软岩流变的一种新力学模型  

A new mechanical model for soft rock rheology

作　　者：陈沅江[1] 潘长良[1] 曹平[1] 王文星[1] 

机构地区：[1]中南大学资源与安全工程学院,湖南长沙410083

出　　处：《岩土力学》2003年第2期209-214,共6页Rock and Soil Mechanics

基　　金：国家"九.五"科技攻关项目(No. 96-116-01-01-02)

摘　　要：软岩在低应力水平下表现为弹性和粘弹性;在较高的应力水平下表现为弹性、塑性和粘弹性;在高应力水平下表现为弹性、塑性、粘弹性和粘塑性。为了对其进行全面描述,首先,提出了两种非线性元件-蠕变体和裂隙塑性体,并将它们和描述衰减蠕变特性的开尔文体及描述瞬弹性的虎克体相结合,得到了一种新的复合流变力学模型。然后,通过其采用的软岩蠕变的分级增量循环加卸载试验证明,该模型可很好地描述软岩在不同应力水平下的蠕变特性特别是裂隙闭合阶段和加速蠕变阶段的特性,可在工程实际中推广应用。Soft rock would display the characteristics of elasticity and viscoelasticity under low stress, of elasticity, plasticity and viscoelasticity under higher stress and of elasticity, plasticity, viscoelasticity and viscoplasticity under very high stress .In order to describe these characteristics comprehensively, firstly the paper brought forward two nonlinear components of creep body and plastic cranny body, and combined them with KELVIN body describing the deceleration creep and HOKE body describing the instantaneous elasticity to gain a new multiple rheological model .Then it used the model to simulate the results of the multi-step incremental cycling loading and unloading creep test of soft rock and drew a conclusion that the new model could effectively describe the creep properties of soft rock under different stress level ,especially the properties of the cranny-closed phase and the creep-accelerated phase so that it could be popularly used in engineering practice.

关 键 词：软岩 流变模型 蠕变 分级增量循环加卸载 力学试验 力学模型 塑性 粘弹性 

分 类 号：TU457[建筑科学—岩土工程]