摘要
边坡变形及稳定问题一直是学者们极为关心的课题,过去大量文献采用极限平衡法(LEM)或强度折减法(SRM)分析了该问题。但无论对于土质边坡还是对于含裂隙岩质边坡,传统的LEM需要先期假定滑裂面的形式,单独采用SRM也一般仅能推算出呈圆弧状的临界滑面,因而为摸清考虑裂隙发育的岩质边坡在外载胁迫下失稳时实际的滑移形状及位置,亟需寻求新的分析方法或另辟蹊径的研究工具,动力扩展有限元法(XFEM)刚好就是其中一种分析工具。尝试将有限元的SRM与XFEM相结合,在事先构思好的若干岩质边坡算例中定义1个场变量(将其取为岩体温度),在自重应力作用维持不变的情况下,分别对内部含不同条预制裂隙的岩质边坡二维平面模型做降强计算,得出了各算例岩质边坡的失稳过程、变形破坏模式与稳定系数(FoS)。结果表明:裂隙结构的空间分布特征对岩质边坡的失稳滑移轨迹、最终失效形态和位移场等均具有较大的影响;含裂隙岩质边坡的FoS比匀质边坡的FoS明显更小;岩质边坡在发生滑动变形的过程中,主控节理裂隙有所延展乃至贯穿,形成破坏通道。用XFEM得到的计算机图形反映了原有裂缝组将构成复杂岩质高大边坡非规则滑裂面一部分的规律(与业内常识及预期皆吻合),表明该方法是可靠的,对深化认识坡体内断续弱面的孕灾机制较为有利。
The problem of slope stability and deformation has been a topic of great concern to Chinese and foreign workers in geotechnical engineering over the years.Numerous academics used rigid body limit equilibrium method(LEM) or strength reduction method(SRM) to evaluate the stability of slope in past studies.However, for both soil slopes and fractured rock slopes, the traditional LEM needs to assume the form of the slip surface in advance, and SRM alone can only generally obtain the critical slip surface in the shape of circle arc.Therefore, in order to find out the actual sliding shape and position of rock slope under external load stress, it is urgent to find another way and seek a kind of engineering technology to resolve effectively, extended finite element method(XFEM) can just serve as one of them.This paper establishes several 2D simulation models for rock slope cases with different number of pre-existing fractures herein in combination with both the FEM and the XFEM,through convenient SRM based on temperature distribution to obtain the slope instability process, failure type and safety factors(FoS) of each case.The results show that spatial combination of internal fracture structures have obvious effects on the sliding path, final failure form, stress nephograms and displacement field of the rock slope;the comprehensive safety factor of rock slope is smaller than that of the pure bedrock slope.During the occurrence and development of rock slope deformation, the main controlling cracks expand and even grow connected.The results obtained by XFEM method reflect the law that cracks will form part of irregular potential sliding surface of rock slope, which is consistent with common sense and expectation.The rationality of this method proposed is verified, and is very helpful for deepening the influence mechanism of weak surface in complicated high rock slope.
作者
马鹏飞
郭德龙
许文年
陈新
夏栋
MA Pengfei;GUO Delong;XU Wennian;CHEN Xin;XIA Dong(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing210024,China;China Railway 14th Bureau Croup Co.,Ltd.,Jinan250014,China;Hubei Provincial Engineering Research Center of Slope Habitat Construction Technique Using Cement-based Materials,China Three Gorges University,Yichang443002,China;School of Hydraulic and Environmental Engineering,China Three Gorges University,Yichang443002,China)
出处
《安全与环境工程》
CAS
CSCD
北大核心
2023年第1期128-139,共12页
Safety and Environmental Engineering
基金
国家自然科学基金重点项目(41831278)。
关键词
多裂隙岩质边坡
动力扩展有限元法
强度折减法
滑动面发展规律
破坏模式
fractured rock slope
extended finite element method(XFEM)
strength reduction method(SRM)
regularity of sliding surface propagation
failure mode
