红砂岩强度特性的微结构试验研究  

EXPERIMENTAL STUDY ON MICROSTRUCTURE OF STRENGTH PROPERTY OF RED SANDSTONE

作　　者：胡昕[1] 洪宝宁[1] 王伟[2] 孟云梅[2] 

机构地区：[1]河海大学岩土工程水利部重点实验室 [2]南京工程学院建筑工程学院,江苏南京211167

出　　处：《岩石力学与工程学报》2007年第10期2141-2147,共7页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(50279008)

摘　　要：为探讨红砂岩强度特性的微观机制,运用自主开发的微细结构光学测试系统,对荷载作用下红砂岩微结构的演化进行全程观测,并测定对应岩样的无侧限抗压强度和提取相应的微结构量化参数。运用多元线性回归分析法对微结构量化参数和无侧限抗压强度进行关联性分析,筛选出对红砂岩无侧限抗压强度有显著影响的微结构要素,并对荷载作用下显著性微结构要素的演化特性进行分析。研究结果表明:在单轴压缩条件下,红砂岩先结构强化,后结构劣化,直至最终破坏;红砂岩的单轴抗压强度主要与密实程度、微孔洞等缺陷的分布情况及矿物颗粒之间的联结状态有关,随着红砂岩风化程度的增强,以上各因素对其单轴抗压强度的影响将更加显著;伴随荷载的增加,红砂岩的矿物颗粒面积比例及欧拉数总体上趋于减小,孔隙向着集中化和集团化的趋势发展,红砂岩抗变形能力逐步丧失。In order to discuss the microstructural mechanism of strength property of red sandstones, the microstructural changes of red sandstone under load are tracked by using optical testing systems; the unconfined compressive strength of corresponding rock specimen is measured and the comparable quantitative parameters are extracted. By using multilinear regression method, the correlations between unconfined compressive strength and microstructural parameters are analyzed. Then the microstructural elements closely linked with unconfined compressive strength of red sandstone are filtered and the evolutionary characteristics of prominent microstructural elements are analyzed. The findings indicate that under uniaxial compression, the red sandstones at first experience structural intensification and then structural degradation until they are failed; the unconfined compressive strength of red sandstone is mainly related with compaction rate, pore distribution and connecting condition of mineral grains; and the above factors have a more notable impact on the unconfined compressive strength of red sandstone with the increase of weathering; with the increase of load, the grains area ratio and Euler number decrease, the pore develops towards centralization or collectivization, and the red sandstones gradually lose their resistance to deformation.

关 键 词：岩石力学 红砂岩 微结构 关联性分析 演化特性 

分 类 号：TU45[建筑科学—岩土工程]