输电铁塔岩石锚杆基础承载性能及影响因素试验研究

Experimental Study on Bearing Performance and Influential Factors for Transmission-line Rock Anchor Foundation

岩石锚杆基础是近期送电线路基建推广应用的主要基础型式之一,针对某500kV送电线路途径的强风化、中风化岩层广泛分布的地质条件,选取典型场地分别进行了单锚、直锚和承台式群锚等三种型式的岩石锚杆基础的现场真型试验,得到了试验基础的位移随荷载变化关系和极限承载力,其承载力满足该500kV送电线路基础承载设计要求。基于荷载与位移关系曲线,分析了岩石锚杆基础承载特征,及锚杆尺寸、基岩风化程度和群锚效应对基础承载力的影响规律,研究表明:承载力随锚杆和锚筋直径的增大而增大;锚杆存在有效抗拔锚固深度,超过该深度时增加锚杆埋深对提高承载力效果不明显、岩石风化程度对锚杆承载力影响较小、群锚效应对群锚基础无影响。

Rock anchor foundation is the one generalized for application in transmission lines. In view of the fact that 500 kV transmission line passes the geological conditions of widespread weathered rock, this test makes three types of field test including single anchor, straight anchor and a group of anchor in place. The relationship curves of uplift loading and uplift displacement and bearing capacity are obtained. The bearing capacity can satisfy the design requirements of 500kV power transmission line foundation. Based on the load-displacement relation, the paper analyses the bearing performance of rock anchor foundation, the affecting rule to overturning resistance about rock anchor dimension, weathered degree of the rock and a group of anchor effect. The results show that the influence of the rock anchor diameter on the overturning resistance is great; for anchor exists effective uplift anchorage depth, an increase in the anchor depth to improve the bearing capacity is not obvious if it more than the effective uplift anchorage depth. The influence of weathered degree of the rock on the overturning resistance is small, and also there is no influence of a group of anchor effect in this test.