The Influence of Weathering on the Engineering Properties of Dunites

The Influence of the Mineralogical Composition of Ultramafic Rocks on Their Engineering Performance: A Case Study from the Veria-Naousa and Gerania Ophiolite Complexes (Greece)

“…Several researchers have studied the effect of mineralogical composition (primary and secondary phases) on the engineering properties of rocks. Many of them have dealt with the influence of primary minerals, such as biotite, quartz and K-feldspar on the mechanical properties of volcanic and granitic rocks, presenting no relationships between these primary minerals of the investigated rocks and their mechanical properties [8,11,53,54], while others have studied the negative influence of weathering/alteration on the engineering behavior of the tested rocks [5,[22][23][24]55]. The generally lower hardness of the secondary minerals relative to the primary relics accompanied by new textures result in differential engineering behaviors, thus contributing to the weakness and easier deterioration of the rocks under stress and subsequently their gradually diminished in-service performance.…”

The impact of petrographic characteristics on the engineering properties of ultrabasic rocks from northern and central Greece

“…Ocean-floor metamorphism typically obscures primary petrographic characteristics of ophiolitic rocks, leading to a modification of their strength properties (e.g. Ramana et al 1986;Marinos et al 2006;Diamantis et al 2009;Ozsoy et al 2010;Rigopoulos et al 2010;Ündül & Tuğrul 2012).…”

The Time-Dependent Failure Mechanism of Rocks and Associated Application in Slope Engineering: An Explanation Based on Numerical Investigation

“…If the element is not damaged in tension, the Mohr-Coulomb criterion is then used. (iv) e time-dependent behaviour of rock is considered as a macroscopic consequence of mesoscopic Figure 1: e degradation characteristics of rocks strength in field observations and laboratory investigations: (a) the degradation of uniaxial compressive strength with weathering (Ündül and Tugrul [25], Arel and Tugrul [26], and Tugrul [27]); (b) freeze-thaw cyclinginduced degradation of compressive strength of granite (Tan et al [28]). damage evolution and the stiffness and strength degradation at the elemental scale; i.e., it is assumed that the time-dependent behaviour of rock is considered as a macroscopic consequence of the instantaneous or short-term damage development depending on the local stress level in a certain time interval (Δt) and strength degradation subjected to environmental change in the long-term period.…”

“…In addition to the soft rock, even hard rock is susceptible to weathering erosion. For example, the weathering of granitic and gneissic rocks in tropical regions can reach depths of more than 100 m [23,24].Ündül and Tugrul [25] investigated the changes in physical properties of dunite due to weathering. As shown in Figure 1(a), it is found that dunites generally show similar trends to other rock types; i.e., uniaxial compressive strength decreases with weathering process [25,[29][30][31].…”

“…For example, the weathering of granitic and gneissic rocks in tropical regions can reach depths of more than 100 m [23,24].Ündül and Tugrul [25] investigated the changes in physical properties of dunite due to weathering. As shown in Figure 1(a), it is found that dunites generally show similar trends to other rock types; i.e., uniaxial compressive strength decreases with weathering process [25,[29][30][31]. e tests on the influences of freeze-thaw cycles on the mechanical properties of biotite granite showed that the elastic modulus reduced exponentially with the number of freeze-thaw cycles, as well as compressive strength and cohesive strength (as shown in Figure 1(b) [28]).…”