Fracture Behavior of Jointed Rocks Subjected to Static Compressive Loads: An Overview

Abstract

ABSTRACT Joints widely distributed in rock masses can possess a noticeable influence on, or even dominate, the mechanical response and fracture behavior of the rock mass. Consequently, considerable efforts have been made to explain the mechanisms involved. This article provides an overview of the mechanical properties, fracturing processes, and failure patterns of jointed rocks, which have been investigated through experimental and numerical tests. The results of these tests indicate that, under the action of static compressive load, the existence of flaws changes the stress distribution mode in jointed rocks, resulting in noticeable anisotropic characteristics. The crack evolution is mainly caused by the redistribution of stress due to the inclusion of joints. Furthermore, the fracturing process of jointed rocks often occurs at the tips of pre-existing microcracks and joints, which can lead to different failure modes. Additionally, the mechanical parameters, fracture process, and failure modes vary depending on the geometry and configuration (such as dip angle, length, and layout) of the joints. Finally, some prospects for studying the fracture behavior of jointed rocks are proposed. This work is expected to contribute to disaster prevention and mitigation in underground projects. INTRODUCTION The rock mass is the primary construction object for underground projects such as mining, nuclear waste treatment, carbon sequestration, and oil and gas reservoir development. The natural rock mass is a complex and inhomogeneous geological body existing in nature (Sagong et al., 2011). After long-term geological tectonic evolution, the crust is randomly distributed with different scales and directions of structural surfaces or discontinuities (such as faults, bedding planes, joints, splits, slits, soft interlayers, and holes), which intersect in the rock mass and form a special structure of discontinuous body (Li et al., 2021; Li and Cai, 2021). They will have a great effect on the mechanical behavior of the rock mass. Numerous studies indicated that many instabilities of jointed rocks are caused by nucleation, expansion, and coalescence of joints, resulting in a large number of deaths and huge losses of material wealth. For example, the typical wedge-shaped destruction along the fault on the steep slope of the Three Gorges Project and the step-type destruction of the rock slope at the Xiaowan Hydropower Station in China are all related to the joints in the rock mass (Huang et al., 2018). These disasters have seriously restricted the safe and stable development of rock engineering.