Deep foundation pit construction has the characteristics of high risky

great difficulty and complex structure stress in deep water-rich sandy stratum. Based on the foundation pit of a subway station

the deformation characteristics of a row-pile supporting foundation pit induced by deep excavation in deep water-rich sandy stratum are studied by field monitoring and numerical simulation method. The research results show that the horizontal displacement distribution curve of retaining wall develops from a “oblique line” shape to that of a “bow” and “inverted-V” with excavation depth. The maximum horizontal displacement of retaining wall and its location with excavation depth could be described by linear function. The maximum horizontal displacement

U

x

is about （

0.03%~0.15%

）

h

e

(

h

e

is excavation depth)

and the location of maximum horizontal displacement

H

x

is about （

0.4~1.0

）

h

e

. The distribution curve of ground vertical displacement behaves as a inverted-S with time

and the ground vertical displacement behaves as a groove shaped curve with an increase of transverse horizontal distance during the construction. The width of settlement trough is about (

1.0~2.0

)

h

e

and the location of maximum ground vertical displacement is about (

0.30~0.50

)

h

e

away from the edge of foundation pit. The control measures such as ensuring construction quality and anti-seepage effect of waterproof curtain

attention to the prediction and feedback function of construction monitoring are proposed to ensure the construction safety of foundation pit in water-rich sandy stratum. The conclusion could be referenced for the supporting structure design and construction deformation control of deep foundation pit in water-rich sandy region.