Mechanical Behavior of Weathered Granite Exposed to Water

Abstract

Weathered granite has been widely used as an emerging foundation filler for constructing transportation infrastructure. However, various softened rocks weathered due to exposure to water have special properties. Thus, it is necessary to gain a thorough understanding of the various physical and mechanical properties of weathered granite after exposure to water in order to avoid engineering accidents. To this end, this paper conducted a series of undrained triaxial shear tests to compare the mechanical behavior of weathered granite in natural and saturated states. The results demonstrate that the strength of the weathered granite significantly declines when it is exposed to water, and it exhibits noticeable water softening characteristics. Consolidation methods also affect the mechanical properties of weathered granite. The degree of softening of weathered granite decreases with an increase in the deviator stress imposed by the deviator stress consolidation. Subsequently, we established an empirical model for the strain softening of weathered granite suitable for natural and saturated conditions. This model took the elastic modulus of weathered granite before the peak strength as a measure and introduced the strength parameters of the internal friction angle (φ) and the internal cohesion (c). First, the fitted function correlating c and φ with the plastic internal variable was determined, and then the relationship between the strength and the strain-softening parameters was established so as to obtain the complete stress–strain curve of the granite rock. Finally, validation studies were performed to address the capability of the model to predict permanent deformation. It provides a theoretical basis for predicting and calculating the strain softening of weathered granite exposed to water.

Study on Seepage Characteristics of Grouting Slurry for Water-Absorbing Mudstone with Rough Fissure

“…The interaction between rocks and water has always been a hot topic of research both domestically and internationally, such as the mechanical properties of water-bearing rocks [3][4][5], the water-rock coupling seepage characteristics [6,7] and the softening mechanism of rocks when encountering water [8][9][10]. Mudstone is a common special soft rock system, and has a certain water absorption ability because its mineral composition contains a large amount of clay minerals such as kaolinite, illite and montmorillonite, and due to capillary phenomenon and the presence of internal fissures in mudstone, the fissured mudstone exhibits strong water absorption [11].…”

Groundwater identification using geophysical tools and its implications for the stability of slopes in an open pit mine

“…Geophysical methods, such as DC (Direct Current) resistivity, have been widely used to map fractured aquifers on rock mass (Porsani et al, 2005; Gomes de Oliveira et al 2014;Hamdan et al 2014;Moreira et al 2016;Pádua and Campos 2020;Whiteley et al 2021;Yan et al 2022). Frequent events of intense precipitation, as recorded in tropical climate countries, can aggravate the risk of rupture from the elevation of pore pressure in the rock mass (Corrêa et al 2021;Sun et al 2021;Wyllie and Mah 2004). The sum of these factors can make the rock mass even more prone to long-term instabilities (Hartwig and Moreira 2021;Perrone et al 2008).…”