{"title":"Effects of fissure locations on the crack propagation morphologies of 3D printing tunnel models: Experiments and numerical simulations","authors":"","doi":"10.1016/j.tafmec.2024.104631","DOIUrl":null,"url":null,"abstract":"<div><p>Hidden fissures widely exist in the surrounding rock of tunnels, and the propagations and interactions of the fissures will directly affect the safety and stability of tunnels. However, experimental and numerical simulation studies are scarce on the tunnel-fissure interactions under complex stress conditions. Based on this background, circular tunnel specimens with different prefabricated fissure locations are prepared by three-dimensional (3D) printing technology. Uniaxial compression fracture tests are conducted utilizing Digital Image Correlation (DIC) technology to obtain strain distributions. An improved Smoothed Particle Hydrodynamics (SPH) method is employed to simulate the crack propagation processes of the tunnel-fissure interactions. The results demonstrate the following: 1) Upper main cracks, upper side cracks, and lower side cracks are produced around the tunnel, and wing cracks initiate from the prefabricated fissure tips. 2) For the different intersection positions, wing crack propagation length decreases as the intersection position moves upward, while the lower side crack propagation length increases. 3) For different distances <em>d</em>, upper side crack does not appear, and the propagation length of upper main crack increases with the increase of the distance <em>d</em>. 4) For different fissure inclination angles <em>α</em>, upper main crack does not appear when <em>α</em> = 15°. The propagation length of wing crack increases with the increase of inclination angle <em>α</em>. 5) The peak stress increases as the intersection position moves upward, while it decreases with the increase of inclination angle <em>α</em>. With increasing distance <em>d</em>, the peak stress initially increases and then decreases. Finally, the crack initiation mechanisms under different fissure orientations and inclinations are discussed. These research findings provide valuable insights into the tunnel-fissure interaction mechanisms under complex stress conditions and the applications of the SPH method in underground engineering simulations.</p></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":5.0000,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Theoretical and Applied Fracture Mechanics","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0167844224003811","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Hidden fissures widely exist in the surrounding rock of tunnels, and the propagations and interactions of the fissures will directly affect the safety and stability of tunnels. However, experimental and numerical simulation studies are scarce on the tunnel-fissure interactions under complex stress conditions. Based on this background, circular tunnel specimens with different prefabricated fissure locations are prepared by three-dimensional (3D) printing technology. Uniaxial compression fracture tests are conducted utilizing Digital Image Correlation (DIC) technology to obtain strain distributions. An improved Smoothed Particle Hydrodynamics (SPH) method is employed to simulate the crack propagation processes of the tunnel-fissure interactions. The results demonstrate the following: 1) Upper main cracks, upper side cracks, and lower side cracks are produced around the tunnel, and wing cracks initiate from the prefabricated fissure tips. 2) For the different intersection positions, wing crack propagation length decreases as the intersection position moves upward, while the lower side crack propagation length increases. 3) For different distances d, upper side crack does not appear, and the propagation length of upper main crack increases with the increase of the distance d. 4) For different fissure inclination angles α, upper main crack does not appear when α = 15°. The propagation length of wing crack increases with the increase of inclination angle α. 5) The peak stress increases as the intersection position moves upward, while it decreases with the increase of inclination angle α. With increasing distance d, the peak stress initially increases and then decreases. Finally, the crack initiation mechanisms under different fissure orientations and inclinations are discussed. These research findings provide valuable insights into the tunnel-fissure interaction mechanisms under complex stress conditions and the applications of the SPH method in underground engineering simulations.
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.