Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with Bedding

The effect of water on fracture toughness in various modes of mudstones was investigated using semicircular bend (SCB) specimens exposed to three-point bendings. Natural mudstone specimens are obtained using a special coring method and are then classified into three types (A, B, and C) corresponding...

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Main Authors: Jianfeng Yang, Li Li, Haojie Lian
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:Advances in Materials Science and Engineering
Online Access:http://dx.doi.org/10.1155/2019/5693654
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author Jianfeng Yang
Li Li
Haojie Lian
author_facet Jianfeng Yang
Li Li
Haojie Lian
author_sort Jianfeng Yang
collection DOAJ
description The effect of water on fracture toughness in various modes of mudstones was investigated using semicircular bend (SCB) specimens exposed to three-point bendings. Natural mudstone specimens are obtained using a special coring method and are then classified into three types (A, B, and C) corresponding to three directions/configurations of bedding planes (divider, arrester, and transverse). The results show that the Type A (divider configuration) specimens possess the largest fracture toughness value for all tested modes and same soaking time, whereas the Type C (transverse configuration) specimens have the smallest one. By increasing soaking time, the fracture toughness in all three modes decreases and the fracture mechanism changes from brittle failure to ductile failure. Among them, the Type C specimens have the highest degree of degradation for each soaking time period. Regarding the fracture modes, the degradation degree of KIc is higher than that of KIIc for all three types of mudstone specimens. In addition, KIIc/KIc ratio increases when soaking time is extended. Furthermore, in the initial and short soaking time stages, the experimental KIIc/KIc results are consistent with theoretical findings from modified MTS criterion. However, after being soaked 300 minutes for three types of specimens, the test curves deviate from the theoretical curves. Analogously, the mixed-mode I/II ratio of Keff to KIc is consistent with the theoretical values in the initial stage when the degree of damage is low. With soaking time increasing, the experimental curve is gradually deviated from the theoretical curve. When soaking time reaches 300 minutes, the deviation is substantial. And the test data for the Type-A specimens are observed to provide better agreements with theoretical predictions by modified MTS criterion than those for the other two types of specimens.
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spelling doaj-art-7a9a139a9a594b9d8d9e67aec0b2e27a2025-08-20T03:35:41ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422019-01-01201910.1155/2019/56936545693654Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with BeddingJianfeng Yang0Li Li1Haojie Lian2School of Energy Engineering, Xi’an University of Science and Technology, Xi’an, Shaanxi 710054, ChinaCivil and Environmental Engineering, University of Waterloo, Ontario, Waterloo N2L3G1, CanadaKey Laboratory of In-Situ Property-Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, Shanxi 030024, ChinaThe effect of water on fracture toughness in various modes of mudstones was investigated using semicircular bend (SCB) specimens exposed to three-point bendings. Natural mudstone specimens are obtained using a special coring method and are then classified into three types (A, B, and C) corresponding to three directions/configurations of bedding planes (divider, arrester, and transverse). The results show that the Type A (divider configuration) specimens possess the largest fracture toughness value for all tested modes and same soaking time, whereas the Type C (transverse configuration) specimens have the smallest one. By increasing soaking time, the fracture toughness in all three modes decreases and the fracture mechanism changes from brittle failure to ductile failure. Among them, the Type C specimens have the highest degree of degradation for each soaking time period. Regarding the fracture modes, the degradation degree of KIc is higher than that of KIIc for all three types of mudstone specimens. In addition, KIIc/KIc ratio increases when soaking time is extended. Furthermore, in the initial and short soaking time stages, the experimental KIIc/KIc results are consistent with theoretical findings from modified MTS criterion. However, after being soaked 300 minutes for three types of specimens, the test curves deviate from the theoretical curves. Analogously, the mixed-mode I/II ratio of Keff to KIc is consistent with the theoretical values in the initial stage when the degree of damage is low. With soaking time increasing, the experimental curve is gradually deviated from the theoretical curve. When soaking time reaches 300 minutes, the deviation is substantial. And the test data for the Type-A specimens are observed to provide better agreements with theoretical predictions by modified MTS criterion than those for the other two types of specimens.http://dx.doi.org/10.1155/2019/5693654
spellingShingle Jianfeng Yang
Li Li
Haojie Lian
Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with Bedding
Advances in Materials Science and Engineering
title Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with Bedding
title_full Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with Bedding
title_fullStr Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with Bedding
title_full_unstemmed Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with Bedding
title_short Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with Bedding
title_sort experimental evaluation of the influences of water on the fracture toughness of mudstones with bedding
url http://dx.doi.org/10.1155/2019/5693654
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