分步施工及预应力损失对框架预应力锚杆加固多级边坡的影响分析

Analysis of the influence of step-by-step construction and prestress loss on the reinforcement of multi-stage slope by frame prestressed anchor

以实际工程为依托,使用PLAXIS3D有限元分析软件建立分析模型,分析了分步施工及预应力损失对框架预应力锚杆加固多级边坡的影响。首先,对各阶段安全系数变化、位移变化、锚杆轴力变化进行分析,进一步对3种不同施工方案下的安全系数变化、位移变化、锚杆轴力变化进行对比分析;其次,设置预应力损失的工况,对位移变化、偏应变增量变化进行分析。研究结果表明,框架预应力锚杆对边坡的变形控制发挥了显著的作用,同时对分步施工过程中的边坡安全状态也应该给予关注,防止边坡分步施工过程中发生局部破坏;逆次序边开挖边支护的施工方案最为安全可靠;边坡的总位移和偏应变增量都随着预应力的损失而不断增大,两者之间的变化趋势呈现相关性。

An numerical model was developed based on a real engineering project using the PLAXIS 3D finite element analysis software to investigate the influence of incremental construction and prestress degradation on multi-stage slope reinforcement employing frame prestressed anchors.Initially,an analysis was performed to examine the variations in safety factors,displacements,and axial forces in the anchors across various stages.Moreover,a comparative assessment was conducted on the variations in safety factors,displacements,and anchor axial forces within three distinct construction scenarios.Subsequently,scenarios involving prestress loss were introduced,and an analysis was conducted to investigate alterations in displacement and incremental strain.The research results demonstrate the pivotal role of frame prestressed anchors in mitigating slope deformations.Additionally,it is crucial to consider the safety of slope during incremental construction to avert localized damage.Among the construction schemes,the strategy of reverse sequence excavation and support is determined to be the most secure and dependable.With prestress loss,both the total slope displacement and the incremental strain increase,revealing a correlated trend.