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 引用本文: 陈云敏, 马鹏程, 唐耀. 土体的本构模型和超重力物理模拟[J]. 力学学报, 2020, 52(4): 901-915.
Chen Yunmin, Ma Pengcheng, Tang Yao. CONSTITUTIVE MODELS AND HYPERGRAVITY PHYSICAL SIMULATION OF SOILS[J]. Chinese Journal of Theoretical and Applied Mechanics, 2020, 52(4): 901-915.
 Citation: Chen Yunmin, Ma Pengcheng, Tang Yao. CONSTITUTIVE MODELS AND HYPERGRAVITY PHYSICAL SIMULATION OF SOILS[J]. Chinese Journal of Theoretical and Applied Mechanics, 2020, 52(4): 901-915.

## CONSTITUTIVE MODELS AND HYPERGRAVITY PHYSICAL SIMULATION OF SOILS

• 摘要: 数值模拟和物理模拟是分析土体沉降和稳定性的主要手段. 本构模型作为描述土体应力应变关系的数学表达式, 是数值模拟的基础. 土体具有碎散性, 这一基本物理特性导致了其具有压硬性、摩擦性和剪胀性, 这是土的力学特性区别于金属的主要特征, 在土体的本构模型中必须反映这3个基本特性. 传统土力学将土体的变形和强度分离考虑, 分别采用弹性理论和基于刚塑性模型的极限平衡理论分析, 虽然应用广泛, 但由于不能全面地反映土的基本力学特性, 计算结果的精度常常难以满足定量分析的需要. 剑桥模型作为第一个全面反映压硬性、摩擦性和剪胀性的弹塑性本构模型, 实现了变形和强度的统一, 能较好地描述饱和正常固结黏土的应力应变关系, 被视为是现代土力学的开端; 统一硬化模型通过引入一个独特的硬化参数进一步发展了剑桥模型, 将适用范围扩大到超固结黏土. 作者认为, 未来岩土体本构模型研究的挑战是: 如何考虑岩土体在受力过程中土骨架相变与多场耦合, 以解决目前本构模型尚无法定量分析的能源、交通、环境和水利相关的重大岩土工程问题. 超重力物理模拟具有缩尺效应和缩时效应, 克服了常重力物理模拟中模型的应力水平低于原型的缺点, 特别适用于大尺度、长历时问题的模拟. 相较数值模拟, 超重力物理模拟的优势在于能够检验本构模型的合理性, 揭示本构模型无法描述的未知特性. 最后, 介绍了采用数值模拟和物理模拟联合分析大直径钢管桩水平受荷特性的工程案例.

Abstract: Numerical simulation and physical simulation are two main methods to analyze the settlement and stability of soil mass. As the mathematical equations of the soil stress-strain relationships, constitutive models are the foundations of numerical simulation. Soil is a type of granular materials, leading to three essential characteristics of it including compressive hardening, shear dilatancy and friction. They are the main characteristics differing soils from metals and should be considered in constitutive model of soils. Traditional soil mechanics, which are widely applied in engineering at present, analyze the deformation and strength of soils separately by elastic theory and limit equilibrium theory based on rigid plasticity, respectively. However, the accuracy of their calculation results is generally difficult to satisfy the requirement of quantitative analysis because the essential characteristics of soils cannot be fully reflected. Cam-clay model is the first elasto-plastic constitutive model that can fully reflect the essential characteristics of soils. It unifies the deformation and strength of soils and can well describe the stress-strain relationships of normal consolidated clays; thus, Cam-clay model is regarded as the beginning of modern soil mechanics. Through introducing a unique unified hardening parameter, unified hardening model further develops the Cam-clay model and enlarges the application scope to over-consolidated clays. The authors believe that the challenge of constitutive model research in the future is how to consider the phase change of soil skeleton and the multi-field coupling in soils, to solve significant geotechnical problems in the field of energy, traffic, environment and hydraulic engineering, which cannot be analyzed quantitatively by current models. Due to the effects of scale compression and time compression, hypergravity physical simulation can overcome the disadvantage that stress level in small-scale model is lower than the prototype level in normal gravity physical simulation. Especially, hypergravity physical simulation is very appropriate to the problems of large scale and long duration. Compared with numerical simulation, hypergravity physical simulation has the advantages of being able to test the rationality of soil constitutive models and reveal the unknown features that cannot be described by current models. Finally, an engineering case of large-diameter steel pipe pile analyzed by combining numerical simulation and hypergravity physical simulation was presented.

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