摘要
【目的】抽水蓄能电站输水系统竖井经常遇到硬-软-硬复合地层,为应对在高外水压力作用下,竖井软岩段开挖过程中出现大变形、支护压力较大等稳定性问题开展本研究。【方法】以某穿越砂砾岩层输水系统竖井为例,采用数值模拟方法分析了竖井区域地应力场分布,以及有、无支护措施下竖井围岩变形、应力和塑性区特征,评价支护措施的合理性,并分析运行期高外水压力作用下支护应力演变特征。【结果】地层由硬岩转变为软岩时,竖井最大主应力减小,之后随埋深逐渐增大,砂砾岩段最大主应力以自重应力为主。采取支护措施后,竖井围岩径向位移、竖向位移和塑性区显著减小,围岩受开挖影响范围由约3倍洞径减小为1倍洞径。【结论】锚杆、混凝土衬砌等的支护应力均在设计范围内,运行期高外水压力下竖井也可以安全运行。研究结果对于竖井穿越软岩地层的开挖支护设计及长期有效运行具有重要参考价值。
【Objective】The shaft of the water conveyance system of pumped storage power station often encounters the hardsoft-hard composite formation.To avoid stability problems such as large deformation and excessive support pressure during excavation of the soft rock section under high external water pressure,this study is conducted.【Methods】Taking a vertical shaft of the water conveyance system passing through sandy conglomerate as an example,the distribution of the in situ stress field in the vertical shaft region and the deformation,stress,and plastic zone characteristics of the surrounding rock of the vertical shaft with or without support measures were analyzed by numerical simulation.The appropriateness of support measures was evaluated and the evolution characteristics of support stress under high external water pressure during operation were analyzed.【Results】When the formation changed from hard rock to soft rock,the maximum principal stress of the shaft decreased and then gradually increased with the burial depth.The maximum principal stress of the sandy conglomerate was mainly selfweight stress.After the support measures were taken,the radial and vertical displacements and plastic zone of surrounding rock of the shaft were significantly reduced,and the affected area of surrounding rock was reduced from about three times the hole diameter to one hole diameter.【Conclusion】The support stresses,such as those of anchor rods and concrete lining,are all within the design range,and the shaft can operate safely under high external water pressure during operation.This study provides important reference value for excavation support design and long-term safe operation of shafts through soft rock stratum.
作者
臧东升
裴书锋
魏福泽
曹冉
刘天鹏
刘佳
曾凤娟
ZANG Dongsheng;PEI Shufeng;WEI Fuze;CAO Ran;LIU Tianpeng;LIU Jia;ZENG Fengjuan(College of Geosciences and Engineering,North China University of Water Resources and Electric Power,Zhengzhou 450046,China;POWERCHINA Hebei Electric Power Engineering Co.,Ltd.,Shijiazhuang 050031,China;Hebei Electric Power Survey and Design Technology Innovation Center,Shijiazhuang 050031,China;Institute of Geohazard Prevention and Control,North China University of Water Resources and Electric Power,Zhengzhou 450046,China;China Water Northeastern Investigation,Design&Research Co.,Ltd.,Changchun 130061,China;China Construction Seventh Engineering Division Co.,Ltd.,Zhengzhou 450000,China)
出处
《华北水利水电大学学报(自然科学版)》
北大核心
2025年第5期60-67,共8页
Journal of North China University of Water Resources and Electric Power:Natural Science Edition
基金
河南省自然科学基金项目(202300410269)
国家自然科学基金项目(52209132,2277141)。
关键词
软岩
竖井
支护
大变形
数值模拟
soft rock
shaft
support
large deformation
numerical simulation
