不同锈蚀度时海底隧道锚固支护结构岩锚相互作用分析

Analysis on interaction of rock-bolts in anchorage support structure of subsea tunnel at different corrosion levels

基于长期氯离子侵蚀及干湿交替环境作用,海底隧道锚固支护结构发生锚杆锈蚀,造成支护结构强度工作性能劣化,结合某海底隧道Ⅳ级围岩锚固支护结构设计,基于前人研究理论及试验成果,采用数值分析软件FLAC3D并借鉴有限元强度折减思想,分析不同锈蚀程度下隧道的位移、应力、塑性区等影响规律,探讨锈蚀对锚固支护结构体系中岩锚相互作用的影响。研究结果表明:随着锈蚀度的增加,隧道加锚围岩区的位移增大,塑性区扩展,说明锚杆锈蚀削弱了锚固支护结构的整体支护强度;锈蚀对隧道加锚围岩起拱线处的收敛变形影响明显。锚杆锈蚀降低了锚固支护结构中岩锚相互作用,锈蚀对锚固注浆体的黏结作用的损失影响比对锚杆应力作用的损失影响大。

Because of long-term chloride erosion and altemate drying-wetting effect, anchorage support structure of sub-sea tunnel is reinforced corrosion and its strength decreases. According to anchorage support structure design of surrounding rock with grade IV and previous research theory and test results, influence rules on displacement, stress and plastic zone of tunnel under different corrosion levels were analyzed, interaction of rock-bolts in anchorage support structure of subsea tunnel caused by corrosion was discussed by means of numerical analysis software FLAC3D and idea of finite element strength reduction. The results show that with the increase of reinforced corrosion, the deformation of tunnel＇s surrounding rock adds bolts and the areas of plastic zone increase, the reinforcement effect of anchorage support structure gets weak due to cable corrosion. The convergence deformation at springing line is obvious. Corrosion decreases bond force of anchorage body and strength of anchor bar. The loss effect of bond force of anchorage body is greater than that of anchor bar strength.