Dewatering Characteristics and Inflow Prediction of Deep Foundation Pits with Partial Penetrating Curtains in Sand and Gravel Strata

Abstract

The dewatering of deep foundation pits excavated in highly permeable geology usually requires waterproofing technologies to relieve groundwater flow. However, no effective prediction formula is yet available for determining water inflow in the presence of partial penetrating curtains. In this study, a dewatering project with partial penetrating curtains is analyzed via a finite difference method to show evident three-dimensional (3D) seepage characteristics. The standard curve and distortion functions are established under the assumption of an equivalent well by quantifying the blocking effects; thus, the empirical inflow prediction formulas for steady flow are further developed. Moreover, a dewatering design method based on the prediction formulas is proposed and applied to the field dewatering project in sand and gravel strata. Measured results show that dewatering efficiency is considerably enhanced by 3D flow, forming appropriate pressure distributions for dewatering construction. The uplift pressure below the pit bottom is controlled within a 25% safety margin to verify the reliability of the design method.

Modeling of Flow and Transport in Saturated and Unsaturated Porous Media

“…Liu et al [43] studied dewatering of deep foundation pits excavated in highly permeable media using a finite difference method and showed evident three-dimensional (3D) seepage characteristics. A dewatering design method based on the prediction formulas was proposed in sand and gravel strata and applied to a field case for verification.…”

Impact of Seepage on the Underground Water Level in a Complex Soil‐Water‐Structure System

“…Moreover, the barrier efect is also related to the structure geometry (i.e., insertion depth and width) [25][26][27][28], and aquifer soil characteristics (i.e., aquifer permeability coefcient and aquifer thickness) [29,30]. However, in most of the studies, the problem is simplifed to a 2D problem [31,32], or in 3D numerical simulations, but the structure is extended to the boundary along the direction perpendicular to the fow direction [27], this can be called quasi-2D, which induces an overestimation of the barrier efect generated by a local impervious structure [33], most importantly, moly the average or maximum magnitude of the water level variation is generally provided considering diferent structure geometry [14,20,34,35]. However, there is little literature on the nonuniform distribution of groundwater level around the structure, and no simplifed calculation method of which can be founded in the previous research for neither homogeneous nor multilayer soil.…”

Impact of the Depth of Diaphragm Wall on the Groundwater Drawdown during Foundation Dewatering Considering Anisotropic Permeability of Aquifer

“…The foundation pit is one major kind of underground structure in the massive construction of underground space [1][2][3][4]. Gradually increased excavation area and depth with the development of urban construction may result in environmental effects.…”