【摘要】 将小净距隧道中岩柱塑性区不重叠的极限塑性区半径定义为塑性区贯穿半径,考虑中间主应力的影响,采用统一强度准则和Schwarz交替法,对小净距隧道的弹塑性状态进行分析,推导小净距隧道塑性区半径的解析表达式.通过算例,分析中间主应力、内摩擦角和黏聚力对理论解的影响.结果表明:当两隧道净距大于2.3倍的开挖半径时,两隧道之间的相互作用较小,塑性区半径趋于一个稳定值,稳定值比单孔隧道塑性区半径大17.7%,可近似按照单孔隧道进行处理;小净距隧的塑性区贯穿半径随着统一强度参数、内摩擦角和黏聚力的增大而减小;与同不考虑中间主应力作用相比,考虑中间主应力作用的塑性区贯穿半径减小9.19%~20.71%,充分发挥围岩的强度性能.更多还原

【Abstract】 The radius of the limit plastic zone without overlapping the plastic zone in the small spacing tunnel is defined as connected radius of the rock plastic zone.Taking account of the influence of intermediate principal stress,the small spacing tunnels’elastic-plastic state is analyzed by the unified strength theory and Schwarz alternating method,and the analytical expression of small spacing tunnels’ plastic zone is deduced.Through the example,the influence of the intermediate principal stress,internal friction angle and cohesion on the theoretical solution is analyzed.The analysis result shows that:when the net space between two tunnels is 2.3 times greater than excavation radius of two tunnels,the interaction between two tunnels is small and the radius of the plastic zone tends to be a stable value.The stability value is 17.7% greater than the radius of the plastic zone of a single-hole tunnel,each of two tunnels can be treated as a single-hole tunnel.The connected radius of the rock plastic zone in small spacing tunnels decreases with increase of the unified strength parameters,the cohesive force and the angle of internal friction.The connected radius of the rock plastic zone in small spacing tunnels considering the intermediate principal stress’effect decreases by 9.19%-20.71%,so consideration of the intermediate principal stress is conducive to the exertion of the surrounding rock strength.更多还原