Taking the lateritic soil collected from Miaoling town

Ezhou city

Hubei province as the study object

the free iron oxide in the undisturbed clay was removed by chemical selective dissolution combined with leaching as the treatment method in gradient

and the relationship between the drenching time of dithionite-citrate-bicarbonate (DCB) solution and the iron removal rate was achieved

and the effects of different leaching times on the physical

mechanical properties and the microscopic pore structure of the lateritic soil were analyzed. The experimental results show that the leaching time of DCB solution has a strong correlation with the iron removal rate

and the iron removal rate first increases rapidly and then gradually stabilizes with the time. Since the free iron oxide primarily plays the role of cementation between lateritic soil

the drenching time has a great influence on the physical and mechanical properties of lateritic soil. With the increase of drenching time

the contents of clay particles and colloidal particles gradually increase

the heat resistance increases marginally

and the unconfined compressive strength decreases significantly

while the overall trend of unconfined compressive strength decreases sharply in the early stage and tends to be stable in the later stage. Results of nuclear magnetic resonance (NMR)

differential thermal analysis (DTA) and scanning electron microscopy (SEM) reveal that as the leaching time increases

the internal pores of the Miaoling lateritic soil enlarge

the free water diminishes

the bound water increases

the microscopic morphology of the agglomerate structure is destroyed

the cemented material is significantly reduced

and the structural form gradually converts from a compact granule stacking structure to an aggregate-loose granular structure.