基于细观结构试验的红砂岩线膨胀系数变化的研究  

On the Change of Linear Expansion Coefficient of Red Sandstone Based on Microstructure Experiment

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作  者:龚俊杰 刘鑫[1] 姚云龙 洪宝宁[1] GONG Junjie;LIU Xin;YAO Yunlong;HONG Baoning(College of Civil Engineering and Transportation,Hohai University,Nanjing 210098,China)

机构地区:[1]河海大学土木与交通学院,江苏南京210098

出  处:《湖南科技大学学报(自然科学版)》2025年第1期15-21,共7页Journal of Hunan University of Science And Technology:Natural Science Edition

基  金:国家自然科学基金资助项目(51609071)。

摘  要:为了解释红砂岩的线膨胀系数变化规律,分别对红砂岩进行了XRD成分分析试验、细观结构试验和线膨胀试验研究,从细观结构的角度讨论红砂岩线膨胀系数的变化规律.研究结果表明:(1)在2℃/min的加热速率下,红砂岩试样的线膨胀系数在常温~400℃增长速度比较缓慢,在400~530℃增长速度随着温度的升高而逐渐加快,在530~620℃出现了一个巨大的峰值,峰值于570~580℃达到顶峰,在620~870℃,红砂岩的线膨胀系数总体处于一个稳定的较低水平,当温度高于870℃时,红砂岩的线膨胀系数有一个微弱上涨的趋势,并且逐渐趋于稳定.(2)红砂岩随着胶结物的解离、矿物颗粒破碎导致裂纹数量增加,结构变得疏松,从而线膨胀系数减小;红砂岩随着颗粒膨胀、石英相变产生的体积增大,使得其膨胀量逐渐填补了结构内部的空隙,结构变得密实,从而线膨胀系数减小.(3)当温度高于870℃时,由于红砂岩微观缺陷、空洞和破坏区的大量出现,其线膨胀系数增幅受石英相变体积膨胀的影响较小.In order to explain the variation rule of the coefficient of linear expansion of red sandstone,XRD composition analysis experiments,fine structure experiments and linear expansion experimental studies are carried out to discuss the variation rule of the coefficient of linear expansion of red sandstone from the point of view of fine structure.The results show that firstly,under the heating rate of 2℃/min,the linear expansion coefficient of red sandstone specimens grows slowly in the temperature range of room temperature to 400℃.The growth rate in the temperature range of 400~530℃has gradually accelerated with the increase of temperature,and a huge peak has appeared in the range of 530~620℃,which has peaked in the temperature range of 570~580℃.In the range of 620~870℃,the coefficient of linear expansion of red sandstone is generally at a stable lower level,when the temperature is higher than 870 ℃,the coefficient of linear expansion of red sandstone has a weak rising trend,and gradually tends to stabilize.Secondly,the linear expansion coefficient of red sandstone decreases with the dissociation of cement and the fragmentation of mineral particles,resulting in the increase of the number of cracks and the structure becomes loose.Red sandstone with the expansion of particles,and quartz phase transition produced by the volume increase,its expansion gradually fills the voids within the structure,and the structure becomes dense,so that the coefficient of linear expansion decreases.Lastly,when the temperature is higher than 870℃,the increase of the linear expansion coefficient is less affected by the volume expansion of quartz phase transformation,due to the large number of microscopic defects,voids and damage zones in red sandstone.

关 键 词:红砂岩 线膨胀系数 细观结构 裂纹 峰值 

分 类 号:TU454[建筑科学—岩土工程]

 

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