高地应力地下厂房预应力锚索预紧系数  

Pre-load factor of the pre-stressed anchor cable in underground powerhouse with high geo-stress

作　　者：张建海[1,2] 王仁坤[3] 周钟[3] 郑路 张茹[1,2] 谢和平[1,2] ZHANG Jian-hai1,2, WANG Ren-kun3, ZHOU Zhong3, ZHENG Lu4, ZHANG Ru1,2, XIE He-ping1,2(1. College of Water Resources ＆ Hydropower, Sichuan University, Chengdu, Sichuan 610065, China; 2. State Key Laboratory of Hydranlics and Mountain River and Protection Engineering, Sichuan Universi .ty, Chengdu, Sichuan 610065, China; 3. Chengdu Engineering Corporation Limited, PowerChina, Chengdu, Sichuan 610072, China; 4. Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, Sichuan 610065, Chin)

机构地区：[1]四川大学水利水电学院,四川成都610065 [2]四川大学水力学及山区河流开发与保护国家重点实验室,四川成都610065 [3]中国电建成都勘测设计研究院有限公司,四川成都610072 [4]四川大学灾后重建与管理学院,四川成都610065

出　　处：《岩土力学》2018年第3期1002-1008,共7页Rock and Soil Mechanics

摘　　要：为了有效控制围岩大变形,避免围岩破坏,常常对围岩变形突出的高边墙、洞室交叉口区域采用预应力锚索加固。目前,对于具有时效变形特征的高地应力、低强度应力比的地下厂房锚索预紧力相关研究尚较少报道。以锦屏一级水电站地下厂房为代表的高地应力地下厂房,在围岩开挖过程中表现出显著的时效变形特征,从而导致锚索、锚杆内力持续增加,甚至内力超出强度极限而破坏。为合理设置锚索预紧力,基于围岩时效变形特征,提出了围岩时效释放荷载计算方法,并推导了预应力锚索预紧系数计算公式。该公式可以解释不同地应力环境以及不同支护强度、不同施锚时间对锚索预紧力的影响。与锦屏一级地下厂房锚索预紧系数实际采用值对比分析可见,所提出的预紧系数公式较为合理,具有工程实践指导作用。To avoid the damage of surrounding rock, pre-stressed anchor cables are installed in high side-wall and cavern intersection area to control the large deformation of surrounding rock. However, research is seldom performed on estimating the pre-load of cables in underground powerhouse with high geo-stress and low strength-stress ratio in the previous literature. Jinping-I hydro-power station is recognised as a typical high geo-stress underground powerhouse. Its cavern exhibits remarkable time-dependent deformation during excavation, which may result in the continuous increase of the inner force of the anchor cable and bars, even the strength failure. To determine an appropriate pre-load, a procedure is proposed for calculating the time-dependent released load of surrounding rock, based on their deformation characteristics. At the same time, a formula is deduced to calculate the pre-load factor of pre-stressed anchor cable. This established formula considers the influences of geo-stress, anchorage force and installation time on the pre-load factor. Comparing the actual values with the theoretical values of pre-load factor of Jinping-I underground powerhouse, the result indicates that the established calculation formula for the pre-load factor is reasonable and can be referenced in practical underground engineering.

关 键 词：预紧系数 高地应力 地下厂房 预应力锚索 锦屏一级水电站 

分 类 号：TU761.4[建筑科学—建筑技术科学]