Numerical Analysis of Soil Arching Development in Geosynthetic-Reinforced Embankments over Extended Cavities

The application of geosynthetic-reinforced embankments over soft soils or cavities has been widely used due to its benefits including the surface settlements limitation effect. Nevertheless, the lack of understanding of the physical mechanisms acting during the cavity’s formation is a major challenge that can affect the design of such structures. Based on numerical analyses, a series of two-dimensional finite element method simulations were carried out to investigate the soil arching development under different embankment heights, geosynthetic tensile stiffnesses, and top load. As a key finding, deformation behaviors classify soil arching into three types based on height-to-diameter ratio: slight arching, partial arching, and full arching. Each arching type demonstrates a multi-arch pattern including a truncated cone, concentric ellipses, and equal settlement planes, respectively. The study also indicates that to apply Terzaghi's formula for calculating the stress on the geosynthetics above the cavities, it is important to select an appropriate value of lateral coefficient ratio, K corresponding to embankments classified into different soil arching types. A formula based on the Gaussian distribution is proposed to simply estimate the stress distribution over extended cavities.