围压条件下砂岩循环冲击损伤的力学与超声分析

发布时间：2018-01-03 23:20

本文关键词：围压条件下砂岩循环冲击损伤的力学与超声分析　出处：《振动与冲击》2015年01期 　论文类型：期刊论文

【摘要】：采用带围压装置的φ100 mm霍普金森压杆系统,对砂岩试样进行了单轴冲击和4 MPa、20 MPa围压条件下的循环冲击试验,并对每次冲击前后的砂岩试样进行超声纵波检测,分析了砂岩在冲击荷载循环作用下的应力、应变特征,定义了砂岩试样的屈服-弹性比用以描述围压下试样应力应变曲线的弹塑性特征,采用纵波波速定义了砂岩试样的冲击损伤并分析了循环冲击试验中砂岩试样纵波波速和应力应变之间的关系。分析发现:在围压作用下,应力-应变曲线呈现典型的弹塑性特征。随着冲击荷载循环作用次数的增加,砂岩试样屈服应力、峰值应力降低,屈服应变、峰值应变增加。随着循环冲击作用次数的增加,砂岩试样的应力、应变特征与纵波波速之间存在良好的相关关系。较低围压状态下累计损伤度明显高于较高围压下砂岩的累积损伤,砂岩循环冲击损伤具有明显的围压效应。研究结果对地下工程的建设和防护有一定的指导意义。
[Abstract]:A 蠁 100mm Hopkinson pressure bar system with a confining pressure device was used to carry out uniaxial impact tests on sandstone samples and cyclic impact tests at 4 MPA ~ 20 MPa confining pressure. The ultrasonic longitudinal wave was used to detect the sandstone samples before and after each impact, and the stress and strain characteristics of the sandstone under the impact load cycle were analyzed. The yield to elastic ratio of sandstone samples is defined to describe the elastic-plastic characteristics of stress-strain curves under confining pressure. The impact damage of sandstone specimen is defined by using P-wave wave velocity and the relationship between P-wave velocity and stress-strain in cyclic impact test is analyzed. It is found that under confining pressure the relationship between P-wave velocity and stress-strain of sandstone specimen is analyzed. The stress-strain curve shows typical elastic-plastic characteristics. With the increase of the cycles of impact load, the yield stress, peak stress and yield strain of sandstone specimen decrease. The stress of sandstone specimen increases with the increase of cyclic impact times. There is a good correlation between strain characteristics and longitudinal wave velocity. The cumulative damage degree of sandstone under lower confining pressure is obviously higher than that of sandstone under higher confining pressure. The cyclic impact damage of sandstone has obvious confining pressure effect and the research results have certain guiding significance for the construction and protection of underground engineering.
【作者单位】：空军工程大学机场建筑工程系;西北工业大学力学与土木建筑学院;空军航空大学飞行基础训练基地后勤部;
【基金】：国家自然科学基金资助项目(51378497)
【分类号】：TU452
【正文快照】： 国民经济和国防建设的不断发展促使岩石工程不断向特殊地域、特殊环境延伸。随着地下工程的深度不断加大,地质条件趋于复杂,深部岩体力学问题[1]已经成为关系国家财产和人民生命安全的重大课题。深部岩体所处的“三高一扰动[1]”特殊地质力学环境导致冲击地压、瓦斯爆炸等现象

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