摘要
在MTS815 Flex test GT岩石力学试验机上对盐岩进行了单轴循环加、卸载试验研究盐岩的变形特性,试验表明,循环加、卸载强化了变形的线性特征,各级卸载、再加载曲线主要是由直线段组成。随着荷载级别的增高,直线段的变形模量总体上呈现微弱上升的趋势,各级卸载、再加载曲线变形模量的变异系数分别为8.05%和7.45%,可以用各级加、卸载曲线直线段变形模量的平均值来分别表征加、卸载的变形特征。每级卸载曲线的变形模量都要大于再加载曲线的变形模量,卸载的泊松比都要小于再加载的泊松比。与单轴试验相比,卸载和再加载的变形模量都要大于单轴应力应变全过程试验。根据以上分析,得出了简单应力状态下加、卸载本构关系。对各级塑性滞回能进行了计算,发现塑性滞回能随着级别的增高而增高,并对其进行了拟合。分析表明,卸载、再加载变形参数比单轴应力应变全过程试验参数更具有规律性,更能表征盐岩地下工程中的变形特性。
Uniaxial cycling loading and unloading tests of rock salt were performed on MTS, and the results showed that loading and unloading progresses strengthen the linear character of curves; the main part of curves is linear. Followed with the step, deformation modulus is in slightly rising trend. The coefficient of variation of deformation modulus of unloading curves is 8.05%, while that of loading curves is 7.45%. So the deformation features can be characterized by the average deformation modulus of loading and unloading curves. In every step, the unloading deformation modulus is higher than the loading＇s, while the loading Poisson ratio is higher than the unloading＇s. Compared with uniaxial test, the loading and unloading deformation moduli are higher. Based on the analysis, the constitutive relation under simple stress state has been built. In every step plastic hysteresis energy was calculated, and the result showed it increased by the step. The analysis showed the deformation parameters under loading and unloading test are much more regular and consistent than those under uniaxial test, these parameters can characterize the deformation of underground engineering of rock salt better.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2009年第12期3562-3568,共7页
Rock and Soil Mechanics
基金
国家重点基础研究发展规划(973)(No.2009CB724602
2009CB724603)
国家杰出青年基金(No.E50725414)
科技部重大国际合作计划项目(No.2007DFB60100)
国家自然科学基金(No.50774076)
关键词
循环加、卸载
盐岩
变形
cycling loading and unloading
rock salt
deformation
