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A novel constitutive model with plastic internal and damage variables for brittle rocks
Engineering Fracture Mechanics ( IF 4.7 ) Pub Date : 2021-04-08 , DOI: 10.1016/j.engfracmech.2021.107731
Chonghong Ren , Jin Yu , Yanyan Cai , Wei Yao , Yongming Lai , Bobo Li

The damage evolution and plastic flow are usually coupled for rocks due to heterogeneity, which is significant for the design and construction of underground structures. In this paper, a novel damage model considering the plastic strain is proposed for rocks. The novelty of the model lies in the damage evolution associated with the plastic flow, which incorporates double variables (damage and plastic internal variables). The damage model consists of three parts, i.e., the stress-strain, cohesive force and dilation angle functions. In these functions, the plastic strain and plastic internal variable follow the Weibull distribution. In the cohesive force and dilation functions, the damage variable can be modified by the plastic internal variable, since the plastic strain is defined as the plastic internal variable. This is a key point in this paper. To validate this model, tri-axial experimental data of different types of rocks under different confining pressures are reported. It was found that the results obtained by the proposed model yield good agreements with the experimental data in most cases, except for a situation of a long stress platform in the strain-softening stage. Characteristics of deformation, strain-hardening/softening, and dilation are controlled by model parameters, which can be determined using the experimental data of yield strength, peak strength and residual strength points. As these parameters are not difficult to obtain, the proposed model can be widely used in underground engineering.



中文翻译:

具有塑性内部和损伤变量的脆性岩石本构模型

由于异质性,岩石的损伤演化和塑性流通常是耦合的,这对于地下结构的设计和施工具有重要意义。本文提出了一种考虑塑性应变的新型岩石损伤模型。该模型的新颖之处在于与塑性流动相关的损伤演化,其中包括双重变量(损伤和塑性内部变量)。损伤模型由三部分组成,即应力应变,内聚力和膨胀角函数。在这些函数中,塑性应变和塑性内部变量遵循Weibull分布。在内聚力和膨胀函数中,损伤变量可以通过塑性内部变量来修改,因为塑性应变被定义为塑性内部变量。这是本文的重点。为了验证该模型,报道了在不同围压下不同类型岩石的三轴实验数据。发现在大多数情况下,除了在应变软化阶段应力平台较长的情况外,所提出的模型获得的结果与实验数据吻合良好。变形,应变硬化/软化和膨胀的特性由模型参数控制,这些参数可以使用屈服强度,峰值强度和残余强度点的实验数据来确定。由于这些参数并不难获得,因此该模型可广泛应用于地下工程。发现在大多数情况下,除了在应变软化阶段应力平台较长的情况外,所提出的模型获得的结果与实验数据吻合良好。变形,应变硬化/软化和膨胀的特性由模型参数控制,这些参数可以使用屈服强度,峰值强度和残余强度点的实验数据来确定。由于这些参数并不难获得,因此该模型可广泛应用于地下工程。发现在大多数情况下,除了在应变软化阶段应力平台较长的情况外,所提出的模型获得的结果与实验数据吻合良好。变形,应变硬化/软化和膨胀的特性由模型参数控制,这些参数可以使用屈服强度,峰值强度和残余强度点的实验数据来确定。由于这些参数并不难获得,因此该模型可广泛应用于地下工程。可以使用屈服强度,峰值强度和残余强度点的实验数据确定。由于这些参数并不难获得,因此该模型可广泛应用于地下工程。可以使用屈服强度,峰值强度和残余强度点的实验数据确定。由于这些参数并不难获得,因此该模型可广泛应用于地下工程。

更新日期:2021-04-21
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