摘要
开挖卸荷作用下裂隙岩体边坡的破坏模式与路径分析是边坡工程灾害研究的热点之一,准确识别边坡的潜在破裂路径对工程安全施工和支护优化设计具有重要意义。依据断裂扩展分析方法,将裂隙扩展判别的理论方法开发并应用于数值模拟分析中,通过裂隙尖端应力强度因子计算、裂隙扩展模式识别、裂隙起裂角演算、裂隙扩展交汇等技术实现了岩体中断续裂隙的起裂、扩展与贯通演化过程的快速模拟;以某高速公路沿线裂隙岩体路堑边坡为对象,采用提出的模拟方法分析了多级开挖卸荷作用下坡体裂隙的扩展机制与边坡的破坏路径。结果表明:裂隙岩体边坡从上至下多级开挖过程中,坡肩裂隙首先起裂,并通过拉张型扩展逐渐发展为优势裂隙;随着边坡下挖,优势裂隙沿坡面向下逐步发生拉张/剪切混合型扩展并与既有裂隙交汇,在边坡中上部形成阶梯状扩展破坏路径;裂隙扩展至边坡下部及坡脚后扩展模式由拉张/剪切混合型转化为剪切型,并最终以弧形剪切面从坡脚出露。研究揭示了裂隙岩体边坡多级开挖卸荷作用下上部阶梯状拉张/剪切混合型破裂-下部弧形剪切型破裂的复合破坏模式,可为边坡工程支护设计和施工稳定性控制提供新思路。
Ltd.;The investigation on failure patterns and paths of cracked rock slopes under excavation unloading is one of the hot issues in the slope engineering field.Accurate identification of the potential failure path is of great significance for excavation safety and support design of the slope.A theoretical method for crack propagation discrimination was embedded into the numerical simulation based on the fracture propagation analysis method,and the quick simulation of initiation,propagation,and coalescence of discontinuous cracks in rock masses was realized through stress intensity factor calculation at crack tip,crack propagation pattern recognition,crack initiation angle derivation,and crack propagation and coalescence.The proposed simulation method was used to analyze the crack propagation mechanism and the failure path of a highway cutting slope under multi-stage excavation unloading.The results show that during the multi-stage excavation from top to bottom of the slope,the crack initiation first occurs at the slope shoulder,and then a dominant propagating crack is formed through tensional propagation.With the downward excavation of the slope,the dominant crack gradually propagates downward the slope in tensile-shear mixed pattern and coalesces with existing cracks,forming a step-path failure in the middle and upper parts of the slope.When the crack propagates to the lower part of the slope,the crack propagation pattern transforms from tensile-shear mixed pattern to shear pattern,and finally the potential sliding body slides out along an arched shear surface at the slope toe.This study reveals a composite failure pattern of the cracked rock slope under multi-stage excavation unloading,which includes the tensile-shear mixed propagation pattern with a step-shaped path in the upper part and the shear propagation pattern with an arched path in the lower part,and can provide new ideas for the support design and construction stability control of rock slopes.
作者
王川
冷先伦
张占荣
杨闯
陈健
WANG Chuan;LENG Xian-lun;ZHANG Zhan-rong;YANG Chuang;CHEN Jian(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan,Hubei 430063,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2023年第4期1190-1203,共14页
Rock and Soil Mechanics
基金
国家自然科学基金(No.52079135)
铁四院科研课题(No.2020K043)。
关键词
裂隙扩展
开挖卸荷
扩展模式
破坏路径
裂隙岩体边坡
crack propagation
excavation unloading
propagation pattern
failure path
cracked rock slope
