV/T system performance is analyzed.The results demonstrated that the entire system efficiency could be achieved in the 85%–90%range by optimizing the PV/T pipe structure arrangements and introducing various nanofluids compared with conventional PV/T modules.
