| 张安林,张朝鹏*,李存宝,刘洋,艾婷,任利,郑良娟.岩石断裂尺寸效应测试装置研制及实验研究[J].实验力学,2021,36(1):69~79 |
| 岩石断裂尺寸效应测试装置研制及实验研究 |
| The development of testing device and experimental study on size effect of rock fracture |
| 投稿时间：2020-04-06 修订日期：2020-08-18 |
| DOI：10.7520/1001-4888-20-062 |
| 中文关键词: 岩石 尺寸效应 三点弯曲装置 Ⅰ型断裂韧度 名义强度 ABAQUS |
| 英文关键词:rock size effect three-point bending device fracture toughness of mode Ⅰ nominal strength ABAQUS |
| 基金项目:国家自然科学基金委重点项目(U1965203)；四川省青年科技创新研究团队资助项目(2017TD0007) |
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| 中文摘要: |
| 面向岩石断裂尺寸效应研究的实验装置需求，针对现有技术中三点弯曲装置对多组尺寸岩石试件适应性差、最小跨距的测试量程不足等问题，研制了一种可灵活用于岩石断裂尺寸效应测试的三点弯曲装置。装置采用“两体分离式”的设计，三种不同型号的滚子与压头体、支座体配合使用，有效避免了不同尺寸试件采用同一直径滚子测试带来的实验精度问题；同时，装置实现了4mm~100mm不同实验跨距的设置，可同时满足尺寸变化较大的多组试件开展断裂测试。借助该装置开展了页岩三点弯曲断裂尺寸效应测试，并利用ABAQUS软件进行了相关数值计算。获得了不同尺寸页岩试件的Ⅰ型表观断裂韧度、名义强度等断裂参数，结果显示：尺寸对页岩的Ⅰ型表观断裂韧度和名义强度有显著影响。实验计算值与Bazant提出的尺度律模型(SEL)对比，结果吻合良好，借助SEL曲线可对页岩的断裂强度进行有效预测，同时表明该装置具有实验高效、高精准性等优点。 |
| 英文摘要: |
| To meet the needs of experimental equipment for the study of size effect of rock fracture, a three-point bending device which can be flexibly applied to the testing was developed, for solving the problems of poor adaptability of three-point bending device to multi-size rock specimens and insufficient testing range of minimum span in the existing technologies. The design of “two-body separation” was adopted for this device, and three different types of rollers were used in combination with the indenter body and the supporting body to avoid the test accuracy problems caused by using rollers with the same diameter for specimens with different sizes. At the same time, the device realized the setting of different experimental spans with 4 mm~100 mm, which simultaneously satisfied the needs of fracture testing of multiple groups of specimens with large size changes. With the help of this device, three-point bending fracture tests and the relevant numerical calculation of shale specimens with different sizes were carried out. Fracture parameters such as apparent fracture toughness of mode Ⅰ and nominal strength of shale specimens with different sizes were obtained. The study results indicated that the rock fracture size had a significant effect on apparent fracture toughness of mode Ⅰ and nominal strength of shale. The calculated results were in good agreement with the Size Effect Law (SEL) proposed by Bazant. It can be concluded that the fracture strength of shale can be predicted effectively by SEL curve, and the device has the advantages of high experimental efficiency and high precision. |
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