不同含水状态砂岩分级循环荷载试验研究  

An experimental study of cyclic loading of sandstone under different water contents

作　　者：冯小东[1] 刘高[2] FENG Xiaodong LIU Gao(Lanzhou Resources ＆ Environment VOC-TECH College, Lanzhou, Gansu 730021 ,China School of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000, China)

机构地区：[1]兰州资源环境职业技术学院地质工程系,甘肃兰州730021 [2]兰州大学土木工程与力学学院,甘肃兰州730000

出　　处：《水文地质工程地质》2017年第1期110-115,共6页Hydrogeology & Engineering Geology

基　　金：国家重点基础研究发展计划(2014CB744701)

摘　　要：为探究不同含水状态砂岩在循环荷载作用下的力学行为差异,对干燥、天然以及饱和三种含水状态下的砂岩进行了单轴分级循环加卸载试验。研究结果表明:由于水对砂岩的物理化学软化作用,饱水、天然以及干燥状态下的强度依次递减,而变形依次增加;卸载模量随着循环周次的增加呈先增大后减小的整体趋势,同一循环周次下,含水量越高,其卸载模量越小;体积应变开始出现拐点时的循环周次正好与卸载模量转折点所处的加卸载周次相对应;能量值随循环周次的增加均呈幂函数型增长,同一循环周次下,含水率越高的砂岩各项能量值越大;基于能量耗散的损伤定义表明:砂岩初始损伤值不为零,且均经历了一个先减小后增大的损伤演化过程,相同循环周次下,饱和、天然以及干燥砂岩的损伤量依次增大。In order to explore the difference in the mechanical behavior of sandstone under cyclic loading with different water contents, the uniaxial cyclic loading and unloading tests are conducted for the sandstone under dry, natural and saturated conditions. The results show that the strength of the saturated, natural and dry conditions decreases but the deformation increases because of the softening effect of physical chemistry. The unloading modulus increases first and then decreases with the increasing cycle times and the higher the water content, the smaller the unloading modulus in the same cycle. The volume strain occur an inflection point when the cycles are coincided with the turning point of unloading modulus through the bad times. The energy value with cycles is a power function of the growth and in the same cycle, the higher the water content is, the greater the energy value of the sandstone is. The damage definition based on energy dissipation shows that the initial damage value of sandstone is not zero, and the damage evolution process reduces and then increases. The damage amount of the saturated, natural and dry sandstone increases in turn in the same cycle.

关 键 词：砂岩 含水率 分级循环加卸载 卸载模量 能量 损伤 

分 类 号：P642.11[天文地球—工程地质学]