基于无网格算法对隧道围岩弹塑性分析

Analysis on Meshless Algorithm of Tunnel Surrounding Rock Elastic-plastic

通过引入广义粒子动力学数值法模拟隧道围岩的弹塑性变形特征,应用于隧道围岩模型结构分析中,确定隧道围岩不同侧压系数下的塑性区和应力场。研究结果表明:随水平应力的提高,隧道围岩塑性区从两帮朝顶部和底部方向转移。当λ<2.0时,随水平应力提高,顶部和底部塑性区宽度开始增加,当λ>2.0时,塑性区从顶底部向两肩和底角区域扩展,导致隧道稳定性突降;随洞壁距离的增加,隧道切向应力表现出一个先递增后下降的变化趋势,径向应力呈现出逐级递增,并在不同洞壁距离处获得原岩应力状态;隧道顶板和边墙水平位移随着λ的增大而不断增大,在λ<1.0情况下,顶底板总位移相较于隧道围岩边墙位移要大;当λ>1.0时,边墙总位移较围岩顶底板位移大;在剪胀角增加的过程中,塑性变形区也在不断的增加,围岩承载力也获得了一定幅度的增加。

in this p a p e r, by introducing the generalized particle dynamics numerical me t h o d tosimulate the elastic-plastic deformation characteristics of surrounding rock , used in the structural analysismodel of tunnel surrounding rock , determine the surrounding rock under difcients of stress field and plastic zone. T h e results show that the increarock plastic zone from two sides m o v e towards the top and bottom. Whe n A 〈 2. 0 , along with the hori-zontal stress , the plastic zone width at the top and bottom began to increase , when A 〉 2. 0 , the plastic zone from the bottom of the top two shoulders and expanding the base area , lead to stability of tunnel fellsharply ; With the increase of the distance of the cave walls , tunnel tangential stress showed a declining trend after increasing first , radial stress presents increasing step by step , and in different distance from the original tunnel wall rock stress state; T h e tunnel roof and wall , horizontal displacement is increasingwith the increase of the A 〈 1. 0 cases , the total displacement of roof and floor compa r e d with larger dis-placement of tunnel surrounding rock wall ; Whe n A 〉 1.0 , the sidewall is total displacement of sur-rounding rock displacement of roof and floor is big; In the process of dilatancy Angle tic deformation area has been increased , the amplitude of the bearing capacity of surrounding rock hasgained a certain increase.