Flume experiments play a pivotal role in studying wave propagation,with wave elements typically assumed to remain constant in the perpendicular direction.However,evident cross wave phenomena were observed within flume...Flume experiments play a pivotal role in studying wave propagation,with wave elements typically assumed to remain constant in the perpendicular direction.However,evident cross wave phenomena were observed within flumes under certain conditions.This paper presents new analytical solutions for both primary and cross waves on double shoals in a flume via linear shallow-water equations,which may be used to idealize dynamic experimental configurations of coral reefs.The primary waves on double shoals are described by the associated Legendre functions,whereas the ultimate solutions are derived by considering the incident and reflected waves in front of a bathymetry and the transmitted waves positioned behind it.The effects of the angular frequency and topographic parameters on the primary waves are subsequently analyzed.Cross waves on double shoals constitute a type of topographically trapped wave whose solutions are formulated by combining the first and second types of the associated Legendre functions.The angular frequency is not only determined by the wavenumber but also influenced by the topographic parameters.Numerical experiments are conducted to investigate the generation mechanism of cross waves.The consistency between the numerical results and analytical solutions confirms the validity of the new analytical framework of cross waves on double shoals.展开更多
Sandy braided river deposits are widely preserved in ancient stratigraphic records and act as a significant type of hydrocarbon reservoir.Due to the frequent and rapid migration of channels within the riverbed,the sed...Sandy braided river deposits are widely preserved in ancient stratigraphic records and act as a significant type of hydrocarbon reservoir.Due to the frequent and rapid migration of channels within the riverbed,the sedimentary architecture is highly complex.In this paper,a flume experiment was conducted to reveal the detailed depositional process and establish a fine sedimentary architecture model for sandy braided rivers.The result showed that(1)Three types of braid channels,including the lateral migration channel,the confluence channel,and the deep incised channel,were recognized based on geometry,scale,distribution,and spatial patterns;they are interconnected,forming a complex channel network.(2)Braid channels were characterized by lateral migration,abandonment,filling,and chute cutoff.Lateral migration of channels shaped the braid bars and dominated the formation,growth,and reworking of braid bars.(3)Controlled by the fast and frequent variations of the braid channel network,braid bars were continuously formed,reworked,reshaped,and composited of multiple accretions with different types,orientations,scales,and preservation degrees.Symmetrical and asymmetrical braid bars pre-sented significantly different composition patterns.(4)Dominated by the continuous reworking of braid channels,temporary deposits were limited preserved,braid channel deposits account for 54.3 percent of the eventually preserved braided river deposits,and four types of amalgamate patterns were recognized.Braid bars were cut and limited preserved,only accounting for 45.7 percent of the eventually preserved braided river deposits.(5)During the experiment,only 28 percent of near-surface temporary deposits were eventually preserved in fragmented forms with the final experimental braided river;the shape,spatial patterns,and most of the deposits observed during the depositional process were largely reworked and poorly preserved.(6)The scale of eventually preserved braid bars and braid channels is significantly smaller than the temporary deposits from geomorphic observations.The aspect ratio of the eventually preserved braid bars and the width-to-depth ratio of the eventually preserved braid channel are also significantly different from that of the temporary ones measured from topography data.展开更多
Fine grains migration is a primary cause of landslides and debris flows.This study investigates the effect of fine-grain migration on slope failure through flume experiments,focusing on the spatiotemporal characterist...Fine grains migration is a primary cause of landslides and debris flows.This study investigates the effect of fine-grain migration on slope failure through flume experiments,focusing on the spatiotemporal characteristics and mechanisms of slope stability.A series of artificial rainfall flume experiments with varying rainfall intensities and slopes were conducted using soil samples collected from Wei Jia Gully.The experiments monitored pore-water pressure,grain migration,and failure sequences.Grain-size distribution parameters(μand Dc)were analyzed to understand the migration path and accumulation of fine grains.The experiments reveal that fine-grain migration significantly alters soil structure,leading to random blockage and interconnection of internal pore channels.These changes result in fluctuating pore-water pressure distributions and uneven fine-grain accumulation,critical factors in slope stability.Slope failures occur randomly and intermittently,influenced by fine-grain content in runoff and resulting pore-water pressure variations.This study highlights that fine-grain migration plays a vital role in slope stability,with significant implications for predicting and mitigating slope failures.The stochastic nature of fine-grain migration and its impact on soil properties should be incorporated into predictive models to enhance their accuracy and reliability.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No. 52071128)the Natural Science Foundation of Jiangsu Basic Research Program (Grant No. BK20220082)
文摘Flume experiments play a pivotal role in studying wave propagation,with wave elements typically assumed to remain constant in the perpendicular direction.However,evident cross wave phenomena were observed within flumes under certain conditions.This paper presents new analytical solutions for both primary and cross waves on double shoals in a flume via linear shallow-water equations,which may be used to idealize dynamic experimental configurations of coral reefs.The primary waves on double shoals are described by the associated Legendre functions,whereas the ultimate solutions are derived by considering the incident and reflected waves in front of a bathymetry and the transmitted waves positioned behind it.The effects of the angular frequency and topographic parameters on the primary waves are subsequently analyzed.Cross waves on double shoals constitute a type of topographically trapped wave whose solutions are formulated by combining the first and second types of the associated Legendre functions.The angular frequency is not only determined by the wavenumber but also influenced by the topographic parameters.Numerical experiments are conducted to investigate the generation mechanism of cross waves.The consistency between the numerical results and analytical solutions confirms the validity of the new analytical framework of cross waves on double shoals.
