| 无侧限压缩条件下黏性土磁各向异性研究 |
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| 引用本文： | 孙茜,阎长虹,刘羊.无侧限压缩条件下黏性土磁各向异性研究[J].水文地质工程地质,2021,48(1):123-130. |
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| 作者姓名： | 孙茜 阎长虹 刘羊 |
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| 作者单位： | 1.南京大学地球科学与工程学院，江苏 南京 210023 |
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| 基金项目： | 江苏省高等学校自然科学研究面上项目资助(18KJB170006);江苏高校哲学社会科学研究基金(专题)项目资助(2018SJA2103)。 |
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| 摘 要： | 近年来基坑、隧洞等开挖工程活动中的卸载导致黏性土体发生过大侧向变形，引起的工程事故越来越多。目前多采用测斜仪对基坑周围土体变形进行水平位移监测，然而由于软土的特殊工程性质，在监测中软土无法带动测斜仪一起变形，往往监测效果不尽人意，不能准确给出实际软土的真实变形。因此，需要加强开挖卸荷工程施工中土体的侧向变形监测技术研究工作。本文基于磁性矿物受荷载变形具有定向性特征，运用磁组构试验对无侧限压缩后的黏性土试样进行磁各向异性研究，同时与有侧限压缩试验变形测试结果进行比较，分析试验轴向应力、土样含水率对无侧限压缩条件下磁各向异性的影响规律，以及主磁化率值与应变的数学关系，探讨了由黏性土磁各向异性推求其受力变形规律的可行性。研究成果表明，受力作用的黏性土变形与其磁性矿物定向性具有较好的一致性。这一认识对于有效监测软土地区卸荷工程周围软土变形情况具有重要的理论意义和实际应用价值。
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| 关 键 词： | 无侧限压缩 侧向变形 含水率 磁各向异性 |
| 收稿时间： | 2020-07-27 |
A study of anisotropy of magnetic susceptibility of cohesive soil under unconfined compression |
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| SUN Qian,YAN Changhong,LIU Yang.A study of anisotropy of magnetic susceptibility of cohesive soil under unconfined compression[J].Hydrogeology and Engineering Geology,2021,48(1):123-130. |
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| Authors: | SUN Qian YAN Changhong LIU Yang |
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| Affiliation: | 1.School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu 210046, China2.Zijin College, Nanjing University of Science & Technology, Nanjing, Jiangsu 210023, China3.Guangzhou Urban Planning & Design Survey Research Institute, Guangzhou, Guangdong 510060, China |
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| Abstract: | In recent years,the unloading of excavation engineering activities such as foundation pits and tunnels has caused excessive lateral deformation of cohesive soil,which result in more and more engineering accidents.At present,the inclinometer is often used to monitor the horizontal displacement of the soil around the foundation pit.However,due to the special engineering properties of soft soil,the inclinometer cannot be driven to deform with the soft soil during monitoring.The effect of monitoring is often unsatisfactory and inaccurate to reflect the true deformation.Therefore,it is necessary to strengthen the research of lateral deformation monitoring technology of soil in the construction of excavation unloading engineering.In this paper,based on the directional characteristics of the deformation of magnetic minerals under loading,the magnetic fabric test is used to study the magnetic anisotropy of the cohesive soil sample after unconfined compression test and then to compare with the results of the confined one.The paper then discusses the mathematical relationship between the main magnetic susceptibility value and the strain as the consequence of the analysis of the influence of the axial stress and the moisture content of soil on the magnetic anisotropy under unconfined compression.Finally,the feasibility of the calculation of the law of force and the deformation from the magnetic anisotropy of the cohesive soil is explored.The research results show that the deformation of the cohesive soil under force has good consistency with its orientation of magnetic mineral.This understanding has important theoretical significance and practical application value for effectively monitoring the deformation of soft soil around unloading projects in soft soil areas. |
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| Keywords: | unconfined compression lateral deformation moisture content magnetic anisotropy |
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