【作者】 余斐；

【导师】 吕建国；

【作者基本信息】 中国地质大学(北京) ， 地质工程， 2012， 硕士

【摘要】 为了能够更好的将声发射技术应用到工程实践中，本文通过室内声发射试验对不同岩石试样在单轴压缩条件下的声发射特征进行了分析，研究了影响岩石声发射特性的因素，探讨了岩石的破坏机理与损伤特性。对大理岩、花岗岩和砂岩进行单轴压缩试验，运用声发射仪器监测岩石破坏过程中的声发射活动。通过对比，分析以上三种岩石的声发射特性，并推断影响岩石声发射特性的主要因素包括岩石自身的颗粒大小、强度、硬度、节理裂隙等。但是岩样的加工过程不同，取样地点不同均对岩石声发射特性造成影响。实验结果同时揭示出：(1)不同的加载方式下，岩石的破坏机理不同；(2)加载速率的不同影响声发射的变化率，加载速度的增加导致岩石的损伤加剧；(3)岩石在破坏失稳前声发射事件存在一段沉寂区，在实际工程中可以将这一重要的特性作为岩体破坏的前兆特征进行预测预报，并且发现岩石强度越高这一沉寂区持续时间越长，越明显；(4)岩石声发射都经历了初始压密区，上升区，峰值区和下降区，不同岩石是否经历每个阶段以及每个阶段持续时间的长短与岩石的性质有关；(5)岩石声发射能率在破坏前的沉寂区比声发射率的更加明显，能更好的反应岩石破坏前的前兆特征，为更加准确的预测预报实际工程中的灾害提供理论依据。在试验的基础上，结合理论分析，研究了各声发射参数特征及参数之间的关系，并总结了各参数的演变规律，基于参数研究，分析了岩石损伤量与岩石声发射的关系，并建立了损伤本构模型。通过声发射事件数拟合出的理论应力应变曲线能够合理地反映岩石实际的应力应变特性，从而验证了本构模型的正确性。采用循环加载的方式，研究不同岩石样本的凯赛效应，实验结果显示损伤发展规律分为初始阶段、稳定阶段和失稳阶段三个阶段。当三种岩石在在应力位于峰值强度的20%~70%之间，凯赛效应明显并且岩石的记忆能力准确、稳定。更多还原

【Abstract】 In order to introduce the acoustic emission technique into the civil engineering, theacoustic emission characteristics of rock specimen were analyzed in the unconfinedcompression condition by the laboratory acoustic emission tests. The influence factors ofacoustic emission characteristics were analyzed, in addition, the failure mechanisms anddamage characteristics were discussed.The uniaxial compression tests were executed in the rock specimen of marble,granite and sandstone, and the acoustic emission was monitored by the acoustic emissionapparatus in the failure process. The acoustic emission characteristics of the above rockswere analyzed, and the main influence factors for the acoustic emission characteristics,which were particle size of different rocks, strength, stiffness, joints, etc, were inferredby the comparative analysis. However, the acoustic emission characteristics are affectedby the process of rock specimen preparation and the sampling locations. The test resultsindicate that:(1) the failure mechanism of the rocks are different when the loading modesare different;(2) the rate of change of the acoustic emission is affected by the loadingrate, and the rock damages exacerbate when the loading rates increase;(3) the acousticemissions present quiet before the rock damage, so the characteristic can be utilized toforecast the rock failure in the engineering, and the quiet time is long and obvious if therock strength is high;(4) the acoustic emissions express initial compaction phase, ascentphase, peak phase and reduction phase;(5) the quiet time of acoustic emission energyrate is more obvious than it of acoustic emission rate, so the quiet time of acousticemission energy rate can reflect the rock failure in more reasonable manner, and itprovides rational basis to forecast the disaster in the engineering.Based on the tests and analysis, the characteristics and relations of acoustic emissionparameters were analyzed, and the evolution law of the parameters was summarized.Based on the parameter research, the amount of rock damage and the relationship withacoustic emission were analyzed, in addition, the damage model was established. Thetheoretical stress-strain curve which was fitted by the number of events in the acousticemission, and then the correctness of damage model was verified. Kaiser effect of different rock specimen was analyzed by the cyclic loading. The testresults demonstrate that the damage are divided three phases, including initial phase,stable phase and Instable phase. Cathay effect is obvious and the memory of rocks iscorrect and stable when the stresses between the20%~70%of peak intensity.更多还原