考虑蠕变剪裂的拉格朗日元与离散元耦合方法及应用  

Lagrangian-discrete element method considering creep shear cracking and its application

作　　者：王学滨 陈双印[2] 郑一方 廖裴彬 WANG Xue-bin;CHEN Shuang-yin;ZHENG Yi-fang;LIAO Pei-bin(Institute of Computational Mechanics,Liaoning Technical University,Fuxin,Liaoning 123000,China;College of Mechanics and Engineering,Liaoning Technical University,Fuxin,Liaoning 123000,China)

机构地区：[1]辽宁工程技术大学计算力学研究所,辽宁阜新123000 [2]辽宁工程技术大学力学与工程学院,辽宁阜新123000

出　　处：《岩土力学》2025年第2期613-624,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.52474101)。

摘　　要：随着煤炭开采向深部转移,巷道冒顶、底臌和两帮移进等软岩大变形问题层出不穷,对煤矿安全生产带来了严峻的挑战。目前,兼具连续方法和非连续方法优势的连续-非连续方法正在快速发展,然而,基于连续-非连续方法的蠕变研究尚少见报道。为了模拟蠕变剪裂现象,以岩石发生蠕变破坏时的应变位于三轴压缩应力-应变曲线峰后区域内这一试验现象为基本依据,在自主开发的拉格朗日元与离散元耦合连续-非连续方法中,考虑了单元的黏弹性,发展了能模拟界面黏塑性的蠕变剪裂模型,并引入了蠕变剪裂判据。单轴压缩岩样的蠕变曲线计算结果与试验结果基本相符,蠕变剪裂开始稍后,岩样即进入加速蠕变阶段,这表明所提出的方法具有模拟加速蠕变的潜力。针对软岩巷道的计算表明,在深部围岩的推挤作用下,离散块体涌向巷道,导致巷道断面急剧缩小,在宏观上表现为大变形,巷道竖直方向收缩率可达58.8%。从单元的黏弹性和界面(虚拟裂纹面)的黏塑性两方面,丰富了软岩巷道大变形机制,即介质的黏弹性小变形、块体的大位移及之间的空隙以及界面的黏塑性变形共同作用。巷道围岩宏观上的大变形无须采用复杂大变形理论即可描述。As mining depth increases,the large deformation of soft rock,such as roof fall,floor heave and two-side movement of the tunnel,poses a severe challenge to safe mining.Currently,continuous-discontinuous methods,combining advantages of both continuous and discontinuous methods,are rapidly developing.However,creep has not yet been introduced into these methods.Based on the experimental phenomenon that rock creep failure strain occurs in the post-peak region of the triaxial compression stress-strain curve,the viscoelasticity of the element is considered.A creep shear cracking model is developed to account for the viscoplasticity of the interface,and a criterion of creep shear cracking is introduced into the combined Lagrangian-discrete element method(a kind of continuous-discontinuous method)to simulate the creep shear cracking.The calculated creep curve under uniaxial compression aligns closely with experimental results.Once creep shear cracking begins,the specimen enters the accelerated creep stage.The proposed method has the potential to simulate accelerated creep.Results of the soft rock tunnel indicate that discrete blocks move into the tunnel due to the pushing of deep rock,sharply reducing tunnel size.Macroscopically,the tunnel exhibits a large deformation.The tunnel’s vertical shrinkage rate can reach 58.8%.The mechanisms of large deformation in the soft rock tunnel,attributed to the viscoelasticity of the element and the viscoplasticity of the interface(fictitious crack surface),result from a combination of small viscoelastic deformation of the medium,large block displacement,and viscoplastic deformation of the interface.It is unnecessary to describe the tunnel’s macroscopic large deformation using complex large deformation theories.

关 键 词：软岩 蠕变 大变形 巷道围岩 连续-非连续方法 黏弹性 剪裂 

分 类 号：TU451[建筑科学—岩土工程]