摘要
掌握岩石的时间依存性,对于估算地下结构的长期变形和稳定性是必不可少的。本文采用恒定加载速率(CLR)和交替加载速率(ALR)方法,对Ⅰ类和Ⅱ类岩石在单轴压缩(UC)和巴西劈裂(BT)条件下的全应力-应变曲线、峰值强度、加载速率效应和杨氏模量进行了比较分析,探寻了两种条件下岩石的相似性和差异性,同时,对荷载速率依存性进行了量化分析和深入研究。结果表明,两种加载条件下的全应力-应变曲线具有相似的规律;不同类型岩石的单轴压缩强度与劈裂强度的相关系数k在0.0424~0.1394的范围内,两者可以相互转化;劈裂模量与弹性模量之间存在线性关系,两个模量具有明显的时间依存性,且可相互转换;把常数n作为岩石荷载速率依存性指标,其值与加载条件、试验环境等因素相关,地下岩体的速率依存性指标值n可定量评价和预测地下结构的长期稳定性。建立了基于n值的可变模量本构方程,模拟了两种试验条件下的实验数据,计算结果的一致性较好。
Understanding time-dependency of rock is indispensable for geotechnical applications to estimate long-term deformation and stability of underground structures.This paper introduced a comparison between uniaxial compressive(UC)and Brazilian tensile test(BT)behavior for class I and class II rocks using constant loading rate(CLR)and alternative loading rate(ALR)method,which includes the similarity and otherness of complete stress−strain curves,peak strength,loading rate effect and elastic modulus of two types of test;and time-dependency was also quantitatively analyzed.The results show that the stress−strain curves have a similar law;the correlation coefficient k between UC and BT strength for different rocks is 0.0424−0.1394,and the two strengths can convert to each other;there is a linear relationship between tensile and elastic modulus,with an obvious time-dependency,and the two moduli also can convert to each other;the constant n was taken as index of loading rate dependency for rock,and analyzed the relation to the loading condition,testing environment.The constant n can quantitatively assess the long-term stability of underground structures.A constitutive equation based on n value was proposed to simulate the experimental data for four rocks and the calculated results are fitted very well.
作者
张海龙
汤杨
俞缙
OKUBO Seisuke
ZHANG Hai-long;TANG Yang;YU Jin;OKUBO Seisuke(School of Civil Engineering,Chongqing University of Arts and Sciences,Chongqing 402160,China;Fujian Research Center for Tunnelling and Urban Underground Space Engineering,Huaqiao University,Xiamen 361021,China;Department of Systems Innovation,The University of Tokyo,7-3-1,Hongo,Bunkyo-ku,Tokyo,113-8656,Japan)
基金
Projects(42077254, 51874144) supported by the National Natural Science Foundation of China
Projects(cstc2019jcyjmsxm X0488, cstc2021jcyj-msxm X0354) supported by the Natural Science Foundation of Chongqing,China
Projects(KJZD-K202201304, KJQN202201314) supported by Science and Technology of Chongqing Municipal Education Commission,China
Project (2021M693751) supported by China Postdoctoral Science Foundation
Project (P2017JG18) supported by Major Cultivation of Chongqing University of Arts and Sciences,China。
关键词
深部岩体
Ⅰ和Ⅱ类岩石
单轴压缩
巴西劈裂
时间依存性
underground structures
class I and class II rocks
uniaxial compression
Brazilian tension
time-dependency
