岩质高挖方边坡锚杆参数优化设计研究

针对某220 kV变电站岩质高挖方边坡，采用极限平衡法和数值分析法，设置不同锚杆打入角度和长度方案对边坡的稳定性进行了计算对比分析，优化了锚杆设计参数，评价了坡顶位移监测、深层水平位移监测和锚杆应力监测对锚杆加固效果。结果表明，（1）随着锚杆打入角度的增加，边坡安全系数先增大后减小，存在最优锚固角度，确定22°为最优锚固角度；（2）边坡下部锚杆受力大于上部锚杆受力，设计时应有重点考虑下部锚杆参数。当边坡安全系数不满足设计要求时，应适当增大下部锚杆截面尺寸或增加锚杆长度；（3）各排锚杆应进行不等长设计，锚杆长度通过极限平衡法量取潜在滑动面到坡面的距离进行确定和验算；（4）现场监测结果显示优化设计后的锚杆参数加固效果良好，经济效益可观。

Parameter optimization design of anchors in high cutting rock slope

Combined with a high cutting rock slope near a 220 kV substation, the parameters of the anchors are analyzed based on the limit equilibrium method and numerical method. The design parameters are optimized by comparative analysis of the slope stability results that are calculated by setting different angles and lengths of the anchors. The anchor reinforcement effect is evaluated by surface displacement monitoring, deep ground displacement monitoring and stress monitoring of the anchors. The results show that: (1) With the increase of anchorage angle, the safety factor increases at beginning and then decreases; so there exists an optimum anchor angle. 22°for this project. (2) The anchors in the lower part of slopes exhibit larger axial force; so it is important to focus more on the design parameters of anchors in the lower part of slopes. If the slope safety factor could not satisfy the design requirement, increase the cross-section size or length of the anchors in the lower part of slopes as appropriate. (3) The length inequality design of the anchors is suggested. The anchor length shall be determined by measuring the distance between the slip surface and slope surface at first; then check the calculation results by the limit equilibrium method. (4) The in site monitoring results show that the optimization design of anchors achieves relatively high performance and good economic benefits.