全长粘结式灌浆锚杆锈胀机制研究

The Mechanism of Corroded Expansion of Grouted Bolt

针对埋设在地下特殊环境条件下全长粘结式灌浆锚杆存在因锈胀致裂,导致结构失效的实际情况,以弹性理论为基础,根据锚杆、灌浆材料以及围岩体三者之间变形协调关系、荷载平衡条件,研究了锚杆锈胀导致灌浆或岩体开裂,进而加速锚杆锈蚀破坏的机制问题,讨论了锚杆锈胀量、灌浆材料特性、保护层厚度以及围岩体力学性质对锚杆锈胀力的影响。结果表明:锚杆锈胀力随着钢筋锈蚀率的增加而增加,随钢筋保护层厚度的增加而减少;砂浆与围岩体之间的锈胀力随砂浆强度、围岩强度的增加而增加,钢筋与砂浆之间的锈胀力随围岩强度的增加而增加,随砂浆强度的增加而降低。

The corroded expansion of grouted bolt often leads to the failure of slope anchor structure in underground special environment. Based on the deformation compatibility relation among bolt, grout material and surrounding rock, and by investigating factors such as the amount of bolt corroding, the property of grouted material, the protective thickness, as well as the mechanical properties influencing the corrode expansion force of the system, a mechanism model of corroded expansion is developed for the corroding grouted bolt. The results show that the corrode expansion force of bolt increases with the increase of the bolt corroding ratio, and decrease with the increase of protective thickness or grout strength. The corrode expansion force between grout and rock increase with increase of surround rock strength and grout strength. However, the corrode expansion force between bolt and grout increase with increase of surround rock strength, but decrease with increase of grout strength.