基于GM(1,1)模型的膨胀土填料CBR指标快速确定方法

开挖膨胀土能否直接用作填料需跟踪开展CBR试验,而试件浸水需4 d将妨碍路堤填筑新技术的工程应用,有必要研究快速获取膨胀土CBR指标的方法。对百色膨胀土按改进CBR试验方法进行试验,设定不同时刻测试试件的变形和强度值,分析得到2指标的浸水时间效应及其变化规律;引入灰色理论中带1阶加权平均弱化缓冲算子的GM(1,1)模型,对测试结果做了指标值的预测和分析。结果表明,用浸水1 d试件的膨胀变形实测值可预测其浸水4 d的实际值,精度能满足工程要求且偏安全。据此,总结并提出膨胀土填料的改进CBR指标快速确定方法。

Rapid Determination Method of CBR Indices for Expansive Soil Filler Based on GM(1,1) Model

CBR test should be carried out and tracked to determine whether the excavated expansive soil can be directly used as filler,however,the specimens soaking period of four days considerably prevents the application of new treatment technology of expansive soil embankment.Therefore,it is necessary to research a rapid determination method to obtain the CBR indices of expansive soil.The modified CBR test on Baise expansive soil was performed to obtain the soaking time effect of two indices and their variation with setting the deformation and CBR strength values of test specimen at different time.The GM(1,1) model with weighted average first-order weakening buffer operator in grey theory was introduced to predict and analyze the index values of test result.The result shows that the measured values of expansion deformation of 1 d soaked specimen can be used for predicting the actual values of 4 d soaked specimen,and the prediction accuracy is partial to security and can meet the requirements of engineering.Accordingly,the rapid determination method of modified CBR indices for expansive soil as filler was summarized and presented.