围岩附加拉力对隧道锚蠕变特性的影响研究

Research on the Influence of Additional Tension of Surrounding Rock on Creep Characteristics of Tunnel Anchorage

研究目的:为研究围岩附加拉力对悬索桥锚碇蠕变特性的影响,结合雅康高速泸定大渡河特大悬索桥雅安侧岸坡隧道锚工程区特定地质条件,依据相似理论,开展隧道锚1∶10原位缩尺模型蠕变试验。根据悬索桥锚碇工作原理,将围岩对锚碇的附加拉力嵌入传统四元件Burgers蠕变模型而得到修正后的锚碇蠕变本构方程,并对修正后的蠕变本构方程进行参数敏感性分析。研究结论:(1)模型锚蠕变试验值和利用修正后的蠕变方程计算出的锚碇最终应变量在量值和变形趋势上都较为相似,表明锚碇蠕变分析中应计入围岩对锚碇附加拉力的影响;(2)修正后的蠕变方程中弹性模量较黏性系数影响显著;(3) Maxwell模型弹性模量较Kelvin模型弹性模量对蠕变结果的影响敏感,Kelvin模型黏性系数较Maxwell模型黏性系数对蠕变结果的影响敏感;(4)本研究成果不仅能为泸定大渡河特大悬索桥隧道锚系统安全性评估提供可靠依据,也可为同类型工程提供技术参考。

Research purposes:In order to study the influence of surrounding rock additional tension on the creep characteristics of anchor anchorage of suspension bridge,combined with specific geological conditions in the anchorage engineering area of Ya'an tunnel of Dadu river suspension bridge in Luding of Ya'an-Kangding Expressway,the creep test of tunnel anchor 1∶10 in situ scale model was carried out according to the similarity theory.According to the working principle of anchor anchorage of suspension bridge,the additional tension of surrounding rock to anchor anchorage is embedded into the traditional four-element Burgers creep model.The sensitivity analysis of the modified creep constitutive equation is carried out.Research conclusions:(1)The creep test values of the model anchorage and the ultimate stress variables calculated by using the modified creep equation are similar in the values and deformation trends,indicating that the influence of surrounding rock on the additional tension of anchorage should be taken into account in the creep analysis of anchorage.(2)In the revised creep equation,the elastic modulus is more significant than the viscosity coefficient.(3)The effect of elastic modulus of Maxwell model on creep results was more sensitive than that of Kelvin model.The viscosity coefficient of Kelvinl model is more sensitive to creep results than Maxwell model.(4)The research results don't only provide reliable basis for safety assessment of tunnel anchor system of Luding Dadu river suspension bridge,but also provide technical reference for similar projects.