摘要
边坡、隧洞、矿井等岩土工程的失稳过程都伴随着岩体的扩容现象,研究各种工程岩体的扩容特性对工程岩体稳定性评价有重要意义。采用TAW-2000电液伺服岩石三轴试验机,通过对8种岩样的单轴、三轴压缩试验结果分析,获得了低围压下的应力–体积应变曲线,寻求不同岩石的扩容起始点的的变化规律,揭示岩石扩容起始特性与峰值点特性的对应关系。研究结果表明:①岩石扩容起始点处的应力随着围压的增大而增大,并且相比峰值点应力变化,扩容起始点的应力随着围压的变化更强烈;②分别定义了岩石的扩容起始点与峰值点的应力比和应变比计算公式,应力比和轴向应变比呈现很强的线性相关性,并且与其岩性和围压无关。如果确定了峰值点的应力应变关系,便可以较方便地找到岩石的扩容起始点。通过岩石扩容起始点与峰值点变化规律的研究,找到了一条确定岩石扩容起始点的新思路,对岩石的长期强度预测提供了理论依据。
The failure process in geo-engineering,such as slope,tunnel and mine,is always accompanied by rock dilatancy.So the studies on the rock dilantancy can really make sense for evaluating the stability of rock mass.TAW-2000 servo-controlled triaxial rock testing system is employed to reveal the rock dilatancy behaviors through uniaxial or triaxial tests on 8 different kinds of rocks.The following conclusions are drawn through the analysis of the test results.The stress of rock dilatancy onset increases with the confining pressure.Compared with that of the peak stress,the variation of stress increment of the rock dilatancy onset is greater.The formula for the stress ratio-axial strain ratio is defined.The relationship between the stress ratio and the axial strain ratio is linear through the origin point regardless of the lithology and the confining pressure.If the stress-strain relationship of the peak is known,the rock dilatancy onset can be found easily.More and more importance should be attached to the studies on the rock dilatancy onset and the peak,that is the key issue for long-term stability estimation of the rock mass.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2013年第8期1478-1485,共8页
Chinese Journal of Geotechnical Engineering
基金
国家重点基础研究发展规划项目(973)计划项目(2010CB731501)
国家自然科学基金项目(41227901
41027001
41272352
41272351
41202217)
中国博士后科学基金项目(2012M520375)
关键词
岩石扩容
扩容起始点
应力应变比
长期抗压强度
rock dilatancy
dilatancy onset
stress ratio-strain ratio
long-term compressive strength
