Strata in Tianjin area are featured as an alternated multi-aquifer aquitard system. Based on this strata condition

lots of numerical calculations investigate the effect of deep foundation pre-dewatering on lateral displacement of support wall in soft ground under different construction conditions

including dewatering time (t)

dewatering depth ( )

pit length (L) and pit width (b). The calculation results were compared with relevant field data

and nonlinear regression analysis was then conducted based on the calculation and observation results. The results indicate that the maximal lateral displacement of support wall ( ) increases nonlinearly with t

and the growth rate decreases continuously. In the first few days of the dewatering

lateral displacement of support wall development can occupy large proportion of its stable value during pre-dewatering. Moreover

has a great influence on the development and the depth of wall with cantilever-type deflection ( ). In general

and will be larger with the increase of . Specifically

before reaches the second permeable stratum of the field

increases linearly with by a small scale. Otherwise

the growth proportion of with increases greatly. Before reaches the center location of the thick aquitard

increases synchronously with increased

and otherwise

the increment is apparently greater than the increment. Furthermore

as to the same pit width (b)

when the pit length (L) reaches a specific value

the corner effect induced by dewatering always appears at a specific distance from the pit corner along the pit length direction. In practical pre-dewatering

cross wall can be used to partition the pit into some parts

and let the ratio of cross wall spacing ( ) to b be less than 4

or let / be less than 3.7

using the corner effect to effectively reduce the maximal lateral displacement of support wall induced by pre-dewatering.