Research on effective pit fencing solutions for the construction of a two-level parking lot of a multi-story building

Abstract

A study on the effective placement of the piles in the retaining wall of the pit was carried out. A comparison of internal forces and horizontal displacements of the retaining wall piles was drawn among three variants of their placements in the wall. The influence on the calculation results of the detailing of the soil excavation process during modeling using the Plaxis 2D was examined. Based on the research on the stress-strain state (STS) of the retaining wall piles using the spatial setting of the problem, a comparison to the problem with the flat setting was drawn. Additionally, an analysis of the bending moments and horizontal displacements in the retaining wall piles with a spatial setting of the problem was made.
 Based on the obtained results, information on the effectiveness of different variants of the pile placement in the retaining wall of the pit, as well as the convergence of the calculation results with different detailing of the excavation process modeling is presented. Also, a comparison of the values of internal forces, horizontal displacements, and the elevation of the pit bottom between flat and spatial problem settings was made. The distribution of forces between piles of the retaining wall using a spatial problem setting is presented.
 The finite element model consists of the soil base and retaining wall structure. Modeling of the base was executed using the Hardening soil model, in which the following soil characteristics are used during the calculation: γ – the specific weight of the soil in its natural state; γsat – the specific weight of the soil in the water-saturated state; c – cohesion; φ – the effective stress friction angle; ψ – dilatancy angle; E50 – stiffness for primary loading; Eoed – oedometer loading stiffness; Eur – stiffness for un-/reloading. The calculation was made using the Plaxis program complex.
 Today, the effective and the most rational way of retaining wall design during the construction of buildings and structures with underground parts is significant. A successful choice of the construction of the excavation fencing not only ensures the reliability of the construction but also allows using building materials in the most efficient way. In addition, the choice of the method of the problem definition and its detailing are important factors when approaching the modeling process of similar problems, as they affect the accuracy of the obtained results, the degree of labor-intensiveness, and the time spent on the calculation.