摘要
围岩脆性破坏是一种常见的破坏形式。不同数值方法模拟的结果往往不同。因此,有必要研究不同方法对于模拟围岩脆性破坏特征的适用性。首先,在连续方法中,推导了改进应力跌落模型中残余应力的计算公式,解除了传统应力跌落模型中强度参数变化量的关联性,并通过模拟单轴压缩试验进行了验证。然后,采用连续方法(方法 1)及连续-非连续方法(方法 2)模拟了静水压力条件下圆形隧道围岩脆性破坏特征。最后,以太平驿隧道为工程背景,采用两种方法模拟了非静水压力条件下围岩的脆性破坏特征。研究发现,在静水压力条件下,采用两种方法均可获得与现场观测或室内试验类似的结果,但采用方法 1获得的破坏区范围更大。在非静水压力条件下,虽然方法 1的结果与太平驿隧道围岩脆性破坏的现场观测结果有相似之处,但方法 2的结果与现场观测结果更为接近。上述结果可能是由于在方法 1中,围岩破坏后仍为连续介质,有利于岩块之间的应力传递,从而利于破坏区的发展;在方法 2中,围岩开裂后转变为非连续介质,接触力和摩擦力反映了岩块之间的相互作用,消耗了系统能量,从而限制了开裂区的发展。
Brittle failure is usually observed during excavation of surrounding rock,while the simulation results of brittle failure often vary with numerical methods.Therefore,it is highly important to study the applicability of different numerical methods to simulate brittle failure characteristics of surrounding rock.Firstly,in the continuous method,the calculation formula of residual stress in the improved stress drop model is deduced,which removes the correlation of the change of strength parameters in the traditional stress drop model,and is verified by simulated uniaxial compression test.Then,the continuum method(method 1) and the continuum-discontinuum method(method 2) were used to simulate brittle failure characteristics of circular tunnel surrounding rock under hydrostatic pressure.Finally,taking Taipingyi tunnel as an application example,two methods were used to simulate brittle failure characteristics of circular tunnel surrounding rock under non-hydrostatic pressure.It is found that under hydrostatic pressure,the results obtained by both methods are similar to those obtained by the field observation or laboratory experiments,while the failure zones obtained by method 1 is larger.Under non-hydrostatic pressure,although the result obtained by method 1 is similar to that obtained by field observation of surrounding rock failure of the Taipingyi tunnel,the results obtained by method 2 are closer to that by the field observation.This phenomenon could be explained as follows.In method 1,the surrounding rock is still a continuous after failure,which is conducive to stress transfer between rock blocks,thus facilitating the development of failure zones;while in method 2,the surrounding rock is converted into a discontinuum after cracking,and the contact and friction forces reflect the interaction between rock blocks and consume the system energy,thus limiting the development of cracking zones.
作者
马冰
王学滨
田锋
MA Bing;WANG Xue-bin;TIAN Feng(College of Mechanics and Engineering,Liaoning Technical University,Fuxin,Liaoning 123000,China;Institute of Computational Mechanics,Liaoning Technical University,Fuxin,Liaoning 123000,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2021年第12期3440-3450,共11页
Rock and Soil Mechanics
基金
国家自然科学基金(No.51874162)。
关键词
脆性破坏
应力跌落
连续方法
连续-非连续方法
接触力
摩擦力
brittle failure
stress drop
continuum method
continuum-discontinuum method
contact force
friction force
