强风化花岗岩边坡锚索长期预应力损失规律及预测模型

边坡预应力锚索在长期运营过程中必然伴随有预应力损失。本文在讨论岩土体蠕变耦合模型适用性的基础上,以福建漳永高速公路一强风化花岗岩边坡工程为背景,通过监测边坡锚索预应力损失情况,分析了锚索预应力随时间的变化关系,得出锚索长期预应力损失呈负指数变化的规律。结合蠕变耦合模型对拟合结果进行反分析,计算得出强风化花岗岩的蠕变参数。利用耦合效应模型的松弛方程,建立锚索长期预应力预测模型。对比监测数据,表明预测模型具有较好的实用性,可对边坡运营期间任一时刻的锚索预应力值进行估算,进而评价锚索应力的异常变化情况,为边坡运营期间的稳定性评价提供参考。

Long-term Prestress Loss Law and Prediction Model of Anchor Cable in Strongly Weathered Granite Slope

The prestressed anchor cable of the slope must be accompanied by prestress loss during the long-term operation.On the basis of discussing the applicability of the creep coupling model of rock and soil mass and taking a strongly weathered granite slope project of Zhangzhou-Yongan Expressway in Fujian Province as the background,the relationship between prestress of anchor cables and time was analyzed and the law of negative exponential change of long-term prestress loss of anchor cables was put forward by monitoring the prestress loss of anchor cables on slope.Combining with the creep coupling model,the f itting results were back analyzed and the creep parameters of strongly weathered granite were calculated.Based on the relaxation equation of the coupling effect model,the long-term prestress prediction model of anchor cable was established.By comparing the monitoring data,it shows that the prediction model has good practicability,can estimate the prestress value of the anchor cable at any time during the slope operation,and then evaluate the abnormal change of the anchor cable stress,which could provide a reference for the stability evaluation of the slope during the operation.