摘要
利用岩石空心圆柱扭剪试验系统针对灰砂岩进行真三轴试验研究,分别开展控制(σ2-σ3)(σ2为中间主应力,σ3为最小主应力)条件压缩试验和恒σ3、变σ2条件压缩试验,对灰砂岩的应力-应变规律、强度特性及破坏特征进行详细分析,并进一步探讨了中间主应力效应,最小主应力效应,应力洛德角效应以及强度准则的适用性。研究结果表明:岩石空心圆柱扭剪试验系统能够实现真三轴应力状态的模拟,相较于常规的实现方式,该方法可避免端部摩擦的影响;内外围压的压差对岩石强度有很大影响,尤其是在高围压下,较大的压差使得岩石强度迅速弱化导致剧烈破坏;中间主应力对岩石强度影响显著且具有区间效应,最小主应力对岩石强度有强化作用,该特点对于实际工程开挖岩体的高效及时支护具有重要的指导意义;进一步地,根据所获试验结果对现阶段用于描述岩石力学特性的强度准则进行分析,认为采用指数强度准则能合理反映岩石真三轴应力状态,具有较好的适用性,可用来评价实际工程中岩石的强度特征。
The hollow cylinder torsional testing system(RHCA)was used to conduct true triaxial test on gray sandstone.Controlled conditional compression tests(σ2-σ3),constantσ3 and variableσ2 conditional compression tests were carried out respectively.σ2 is the intermediate principal stress,σ3 is the maximum principal stress.Strength and failure characteristics were analyzed in detail,and intermediate principal stress effects,minimum principal stress effects,stress Lord angle effect and applicability of strength criterion were further analyzed.The results indicate that rock hollow cylindrical apparatus can realize the simulation of true triaxial stress path and the end friction can be avoided.The pressure difference between the inner and outer confining pressure has a great influence on the strength of the rock,especially under high confining pressure,a large pressure difference makes the strength of the rock weaken rapidly,resulting in severe damage.The intermediate principal stress has a significant effect on the strength of the rock and has an interval effect,and the minimum principal stress has a strengthening effect on the strength of the rock.This feature has an important guiding significance for the efficient and timely support of the rock mass in actual engineering excavation.Further,according to the obtained test results,the strength criteria used to describe the mechanical properties of the rock at this stage were analyzed.It is considered that the calculated rock strength obtained by using the exponent criteria can better reflect the stress state of rock and has a relatively good applicability.It can be used to evaluate the strength of rock in practical engineering.
作者
姜玥
周辉
卢景景
高阳
JIANG Yue;ZHOU Hui;LU Jing-jing;GAO Yang(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;School of Civil Engineering,Suzhou University of Science and Technology,Suzhou,Jiangsu 215000,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2022年第4期932-944,共13页
Rock and Soil Mechanics
基金
岩土力学与工程国家重点实验室开放基金(No.Z2019023)
国家自然科学基金(No.41941018,No.42102307,No.52009128)
江苏省自然科学基金(No.BK20209992)。
关键词
岩石力学
空心圆柱试样
真三轴试验
强度准则
rock mechanics
hollow cylindrical specimen
true triaxial test
strength criterion
