冻融循环作用下单裂隙类砂岩局部化损伤效应及端部断裂特性分析

发布时间：2018-02-26 06:00

本文关键词： 岩石力学冻融循环单裂隙岩体局部化损伤效应应力叠加原理　出处：《岩石力学与工程学报》2017年03期 　论文类型：期刊论文

【摘要】：寒区饱水裂隙岩体受反复冻融作用影响,沿裂隙端部出现裂纹萌生、延展、偏转、分叉等现象,造成裂隙端部局部化区域损伤,进而诱发端部断裂造成岩体整体失稳。现采用相似材料配制0°,30°,45°,60°,90°的单裂隙类砂岩试样,并对裂隙内部充分饱水,展开10,20,30,50次冻融循环试验,而后观测裂隙端部区域在不同裂隙倾角、冻融循环次数下局部化损伤效应差异规律。藉此,对裂隙岩体在冻融循环作用下的局部化损伤效应进行分析,并结合断裂力学应力叠加理论,验证了因局部化损伤效应造成的裂隙端部断裂特性及扩展路径规律。结果表明:(1)冻融循环作用下单裂隙岩体存在局部化损伤效应,按照局部区域宏观裂纹发育状况,可将裂隙端部划分为:断裂区、渐进损伤区、系统损伤区;(2)随着裂隙倾角增大,冻融循环过程造成的局部化损伤效应越不显著,对应的声波波速值越大;(3)冻融循环过程中,主要在30°,45°,60°斜裂隙岩体出现主裂纹分叉、偏转现象;(4)裂隙角度愈缓,冻融循环作用造成的主裂纹偏转现象越早产生,偏转方向逐渐趋于水平,且沿初始裂隙走向的延展长度越短;(5)冻融循环引起局部化损伤在上下端部存在差异,裂隙下端部较早发生宏观断裂,且倾角越大,差异现象越明显。研究将为冻融作用下裂隙岩体局部损伤及端部断裂演化规律提供技术参考。
[Abstract]:Under the influence of repeated freezing and thawing, crack initiation, extension, deflection, bifurcation and other phenomena appear along the end of the crack, which results in the damage of the localized area of the crack end. In this paper, a sample of single fissure sandstone of 0 掳~ 30 掳~ 45 掳~ 60 掳~ 90 掳is prepared by using similar materials, and 50 freeze-thaw cycle tests are carried out for 10 ~ 20 ~ 30 ~ 50 times of freezing and thawing in the fracture interior, and then the inclination of the fracture end region in different fracture inclination is observed. This paper analyzes the localized damage effect of fractured rock mass under freeze-thaw cycle, and combines with the theory of stress superposition of fracture mechanics. The fracture characteristics and propagation path of crack tip caused by localized damage effect are verified. The results show that there exists localized damage effect in cranny rock mass due to freeze-thaw cycle, according to the macroscopic crack development in local area. The fracture tip can be divided into three parts: fracture zone, progressive damage zone and system damage zone. (2) with the increase of crack inclination, the localized damage effect caused by freeze-thaw cycle is less significant, and the corresponding acoustic wave velocity is larger during freeze-thaw cycle. The main crack bifurcation occurs mainly in 30 掳~ 45 掳~ 60 掳oblique fissure rock mass, and the angle of the crack is slower. The deflection of the main crack caused by freeze-thaw cycle is more early, and the deflection direction tends to be horizontal. And the shorter the extension length along the initial fracture strike is, the shorter the freeze-thaw cycle causes the local damage in the upper and lower end, the earlier the macroscopic fracture occurs in the lower end of the crack, and the greater the dip angle is. The more obvious the difference is, the more the research will provide a technical reference for the local damage of fractured rock mass and the evolution law of the end fracture under the action of freezing and thawing.
【作者单位】：西安科技大学建筑与土木工程学院;中国矿业大学(北京)力学与建筑工程学院;
【分类号】：TU45

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