新型锚杆基础破坏机理及影响因素研究

Research on Failure Mechanism and Influencing Factors of New Type Anchor Foundation

摘要:

为克服锚杆基础在山区输电线路中应用的局限，文中提出了一种由自由段和锚固段组成的新型锚杆基础，通过有限元数值方法研究了新型锚杆的应力分布及失效机理，并对黏结强度、锚杆长度、岩石类型及孔杆直径比等因素进行了参数分析。研究结果表明：注浆体与岩石及锚筋与注浆体之间，其黏结应力的分布范围只在锚固段靠近张拉端的有限长度上且应力分布极不均匀；黏结强度是判断锚杆失效界面类型的重要参数指标，对承载力有较大影响；锚固长度存在峰值，破坏面发生在注浆体和岩石界面时，硬岩承载力明显高于软岩承载力；锚孔直径/锚杆直径的最佳比例为4～5倍。

Abstract:

In order to overcome the application limitation of anchor foundation in mountainous transmission lines, a new type of anchor foundation composed of free section and anchored section is proposed. The stress distribution and failure mechanism of the new anchor are studied by finite element numerical method, and the factors such as bond strength, anchor length, rock type and hole rod diameter ratio are analyzed. The results show that: the distribution range of bond stress between grouting and rock and between anchor bar and grouting is only in the limited length of anchored section near the tension end, and the distribution of stress is extremely uneven; the bond strength is an important parameter to judge the failure interface type of anchor rod, and has a great impact on the bearing capacity; there is a critical value of the anchorage length, and the failure surface occurs at the interface between grouting and rock, the bearing capacity of hard rock is obviously higher than that of soft rock, and the optimal ratio of hole diameter to bolt diameter is 4~5 times.