合-宁客运专线膨胀土不同高度路堤动力特性分析

Analysis of vibration character of expansive soil embankments with different heights of He-Ning High-speed Railway

通过合-宁快速客运专线膨胀土地段的现场动力试验,分析了高路堤和低路堤在模拟列车动荷载作用下的工程特性。测试结果表明,低路堤段动应力衰减系数在路基面以下相对应处与高路堤的衰减系数基本相同;低路堤和高路堤的弹性变形最大值分别为0.39 mm和0.48 mm,在允许范围之内;高路堤与低路堤的塑性变形最大值分别为0.7 mm和1.5 mm;高路堤在干态情况下动刚度系数约317 MPa,暴雨后下降到220 MPa/m;低路堤路基综合动刚度最后均为356 MN/m。改良土厚度不同造成路基的综合动刚度不同。

By in-situ dynamic test on expansive soil section in high and low embankments of He-Ning High-speed Railway, their engineering characters under simulative dynamic loads are analyzed. It is verified that the principle of dynamic stress attenuation coefficient of both depth is alike; the elastic deformations of both depth＇s embankments are 0.39 mm and 0.48 mm separately, which is allowable; the plastic deformations of both depth＇s embankments are 0.7 mm and 1.5 mm separately; on the dry condition, combined dynamic rigidity coefficient of high embankment is about 317 MPa and 220 MPa after storm rainfall, while low embankment is 365 MPa nearly all the time, different modified soil thickness causes different dynamic rigidity coefficients.