以等应变速率曲线为基础的岩石长期强度确定方法

发布时间：2018-03-02 23:22

本文选题：岩石流变　切入点：长期强度　出处：《哈尔滨工业大学学报》2017年06期 　论文类型：期刊论文

【摘要】：长期强度是岩石时效强度的一种,是影响和评价岩体工程长期稳定性的一个重要性质.为更准确地求解长期强度,以等应变速率曲线为基础,提出了等应变速率曲线拐点法及极限应变法两种确定岩石长期强度的新方法.对锦屏二级水电站的绿片岩开展了单轴和三轴应力状态的常规和分级加载蠕变试验以验证上述方法,并利用文中提出的方法对绿片岩长期强度求解,得到了不同围压状态下绿片岩的长期强度值.同时,在极限应变法的求解过程中,结合蠕变曲线,得到了蠕变变形稳定时间以及相应的极限应变值.试验成果表明:两种方法均可求得长期强度,数值接近且符合长期强度的经验值;单轴以及三轴应力状态下长期强度分别为瞬时强度的66.9%(单轴)、68.0%(围压10 MPa)、79.6%(围压10 MPa).文中提出的确定长期强度的方法具有一定的可行性,同时,围压是影响长期强度的主要因素之一,具体表现为随着围压的升高,长期强度与瞬时强度的比值升高.
[Abstract]:Long-term strength is one of the age strength of rock, which is an important property to affect and evaluate the long-term stability of rock mass engineering. In order to solve the long-term strength more accurately, the iso-strain rate curve is used as the basis. Two new methods for determining the long-term strength of rock are presented, I. e., the inflection point method of equal strain rate curve and the limit strain method. The creep tests under uniaxial and triaxial loading are carried out for the greenschist rock in Jinping II Hydropower Station. To verify the above method, The long-term strength of greenschist under different confining pressure is obtained by using the method proposed in this paper. At the same time, the creep curve is combined with the solution of limit strain method. The creep deformation stability time and the corresponding limit strain value are obtained. The experimental results show that the long-term strength can be obtained by the two methods, and the values are close and consistent with the experience value of the long-term strength. The long-term strength under uniaxial and triaxial stress states is 66.9% of the instantaneous strength respectively. Confining pressure is one of the main factors affecting the long-term strength, which shows that the ratio of long-term strength to instantaneous strength increases with the increase of confining pressure.
【作者单位】：同济大学地下建筑与工程系;岩土及地下工程教育部重点实验室(同济大学);青岛理工大学土木工程学院;
【基金】：国家自然科学基金(41072203)
【分类号】：TU45

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