摘要
以澜沧江某水电站坝址区碎裂松动岩体为研究对象,通过对岩质边坡现场调查,并运用ANSYS有限元软件模拟河谷演化和冻融循环过程,综合分析碎裂松动岩体的成因。调查结果表明,碎裂松动岩体的形成与区域赋存的地应力场、地层岩性、河谷演化及高原冻融风化有关。数值模拟揭示了河谷演化过程中边坡岩体持续经历主应力降低、剪应力增大的状态,应力释放而驱动边坡岩体结构面破裂,形成大量的卸荷拉张裂隙,初现"松动"特征;在大温差冻融循环作用下,原本存在裂隙面的岩体不断扩展延伸直至发生疲劳性损伤裂化。由此,总结了碎裂松动岩体的成因机制,该成果对高寒山区深切河谷碎裂松动岩体的形成机制提供依据。
The object of the study is the cataclastic loose rock mass in the dam site of a hydropower station in Lancang River. Through site investigation of the rock slope,and by using ANSYS finite element software to simulate the valley evolution and freeze-thaw cycles,the causes of cataclastic rock mass is analyzed comprehensively. The results of the survey show that the formation of cataclastic loose rock mass is related to the in-situ stress field,stratum lithology,valley evolution and plateau frozen-thawed weathering. Numerical simulations reveal that the slope rock mass has experienced a decrease in principal stress and an increase in shear stress during the evolution of the valley. Stress releases lead to structure plane rupture of the slope rock mass,forming a great amount of unloading tensile cracks,showing the start of"loosening". Under the effect of the severe temperature difference in freeze-thaw cycles,the rock mass with fissured surface continues to expand and extend until the occurrence of fatigue damage cracking,and evolves into the cataclastic shapes apparently. Thus,the genetic mechanism of cataclastic rock mass is summarized,which will provide the basis for the formation mechanism of cataclastic rock mass in the Alpine mountain regions and deep valley.
作者
姚青
郑达
王宇
李文龙
YAO Qing;ZHENG Da;WANG Yu;LI Wenlong(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China)
出处
《防灾减灾工程学报》
CSCD
北大核心
2020年第5期706-713,共8页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家自然科学基金项目(41772317)
中国华能集团科技项目(HNKJ16-H15)资助。
关键词
高寒山区
碎裂松动岩体
成因机制
河谷演化
冻融循环
alpine mountain regions
cataclastic loose rock mass
genetic mechanism
valley evolution
freeze-thaw cycle
