沉积方向角对砂土抗液化强度影响电阻率表征研究

    Study on Resistivity Characterization of the Influence of Deposition Angle on the Anti‑Liquefaction Strength of Sand

    • 摘要: 为探究沉积方向角对饱和砂土抗液化强度的影响,本文以饱和砂土为研究对象,引入电阻率测试作为关键分析手段,设计5种沉积方向角开展动三轴液化电测试验。结果表明:沉积方向角为45°的试样抗液化强度最低,液化所需循环振次最少,0°~45°区间抗液化强度随沉积方向角增大而减小,45°~90°区间则呈相反趋势;电阻率初值随沉积方向角增大呈先增后减的趋势,于45°处出现拐点,这表明电阻率初值与沉积方向角存在定量关系,电阻率初值与15次循环破坏比(CRR15)呈显著反向关联,说明电阻率初值可作为预测砂土抗液化能力的表征指标;在循环荷载作用下,不同沉积角试样的电阻率变化量发展模式存在显著差异:45°试样呈线性变化,而其他角度试样均经历先缓后快的两阶段发展;液化过程中试样的电阻率变化总量与CRR15存在明显的反向定量关系,电阻率变化总量越大,抗液化能力越弱,电阻率变化可作为抗液化强度的有效表征形式,能精准反映砂土液化过程中抗液化强度的演变规律。研究证实,沉积方向角是影响砂土抗液化特性的关键因素,电阻率可有效地表征抗液化能力。

       

      Abstract: This study investigates the influence of deposition angle on the liquefaction resistance of saturated sand using electrical resistivity measurements. Dynamic triaxial liquefaction tests coupled with resistivity monitoring were conducted on specimens prepared at 5 distinct deposition angles. The key findings are as follows:1) The specimen with a deposition angle of 45° exhibited the lowest liquefaction resistance, requiring the fewest cycles to reach liquefaction. Liquefaction resistance decreased with increasing deposition angle within the 0°~45° range, while an opposite trend was observed between 45° and 90°. The initial resistivity showed a non-linear relationship with deposition angle, peaking at 45°. A strong inverse correlation was identified between initial resistivity and the cyclic resistance ratio at 15 cycles (CRR15), suggesting that initial resistivity can serve as a predictive indicator for the liquefaction resistance of sandy soils. 2) Under cyclic loading, the evolution of resistivity varied significantly with deposition angle. The 45° specimen displayed an approximately linear reduction in resistivity. In contrast, specimens at other angles exhibited a two-stage response: a gradual initial decrease followed by an accelerated reduction phase. 3) The total resistivity change during liquefaction demonstrated a clear inverse quantitative relationship with CRR15. A larger total change in resistivity corresponded to lower liquefaction resistance. Resistivity evolution proved to be an effective parameter for characterizing both the magnitude and the progression of liquefaction resistance. This study confirms that deposition angle is a critical factor governing the liquefaction resistance characteristics of sand, and that electrical resistivity provides an effective means of quantifying this resistance.

       

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