Swelling soils, particularly those rich in smectite, present significant challenges to civil engineering due to their shrinking–swelling behaviour. Lime stabilization is a commonly used practice to address this, but the reactivity of smectite minerals in an alkaline limestone environment differs widely. This study investigates the reactivity of two Moroccan smectite-rich clays – montmorillonite-dominated bentonite and stevensite/saponite-rich bentonite – when treated with aerial lime. Through mineralogical, microstructural and mechanical analyses, this study highlights the distinct behaviour of montmorillonite, which reacts with lime to form calcium silicate hydrate gels, compared to the inert response of stevensite/saponite. Despite its low pozzolanic activity, stevensite-bentonite demonstrates greater mechanical strength, reaching 2.5 MPa in the S3 mixture (90% stevensite-bentonite and 10% lime). This strength is attributed to the formation of calcite through the de-dolomitization of dolomite. The findings reveal different stabilization mechanisms between dioctahedral and trioctahedral smectites, offering new insights for soil stabilization strategies involving these smectite types.

The present study documents coastal processes of movement and subsidence that affect the clayey sediments of the exposed mudflats (‘mudflat sediments’) on the receding western shore of the Deep Dead Sea (‘western Dead Sea shore’) and the formation of subsidence features: subsidence strips and clustered sinkholes. The properties of the clayey sediments that promote movement and subsidence and the development of the subsidence features in the exposed mudflats are the unconsolidated fine-particle texture composed of clay and carbonate minerals, their being dry near the surface and wet at the subsurface, their soaking with saline water and brine and the abundance of smectitic clays saturated with sodium and magnesium. Field observations indicate that narrow subsidence strips with/without clustered sinkholes were developed by movement and subsidence in mudflat sediments via lateral spreading. Wide subsidence strips with clustered sinkholes were developed via increased subsidence in mudflat sediments due to the progress of dissolution within a subsurface rock–salt unit. The emergence of sinkholes occurs via subsidence of mudflat sediments into subsurface cavities resulting from dissolution within a subsidence rock–salt unit. The coastal processes on the receding Dead Sea shore and the formation of the subsidence features are part of the adjustment of the Dead Sea periphery to the lowering of the base level. A contribution of slow mass movement seaward to the coastal processes on the receding Dead Sea shore is indicated.