SPH model simulates water pressure and soil deformation in large slope failures
A $u$-$p_w$ SPH framework with mechanical-hydraulic boundary treatment in GeoDualSPHysics for large-deformation geomechanics
Computational Engineering, Finance, and Science
Summary
When soil is wet, water pressure inside the ground changes how the soil moves and settles. The authors created a computer simulation that connects how water pushes inside the soil with how the soil deforms and moves, especially during big landslides. They improved an existing tool to better handle water pressure at boundaries like the ground surface and walls. Their tests with different problems show the model can capture important behaviors, although some accuracy issues remain. This helps understand soil behavior during events like slope failures.
What this means in practice
- •For geotechnical engineers: Simulate soil consolidation and large slope failures by modeling coupled water pressure and soil deformation with improved boundary treatments.
- •For civil infrastructure planners: Assess stability and failure progression in sensitive clay slopes using the integrated hydromechanical SPH framework for safer construction design.
Authors
Yangfan Ma, Bin Su, Zheng Han, Changze Li, Mitsuteru Asai
Abstract
Pore-water pressure changes the effective stress and deformation of saturated geomaterials, while skeleton deformation generates pressure and drives drainage. Resolving this feedback together with hydraulic boundary conditions is necessary for simulations that connect consolidation to large post-failure movement. This paper presents a hydromechanical extension of GeoDualSPHysics using a single-layer displacement-pore-water-pressure ($u$-$p_w$) smoothed particle hydrodynamics (SPH) framework. An explicit pressure-rate equation combines volumetric compression and Darcy diffusion, and the resulting pore pressure feeds back into the skeleton momentum balance. The implementation extends the existing modified dynamic boundary condition (mDBC) infrastructure to carry hydraulic ghost values alongside mechanical boundary data. Prescribed pressure at drained surfaces is combined with impermeable walls and impermeable loaded contacts, with separate control of loading and drainage activation. The formulation is assessed through one-dimensional consolidation, two-dimensional flexible-strip loading, and the three-dimensional Cryer problem. The Cryer simulations reproduce the non-monotonic central pressure response over four Poisson ratios, with normalized pressure root-mean-square errors of 0.012-0.030. The consolidation tests also expose remaining settlement and late-time pressure discrepancies. Applications to 5 m and 8 m sensitive-clay slopes illustrate sequential retrogressive failure and large deformation. The contribution is the integration of hydraulic feedback and boundary handling within GeoDualSPHysics; the results establish an initial verification basis while identifying remaining accuracy and convergence questions.