Deformation behavior of shored mechanically stabilized earth (SMSE) wall systems

Increasing traffic volume on mountain highways has led to the need for width expansions of existing roads in areas of limited rights-of-way. Shored mechanically stabilized earth (SMSE) walls are a viable alternative to expand the width of embankments and roadways on existing and stable slopes. SMSE walls typically have an aspect ratio (ratio of wall height to reinforcement length) less than the recommended aspect ratio for conventional fill-type MSE walls (i.e., 0.7). However, SMSE walls that are designed well can still be stable when constructed in front of an existing, stable slope such as a man-made shoring wall and bedrock. Although various studies including numerical analyses, centrifuge tests, and field scale tests have reported that these wall systems have contrasting behavior to conventional MSE walls, there is limited experimental or analytical evaluation of their deformation behavior.;A series of centrifuge tests were conducted to investigate the deformation performance of highly-instrumented SMSE wall models with various surcharge loadings under well-controlled conditions in a geotechnical centrifuge. The centrifuge model results identified more realistic mechanisms of behavior suitable for the validation of analytical model as well as the calibration of numerical model. Internal strain distributions obtained using tell tail wires and digital image analyses matched well, and indicated a line of maximum tensile strain with the height of wall different from that of conventional MSE walls. The location of the maximum reinforcement strain was found to be underneath the center of the footing for the SMSE walls in the upper portion of the wall. In the lower portion of the wall, the location of the maximum reinforcement strain was consistent with the Rankine active failure surface.;An analytical model was proposed to predict the lateral wall movement of SMSE wall with a wrapped-around facing. The model was verified using the data measured from the centrifuge tests and could provide a simplified and approximate solution for the prediction of lateral wall deformation in a preliminary design of SMSE wall. For similar stiffness of reinforcements, the use of geogrid having denser mesh was observed to be in much better prediction with experiment results.;This study also includes a series of parametric studies using the finite element simulations to investigate the effect of design variables on the behavior of SMSE wall systems based on the numerical models validated by the results of centrifuge test. The results from parametric studies demonstrated that the reinforcement vertical spacing of design variables considered in this study affected the deformations of SMSE wall systems much more significantly. The results permitted the identification of the location of maximum reinforcement strain for different aspect ratios less than or equal to 0.7 and indicated that there is little difference in the line locations of maximum reinforcement strain with wall height.