摘要
为研究卢氏膨胀岩湿胀软化特性,开展了膨胀性试验和常规三轴试验。并将泡水前后的膨胀岩进行扫描电子显微镜(SEM)试验和氮气吸附(NA)试验。为充分考虑膨胀岩内部颗粒之间的胶结作用和原始结构,试验样品采用原状膨胀岩。试验研究结果表明:膨胀岩吸水膨胀具有明显的各向异性,轴向膨胀率大于径向膨胀率且在1.5倍左右;随着相对含水率的增加,峰值强度呈先快速降低再缓慢降低的变化趋势,弹性模量和黏聚力呈增加趋势;在围压保持不变的情况下,随着含水率的增加,膨胀岩破坏形式由张拉破坏、张剪破坏向剪切破坏转变,并且膨胀岩破坏时表面裂缝增多。微观试验结果显示,泡水后膨胀岩微观结构裂隙比泡水前增多,孔隙发育明显,这是膨胀岩软化的根本原因。
To investigate the swelling and softening characteristics of expansive rocks,swelling test and conventional triaxial test were carried out.The scanning electron microscopy(SEM)and nitrogen adsorption(NA)techniques were conducted before and after soaking water.Undisturbed expansive rock samples were selected to fully consider the cementation among the particles inside the expansive rock and original structure.Experimental results show that the expansion has apparent anisotropy and the axial expansion is 1.5 times of the radial one.With the increase of relative water content,the peak strength decreases rapidly and then slowly decreases,the elastic modulus and cohesion decrease.Under the condition that the confining pressure remains unchanged,the deformation form of the expansive rock changes from tensile failure,tensile-shear failure to shear failure,and surface cracks increase when the expansion rock fails.SEM results show that the microcracks of the expansive rock increases after the water soaking,and the pore development is obvious,which is the softening fundamental of the expansive rock.
作者
张善凯
冷先伦
盛谦
ZHANG Shan-kai;LENG Xian-lun;SHENG Qian(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2020年第2期561-570,共10页
Rock and Soil Mechanics
基金
国家重点研发计划项目(No.2017YFF0108705,No.2017YFF0108706)
陕西省交通运输厅2016年度交通科研项目(16-18K)
国家自然科学基金(No.51679232)。
关键词
膨胀岩
力学性质
软化特性
微观结构
expanded rock
mechanical properties
softening characteristics
microstructure
作者简介
第一作者:张善凯,男,1989年生,博士研究生,主要从事边坡工程及膨胀岩膨胀特性方面的研究工作。E-mail:shankaizhang@foxmail.com;通讯作者:冷先伦,男,1980年生,博士,副研究员,主要从事岩石力学与工程方面的研究。E-mail:xlleng@whrsm.ac.cn。
