Bruchbedingungen für schauminjizierte Kiese unter mehraxialer Beanspruchung

Failure criteria for foam-grouted gravel under multiaxial loading. Foam grouting is an innovative method for improving the mechanical properties of cohesionless, coarse-grained soils. Despite this, only a few experimental studies have been conducted to assess the failure of foam-injected soils under multiaxial loading. This paper aims to fill this gap in knowledge. The stiffness and strength of the natural soil, which serve as reference values for the evaluation of the improvement effect due to the injection, are derived from drained triaxial tests. The mechanical behaviour of the foam-injected soil is investigated using uniaxial, triaxial, and splitting tensile tests. The foam-injected soil, exhibits significantly higher strength and stiffness but lower ductility than the untreated soil. The ductility of the foam-injected soil increases with increasing lateral pressure. The splitting tensile strength is only a small fraction of the compressive strength. The adequacy of the failure criteria Mohr-Coulomb, Hoek-Brown and Lade for the description of the failure of foam-injected coarse-grained soils is verified. All three failure criteria are basically suitable to describe the state of failure in triaxial compression. For compressive and tensile loading, the Hoek-Brown and Lade failure criteria seem to be more appropriate compared to Mohr-Coulomb.