Abstract: The most soil layers are soft soils and their rheology is stronger, so the earth pressure and deformation of retaining structures are significantly influenced by time and space during the construction process of deep foundation pit. It is derived that rheological properties of silty clay in Wuxi region accord with Kelvin rheological model with three parameters based on the rheological test results of silty clay under different stress paths. A modified model of three parameters for the coefficient of horizontal sub-grade reaction is proposed considering the rheological propertices of silty soils. The coefficient of horizontal sub-grade reaction is back analyzed through the measured displacement of diaphragm wall, and the analysis shows that the coefficient decreases with the increase of the construction period, but it increases with the increase of the buried depth of soil layers and finally tends to a stable value. The ranges of various parameters of the modified model are determined, and then a modified formula for the coefficient of horizontal subgrade reaction of silty clay is obtained considering the rheological properties in Wuxi region. The results may provide guidance for the calculation and analysis of the deep foundation pit.