Performance evaluation of MSE walls on rigid inclusions-PPT Presentation

PPT Presentation

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The presentation evaluates mechanically stabilized earth (MSE) walls and embankments supported by rigid inclusions, emphasizing that the full system—soil, columns, geogrids, wall panels, construction stages, and geometry—must be analyzed together. Simplified, component-by-component design may miss important interactions and create risk.<br /><br />The work covers two Minnesota projects: the Twin Ports Interchange and TH169. Numerical models used soil properties interpreted primarily from CPT data, effective-stress strength, and PHSmall and Soft Soil Creep (SSC) constitutive models. Columns were modeled with nonlinear structural behavior, including cracking and changing bending and shear capacity. Field instrumentation at the Twin Ports project showed good agreement with predicted lateral movements; modest, rapidly dissipating pore-pressure increases supported drained analysis.<br /><br />At TH169, modeling identified a critical area beneath a reinforced soil slope (RSS): low axial loads reduced column bending capacity, while relatively flexible geogrids required substantial deformation to mobilize lateral restraint. Predicted horizontal movement beneath the RSS was about 90–100 mm. Adding steel rebars at the RSS base reduced movement by roughly half; the final proposed layout also removed two outer column rows while retaining reinforcement where needed.<br /><br />For another MSE-wall analysis, the basic configuration predicted substantial movement, including about 230 mm at the right wall. Early placement of lateral backfill reduced that to about 100 mm. Adding two layers of #10 rebars further reduced movement to about 40 mm, kept bar stress below yield, and brought column bending demands within the modeled unreinforced section’s capacity. Removing the external backfill later had only a minor effect.<br /><br />The presentation concludes that reliable design depends on integrated numerical analysis, realistic construction staging, and site-specific soil characterization. CPTU data combined with laboratory testing—particularly for index properties and effective shear strength—can provide useful input, while laboratory tests alone may not represent field-scale deformation and consolidation.

Keywords

mechanically stabilized earth

rigid inclusions

embankment support

geogrid reinforcement

soil-structure interaction

finite element modeling

CPT data

construction staging

lateral movement

Minnesota projects