Mineralogical and Micro-structural Investigation into the Mechanical Behaviour of a Soft Calcareous Mudstone

Abstract The construction industry in Abu Dhabi is thriving and its coastline has some of the most ambitious structures world. Whilst subsurface evaporitic calcareous soft rocks this region are great geological interest, they relatively poorly understood from a geotechnical engineering perspective, forcing foundation designs to be overly conservative. Understanding stiffness underlying geology at small strains importance for accurate estimation ground movements around excavations foundations, yet routine post-SI laboratory testing programmes tend focus on basic rock mechanics tests such as UCS tests. These procedures generally unsuitable use with due their friable moisture sensitive nature, rarely obtain parameters representative actual situ behaviour. mudstone investigated paper mechanical structural characteristics falling between those soil typical and, such, requires approach that combines methods both disciplines. mineralogical, micro-structural lithology have been examined via suite techniques, including XRPD, SEM, advanced triaxial bender elements, along standard procedures. Shearing, tensile consolidation behaviours explored. Examination micro- macro-scale features material shows it highly structured, strength being controlled by inter-granular bonding Dolomite grains, well mean effective stress state rate strain. presence fibrous Palygorskite acts reduce degree bonding, causing specimens rich clay mineral more ductile