考虑底部塑性区的深埋隧洞围岩压力上限解  

Upper bound solution of surrounding rock pressure in deep tunnel cavity considering plastic zone below tunnel

作　　者：傅鹤林[1] 易海东 胡凯巽 李鲒 FU Helin;YI Haidong;HU Kaixun;LI Jie(School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075

出　　处：《中南大学学报（自然科学版）》2024年第7期2625-2634,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51978668)。

摘　　要：基于极限分析理论,提出一种适用于软弱围岩的深埋隧道围岩压力的计算方法。考虑隧道底部塑性变形区的影响,构建纺锤形的破坏模型。基于该破坏模型构建围岩速度场,引入侧压系数λ_(1)和底压系数λ_(2),推导围岩压力的理论计算公式。根据计算公式进行编程优化计算,分析不同非线性系数m下,侧压系数λ_(1)、底压系数λ_(2)对围岩压力的影响。研究结果表明:随着内摩擦角减小,“纺锤”上下两端塑性区不断向外延伸;非线性系数m对围岩压力有显著影响,当非线性系数一致时,提高侧压系数λ_(1)可以降低拱顶和隧道底部压力,提高底压系数λ_(2)可以降低拱顶和边墙压力;在岩土体非线性特征明显的地区,计算深埋隧洞围岩压力时应考虑底部塑性区。A calculation method for surrounding rock pressure of deep tunnels suitable for weak surrounding rock was proposed based on the limit analysis theory.Considering the influence of plastic deformation zone below tunnel,a spindle-shaped calculation model was constructed,and velocity field of this model was constructed.The lateral coefficientλ_(1) and the bottom coefficientλ_(2) were introduced to derive the theoretical equations for calculating surrounding rock pressure.Optimization calculations were performed according to the equations.The effects of lateral coefficientλ_(1) and bottom coefficientλ_(2) on surrounding rock pressure were analyzed at different nonlinear coefficients m.The results indicate that the damage area at the top and bottom of the"spindle"extends outward when the internal friction angle decreases.The nonlinear coefficient m has obvious influence on the surrounding rock pressure.When the nonlinear coefficients are consistent,increasing the lateral coefficientλ_(1) can reduce the pressure at the bottom and vault,and increasing the bottom coefficientλ_(2) can reduce the pressure at the vault and side wall.In the area with obvious nonlinear characteristics of surrounding rock,the plastic zone below tunnel should be considered in calculation.

关 键 词：深埋隧道 极限分析 围岩压力 上限解 

分 类 号：U45[建筑科学—桥梁与隧道工程]