边坡预应力锚索服役寿命预测模型对比分析

Comparative analysis of in-service life prediction models for slope pre-stressed anchor cables

高边坡开挖加固一般需要采用大量的预应力锚索,这些预应力锚索在长期恶劣腐蚀环境下服役寿命通常难以准确预测.本文系统比较了3种常用的预应力锚索服役寿命预测模型,说明了各自的优缺点及适用性,并以一高速公路边坡为例,通过参数敏感性分析探讨了模型参数对锚索服役寿命的影响规律.结果表明:李英勇模型与邓东平模型计算的服役寿命接近,与刘贞国模型计算的服役寿命相差较大.李英勇模型适用于注浆体较完整、无缺陷、厚度适宜、张拉力变化较大的情况;邓东平模型适用于降雨少、温度变化小、张拉力较小的情况;刘贞国模型适用于氯离子浓度较大,特别是近海地区服役的预应力锚索.此外,锚索钢绞线直径增大对李英勇模型具有较大的积极作用,而对邓东平和刘贞国模型具有不利的影响.采用邓东平与刘贞国模型计算的锚索服役寿命均随着注浆体厚度增加而增大.在常用的水胶比范围内,刘贞国模型预测的锚索服役寿命会随着温度的增大而减少.

A large number of pre-stressed anchor cables are used in slope anchoring,but in the long-term bad corrosion environment,the service life of pre-stressed anchor cables is difficult to accurately predict.Based on the previous studies,the basic principles of the calculation methods of three pre-stressed anchor cables are introduced.Based on the actual engineering data of the slopes of the Shandong ring expressway,the advantages of the three methods are compared.Disadvantages and applicability,and analysis of parameters affecting service life.The results show that the service life of Li's model and Deng's model is relatively close,and the service life calculated by Liu's model is quite different.This project is not applicable to Liu's model;Liu's model is suitable for pre-concentration of chloride ion concentration,especially in offshore areas.Li's model are suitable for the case where the grouting body is relatively complete,without defects,the thickness is suitable,and the tensile force varies greatly.The Deng's model is suitable for the case of less rainfall,small temperature change and small tension;and the increase of cable diameter has a positive effect on Li's model,and has a negative effect on Deng's model and Liu's model.Deng's model and Liu's models increase the service life with the increase of grouting thickness,within the range of water-to-binder ratio.The increase in temperature will reduce the service life of the Liu's model.