Strength Failure and Crack Evolution Behavior of Rock Materials Containing Pre-existing Fissures

verfasst von: Sheng-Qi Yang

Verlag: Springer Berlin Heidelberg

Buchreihe : Springer Environmental Science and Engineering

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik" , Springer Professional "Wirtschaft"

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Über dieses Buch

This book has following unique features that distinguish it from other works from the same area: 1) Investigates the influence of fissure geometry on strength failure and crack evolution behaviour of real rock material; 2) Analyzes the effect of pre-experiment high-temperature treatment on fracture mechanical behaviour of rock material with a single fissure or two parallel fissures; 3) Compares quantitatively simulated results using discrete element modelling and experimental results of fracture mechanical behaviour of rock material with two fissures; 4) Constructs the relationship between crack evolution processes and acoustic emission distribution of pre-fissured rock material under entire deformation; and 5) Discusses the crack evolution mechanism of pre-fissured rock material with respect to different confining pressures. This book can become the reference for technicians in the field of geotechnical engineering, mining engineering and geology engineering. At the same time, this book can be regarded as a good reference for scientific researchers carrying out fissured rock mechanics and correlated specialties.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract

Rock is a complicated geological medium that usually contains all kinds of fissures with unequal scales. Under an applied load, new cracks are readily initiated at the tips of nearby pre-existing fissures, and these new cracks propagate along the direction of axial stress in the rock (Li et al. in Int. J. Solids Struct 42:2505–2516, 2005; Wong and Einstein in Rock Mech Rock Eng 42(3):475–511, 2009a; Wong and Einstein in Int J Rock Mech Min Sci 46(2):239–249, 2009b; Park and Bobet in Int J Rock Mech Min Sci 46(5):819–829, 2009; Yang and Jing in Int J Fract 168(2):227–250, 2011), resulting in an unstable failure due to crack initiation, propagation, and coalescence.

Sheng-Qi Yang

Chapter 2. Experimental Investigation on Strength Failure and Crack Evolution Behavior of Brittle Sandstone Containing a Single Fissure

Abstract

In this chapter, in order to better understand the strength and fracture coalescence phenomena in brittle rock material, uniaxial compression experiments were conducted for brittle sandstone specimens containing a single fissure by a rock mechanics servo-controlled testing system. Moreover, this experiment relied on photographic monitoring and AE technique to obtain the real-time crack coalescence process in the process of the whole deformation failure, which was not performed for brittle sandstone in previous studies.

Sheng-Qi Yang

Chapter 3. Experimental Investigation on Crack Evolution Behavior of Brittle Sandstone Containing Two Coplanar Fissures in the Process of Deformation Failure

Abstract

Photographic monitoring is a kind of very effective technique, which can be used to analyze real-time crack coalescence process in the process of deformation failure of rock specimen (Yang and Jing in Int J Fract 168(2):227–250, 2011; Ferrero et al. in Eng Fract Mech 75:652–663, 2008; Ferrero and Migliazza in Mech Mater 41:561–572, 2009; Roncella et al. in Optical 3-D Measurement Techniques II:51–60, 2005).

Sheng-Qi Yang

Chapter 4. Experimental Investigation on Fracture Evolution Behavior of Brittle Sandstone Containing Three Fissures

Abstract

In the past, the relationship between real-time crack coalescence process using photographic monitoring and the axial stress–strain curve of rock material has so far not been investigated for brittle sandstone specimens containing three pre-existing fissures. Therefore in this chapter, a rock mechanics servo-controlled testing system was used to conduct uniaxial compression tests with brittle sandstone specimens containing three fissures. Moreover, photographic monitoring technique was used to obtain the relationship between the real-time crack coalescence process and the axial stress-strain behavior for brittle sandstone containing three fissures.

Sheng-Qi Yang

Chapter 5. Experimental Investigation on Fracture Coalescence Behavior of Red Sandstone Containing Two Unparallel Fissures

Abstract

In nature, engineering rock masses do not always contain parallel fissures and are generally composed of unparallel fissures (Lajitai et al. in Rock Mech Rock Eng 27:89–111, 1994; Lee and Jeon in Int J Solids Struct 48(6):979–999, 2011). Lee and Jeon (Int J Solids Struct 48(6):979–999, 2011) carried out uniaxial compression experiment for Diastone (types of molded gypsum) and Hwangdeung granite containing two unparallel fissures (a horizontal fissure and an inclined fissure underneath). The results showed that crack initiation and propagation had similar and different patterns depending on the material. For Diastone and Hwangdeung granite, tensile cracks were observed followed by the initiation of shear cracks and coalescence occurred mainly through the tensile cracks or tensile and shear cracks. But up to now, no laboratory experiments have been carried out on red sandstone specimens containing two unparallel fissures with different fissure angles. Besides, in the previous investigation for rock specimens containing two unparallel fissures, AE monitoring technique had not been adopted and the relationship between macroscopic deformation and fracture coalescence process was not constructed.

