基于角度量测的岩土圆柱试件环向变形测试方法及系统应用  

Testing method and system application of circumferential deformation of cylindrical rock and soil specimens based on angle measurement

作　　者：王汉鹏[1] 李清川[1] 李术才[1] 张强勇[1] 袁亮 刘众众 WANG Hanpeng;LI Qingchuan;LI Shucai;ZHANG Qiangyong;YUAN Liang;LIU Zhongzhong(Research Centre of Geotechnical and Structural Engineering,Shandong University,Jinan,Shandong 250061,Chinm;School of Ming and Safety Engineering,Anhui University of Science and Technology,Huainan,Anhui 232001,China)

机构地区：[1]山东大学岩土与结构工程研究中心,山东济南250061 [2]安徽理工大学能源与安全学院,安徽淮南232001

出　　处：《岩石力学与工程学报》2018年第11期2576-2583,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重大科研仪器研制项目(51427804);山东省自然科学基金面上项目(ZR2017MEE023);泰山学者工程专项经费资助项目~~

摘　　要：为精确获取和深入研究岩土力学试验中标准圆柱试件在全应力–应变过程中环向变形规律与峰后扩容力学特性,借鉴MTS链式环向引伸计,提出一种基于角度量测的岩土圆柱试件环向变形测试方法,阐明测试方法原理并研发仪器系统。系统采用链式滚带环绕标准圆柱试件,角位移传感器通过加持锁定机构与链式滚带连接,DAQ数据采集卡和配套LABVIEW编制的采集程序实现了环向位移的实时采集与记录,测量精度0.004 mm,量程30mm,可适用于气固耦合、三轴加载等多种加载环境。与MTS链式引伸计和近景摄影测量的对比试验验证了系统可靠性和重复精度,开展不同气体对煤体的吸附劣化试验应用,试验对相同预制强度的型煤试件充入相同压力的He,N_2,CH_4和CO_2,待充分吸附后进行轴向加载,获取加载过程中煤体变形和失稳破坏规律,对比分析气体性质对体积扩容、煤体强度和裂隙发育的影响规律,试验结果表明:随着气体吸附性能的提高,煤体更早的由压密阶段进入扩容阶段,达到极限承载值与体积扩容点的位置不断提前,先后顺序为:CO_2>CH_4>N_2>He;充入无吸附性的He对煤体无劣化作用,充入吸附性的CO_2显著降低了煤体强度,其中1.0 MPa气压CO_2吸附后煤体强度降低了32.05%。整套系统采用模块化设计,测试方法原理清晰,可与轴向LVDT位移计实现同步采集,对于丰富岩石力学试验方法和实现对老旧试验机的改造升级具有重要意义。In order to obtain the accurate circumferential deformation and the mechanical characteristics of post-peak dilation of the standard cylindrical specimen during the whole process of stress-strain test,a new type of circumferential deformation test method for standard specimens was proposed with the angle measurement based on the MTS chain circumferential extensometer.The principle of measurement was described in the paper.A chain rolling belt connected with the angle sensor is used in the system to twine around the standard circular specimen.The data acquisition system programmed by LABVIEW is used to achieve the automatic high precision acquisition and rapid recording.The measurement accuracy is 0.004 mm and the measurement range is 30 mm,which is adequate for many loading environments such as the gas-solid coupling loading and the tri-axial loading.The reliability and accuracy of this system were verified by the MTS chain extensometer and the close-range photogrammetry.The adsorption degradation test of coal with different gases was carried out.The briquettes with the same prefabricated strength were filled with the gases under the same pressure（He,N2,CH4 and CO2）,and then the axial loading test was carried out after the full adsorption.The deformation and instability of coal body during loading were obtained.The effects of gas properties on the volume expansion,the strength and fracture development of coal were compared and analyzed.The experimental results show that with the improvement of gas adsorption,the coal enters the expansion stage from the compaction stage earlier,and the position of the ultimate load value and volume expansion point reached earlier with the sequence for gases：CO2CH4N2He.The impregnation of He without adsorption does not degrade the coal,but the coal body strength is significantly reduced by adding the adsorptive CO2.The peak strength decreases by 32.05%after the CO2 adsorption under the pressure of 1.0 MPa.The whole system is made of modules and can work synchronously with the

关 键 词：岩石力学 圆柱试件 环向变形 测试方法 系统应用 

分 类 号：TU45[建筑科学—岩土工程]