三点弯曲试验条件下重庆砂岩声发射特性的影响因素试验研究

发布时间：2018-05-31 09:18

本文选题：声发射 + Kaiser效应　；参考：《重庆大学》2015年硕士论文

【摘要】：近年来,由于水利水电、采矿、土建、铁道桥梁、公路隧道等工程需要,对于岩石声发射特性的研究一直以来都是一个非常重要的课题。尤其是针对岩石Kaiser效应的研究探讨,比如Kaiser点位置判断方法的研究,岩石Felicity效应以及Felicity比的研究,以及岩石记忆效应的研究等,都在一定程度上得到了国内外学者们的青睐。影响岩石声发射特性以及Kaiser效应的因素也越来越成为关注的话题,诸如尺寸效应、温度效应、加载速率、加载方式、均质性以及环境效应等。虽然这方面的研究成果已经很多,但是岩石声发射特性以及Kaiser效应影响因素的研究还有待进一步深入。本文主要通过实验室试验和数值模拟的手段分析研究重庆地区砂岩在三点弯曲试验条件下的声发射特性以及Kaiser效应的影响因素。试验采用TAW 2000D微机控制电液伺服岩石三轴试验机和DS2数字声发射检测仪及相应配套仪器组成的控制系统,可实现电脑控制和实时采集信号,并通过声发射处理软件将电信号转化为试验数据。试验主要对尺寸效应、加载速率、不同材料均质性和加载方式进行了研究,观察和讨论了这些试验条件下的声发射特性和是否存在Kaiser效应,以及岩石记忆效应的探讨。数值模拟试验采用的是RFPA-BASIC软件对尺寸效应、加载速率、不同材料均质性和加载方式进行试件破坏过程以及声发射特性分析。通过对比分析实验室试验和数值模拟计算结果,得出以下结论:1)数值计算模拟结果和实际试验现象吻合程度较高,声发射规律基本上是一致的,Kaier效应现象明显,但是与试验相比,数值计算结果的Felicity比都大于1,记忆效应相对滞后。2)砂岩在三点弯曲试验条件下的声发射特性和Kaiser效应受到尺寸效应的影响,试件尺寸越大,砂岩破坏的时候需要的能量就越大。3)通过花岗岩和砂浆与砂岩的对比,材料的强度越大,累计声发射数量越大,并且声发射能量也更大;材料的均质程度越小,累计声发射数量以及累计振铃数就越大。4)从加载方式上来说,与三点弯曲试验条件下相比,砂岩在单轴压缩和劈裂试验条件下产生的累计声发射数越大,而且释放的能量也越大。
[Abstract]:In recent years, due to the need of water conservancy and hydropower, mining, civil construction, railway bridge, highway tunnel and so on, the study of acoustic emission characteristics of rock has been a very important subject. Especially for the study of rock Kaiser effect, such as the study of Kaiser point location judgment method, the study of rock Felicity effect and Felicity ratio, and the study of rock memory effect, all of them have been favored by scholars at home and abroad to some extent. The factors affecting the acoustic emission characteristics of rock and the Kaiser effect have become more and more important topics, such as size effect, temperature effect, loading rate, loading mode, homogeneity and environmental effect. Although much research has been done in this field, the characteristics of rock acoustic emission and the influence factors of Kaiser effect need to be further studied. In this paper, the acoustic emission characteristics of sandstone in Chongqing area under three-point bending test and the influencing factors of Kaiser effect are studied by means of laboratory tests and numerical simulation. The control system composed of TAW 2000D microcomputer controlled electro-hydraulic servo rock triaxial testing machine, DS2 digital acoustic emission detector and corresponding instruments can be used to realize computer control and real-time acquisition of signals. The electrical signal is converted into test data by acoustic emission processing software. The size effect, loading rate, homogeneity of different materials and loading mode were studied. The acoustic emission characteristics and the existence of Kaiser effect under these experimental conditions were observed and discussed, as well as the study of rock memory effect. RFPA-BASIC software is used to analyze the size effect, loading rate, material homogeneity and loading mode. By comparing and analyzing the results of laboratory tests and numerical simulation, the following conclusions are drawn: (1) the numerical simulation results are in good agreement with the actual experimental phenomena, and the acoustic emission law is basically consistent with the Kaier effect phenomenon. However, compared with the experimental results, the Felicity ratio of the numerical results is greater than 1, and the memory effect is relatively lagged. 2) the acoustic emission characteristics and the Kaiser effect of sandstone under three-point bending test are affected by the size effect. The larger the specimen size is, the larger the size of the specimen is. The larger the energy required for the destruction of sandstone, the greater the intensity of materials, the greater the amount of cumulative acoustic emissions, and the greater the energy of acoustic emission; the smaller the homogeneity of the materials, the greater the strength of the materials compared with the sandstone. The cumulative number of acoustic emissions and the cumulative number of ringing bells. 4) in terms of loading mode, the cumulative number of acoustic emissions produced by sandstone under uniaxial compression and splitting tests is larger than that under three-point bending test. And the greater the energy released.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45

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