Suffusion is the process defined as the migration of relatively small soil particles through the pores of a soil matrix composed of relatively large particles,driven by substantial hydrodynamic forces and weak attract...Suffusion is the process defined as the migration of relatively small soil particles through the pores of a soil matrix composed of relatively large particles,driven by substantial hydrodynamic forces and weak attraction energies.This study investigates the influence of flow direction(upward and downward)on suffusion induced by interaction energies in sand-clay mixtures under both saturated and unsaturated conditions.The impact of clay mineralogy(kaolinite,illite,and montmorillonite),sand-grain size,and ionic concentration(IC)gradient were discussed based on the observed breakthrough curves(BTCs)and relative saturation rate(Sr)during injection(particularly for unsaturated conditions).Under saturated conditions,higher susceptibility to suffusion was observed in sand-kaolinite and sand-illite mixtures under downward flow compared to upward flow,whereas the suffusion of montmorillonite was more significant under upward flow than under downward flow.In contrast,for unsaturated conditions,more substantial suffusion of kaolinite and illite particles occurred under upward flow compared to downward flow,whereas the opposite trend was observed in sand-montmorillonite mixtures.In addition,the impact of sand-grain size(or the size ratio between sand and clay)on the suffusion of kaolinite and illite under unsaturated conditions suggests a reduced size ratio that leads to relatively significant suffusion under downward flow compared to upward flow.The findings presented in this study contribute to a comprehensive understanding of the influence of flow direction on suffusion in sand-clay mixtures under both saturated and unsaturated conditions.展开更多
The detached clay particles directly filtrated through the sand-clay mixture lead to suffusion;however,if the detached clay particles are subjected to reattachment,the degree of suffusion may be less significant.This ...The detached clay particles directly filtrated through the sand-clay mixture lead to suffusion;however,if the detached clay particles are subjected to reattachment,the degree of suffusion may be less significant.This study investigates the impact of clay particle reattachment on suffusion of sand-clay mixtures through laboratory soil-column experiments.The observed breakthrough curves(BTCs)of kaolinite,illite,and montmorillonite for 5 different column lengths(3 in,6 in,9 in,12 in,and 18 in;1 in=2.54 cm)indicated that a higher breakthrough concentration was observed as the column length(L)decreased for kaolinite and illite,whereas a reverse trend was observed for montmorillonite.In addition,the increase in the fraction of filtrated clay particles(Me)with an increase in L(Me=10.42%for L=3 in and Me=3.59%for L=18 in)for the sand-illite mixture indicated that the reattachment effect became more significant as the travel length of detached clay particles increased.The observed BTCs,retention profiles after injection,and fraction of filtrated clay presented herein suggest the need to incorporate the reattachment effect when assessing the suffusion of clay-containing soils.展开更多
基金supported by the Korea Agency for Infrastructure Technology Advancement under the Ministry of Land,Infrastructure and Transport (Grant No.RS-2024-00410248)by National Research Foundation of Korea (NRF)grants funded by the Korean government (MSIT) (Grant No.RS-2022R1C1C1007296).
文摘Suffusion is the process defined as the migration of relatively small soil particles through the pores of a soil matrix composed of relatively large particles,driven by substantial hydrodynamic forces and weak attraction energies.This study investigates the influence of flow direction(upward and downward)on suffusion induced by interaction energies in sand-clay mixtures under both saturated and unsaturated conditions.The impact of clay mineralogy(kaolinite,illite,and montmorillonite),sand-grain size,and ionic concentration(IC)gradient were discussed based on the observed breakthrough curves(BTCs)and relative saturation rate(Sr)during injection(particularly for unsaturated conditions).Under saturated conditions,higher susceptibility to suffusion was observed in sand-kaolinite and sand-illite mixtures under downward flow compared to upward flow,whereas the suffusion of montmorillonite was more significant under upward flow than under downward flow.In contrast,for unsaturated conditions,more substantial suffusion of kaolinite and illite particles occurred under upward flow compared to downward flow,whereas the opposite trend was observed in sand-montmorillonite mixtures.In addition,the impact of sand-grain size(or the size ratio between sand and clay)on the suffusion of kaolinite and illite under unsaturated conditions suggests a reduced size ratio that leads to relatively significant suffusion under downward flow compared to upward flow.The findings presented in this study contribute to a comprehensive understanding of the influence of flow direction on suffusion in sand-clay mixtures under both saturated and unsaturated conditions.
基金supported by National Research Foundation of Korea(NRF)grants funded by the Korean government(MSIT)(Grant.Nos.2019R1A2C2086647 and 2022R1C1C1007296).
文摘The detached clay particles directly filtrated through the sand-clay mixture lead to suffusion;however,if the detached clay particles are subjected to reattachment,the degree of suffusion may be less significant.This study investigates the impact of clay particle reattachment on suffusion of sand-clay mixtures through laboratory soil-column experiments.The observed breakthrough curves(BTCs)of kaolinite,illite,and montmorillonite for 5 different column lengths(3 in,6 in,9 in,12 in,and 18 in;1 in=2.54 cm)indicated that a higher breakthrough concentration was observed as the column length(L)decreased for kaolinite and illite,whereas a reverse trend was observed for montmorillonite.In addition,the increase in the fraction of filtrated clay particles(Me)with an increase in L(Me=10.42%for L=3 in and Me=3.59%for L=18 in)for the sand-illite mixture indicated that the reattachment effect became more significant as the travel length of detached clay particles increased.The observed BTCs,retention profiles after injection,and fraction of filtrated clay presented herein suggest the need to incorporate the reattachment effect when assessing the suffusion of clay-containing soils.
