温度、三轴应力条件下砂岩渗透率阶段特征分析  

Analysis of stage characteristics of sandstone permeability under conditions of temperature and triaxial stress

作　　者：张渊[1] 万志军[2] 康建荣[3] 赵阳升[4] 

机构地区：[1]淮阴工学院建筑工程学院,江苏淮安223001 [2]中国矿业大学矿业工程学院,江苏徐州221008 [3]徐州师范大学科技处,江苏徐州221116 [4]太原理工大学矿业工程学院,太原030024

出　　处：《岩土力学》2011年第3期677-683,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金重点项目(No.50534030);国家自然科学基金项目(No.40872180)

摘　　要：利用20 MN伺服控制高温高压岩体三轴试验机进行了长石细砂岩的渗透率试验,研究了恒定三轴压力和常温至600℃条件下砂岩渗透率变化特征。试验表明,随着温度增加,长石细砂岩渗透率变化规律表现为5阶段特征:①低温段,随温度升高渗透率略有下降;②阈值温度前段,达到阈值温度后,渗透率急剧增大,产生一个突跃,增加了65倍;③阈值温度后段,随着温度的继续升高,渗透率出现下降;④稳定段,渗透率达到谷值后不再下降,并稳定在一个较高水平,是室温渗透率的8倍;⑤高温段,渗透率重新增大。通过对长石细砂岩的细观结构变化及声发射事件(AE events)计数率分析后认为:渗透率的阶段性变化规律主要与内部矿物颗粒之间及其内部因局部热应力集中而诱发产生的微裂缝的开闭有关;高温条件下的长石细砂岩渗透率二次剧烈变化则主要与砂岩中部分矿物晶体颗粒成分在高温环境下的熔融、重结晶等现象有关。By means of 20 MN servo control rock mass triaxial testing machine with high temperature and high pressure,the experiment of feldspar fine sandstone permeability was carried out.Under the condition of constant triaxial pressure and room temperature up to 600 ℃,the change characteristic of sandstone permeability were researched.It is observed that the permeability of feldspar fine sandstone appears five stage characteristics with temperature rising： ① Low temperature stage,its permeability declines with temperature rising.② Fore-stage of temperature threshold,its permeability acutely rises,the value increased 65 times as much as that in room temperature.③ Back-stage of temperature threshold,its permeability declines with temperature continuously rising.④ Stabilizing stage,its permeability is stabilized at a high level upon to valley value,which is 8 times as much as the permeability value in room temperature.⑤ High temperature stage,its permeability rises again.After the comprehensive analysis of micro configuration,and AE events of feldspar fine sandstone,it is considered that the stage characteristic law of feldspar fine sandstone permeability is correlated with the opening and closing of micro cracks induced by partial thermal stress centralizing in rock minerals granule edge and interior,and the second acutely increased phenomena of feldspar fine sandstone permeability is mainly affected by some minerals crystal granule fusing and recrystallizing in high temperature environment.

关 键 词：渗透率 温度 三轴压力 阶段特征 

分 类 号：TU432[建筑科学—岩土工程]