摘要
为更好地描述砂土力学行为的围压相关性,首先,分析总结了砂土基本力学特性随围压的变化规律:随围压的降低,砂土基本力学性质表现出更为强烈的围压依赖性,临界状态应力比由常量变为随围压敏感的变量,剪胀也由随围压平缓变化转变为急剧增加。随后,在黏土和砂土的统一硬化模型(unified hardening model for cloy and sand,CSUH模型)的理论框架下,引入了咬合应力参数以描述临界状态的强度特征;提出了非耦合塑性体应变的概念,从微观层面解释了低围压下强剪胀的机制,在分析围压对压剪耦合影响规律的基础上,构造了非耦合塑性体应变的表达式,继而建立了一个可细化描述围压效应的砂土统一硬化(unified hardening,UH)模型。相较于CSUH模型,考虑围压效应的UH模型仅增加了两个参数,且参数易于确定。最后,通过与试验数据、CSUH模型预测结果对比,验证了所建立模型的合理性及适用性。
This paper intends to describe the confining pressure correlation of the mechanical behavior of sand in a reasonable way.Firstly,the relationship between the mechanical properties of sand and the confining pressure is analyzed and summarized.As the confining pressure decreases,the basic mechanical properties of sand show a stronger confining pressure dependence,the critical state stress ratio changes from a constant to a sensitive variable with the confining pressure,and the dilatancy changes from gentle to a sharp increase.Then,under the theoretical framework of unified hardending model for clays and sand,namely CSUH model,the occlusal stress parameters are introduced to describe the critical state strength characteristics.The concept of uncoupled plastic volumetric strain is proposed,and the mechanism of strong dilatation under low confining pressure is explained from the microscopic level.Based on the analysis of the influence of confining pressure on compression-shear coupling,the expression of uncoupled plastic volumetric strain is constructed,and then a unified hardening(UH)model of sandy soil which can consider the confining pressure effect is established.Compared with CSUH model,UH model considering confining pressure effect only adds two parameters,and the parameters are easy to determine.Finally,the rationality and applicability of the model are verified by comparing with the experimental data and the prediction results of CSUH model.
作者
王宁博
姚仰平
刘林
李翔宇
毛安琪
李宁
WANG Ning-bo;YAO Yang-ping;LIU Lin;LI Xiang-yu;MAO An-qi;LI Ning(China Academy of Building Research,Beijing 100013,China;State Key Laboratory of Building Safety and Environment,China Academy of Building Research,Beijing 100013,China;Beijing Engineering Technology Research Center of Foundation and City Underground Space Development and Utilization,CABR Foundation Engineering Co.,Ltd.,Beijing 100013,China;School of Transportation Science and Engineering,Beihang University,Beijing 100083,China)
出处
《岩土力学》
北大核心
2025年第S1期297-308,共12页
Rock and Soil Mechanics
基金
中国建筑科学研究院有限公司青年科研基金(No.20241602331030015)
建研地基基础工程有限责任公司青年科研基金(No.20241602341030001)
