第二次青藏高原综合科学考察研究

冻结土石混合体在单轴压缩下的变形和声发射特征研究

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  • 1.浙江数智交院科技股份有限公司, 浙江 杭州 310012
    2.浙江大学 建筑工程学院, 浙江 杭州 310058
    3.中国科学院 地质与地球物理研究所 页岩气与地质工程重点实验室, 北京 100029
胡峰,工程师,主要从事岩土力学研究. E-mail: 18810550150@163.com

网络出版日期: 2024-06-24

基金资助

浙江省重点研发计划项目(2021KCKT2011);第二次青藏高原综合科学考察研究项目(2019QZKK0904);国家自然科学基金面上项目(42177146);自然资源部浙江地质灾害野外观测开放基金项目(ZJDZGCZ-2021)

Study on deformation and acoustic emission characteristics of frozen soil-rock mixture in uniaxial compression test

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  • 1.Zhejiang Institute of Communications CO. ,LTD. ,Hangzhou 310012,China
    2.College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China
    3.Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China

Online published: 2024-06-24

摘要

冻结土石混合体具有明显的各向异性和结构效应,相比于冻土,其物理力学行为更加复杂。为了研究冻结土石混合体受压条件下的破坏过程和声发射特征,本文对含石量分别为30%、40%、50%的人工冻结土石混合体试样和不同含水量青藏公路冻结路基砂土石混填物试样进行单轴压缩下的声发射试验。结果表明:(1)与常温土石混合体相比,冻结土石混合体试样受冰晶和冻土的蠕变作用,在单轴压缩过程中表现出轴向应力峰后裂纹发育的变形模式。(2)受冰晶体破裂的影响,冻结土石混合体在加载初始压密阶段就出现一定数量的声发射事件,轴向应力峰后阶段也存在明显的声发射活动,呈现声发射活动的多峰特征。含石量越大,峰后声发射活动越强,且基质土为黏质粉土的土石混合体峰后声发射活动要强于基质土为砂土的冻结土石混合体。(3)冻结黏质粉土的蠕变性质和含石量的大小共同影响试样内部的变形特征。冻结土含量越高,土体越易裹挟块石做整体运动,不利于裂隙的发育,试样多见鼓胀变形,声发射活动较少;当含石量较大时,土石界面数量多,土体与块石差异运动明显,试样以裂隙扩展为主,声发射事件增多,整体变形不明显。

本文引用格式

胡峰, 李志清, 朱益军, 王双娇, 吕庆 . 冻结土石混合体在单轴压缩下的变形和声发射特征研究[J]. 冰川冻土, 2023 , 45(5) : 1463 -1474 . DOI: 10.7522/j.issn.1000-0240.2023.0111

Abstract

Frozen soil-rock mixtures have the properties of distinct heterogeneity and an obvious structural effect, which make their physical and mechanical properties more complex compared with frozen soil. To investigate the failure model and acoustic emission (AE) properties of frozen soil-rock mixtures, uniaxial compression and AE tests of artificial frozen soil-rock mixture specimens with volumetric rock contents of 30%、40%、50%, and Qinghai-Tibet highway subgrade sandy soil rock mixture specimens with different water contents were carried. The mechanical properties of the frozen soil-rock mixture and AE parameters were obtained. The results show that: (1) The post-peak ruptures mode of the frozen soil-rock mixture is the main difference from the soil-rock mixture in a normal temperature state; (2) ice crystals breakage causes the initial AE signal, obvious multimodal AE signals were observed after post-peak compression stage, and the amount of AE signal of a sample with clayey silt is much more than that of frozen subgrade sandy soil rock mixture; (3) Rock content and creep properties of frozen matrix soil are the main factors affecting the deformation properties and the amount of AE signal. The deformation of the specimens is dominated by overall compression bulging deformation in the low rock content stage, and the amount of AE signals is less than the specimens in a high rock content stage, where deformation is dominated by crack propagation. Specimen with low rock content and strong creep frozen soil in which rocks are wrapped by frozen soils, and motion both as a whole together, the amount of AE signals is less than the specimen with high rock content and weak creep frozen soil that uncoordinated deformation between rocks and soil lead to obvious cracks propagation.

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