顺层岩质边坡锚索锚固参数与优化设计分析

Analysis on Anchoring Parameters and Optimization Design of Anchor Cables for Bedding Rock Slopes

为研究预应力锚索加固节理化岩质高边坡稳定性变化规律,依托京沪高速公路改扩建工程中岩质高边坡,通过FLAC建立有限差分模型,研究了在不同锚索长度、倾角和预应力大小等因素影响下,边坡的稳定性和锚索锚固段轴力的变化规律,并结合敏感性分析进行了锚索参数设计。结果表明:锚索长度在最优范围内与边坡稳定性正相关,但过长后支护效果改善并不显著;在0°~30°内,锚索倾角变化对顺层岩质边坡稳定性影响不显著;锚索预应力施加时存在最佳值,在一定范围内预应力的增大会在岩层间附加法向应力,由此增大了支护范围内岩层间滑动阻抗力,锚固作用显著;锚索各参数对边坡稳定系数的敏感度由大到小排序为锚索预应力f>锚索长度l>锚索倾角θ。

In order to study the stability change law of jointed rock high slope reinforced by prestressed anchor cable anchorage,based on the high rocky slope in the project of Beijing-Shanghai Expressway,in this paper a finite difference model is established through FLAC3 D to study the stability of slope and the axial force change law of anchor cable anchorage section under different anchor cable length,inclination and prestressing,Combined with sensitivity analysis,the design parameters of anchor cable are analyzed.The results show that the length of anchor cable is positively correlated with slope stability in the optimal range,but the effect of exceeding long support is not significant;in the range of 0~30°,the change of anchor cable inclination has no significant impact on the stability of bedding rocky slope;and there is an optimal value when the anchor cable prestressing is applied.In a certain range,the increase of prestressing will add normal stress between rock strata,which increases the sliding impedance force between rock strata within the support range,and the anchoring effect is significant.The order of sensitivity of anchor cable parameters to slope stability coefficient from large to small is:anchor cable prestress f>anchor cable length L>anchor cable inclination θ.