Dynamic compressive micro-macro fracture mechanism with the water-saturated strengthening and weakening effect in brittle rocks

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics Pub Date : 2025-02-13 DOI:10.1016/j.tafmec.2025.104871

Xiaozhao Li , Qiulin Luo , Fayuan Yan , Chengzhi Qi

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引用次数: 0

Abstract

The dynamic compressive mechanical properties of water-saturated brittle rocks are of significant practical importance for assessing the stability of deep underground rock masses during excavation. The coupled dynamic effect of free water and microcrack extension within the rocks severely affects the dynamic compressive mechanical properties of saturated rocks. However, there is a significant lack of research on the mechanisms relating the microcrack evolution to the macroscopic deformation behavior of saturated brittle rocks under dynamic compressive loading. This article aims to propose a feasible micro–macro fracture model to explain the enhancement and weakening mechanisms of free water on the dynamic mechanical properties of rocks. Based on the stress–strain constitutive model of dry rock under quasi-static crack extension action, the stress–strain constitutive model of water-saturated rock under quasi-static action is obtained by combining the change of mechanical parameters of rock with free water. Then the quasi-static fracture toughness and dynamic fracture toughness relationship, the crack extension rate and crack opening rate relationship and the crack extension rate and strain rate relationship are introduced and combined with the Stefan effect to derive the stress–strain constitutive model for water-saturated brittle rocks under dynamic compression. And the reasonableness of the theoretical model is verified by the experimental results. The changes in the intercrack friction coefficient µ, initial damage D₀ and quasi-static fracture toughness K_ICQ due to free water have a weakening effect on the dynamic mechanical properties of the rock. The alterations in dynamic fracture toughness amplification factor K_V resulting from changes in the quasi-static elastic modulus E and density ρ, along with the Stefan force F_S effect, contribute to the enhancement of the dynamic mechanical characteristics of the rock. The changes in mechanical parameters and the Stefan effect together constitute the strengthening and weakening mechanisms through which free water affects the dynamic mechanical properties of the rock. And discusses the effects of confining pressure and strain rate on the dynamic compressive strength and crack initiation stress of water-saturated rock. These findings provide theoretical support for the stability analysis of saturated rock masses during deep underground excavation.

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来源期刊

Theoretical and Applied Fracture Mechanics 工程技术-工程：机械

CiteScore

8.40

自引率

18.90%

发文量

435

审稿时长

37 days

期刊介绍： Theoretical and Applied Fracture Mechanics'' aims & scopes have been re-designed to cover both the theoretical, applied, and numerical aspects associated with those cracking related phenomena taking place, at a micro-, meso-, and macroscopic level, in materials/components/structures of any kind. The journal aims to cover the cracking/mechanical behaviour of materials/components/structures in those situations involving both time-independent and time-dependent system of external forces/moments (such as, for instance, quasi-static, impulsive, impact, blasting, creep, contact, and fatigue loading). Since, under the above circumstances, the mechanical behaviour of cracked materials/components/structures is also affected by the environmental conditions, the journal would consider also those theoretical/experimental research works investigating the effect of external variables such as, for instance, the effect of corrosive environments as well as of high/low-temperature.