| 热处理砂岩不同接触角巴西劈裂数值模拟研究 |
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| 引用本文： | 徐浩淳,金爱兵,赵怡晴,陈哲.热处理砂岩不同接触角巴西劈裂数值模拟研究[J].岩土力学,2022,43(Z2):588-597. |
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| 作者姓名： | 徐浩淳 金爱兵 赵怡晴 陈哲 |
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| 作者单位： | 1. 北京科技大学 金属矿山高效开采与安全教育部重点实验室，北京 100083；2. 北京科技大学 土木与资源工程学院，北京 100083；
3. 北京科技大学 高等工程师学院，北京 100083 |
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| 基金项目： | 国家自然科学基金（No.52174106）；北京科技大学本科生科技创新项目（No.2021279011）。 |
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| 摘 要： | 基于颗粒流程序（particle flow code，PFC），对不同接触角（2a = 6º～30º）条件下25～1 000 ℃砂岩进行巴西劈裂模拟试验，研究其应力分布和破裂模式，并将巴西劈裂与直接拉伸进行对比。研究表明：（1）巴西劈裂中，面接触加载可以降低端部效应，加载过程中首先在圆盘中部产生拉裂纹，随着荷载的升高，拉裂纹汇集、扩展、贯通。（2）平板点接触巴西劈裂测得的抗拉强度小于直接拉伸强度，其抗拉强度计算公式的修正系数k随温度T的升高线性减小，满足k = ?3.303×10?4T+1.468。随着接触角的增大，不同温度处理后巴西圆盘的抗拉强度均呈现出增大的趋势。（3）在2a≥18º时，巴西圆盘可以保证中心起裂；2a = 18º～24º时，圆盘在不同温度下破裂模式稳定；在接触角过大（2a = 30º）时，圆盘在较低温度（≤600 ℃）下会形成倾斜裂纹。（4）结合修正系数和破裂模式分析，推荐接触角为18º～24º时，修正系数在0.802 6～ 0.856 0之间，可以保证所有温度试样中心起裂且破裂模式稳定。
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| 关 键 词： | 高温 巴西劈裂 加载接触角 裂纹扩展 颗粒流程序 |
| 收稿时间： | 2021-10-23 |
| 修稿时间： | 2021-12-10 |
Numerical study on Brazilian splitting of heat-treated sandstone
under different contact angles |
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| XU Hao-chun,JIN Ai-bing,ZHAO Yi-qing,CHEN Zhe.Numerical study on Brazilian splitting of heat-treated sandstone
under different contact angles[J].Rock and Soil Mechanics,2022,43(Z2):588-597. |
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| Authors: | XU Hao-chun JIN Ai-bing ZHAO Yi-qing CHEN Zhe |
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| Institution: | 1. Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine, University of Science and Technology Beijing, Beijing 100083, China;
2. School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China;
3. School of Advanced Engineers, University of Science and Technology Beijing, Beijing 100083, China |
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| Abstract: | Based on the particle flow code (PFC), the Brazilian splitting of sandstone treated at 25?1 000
℃ under different contact angles (2a = 6º?30º) was carried out to study the stress distribution and fracture mode,
and the Brazilian splitting was compared with
the direct tensile test. The results show that: 1) The surface contact loading
can reduce the end effect in Brazilian splitting.
During the loading process, tensile cracks appear in the middle of the disc
firstly. With the increase of the load, the tensile cracks converge and connect
at the central part of the disc, and then extend to the end of the disc. 2) The
tensile strength measured by Brazilian splitting
at point contact of flat plate is less than that of direct tensile strength.
The correction coefficient k of the tensile strength calculation formula
decreases linearly with the increase of temperature T, satisfying k = ?3.303×10?4T+1.468. With the increase of
the contact angle, the tensile strength of the Brazilian disc increases after
heat treatment of different temperatures. 3) When 2a≥18º, the Brazilian disc can guarantee to have a central crack initiation. When 2a = 18º?24º, the fracture mode of the disk keeps unchanged at different temperatures. The disk will
develop an inclined crack at a lower temperature (≤600 ℃) when the contact angle is too large (2a = 30º). 4) Combined with the correction coefficient and the fracture mode
analysis, the contact angle is recommended to be 18º?24º and the correction coefficient is between 0.802 6 and 0.856 0. It can
ensure the center crack initiation and the stability of the fracture mode at
different temperatures. |
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| Keywords: | high temperature Brazilian splitting loading contact angle crack propagation particle flow code |
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