Recently

field data shows that considerable wall deflection can be induced by pre-excavation dewatering. A numerical model was established and verified based on field data

and a parametric study was carried out to investigate the effect of soil permeability on wall deflection. The results indicate that the wall deflection

in a prescribed dewatering time

will be more obvious with the better soil permeability

the larger anisotropy coefficient of soil permeability within the dewatering depth. That is because

in this case

greater pore pressure decrease will appear at the soil layers

and larger total stress redistribution will appear at the soil-wall interface. Moreover

the depth of wall deflection has relation with the permeability of soil below the bottom of dewatering depth. If the soil below the bottom of dewatering depth is aquiclude and the center of the aquiclude thickness is deeper than the dewatering depth

the wall deflection will roughly appear within the dewatering depth. If the soil below the bottom of dewatering depth is well-drained soils

the wall deflection may reach the location of another aquiclude below the well-drained soils. Besides

when dewatering wells enter the well-drained soils

greater deflection increment will occur with the dewatering depth increase

and over dewatering should be avoided strictly. However

when thick and poorly drained soils appear below the bottom of dewatering depth

wall deflection increment induced by increasing dewatering depth is not apparent.