Analysis of the lateral pressure of wet concrete on neighboring foundations-Paper

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The paper examines how fresh concrete poured during diaphragm-wall construction can impose lateral pressure on nearby foundations and retaining structures. This risk is particularly important in dense urban areas, where new deep walls may be built close to existing infrastructure.<br /><br />A review of established guidance—including ACI, CIRIA, DIN and French recommendations—finds that many formulas were developed for conventional formwork and may underestimate pressure for deep walls, especially when concrete is fluid, placed rapidly or sets slowly. The authors assess the model developed by Nicolas Roussel, which accounts for concrete properties such as slump, density and thixotropy. Laboratory tests and previous field trials support its ability to estimate pressure more reliably. The authors also present a simplified pressure profile for design.<br /><br />The paper reports monitoring from a 59 m-deep circular diaphragm wall built near a Seine river quay supported by sheet piles. Instrumentation tracked wall movements and stresses during excavation and concreting. At one panel, concreting produced a bulge of about 1 mm without measurable stress in the quay. At the closer panel, the bulge reached about 15 mm before stabilizing near 9 mm, with sheet-pile stresses around 20 MPa. Overall, excavation caused greater effects than concreting, and monitored concrete pressures were lower than expected. The observations supported avoiding planned reinforcement of the existing wall.<br /><br />To estimate effects on surrounding soil, the authors explore a simplified cylindrical cavity-expansion model. It can provide an efficient estimate of stress distribution, but assumes idealized soil behavior and elastic conditions, limiting its suitability where soil yields or behaves nonlinearly. More advanced analysis, particularly finite-element modeling, is recommended for complex cases.<br /><br />The study concludes that current guidance may be inadequate for deep diaphragm-wall applications, while the Roussel approach appears promising. Further work is needed to improve prediction of soil and foundation response.

Keywords

diaphragm wall

fresh concrete pressure

lateral pressure

foundation impact

retaining structures

Roussel model

concrete rheology

urban excavation

cylindrical cavity expansion

finite element modeling