输电线路节理化岩体注浆锚杆基础抗拔力模型试验研究

Tension model test research on grouted bolts foundation in jointed rock masses for transmission lines

针对输电线路注浆锚杆基础特点,根据相似理论设计了节理化岩体注浆锚杆基础抗拔模型试验,模型设计中考虑了岩石弹性模量、浆体弹性模量、节理迹长、节理倾角、锚杆埋深5个因素的变化,选择5因素4水平的正交试验方法进行了模型试验研究。结果表明,岩石弹性模量对注浆锚杆基础抗拔力的影响最大,其次为锚杆埋深、节理倾角、浆体弹性模量、节理迹长。试验过程中以剪切破坏和开裂破坏为主,并以此分析了注浆锚杆的传力机制,得出浆体与锚杆和岩体之间的黏结强度是控制试验结果的主要因素,影响着锚杆的极限抗拔力和破坏状态,在施工过程中应注意质量控制。

According to the character of grouted bolts foundation in jointed rock masses for transmission lines, the model tests are designed based on the similarity theory. The model tests are carried out with focus on the following five factors： elasticity modulus of rock, elasticity modulus of mortar, trace lengths and joint inclination angle in rock mass, embedding depth of the bolt in the rock mass on four different levels of every factor. The experimental results reveal that the elasticity modulus of rock is the most important and sensitive factor influencing the pullout strength of grouted bolt foundation, and the factors next are embedding depth of the bolt in the rock mass, joint inclination angle in rock mass, elasticity modulus of mortar and trace lengths in rock mass. The destruction forms in the model tests are mainly shear failure and split failure. The force transferring mechanism of the bolt is also analyzed. It is concluded that the bond strength between the mortar and the rock, the mortar and the bolt are the main factors controlling test results and affecting the pullout strength of the bolt and failure status. It should be paid more attention to control the quality in the procedure of construction.