Experimental and numerical study of the Kaiser effect in cyclic Brazilian tests with disk rotation

Abstract

Sensitivity of the Kaiser effect to the deviations of the directions of s 1 -principal stress experienced by rock in successive loading cycles has an important impact on the application of this effect for stress measurements in rocks. The paper presents an analysis of the gradual Kaiser effect degradation with increasing deviation of the principal stress axes between loading cycles in Brazilian experiments. An experimental study was carried out to investigate the Kaiser effect in cyclic loading tests of disk specimens of a brittle limestone in diametrical compression with acoustic emission measurement. Tests were performed in which disks were loaded in two cycles without or with rotations between successive cycles. The rotation angle varied between 01 and 901. The Kaiser effect became gradually less pronounced with increasing rotation angle, but remained detectable for angles o101. Rotation by more than 101 resulted in complete disappearance of the effect. These experimental results were confirmed by numerical simulations using the displacement discontinuity method. r

Cyclic and Fatigue Behaviour of Rock Materials: Review, Interpretation and Research Perspectives

“…The classical Kaiser effect is observed by several authors during damage-controlled tests, among which (Li and Nordlund 1993;Gatelier et al 2002;Lavrov 2001;Lavrov et al 2002). Heap et al (2009) observe a different manifestation of the Kaiser effect where acoustic emissions are recorded also during a part of the unloading.…”

Brazilian Test of Concrete Specimens Subjected to Different Loading Geometries: Review and New Insights

“…It is advisable to introduce low values of the t/D ratio such that the state of the stress in the specimen is one of the plane stresses in the loading plane. With a plane stresses the stress distribution across the thickness is more homogeneous (Lavrov et al 2002). Yu et al (2006) adopted a 3-FEM and considered the effect of disk thickness (0:2 t=D 1) in the BT.…”

Study on Brazilian splitting test of bedding limestone slope deformation failure

“…And each group have six pieces. When the rock sample is destroyed, the failure load is recorded and the tensile strength would be calculated according to formula (2). The geometrical parameters, ultimate load and converted tensile strength of the specimen are shown in Table 1, and the relationship between the limestone tensile strength and the bedding angle h is shown in Fig.…”

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