Performance of Diaphragm Wall Constructed Using Top-Down Method

TLDR

The study evaluates the performance of top‑down diaphragm wall construction, emphasizing the need to account for creep and pore‑water pressure dissipation in soft clay excavations. The authors monitored strut loads, wall displacement, bending moments, ground settlement, pore‑water pressure, and bottom heave, correlating these measurements with construction stages and deriving bending moments from strain gauge and inclinometer data. Field data show that strut loads, wall displacement, and ground settlement match literature values, while deep inward movement of the wall and surrounding soil explains lateral earth pressure and aligns with pore‑water pressure changes over time.

Abstract

This paper presents the performance of an excavation using the top-down construction method. Strut loads, wall displacement, wall bending moment, ground surface settlement, pore-water pressure and bottom heave were measured. Results obtained from those observations are correlated with the construction activities. Field observations indicate that strut loads, wall displacement, and ground surface settlement correspond to those reported in the literature. Bending moments of the wall are studied based on the results of the rebar strain gauge and inclinometer measurements. The supported wall and the soil near the wall have a deep inward movement, which accounts for the magnitude of the lateral earth pressure acting on the wall. The behavior of the supported wall and soil over time is consistent with the variation of pore-water pressure during excavation. Analysis of excavations in soft clay should therefore consider the creep factors and/or pore-water pressure dissipation.