主动围压状态人工冻结砂土SHPB试验与分析

发布时间：2018-01-15 01:33

本文关键词：主动围压状态人工冻结砂土SHPB试验与分析　出处：《岩土力学》2017年10期 　论文类型：期刊论文

【摘要】：为研究主动围压状态人工冻结砂土的动态力学性能,利用直径50 mm变截面分离式霍普金森压杆试验装置,以取自山东济宁某矿-94.52 m处冻结砂土为研究对象,对长径比为0.5的冻结砂土试件进行主动围压状态下的冲击压缩试验,分析了主动围压和应变率对冻结砂土动态力学性能的影响。研究结果表明,无围压状态下,冻结砂土动态应力-应变曲线可分为弹性阶段、塑性阶段、黏性阶段和破坏阶段,冻结砂土呈脆性破坏;主动围压状态下,应力-应变曲线塑性阶段明显增长,无黏性阶段,冻结砂土呈微裂破坏。相同条件下,主动围压状态下冻结砂土的动态抗压强度均高于无围压状态,且随着围压的增大,动态抗压强度逐渐增大;当应变率为220 s~(-1),温度为-15℃时,主动围压为0.5、1.0、1.5、2.0 MPa的动态抗压强度为无围压状态下的119%、140%、158%和181%。不同主动围压下的应力-应变曲线表现出汇聚现象,汇聚点趋向于无围压状态。冻结砂土的动态抗压强度随应变率的提高而增加。
[Abstract]:For the dynamic mechanical properties of the confining pressure state artificial frozen soil, with a diameter of 50 mm variable cross-section split Hopkinson pressure bar test device, from a mine in Jining Shandong -94.52 m of Frozen Sandy Soil as the research object, the length diameter ratio of frozen sandy soil specimens were 0.5 main dynamic confining pressure shock compression test and analysis of the active effect of confining pressure and strain rate on the dynamic mechanical properties of frozen sandy soil. The results showed that no confining pressure, the stress-strain curves can be divided into elastic stage of frozen sand dynamic, viscous plastic stage, stage and failure stage, frozen sand brittle failure; active confining pressure. Next, the stress-strain curve of plastic stage significantly increased, cohesionless stage, frozen sand in micro crack damage. Under the same conditions, the dynamic compressive strength with confining pressure is higher than that of frozen soil under no confining pressure, with the confining pressure The increase of dynamic compressive strength gradually increases; when the strain rate is 220 s~ (-1), the temperature is -15 DEG C when the confining pressure for the dynamic compressive strength of 0.5,1.0,1.5,2.0 MPa is no confining pressure under the condition of 119%, 140%, 158% and 181%. of different confining pressure and the stress - strain curves show convergence phenomenon no, the convergence point tends to confining pressure. The dynamic compressive strength of Frozen Sandy Soil with strain rate increasing.

【作者单位】：安徽理工大学矿山地下工程教育部工程研究中心;安徽理工大学土木建筑学院;
【基金】：国家自然科学基金(No.50874003) 安徽理工大学研究生创新基金(No.2017CX1001)~~
【分类号】：TU41
【正文快照】： 各类地下工程时,在其四周建造起临时冻结壁,以1引言保证不稳定的饱水土体在掘进施工中稳定性的方人工冻结法是指在复杂水文地质条件下掘进法,其实质是利用人工制冷临时改变岩土性质以固结地层。适用于开挖竖井和地铁隧道、建造地下硐取101.37 g土样放入内径为50 mm、高度为2

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