The Haidong Tunnel is one of the four soft rock tunnels of the Central Yunnan Water Diversion Project(CYWDP),where large deformation hazards of soft rock occur frequently,which seriously affect construction safety.The...The Haidong Tunnel is one of the four soft rock tunnels of the Central Yunnan Water Diversion Project(CYWDP),where large deformation hazards of soft rock occur frequently,which seriously affect construction safety.The effect of highly prestressed anchor cable support was studied based on the active support test in the No.3 branch tunnel of Haidong Tunnel.Firstly,the geological conditions and failure causes were analyzed on the basis of the results of geological survey,in-situ test,and rock laboratory test.Then,the Mohr circle form of the highly prestressed anchor cable active support theory for the support of bedded rock mass was given in combination with the excavation compensation method.It is considered that the prestress active compensation value required for the bedded rock mass is larger than that for the homogeneous rock mass.The deformations of rock mass under both passive and active supports were analyzed by numerical simulations.Furthermore,the'pressure bubble'mechanical model for anchor cable support of bedded rock mass in Haidong Tunnel is given.Field monitoring results show that the highly prestressed anchor cable support can control rock mass deformation well,with a maximum deformation of about 200 mm.The prestressed anchor cable is effective in the bedded stratum,which makes the stress of rock mass uniform and reduces the risk of failure of steel arches due to local bias.Meanwhile,the expansion of plastic zone was efficiently controlled,which is of positive significance for the overall stability of rock mass.展开更多
为提高软岩大变形隧道预应力锚索的施工质量与施工速度,推进软岩大变形隧道机械化施工进程,依托木寨岭公路隧道,基于预应力锚索机械化施工关键技术研发,以实现预应力锚索钻、装、锚、拉一体化施工为突破口,通过悬臂掘进机、多功能锚索...为提高软岩大变形隧道预应力锚索的施工质量与施工速度,推进软岩大变形隧道机械化施工进程,依托木寨岭公路隧道,基于预应力锚索机械化施工关键技术研发,以实现预应力锚索钻、装、锚、拉一体化施工为突破口,通过悬臂掘进机、多功能锚索台车等大型关键设备构建软岩大变形隧道全机械化施工方法,于武都右线方向开展试验段研究。得出主要结论:1)预应力锚索机械化施工关键技术的研发与集成,实现了软弱破碎围岩预应力锚索高效、稳定施工,锚索施工质量显著提升,锚索有效预应力提高近100 k N;2)软岩大变形隧道全机械化施工方法转变了传统依靠人力的施工模式,施工质量、施工速度得以大幅提升,初期支护施工人员减少1/5,单个初期支护施工循环时间缩短近2 h,洞周收敛减小值最大达48.6%。展开更多
基金supported by the China Yunnan Province Major Science and Technology Special Plan Foundation Project(Grant No.202002AF080003)the China Railway No.5 Engineering Group Co.,Ltd.The support is greatly appreciated.
文摘The Haidong Tunnel is one of the four soft rock tunnels of the Central Yunnan Water Diversion Project(CYWDP),where large deformation hazards of soft rock occur frequently,which seriously affect construction safety.The effect of highly prestressed anchor cable support was studied based on the active support test in the No.3 branch tunnel of Haidong Tunnel.Firstly,the geological conditions and failure causes were analyzed on the basis of the results of geological survey,in-situ test,and rock laboratory test.Then,the Mohr circle form of the highly prestressed anchor cable active support theory for the support of bedded rock mass was given in combination with the excavation compensation method.It is considered that the prestress active compensation value required for the bedded rock mass is larger than that for the homogeneous rock mass.The deformations of rock mass under both passive and active supports were analyzed by numerical simulations.Furthermore,the'pressure bubble'mechanical model for anchor cable support of bedded rock mass in Haidong Tunnel is given.Field monitoring results show that the highly prestressed anchor cable support can control rock mass deformation well,with a maximum deformation of about 200 mm.The prestressed anchor cable is effective in the bedded stratum,which makes the stress of rock mass uniform and reduces the risk of failure of steel arches due to local bias.Meanwhile,the expansion of plastic zone was efficiently controlled,which is of positive significance for the overall stability of rock mass.
文摘为提高软岩大变形隧道预应力锚索的施工质量与施工速度,推进软岩大变形隧道机械化施工进程,依托木寨岭公路隧道,基于预应力锚索机械化施工关键技术研发,以实现预应力锚索钻、装、锚、拉一体化施工为突破口,通过悬臂掘进机、多功能锚索台车等大型关键设备构建软岩大变形隧道全机械化施工方法,于武都右线方向开展试验段研究。得出主要结论:1)预应力锚索机械化施工关键技术的研发与集成,实现了软弱破碎围岩预应力锚索高效、稳定施工,锚索施工质量显著提升,锚索有效预应力提高近100 k N;2)软岩大变形隧道全机械化施工方法转变了传统依靠人力的施工模式,施工质量、施工速度得以大幅提升,初期支护施工人员减少1/5,单个初期支护施工循环时间缩短近2 h,洞周收敛减小值最大达48.6%。
