摘要
大型水电工程库区内的软硬互层反倾岩质边坡,坡脚岩体位于消落带范围内时其物理力学性质在周期性水-岩作用下可能劣化,威胁边坡的整体稳定性。基于三峡库区典型岩石和结构面在干湿循环作用下的物理力学性质劣化研究成果,选取砂岩和砂质泥岩为硬岩和软岩原型,建立软硬岩层等厚的互层反倾边坡数值模型,使用GDEM软件模拟坡脚岩体劣化条件下的边坡变形破坏过程,揭示其破坏机制并明确稳定性演化规律。研究表明:坡脚岩体劣化条件下软硬互层反倾岩质边坡的破坏存在诱发型和触发型两种机制。诱发型机制下坡脚岩体劣化后的变形导致边坡破裂面出现,随着劣化程度增加破裂面不断向上延伸,最终边坡失稳或形成倾倒趋势。触发型机制下坡脚岩体劣化打破了边坡沿已存在的非贯通破裂面的力学平衡,导致边坡失稳破坏。诱发型机制下,边坡破裂面多为上陡下缓的折线,转折点位于劣化区与非劣化区的区域分界,岩层倾角α和坡角β是决定该折线形态的主要因素。坡脚岩体劣化条件下边坡安全系数初期下降幅度较大,后期下降幅度趋缓,安全系数的下降幅度与岩层倾角α之间存在明显的正相关关系。
A lot of soft and hard interlayer anti-dipping rock slopes are located in the reservoir area.Considering that the physical and mechanical properties of slope toe are possibly degraded by the cyclic water-rock interaction if the slope toe is situated in the hydro-fluctuation belt,threatening the stability of slope.Based on the previous studies on the physical and mechanical property degradations for the typical rock and joints under wet-dry cycles,sandstone and sandy mudstone in Three Gorges reservoir are selected as the prototypes for the hard and soft rocks.Numerical models of soft and hard interlayer anti-dipping rock slope with the hard and soft rock strata of uniform thickness are established,and GDEM is employed to simulate the deformation and failure behavior of the slope under the condition of slope toe deterioration.Furthermore,the failure mechanism and stability evolution of the slope are revealed.Results show that the failure mechanisms of soft and hard interlayer anti-dipping rock slopes under the condition of slope toe deterioration fall into two categories,namely the inducing mechanism and the triggering mechanism.Under the inducing mechanism,the deformation of the slope toe induces the occurrence of the fracture plane in the slope,and the fracture plane extends upwards with the deterioration the slope toe,and eventually the slope fails or tends to topple.Under the triggering mechanism,the force nonequilibrium of the slope along the existing non-penetrating fracture plane is triggered by the slope toe deterioration,resulting in the slope failure.Under the inducing mechanism,the fracture plane in the slope tend to be polyline with the steep upper part and the gentle lower part,and the transition point is located at the boundary of the degradation and the non-degradation regions.The forms of the polyline-shaped fracture planes are dominated by the dipping angleαand the slope angleβ.Under the condition of slope toe deterioration,the safety factor of slope decreases rapidly in the initial stage,while t
作者
江巍
齐志宇
邓华锋
徐建城
王彦海
Jiang Wei;Qi Zhiyu;Deng Huafeng;Xu Jiancheng;Wang Yanhai(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area Ministry of Education China,Three Gorges University,Yichang,443002,China;Hubei Key Laboratory of Disaster Prevention and Mitigation China,Three Gorges University,Yichang,443002,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2023年第S01期181-193,共13页
China Civil Engineering Journal
基金
国家自然科学基金(U22A20600,52079070)
湖北省重点实验室开放基金资助项目(2022KJZ07)
关键词
软硬互层反倾岩质边坡
坡脚劣化
破坏机制
稳定性
Soft and hard interlayer anti-dipping rock slope
Slope toe deterioration
Failure mechanism
Stability
