于庆博, 王清, 李兴华. 2022. 土结构性的动态特征与概念表达[J]. 工程地质学报, 30(6): 1914-1928. doi: 10.13544/j.cnki.jeg.2022-0761.
    引用本文: 于庆博, 王清, 李兴华. 2022. 土结构性的动态特征与概念表达[J]. 工程地质学报, 30(6): 1914-1928. doi: 10.13544/j.cnki.jeg.2022-0761.
    Yu Qingbo, Wang Qing, Li Xinghua. 2022. Dynamic characteristics and concept expression of soil structure[J]. Journal of Engineering Geology, 30(6): 1914-1928. doi: 10.13544/j.cnki.jeg.2022-0761.
    Citation: Yu Qingbo, Wang Qing, Li Xinghua. 2022. Dynamic characteristics and concept expression of soil structure[J]. Journal of Engineering Geology, 30(6): 1914-1928. doi: 10.13544/j.cnki.jeg.2022-0761.

    土结构性的动态特征与概念表达

    DYNAMIC CHARACTERISTICS AND CONCEPT EXPRESSION OF SOIL STRUCTURE

    • 摘要: 随着国家重大工程的开发建设,大量的基础工程应运而生,部分结构物对地基土变形问题尤为敏感,需要专门研究以确保重大工程安全。然而,土体的天然的结构性与固结状态的差异,不仅会对土体的压缩特性和相关力学指标产生重要影响,也给变形的分析与沉降计算带来挑战。厘清土的结构性与固结状态的表现形式,探讨两者之间的辩证关系,将对工程实践有一定的实际意义。基于课题组多年研究成果,立足于土的侧限压缩特征,本文着重分析了土体反常“超固结”特征的成因机制,讨论了结构性的动态变化,并尝试给出了结构性的概念表达。初步得到以下几点认识:(1)土的结构性产生的实质包括颗粒排列和结构连结两方面要素。颗粒排列的紧密程度代表固相成分的空间分布特征,是包括固结压力在内的多种作用力的合并体现;结构连结是土颗粒间相互作用力的总和,其在侧限压缩条件下,主要表现为抵抗变形的结构强度。一般来说,所有土均有不同程度的结构性,包括原状土与重塑土;(2)土的颗粒排列和结构连结存在动态的耦合关系。土体与应力历史不符的“超固结”性质正是来自结构连结对土骨架的差异“强化”以及除自重荷载外其他作用力对土体的压密作用;(3)提出了考虑附加排列效应ΔPa的结构屈服压力σk的概念表达形式,即σk=PcPa+qPc与ΔPa共同反映颗粒排列特征,由q反映结构强度。相关成果可能为土体力学特性的评价与分析提供一些参考。

       

      Abstract: With the development and construction of national major projects,a large number of foundation projects emerged as the times require. Some structures are particularly sensitive to the deformation of foundation soil,which requires special research to ensure the safety of related projects. However,the differences of the natural structure and consolidation state of soil can not only present an important impact on the compression characteristics and relevant mechanical indicators of soil,but also bring challenges to the analysis of deformation and settlement calculation. It would be of certain practical significance for engineering practice to clarify the combined manifestation of soil structure and consolidation state,and to discuss the dialectical relationship between them. Based on the previous studies of research group,as well as the confined compression characteristics of soil,this paper analyzes the mechanism of the abnormal 'over-consolidation' characteristics of soil,discusses the dynamic changes of the structure,and attemptes to give the concept pattern of soil structure. The following preliminary understandings are presented:(1)The essence of soil structure includes particle arrangement and structural connection. The compactness of particle arrangement reflects the spatial distribution of solid components,which is considered as the combined embodiment of multiple forces including consolidation pressure. The structural connection refers to the sum of the interaction forces between soil particles,which is characterized as the structural strength to resist deformation during confined compression. Generally speaking,all soils including undisturbed soil and remolded soil have different degrees of structure. (2)There is a dynamic coupling relationship between particle arrangement and structural connection of soil. The ′over-consolidation' property of soil,inconsistent with the stress history,results from the differential ′strengthening' derived by structural connection to soil skeleton. In addition,the compaction of soil derived by other forces except self-weight also plays an important role. (3)The concept expression of structural yield pressure σk,considering additional arrangement effect ΔPa,is proposed,i. e. σk=PcPa+q. Pc and ΔPa jointly reflect the particle arrangement characteristics,and q represents the structural strength. The related results may provide some reference for the evaluation and analysis of soil mechanical properties.

       

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