锚固参数对顺层岩质高边坡稳定性敏感度分析

Sensitivity Analysis of Anchoring Parameters to the Stability of Bedding High Rock Slope

为研究锚固参数对顺层岩质高边坡稳定性的影响规律,依托京沪高速公路改扩建工程中顺层岩质高边坡,采用有限差分软件FLAC3D建立数值仿真模型,研究了二次开挖后边坡不同锚杆长度、锚固倾角和注浆体黏结强度锚固下,顺层岩质高边坡的稳定性和锚杆轴力分布规律,并对锚固参数进行敏感性分析,结合敏感性分析对二次开挖锚固工程提出建议。结果表明:边坡稳定系数随着锚杆长度的增加先增加后趋于稳定,锚杆锚固中存在最佳长度,锚杆长度12 m锚固效果最佳;边坡稳定系数随锚固倾角的增大先增大后减小,锚杆锚固中存在最佳倾角,锚固角度25°锚固效果最佳;边坡稳定系数随黏结力增大先增大后趋于稳定,注浆体选用M30水泥砂浆能提供足够的黏结力;各锚杆参数对边坡稳定系数的敏感度由大到小排序为黏结强度f_(b)>锚杆长度L>锚固倾角α。

In order to study the variation law of bolt anchorage parameters on the stability of bedding rock high slope,relying on the bedding rock high slope in the Beijing-Shanghai Expressway reconstruction and expansion project,the finite difference software FLAC 3D software is used to establish the numerical simulation model.The stability and distribution of anchor bolt axial force of bedding rock high slope under different anchor length,anchor angle and grouting bond strength after secondary excavation are studied,the sensitivity analysis of anchorage parameters is carried out,and based on sensitivity analysis,some suggestions for secondary excavation anchoring is put forward.The results show that the slope stability coefficient increases first and then tends to be stable with the increase of bolt length.The optimal bolt length exists in the reinforcement process.Bolt length of 12 m has the best supporting effect.The stability coefficient of slope increases first and then decreases with the increase of the anchorage angle,so there is the best angle in bolt reinforcement,and the supporting effect is the best when the anchorage angle is 25°.The stability coefficient of slope increases firstly and then tends to be stable with the increase of cohesive force,thus M30 cement mortar can ensure enough bond.The sensitivity of rock bolt parameters to slope safety factor is in the descending order as follows:bond strength>rock bolt length>rock bolt Angle.