Sheng-Qi Yang

Chapter 6. Discrete Element Modeling on Fracture Coalescence Behavior of Red Sandstone Containing Two Unparallel Fissures

Abstract

In this chapter, we use PFC^2D to carry out numerical simulation for red sandstone containing two unparallel fissures under uniaxial compression (Yang et al. in Eng Geol 178:28–48, 2014). Compared with other numerical softwares (SAP2000 and X-FEM, et al.), PFC^2D code can better simulate the crack coalescence behavior of rock material by assembly of rigid circular particles bonded together at their contact points. First, the numerical micro-parameters of red sandstone are calibrated from the experimental results of intact specimen by the method of trial and error. Then, systematic numerical simulation is performed for red sandstone containing two unparallel fissures under uniaxial compression by comparing quantitatively the numerical results with the experimental results. According to the simulated cracking process during the entire deformation, some significant features on the cracking characteristics are summarized. Finally, the stress field in red sandstone containing two unparallel fissures under uniaxial compression is analyzed in detail.

Sheng-Qi Yang

Chapter 7. Fracture Mechanical Behavior of Red Sandstone Containing a Single Fissure and Two Parallel Fissures After Exposure to Different High-Temperature Treatments

Abstract

It is well known to us that the stability and safety of deep underground mining excavations and nuclear waste depositories rely on accurate knowledge of the physical and mechanical properties of representative rocks under the action of high temperature (Zhang et al. in Int J Plast 34:93–113, 2012).

Sheng-Qi Yang

Chapter 8. Experimental Investigation on Strength and Failure Behavior of Pre-cracked Marble Under Conventional Triaxial Compression

Abstract

In the preceding sections, physical experiments on pre-fissured rock materials under uniaxial compression have been performed. Engineering rock mass is usually located in a triaxial stress state. Up to now, the strength behaviors of pre-cracked rock materials under triaxial stress have not been fully investigated, and the fundamental mechanisms of crack coalescence in real rock materials with confining pressures are still not fully understood. Therefore, we have carried out the experimental investigation on real pre-cracked marble samples under conventional triaxial compression (Yang et al. in Int J Solids Struct 45:4796–4819, 2008). The emphasis of this chapter is focused on to investigate the influence of the geometry of fissure on strength parameters of marble material, to put forward a new evaluation criterion of confirming the cohesion and internal friction angle of pre-cracked marble, to analyze the crack initiation, propagation, and coalescence in real marble material under different confining pressures.

Sheng-Qi Yang

Chapter 9. Numerical Investigation on the Failure Mechanical Behavior of Red Sandstone Containing Two Coplanar Fissures Under Conventional Triaxial Compression

Abstract

Deep underground engineering rock masses are usually located within triaxial stress state; therefore, it is more relevant to investigate the failure mechanical behavior of rock material containing pre-existing fissures under triaxial compression. However, only few experimental or numerical investigations are carried out for failure mechanical behavior of pre-cracked rock material under triaxial compression. Therefore, in this chapter, to better understand the strength failure crack coalescence phenomena in fractured rock mass under triaxial stress state, two-dimensional discrete element simulation was conducted for red sandstone specimens containing two coplanar fissures under triaxial stress state. The emphasis of this chapter is focused on to investigate the influence of coplanar fissure angle on deformation strength parameters of red sandstone material under triaxial compression to analyze the crack initiation propagation coalescence processes in red sandstone material under different confining pressures.

Sheng-Qi Yang

Titel: Strength Failure and Crack Evolution Behavior of Rock Materials Containing Pre-existing Fissures
verfasst von: Sheng-Qi Yang
Verlag: Springer Berlin Heidelberg
Electronic ISBN: 978-3-662-47303-0
Print ISBN: 978-3-662-47302-3
DOI: https://doi.org/10.1007/978-3-662-47303-0