深埋隧洞三岔口围岩稳定性计算理论

来源期刊:中南大学学报(自然科学版)2019年第8期

论文作者:饶军应 谢财进 赵霞 刘灯凯 聂崇欣 刘宁

文章页码:1949 - 1960

关键词:深埋隧洞;三岔口;围岩应力;弹塑性理论;圆形孔口应力

Key words:deep tunnel; divergence; surrounding rock stress; elastoplastic theory; circular orifice stress

摘    要:为研究辅洞与隧洞主洞相交的三岔口区围岩稳定性,基于弹塑性理论圆形孔口应力计算方法,推导出深埋隧洞三岔口围岩稳定性计算理论。研究结果表明:当辅洞与隧洞主洞夹角( )为90°时,三岔口区围岩垂直应力σh达最大值,且σh随α和侧压力系数λ减小而减小;随着塑性圈半径R0减小,σh逐渐增大;由三岔口围岩到深部围岩,其应力集中系数K呈下降趋势;随着α增大,K也逐渐增大,直至α=90°时,K达到最大值;随着围岩等级降低,破坏深度Q逐渐增加,Ⅰ~Ⅳ级围岩三角区破坏深度递增趋势不明显,Ⅴ级围岩中破坏深度呈指数形式增加;当α一定时,理论最大等效跨度Ltmax仅与隧洞尺寸有关,极限等效跨度Lpmax还与Q有关;通过理论计算划定辅洞修建跨度的安全范围与极限范围。

Abstract: In order to study the stability of the surrounding rock in the divergence area, based on elastoplastic theory, the calculation theory of the surrounding rock stability of the divergence deep tunnel was derived. The results show when the hole angle (α) of auxiliary tunnel and tunnel main is 90 °, the vertical stress σh of the surrounding rock in divergence reaches the maximum value, and σh decreases with the decrease of α and side pressure coefficient λ. As the circle radius R0 decreases, σh increases gradually. The stress concentration factor K decreases from the surrounding rock of divergence to the deep surrounding rock. As α increases, K also increases. When α is 90°, K reaches the maximum value. As the surrounding rock grade decreases, the depth of failure Q increases gradually. The depth of damage of the I~IV surrounding rock triangle is not obvious. The depth of damage in the V-class surrounding rock increases exponentially. When α is constant, the theoretical maximum equivalent span Ltmax is only related to the tunnel size. The limit equivalent span Lpmax is also related to Q, and the safe range and limit range of the auxiliary tunnel construction span are delineated by theoretical calculation.

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