外部激励对类岩石材料阻尼比的影响  

EFFECT OF EXTERNAL EXCITATION ON DAMPING RATIO OF ROCK-LIKE MATERIAL

作　　者：宋全杰[1,2] 李海波[1] 李俊如[1] 王秒[1] 刘婷婷[1] 吕士展[1] 宋亮[1] 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]贵州省贵安新区建设规划管理局,贵州贵阳550025

出　　处：《岩石力学与工程学报》2013年第S2期3258-3265,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家杰出青年基金项目(51025935);国家重点基础研究发展计划(973)项目(2010CB732001);国家科技重大专项资助项目(2011ZX06002–010–15)

摘　　要：岩石阻尼比是衡量岩石因激励而振动时能量耗散能力的重要参数,受多种因素影响,并极为敏感。为了研究岩石阻尼比在不同激励方式及振动形式下的变化规律,利用类岩石材料(石膏)试样,在强迫非共振、强迫共振以及不同波动形式下的自由振动形式下,测得石膏试样在该状态下的阻尼比。测试应变幅值、振动频率、振动波形(P波和S波)对岩石阻尼比的影响。试验结果表明,石膏试样阻尼比随应变增大的过程中大致经历3个阶段:调整段、平稳段、稳定增长段。在平稳段,试样阻尼比随频率变化存在一峰值,即在某一频率下,石膏试样的阻尼比值最大;高于此频率时,石膏试样阻尼比随着频率的增大而减小;低于此频率时,石膏试样阻尼比随着频率的增加而增加;此外,石膏试样在P波激励下的阻尼比明显大于S波激励下的阻尼比。Rock damping ratio,as an important parameter that reflects capacity of dissipating energy of vibrating rock,is influenced by multiple factors and very sensitive. To study the rock damping ratio′s change law in different excitation modes and vibrating ways,gypsum specimen′s damping ratio is obtained in experiments in the states of forced non-resonance,forced resonance and free vibration of different wave forms. The influences of strain amplitude,vibration frequency and wave forms(P wave and S wave) on the gypsum specimen′s damping ratio are considered. Test results show that adjustment stage,smooth stage,steady growth stage of damping ratio will follow in proper sequence as the specimen′s strain increasing. In the smooth stage,there is a damping ratio peak under a certain frequency. When more than this frequency,gypsum specimen′s damping ratio increases with frequency′s increasing. And when less than this frequency,gypsum specimen′s damping ratio decreases with frequency′s increasing. What′s more,the damping ratio of gypsum specimen inspired by P-wave is larger than that by S-wave.

关 键 词：岩石力学 阻尼比 激振方式 强迫振动 自由衰减 频率峰 

分 类 号：TU458.4[建筑科学—岩土工程]