Upper bound solution of surrounding rock pressure in deep tunnel cavity considering plastic zone below tunnel
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 coefficient λ1 and the bottom coefficient λ2 were introduced to derive the theoretical equations for calculating surrounding rock pressure.Optimization calculations were performed according to the equations.The effects of lateral coefficient λ1 and bottom coefficient λ2 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 coefficient λ1 can reduce the pressure at the bottom and vault,and increasing the bottom coefficient λ2 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.
deep tunnellimit analysissurrounding rock pressureupper bound solution
傅鹤林、易海东、胡凯巽、李鲒
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中南大学土木工程学院,湖南长沙,410075
深埋隧道 极限分析 围岩压力 上限解
国家自然科学基金资助项目National Natural Science Foundation of China
万方数据
维普
