围岩塑性区不同弹性应变对隧道位移的影响

Influence of Different Elastic Strains in Plastic Zone of Surrounding Rock on Tunnel Displacement

为了研究围岩塑性区不同弹性应变对隧道位移的影响,基于弹脆塑性模型和统一强度理论,采用两种情况下塑性区弹性应变推导了围岩弹性区、塑性区的应力和位移以及塑性区半径,并以硬岩和软岩为例分析了不同弹性应变下的脆性软化和剪胀特性参数对隧道洞壁径向位移的影响。研究结果表明:在塑性区弹性应变为常数(即情况1)和塑性区弹性应变采用广义胡克定律确定(即情况2)时,洞壁处径向位移均随残余黏聚力的增大而减小,并且情况2求得的洞壁处径向位移均大于情况1;在情况1和情况2两种情况下时,洞壁处径向位移随剪胀特性参数的增大而线性增大,并且两种情况下洞壁处径向位移和剪胀特性参数变化曲线几乎平行。

In order to study the influence of different elastic strains in the plastic zone of surrounding rock on tunnel displacement,based on the elastic-brittle-plastic model and the unified strength theory,the stress and displacement of the elastic zone,the plastic zone and the radius of the plastic zone of surrounding rock were derived using the elastic strains of the plastic zone in two different cases.Taking hard rock and soft rock as examples,the influence of brittle softening and dilatancy characteristic parameters under different elastic strains on radial displacement of tunnel wall is analyzed.The results show that when the elastic strain in plastic zone is constant(i.e.Case 1)and the elastic strain in plastic zone is determined by generalized Hooke's law(i.e.Case 2),the radial displacement at the wall decreases with the increase of residual cohesive force,and the radial displacement at the wall obtained in Case 2 is larger than that in Case 1;In both cases 1 and 2,the radial displacement at the wall increases linearly with the increase of dilatancy characteristic parameters,and the curves of radial displacement and dilatancy characteristic parameters at the wall are almost parallel.