Analysis of lateral earth pressure on a vertical circular shaft considering the 3D arching effect

• This study focuses on the lateral earth pressure acting on a vertical circular shaft.
• The centrifuge model test and 2D FE analysis were performed.
• Parametric studies were carried out to investigate the influencing factor of the arching effect.
• This paper has clearly demonstrated the important arching effect of vertical circular shaft.

The lateral earth pressure on a vertical circular shaft is investigated using both experiments and numerical analyses. The study focused on quantifying the magnitude and distribution of the lateral earth pressure, which was measured by considering the three-dimensional arching effect. A framework for determining distribution of the earth pressure based on centrifuge model tests and 2D FE analysis is introduced. The FE modelling techniques and the constitutive relationships of the soil are presented in detail. Parametric analyses showed that the arching effect on the lateral earth pressure is highly dependent on the diameter and height of the shaft, the internal friction angle and the cohesion value of the soil, the end-bearing conditions and the flexural modulus of the shaft. The study found that when the arching effect is considered, the lateral earth pressure on a vertical circular shaft is approximately 80% less than that calculated using Rankine’s theory. The study also found that the arching effect of the soil is more significant for flexible vertical shafts than for rigid vertical shafts embedded in weathered soil.

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