基金funded by two projects of the National Natural Science Foundation of China(No.41802123,42130813).
文摘Sandy braided river deposits are widely preserved in ancient stratigraphic records and act as a significant type of hydrocarbon reservoir.Due to the frequent and rapid migration of channels within the riverbed,the sedimentary architecture is highly complex.In this paper,a flume experiment was conducted to reveal the detailed depositional process and establish a fine sedimentary architecture model for sandy braided rivers.The result showed that(1)Three types of braid channels,including the lateral migration channel,the confluence channel,and the deep incised channel,were recognized based on geometry,scale,distribution,and spatial patterns;they are interconnected,forming a complex channel network.(2)Braid channels were characterized by lateral migration,abandonment,filling,and chute cutoff.Lateral migration of channels shaped the braid bars and dominated the formation,growth,and reworking of braid bars.(3)Controlled by the fast and frequent variations of the braid channel network,braid bars were continuously formed,reworked,reshaped,and composited of multiple accretions with different types,orientations,scales,and preservation degrees.Symmetrical and asymmetrical braid bars pre-sented significantly different composition patterns.(4)Dominated by the continuous reworking of braid channels,temporary deposits were limited preserved,braid channel deposits account for 54.3 percent of the eventually preserved braided river deposits,and four types of amalgamate patterns were recognized.Braid bars were cut and limited preserved,only accounting for 45.7 percent of the eventually preserved braided river deposits.(5)During the experiment,only 28 percent of near-surface temporary deposits were eventually preserved in fragmented forms with the final experimental braided river;the shape,spatial patterns,and most of the deposits observed during the depositional process were largely reworked and poorly preserved.(6)The scale of eventually preserved braid bars and braid channels is significantly smaller than the temporary deposits from geomorphic observations.The aspect ratio of the eventually preserved braid bars and the width-to-depth ratio of the eventually preserved braid channel are also significantly different from that of the temporary ones measured from topography data.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA23090202)the Key Science and Technology Projects of Transportation Industry(Grant No.2021-MS4-104)the National Key Research and Development Program of China(Grant No.2019YFC1509900).
文摘Fine grains migration is a primary cause of landslides and debris flows.This study investigates the effect of fine-grain migration on slope failure through flume experiments,focusing on the spatiotemporal characteristics and mechanisms of slope stability.A series of artificial rainfall flume experiments with varying rainfall intensities and slopes were conducted using soil samples collected from Wei Jia Gully.The experiments monitored pore-water pressure,grain migration,and failure sequences.Grain-size distribution parameters(μand Dc)were analyzed to understand the migration path and accumulation of fine grains.The experiments reveal that fine-grain migration significantly alters soil structure,leading to random blockage and interconnection of internal pore channels.These changes result in fluctuating pore-water pressure distributions and uneven fine-grain accumulation,critical factors in slope stability.Slope failures occur randomly and intermittently,influenced by fine-grain content in runoff and resulting pore-water pressure variations.This study highlights that fine-grain migration plays a vital role in slope stability,with significant implications for predicting and mitigating slope failures.The stochastic nature of fine-grain migration and its impact on soil properties should be incorporated into predictive models to enhance their accuracy and reliability.
