排序方式: 共有44条查询结果,搜索用时 186 毫秒
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丽江7级地震为何比预计发生的晚?:应力循环和地震 总被引:1,自引:0,他引:1
用循环加载研究岩石破裂孕育过程中变形模量,纵波速度和声发射的变化特征,进而探讨认为丽江地区外部地震的发生使受力过程发生了变化,从而使丽江7级地震延迟发生,也使临近地震的前兆异常不明显或更复杂,并使丽江地震震级减小。 相似文献
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Experimental studies on the evolution process of microcrack patterns in concrete samples con-taining hard inclusions 总被引:1,自引:0,他引:1
ExperimentalstudiesontheevolutionprocesofmicrocrackpaternsinconcretesamplescontaininghardinclusionsZHAOYONGXU1)(许昭永)BINWAN... 相似文献
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An experimental study on fractural features of concrete samples containing hard inclusion 总被引:1,自引:0,他引:1
AnexperimentalstudyonfracturalfeaturesofconcretesamplescontaininghardinclusionZHAOYONGXU(许昭永)1)BINWANG(王彬)1)JINMINGZHAO(赵晋... 相似文献
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Introduction To the impact pattern, the dynamic test with high strain is generally grouped into two kinds.One is stricken by hammer and another is by rocket. The former is widely used and the latter isused widely abroad and seldom used at home. To the analyzing method, it is also divided into twokinds. One is the method of wave equation and another is the method of experimental formula.The methods of Smith, Case and Capwap and other improved methods belong to the former, andthe methods … 相似文献
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IntroductionCHEN (1981), GENG, et al (1980), YAO (1981) and others have found out that different stress paths can lead to fracture. They have further studied the precursory features of wave velocity ratio, acoustic emission, and so on, in this situation. YIN (1987), YIN and YIN (1991), Yin, et al (1994, 1995, 2000) have put forward the concept of loading-unloading response ratio. When a mechanical test system is in a stable state, the path of its response to loading is the same as that… 相似文献
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Y形块体交界处多点大破裂的模拟实验研究 总被引:8,自引:0,他引:8
采用有机玻璃试样,在其上用激光刻划出雁列式断层组成的Y形块体边界.用特殊加载方式,使夹在Y形上部中间的块体能相对于两边向下移动.用实时全息干涉计量方法(激光)、焦散阴影光学法和微破裂(声发射)信息采集分析技术研究块体交界处多点大破裂的特征.结果显示:随着加载,在切缝端点处的条纹逐步变密,进而形成有明显边界的阴影区.这些阴影区会随荷载增加变大,随卸载而减小.荷载再增大,相邻两切缝端点处的阴影区会连成一片.这些阴影区为强烈应变或应力集中区,即应变核或应力核.微破裂定位资料同时证实:阴影区达到足够大后会有破裂发生;并且先变大并达到额定值(如破裂强度)的阴影区先发生破裂.荷载再增大,多个阴影区先后达到额定值,以后,大破裂在各个阴影区交替发生. 相似文献
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加载破裂和卸载破裂的焦散阴影区动态特征的实验研究 总被引:6,自引:3,他引:6
以实时全息干涉计量方法和焦散阴影光学法,用有机玻璃试样直观、形象地研究加载过程和卸载过程破裂时的应力(应变)场、塑性区或成核区(阴影区)不同地动态特征变化.结果发现,在低应力时,预制裂缝端点先出现应变核(条纹密集区),进而形成焦散阴影区.这些核和阴影区会随荷载增加变大,随卸载而减小.在一定的压力范围内重复加载卸载(循环加载),焦散阴影区则反复增大缩小;但在高应力时,尤其在将出现大破裂时,加载和卸载的焦散阴影区变化是不可逆的,其变化也完全不同.加载破裂时的焦散阴影区由慢到快迅速扩展;而卸载时的焦散阴影区则扩展较慢,并且在尖角形前方有一圆形阴影. 相似文献