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The present study focusses on optimising a single supported excavation pit to achieve a more economical design using finite element analyses. Two methods for automating the derivation of the excavation pit's necessary embedment depth are presented, which involve either embedment depth reduction using additional calculation phases or adapting the entire model with renewed discretisation. The bending moments as well as the earth pressure distribution along the wall show good agreement, indicating that both methods are suitable for application. Subsequently, the feasibility of using optimisation algorithms (Particle Swarm Optimisation and Differential Evolution) for dimensioning the single supported excavation pit regarding stress analysis of the wall is investigated. Therefore, the embedment depth and the position of the strut are varied for five different sheet pile walls and three different strut profiles. The results demonstrate that both algorithms perform well, particularly with a higher number of calculation steps. After varying iteration steps and population size, the Differential Evolution approach shows better performance compared to Particle Swarm Optimisation by means of finding the optimal solution after a lower number of computational steps. [ABSTRACT FROM AUTHOR]

Soil plugging in open-ended piles is likely to occur in dense sandy soils which has been the subject of numerous scientific investigations. In contrast, the plugging behaviour in clayey soils is relatively unknown. In this paper an analytical approach to determine the soil plug resistance and its development during jacking in clayey soils is proposed. The new approach was developed using numerical simulations and was validated by back-calculating a field test from the literature. A total stress approach for the numerical simulations was chosen. The values calculated with the analytical formulas and the numerical solutions as well as the measurements from field tests are in very good agreement, given the high complexity of the interactions between pile and soil. Both the plug resistance and the plug height can be calculated during the jacking process. Further research is required to refine the proposed approach for soil plug resistance evaluation, as the proposed method is believed to enhance the understanding of occurring mechanisms. [ABSTRACT FROM AUTHOR]

Soil plugging in open-ended piles leads to an increase in compressive bearing capacity but also influences pile driving resistance. Many different factors affect the tendency for soil plugging, for example, pile diameter, penetration depth and installation method. In this paper, the influence of the installation method on soil plugging is investigated. In situ measurements during the installation of two instrumented tubular piles are carried out to investigate the internal and external stresses acting on the pile during the installation process. Furthermore, the cone penetration resistance inside one pile is measured during the installation, and the accelerations and strains at the pile head are monitored to predict the bearing capacity. The installation method is varied between vibratory and impact pile driving. The results show that a significant increase in horizontal stresses inside the pile occurs during impact driving which leads to the conclusion that a soil plug is formed. During vibratory pile driving, no stress increase was observed. [ABSTRACT FROM AUTHOR]

The development of a soil plug inside an open-ended pile with respect to the installation method is examined using numerical simulations. In this paper, the penetration process of an open-ended tubular pile with diameter D = 61 cm into granular soil is investigated. The aim is to achieve a better understanding of the mechanisms of soil plugging inside open-ended piles with respect to the installation method. As an example, the horizontal stress distribution inside the tubular pile after installation shows significant increase depending on the installation method. The numerical results are compared to experimental data. [ABSTRACT FROM AUTHOR]