不同含水率膨胀土动剪切模量特征与原位G-γ衰减曲线确定方法

李甜果1,2,孔令伟1,2,舒荣军1,2

振动与冲击 ›› 2021, Vol. 40 ›› Issue (23) : 91-99.

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振动与冲击 ›› 2021, Vol. 40 ›› Issue (23) : 91-99.
论文

不同含水率膨胀土动剪切模量特征与原位G-γ衰减曲线确定方法

  • 李甜果1,2,孔令伟1,2,舒荣军1,2
作者信息 +

Dynamic shear modulus characteristics of expansive soil with different moisture contents and determination method of in situ G- γ decay curve

  • LI Tianguo1,2, KONG Lingwei1,2, SHU Rongjun1,2
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文章历史 +

摘要

考虑到膨胀土与水作用的特殊性以及实际工程中膨胀土含水率处于不断变化的状态,开展了不同含水率下膨胀土的室内共振柱(RCT)试验,同时结合原位地震扁铲侧胀(SDMT)试验,提出了改进的原位G-γ衰减曲线推求方法。结果表明,含水率对膨胀土剪切模量影响显著,剪切模量G随着含水率的增加而减小;将原状饱和膨胀土脱湿至不同含水率引起的体积变化对最大动剪切模量Gmax的影响归为含水率的影响,提出了适用于不同含水率膨胀土的Gmax预测模型,对佳木斯膨胀土的预测具有良好的效果。含水率相同时,最大动剪切模量Gmax和参考剪应变γr具有良好线性关系,借助这一规律提出了推求膨胀土原位G-γ衰减曲线改进方法,在初始阶段改进曲线与未改进曲线较接近,与原位地震波速试验结果一致;通过对比发现,改进曲线衰减速率更小,在膨胀土刚度分析中具有更好的适宜性,改进方法可为合理选取室内参考曲线与准确预测原位动剪切模量衰减规律提供帮助。

Abstract

Considering the particularity of the interaction of expansive soil and water , and the fact that the water content of expansive soil is changing in the actual project, the laboratory resonant column tests  (RCT)of expansive soil with different water contents were carried out. Meanwhile, combined with in-situ seismic dilatometer tests (SDMT). The results showed that water content have significant effects on the shear modulus of expansive soils, the shear modulus G decreases as the increase of water content ; The influence of the volume change of expansive soil caused by the change of water content on the maximum dynamic shear modulus Gmax was classified as the effect of water contents, a Gmax prediction model for the expansive soil with different water contents was proposed has a good prediction of Jiamusi expansive soil. The maximum dynamic shear modulus Gmax in good linearity with the reference shear strain γr at the same water content, based on this law, an improved method for calculating the in-situ G-γ decay curve of expansive soil was proposed, the improved curve is close to the unmodified curve in the initial stage and is consistent with the field seismic velocity test results; it is found that the improved curve has a smaller attenuation rate and a better suitability in the stiffness analysis of expansive soil, the improved method can help to select the laboratory reference curve reasonably and accurately predict the attenuation law of in-situ dynamic shear modulus.

关键词

弱膨胀土;共振柱;地震扁铲侧胀;G-&gamma / 衰减曲线;动剪切模量

Key words

weak expansive soil / resonant column / seismic dilatometer test / G-&gamma / decay curve / dynamic shear modulus

引用本文

导出引用
李甜果1,2,孔令伟1,2,舒荣军1,2. 不同含水率膨胀土动剪切模量特征与原位G-γ衰减曲线确定方法[J]. 振动与冲击, 2021, 40(23): 91-99
LI Tianguo1,2, KONG Lingwei1,2, SHU Rongjun1,2. Dynamic shear modulus characteristics of expansive soil with different moisture contents and determination method of in situ G- γ decay curve[J]. Journal of Vibration and Shock, 2021, 40(23): 91-99

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