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  

Localized damage effects of quasi-sandstone with single fracture and fracture behaviors of joint end under cyclic freezing and thawing

作　　者：申艳军[1] 杨更社[1] 荣腾龙 贾海梁[1] 王铭[1] 刘慧[1] SHENYanjun YANG Gengshe RONG Tenglong JIAHailiang WANG Ming LIU Hui(School of Architecture and Civil Engineering, Xi＇an University of Science and Technology, Xi＇an, Shaanxi 710054, China School of Mechanics and Civil Engineering, China University of Mining and Technology（Beijing）, Beo＇ing 100083, China)

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054 [2]中国矿业大学(北京)力学与建筑工程学院,北京100083

出　　处：《岩石力学与工程学报》2017年第3期562-570,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(41302228);中国博士后科学基金资助项目(2014T70931);陕西省博士后科学基金项目(2014051)~~

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。Saturated fractured rocks in cold regions under cyclic freezing and thawing experience the crack initiation, crack extension, deflection and branching along the crack end, which results in localized damage and fracturing at the crack end and overall failure. The quasi-sandstone samples of similar materials containing a single fracture with the inclination angles of 0°, 30°, 45 °, 60°, 90°, were prepared. The freezing and thawing cycles of 10, 20, 30, 50 were applied in the experiments respectively. The samples with a single fracture exhibit the localized damage under the cyclic freezing and thawing and the fracture end can be divided into fracture zone, progressive damage zone and systematic damage zone. The localized damage effect becomes weaker and the acoustic wave velocity becomes faster as the increase of the crack dip angle. The bifurcation and deflection of main cracks under cyclic freezing and thawing occur in the＇ samples with a single fracture at the inclination angles of 30 °, 45 ° and 60 °. The deflection of main crack occurs earlier, the deflection direction tends to be horizontal, and the extended length along the initial fracture direction is shorter as the decrease of the Crack tip angle. The localized damages in the upper and lower of crack are different and the macroscopic fracture occurs earlier at the bottom of the crack, and the difference is more notable with the increase of the crack dip angle.

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 

分 类 号：TU45[建筑科学—岩土工程]