Application of soil mixing (CSM) in stiff clay for dike stabilization.
Along one side of the river Scheldt (Belgium), several slope instabilities have occurred over the last decades. All instabilities are related to a stiff tertiary clay layer with a limited thickness (3m) and with very low residual strength characteristics. Due to the low strength, it is nearly impossible to restore the slopes with a natural gentle slope and stabilizing measures are required. One of the aspired techniques is to install transverse soil mix panels in the dikes to stabilize the slopes. An on-site test was performed to validate the possibility of improving the soil characteristics of the stiff clay by using the cutter soil mix (CSM) technique. It is well known that stiff clays are difficult to mix, therefore, different W/C ratios, mixing depths and mixing energies were used to optimize the results. An extensive set of laboratory tests was performed to quantify the obtained strength. Furthermore, 3D finite element calculations are performed to validate the stabilizing technique with the obtained soil mix characteristics. An overview will be given of the laboratory tests, as well as the results of the 3D finite element model.