能源桩是利用地热能的一种新型建筑节能技术,工作时会使桩周土温度发生变化,在黄土地区施作时,会直接影响黄土结构性,进而影响黄土的力学特性,因此研究变温条件下结构性黄土的变化规律具有重要意义。通过对不同温度下结构性黄土进行三轴剪切试验和核磁共振试验,研究温度对结构性黄土变形和强度的影响;基于现有黄土统计损伤理论,假定黄土微元强度服从Weibull分布,利用应变等效性假说,构建了结构性黄土在高温作用下的统计损伤本构模型;利用室内试验对该模型进行验证。结果表明:Weibull分布参数m和F0影响结构性黄土损伤本构模型的曲线形状;建立的黄土统计损伤本构模型能够很好地反映结构性黄土颗粒骨架的损伤,有效预测结构性黄土在剪切作用下的结构损伤变形。研究成果可为后续的工程建设提供理论基础。
Abstract
Energy pile is a novel geothermal-based energy-saving building technology that induces temperature changes in the surrounding soil. In loess areas,the implementation of energy pile directly impacts the structural properties of the loess,subsequently affecting its mechanical characteristics. Hence,it is crucial to investigate the variations in loess structure under changing temperature.We examined the influence of temperature on the deformation and strength of structural loess through triaxial shear tests and NMR tests conducted at varying temperature. Based on the existing statistical damage theory of loess, we develop a statistical damage constitutive model for structural loess subjected to high temperatures. This model assumes a Weibull distribution for the strength of loess microelements and employs the strain equivalence hypothesis. Indoor experiments validate the model, demonstrating its ability to comprehensively capture the damage to the particle skeleton of structural loess and accurately predict its deformation under shear forces.Weibull distribution parameters,such as m and F0,affect curve shape of the model.The findings of this study provide vital theoretical underpinnings for subsequent engineering designs and constructions.
关键词
结构性黄土 /
Weibull分布 /
温度变化 /
围压 /
结构损伤
Key words
structural loess /
Weibull distribution /
temperature change /
confining pressure /
structural damage
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基金
西安市岩土与地下工程重点实验室开放基金项目(2060521002)
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