卸荷条件下砂岩变形模量弱化规律  

Degradation Law of Sandstone Deformation Modulus Under Unloading Condition

作　　者：王兴霞[1] 黄建文[1] 黄曼丽 

机构地区：[1]三峡大学水利与环境学院,湖北宜昌443002 [2]湖北省水利水电规划勘测设计院,湖北武汉430070

出　　处：《人民黄河》2015年第6期131-134,共4页Yellow River

基　　金：国家自然科学基金面上项目(51279091);水利部公益性行业科研专项(201401029);宜昌市自然基础科学研究与应用专项(A14-302-a01);三峡大学人才科研启动基金资助项目(KJ2012B027)

摘　　要：卸荷作用将导致岩体的力学参数劣化,卸荷过程中岩体的力学参数是动态变化的。针对宜昌地区的砂岩进行了三轴加卸荷试验,研究升轴压卸围压条件下岩样变形模量的弱化规律。试验结果表明：卸围压过程中,岩样变形模量随围压的降低而加速减小;卸荷程度越高,相同围压卸荷量引起的变形模量减小比例越高,其弱化规律可定量分析;当岩样发生卸荷破坏后,岩样变形模量减小至三轴压缩破坏变形模量的24%~49%;卸荷速率对试验结果有明显影响,当初始围压值相同时,卸荷速率越大,相同围压卸荷量引起的岩样变形模量劣化程度越高;卸荷过程中岩样变形模量与围压卸荷量的关系曲线可用多项式很好地拟合。The mechanical parameters of rock mass will be degraded due to unloading effect and the degradation is a dynamic process. The deformation modulus degradation law of sandstone in Yichang area was studied based on tri-axial loading and unloading tests. Test results show that the deformation modulus of rock samples decrease in the unloading process with the decrease of the confining pressure. The greater the unloading degree is, the bigger the deformation modulus changing ratio is, according to the same unloading degree. The degradation law is also analyzed quantitatively, and deformation changing ratio according to certain unloading degree is obtained. When unloading failure occurs, the deformation modulus is only 24% to 49% of the values in tri-axial compression failure. Unloading rate shows significant impact on test results. With the same initial confining pressure, the bigger the unloadingrate is, the bigger the decrease ratio of deformation modulus is, due to the same unloading degree. The relation curves between deformation modulus of rock samples and unloading ratio can be well fitted by polynomial.

关 键 词：砂岩 变形模量 卸荷 卸荷比 卸荷速率 弱化 

分 类 号：TV541[水利工程—水利水电工程]