层状岩质边坡变形破坏及其支护设计的颗粒流数值模拟

Numerical Simulations for Deformation and Failure of Layered Rock Slopes and Their Support Design by Particle Flow Code

在工程建设中,层状岩质边坡十分常见。该类边坡受其结构面的影响,失稳变形特征较为复杂,且由于边坡滑动面不明确,给工程支护设计带来一定的困难。为此,通过PFC2D软件,以高陡岩质顺层边坡为原型,建立含不同岩层倾角的岩质边坡数值模型,提出了一种通过临界荷载反演搜索边坡潜在滑动面的方法,对层状岩质边坡变形、失稳和破坏过程进行细观分析。通过对比临界荷载系数,得出了不同岩层倾角边坡的相对稳定性;不同岩层倾角的墙锚支护效果差异明显,水平岩层边坡和高倾角切层边坡支护效果较好,而反倾边坡支护的效果欠佳;在边坡支护设计优化上,发现在一定范围内增大嵌入比和嵌入角度均能提高支护效果。从施工和经济的角度,建议采取嵌入比为0.33,嵌入角度90°的支护设计方案。

In engineering construction,layered rock slopes are very common.Affected by their structural planes,the instability and deformation characteristics of those slopes are more complicated,therefore,it has caused certain difficulties in the design of support engineering.Thus,numerical models with different dip angles of strata were constructed based on a high and steep rock bedding slope as the prototype by the software PFC2D.A method of searching for potential sliding surfaces of slopes by the inversion method of critical loads was proposed and mesoscopic analysis on the process of deformation,instabibity and failure was performed.By comparing critical load coefficients,the relative stability of slopes with different dip angles of strata was obtained.The support effect of wall-anchor systems with different dip angles of strata was obviously different.The support effect of horizontal rock slopes and cut bedding slopes with large dig angles were better,while the supporting effect of reverse slopes were worse.In the optimization of support design for slopes,to increase the embedment ratio and embement angle within a certain range could improve the support effect.From the perspective of construction and economy,the support design with an embedment ratio of 0.33 and an embedment angle of 90°was recommended.