摘要
高温作用后岩石内部结构会发生变化,并导致其抗拉强度也发生相应变化。本次试验利用高温炉和电液伺服试验机研究了高温作用后砂岩抗拉强度的变化特征。研究结果表明:砂岩抗拉强度随温度的升高(25~900℃)整体呈下降趋势,抗拉强度—温度的变化曲线可分为四个阶段:温度从25℃至300℃,砂岩抗拉强度因自由水、结合水的蒸发缓慢减小;温度从300℃至600℃,砂岩因结晶水、结构水蒸发以及结构热应力的作用,抗拉强度迅速降低;从600℃升至800℃,砂岩矿物的熔融及钙、镁等碳酸盐的分解使其抗拉强度持续下降;温度从800℃升至900℃,热应力继续增大,砂岩抗拉强度随着宏观裂隙的形成而急剧减小。
The internal structure of the rock will change after high temperature heating, which has a significant impact on its mechanical properties. The tensile strength of sandstone after high temperature heating is studied using a high temperature furnace and electro-hydraulic servo-controlled testing machine. The results show that the tensile strength of the sandstone decreases with the increase of temperature generally. The changing can be divided into four stages according to temperature. The tensile strength decreases slowly due to the evaporation of free water and combined water when the temperature ranges from 25℃ to 300℃ ; the strength reduces rapidly from 300℃ to 600℃ due to the evaporation of crystal water, structure water and the thermal stress effect; from 600℃ and 800℃ , the strength reduces continuously with the melt of minerals, dissociation of carbonate and fracture of metallic bonding; the strength will decline sharply after 800℃ when the macro-fissure appears under the thermal stress.
出处
《工程勘察》
2017年第1期12-15,共4页
Geotechnical Investigation & Surveying
基金
中央高校基本科研业务费专项资金资助(No.2015XKMS033)
关键词
砂岩
高温作用
抗拉强度
热应力
sandstone
high temperature
tensile strength
thermal stress
