土石坝坝基覆盖层动力特性参数试验研究

Experimental studies on dynamic characteristic parameters of covering layer of earth rockfill dam foundation

  • 摘要: 采用室内动力特性试验和现场剪切波速测试,对某水电站土石坝坝基各土层最大剪切模量进行了分析。其中现场剪切波速测试分别采用了单孔法和跨孔法,共获得4组剪切模量随深度变化的曲线,分析表明,4组曲线的变化规律一致,即随深度的增加,土体越密实,剪切模量总体趋势变大;数据的波动性也反应了土性差异对剪切模量的影响。文中还分土层分析了室内试验中的固结比取值、密度取值以及波速测试中土的不均匀性对波速测试和室内试验结果的影响,认为密度取值、土的不均匀性为主要影响因素,固结比为次要因素,试样制备中的密度取值越接近实际土层,所得到的室内试验值与现场测试值就越接近。

     

    Abstract: By use of the indoor tests and field tests on dynamic characteristics of shear wave velocity, experimental studies on the maximum shear modulus parameters of the foundation soil layers of the earth rockfill dam of a hydropower station have been carried out. The shear wave velocity field tests were conducted by the single hole and cross hole methods, and a total of four groups of the shear modulus with the depth curves were obtained. The curves are consistent with the depth of soil layer and their changes, namely, with the increase in depth, the more dense the soil shear modulus, the overall trend of change. In addition, the volatility of the data also reflects the impacts of the differences on the shear modulus of the soil. The indoor tests on soil consolidation ratio values, density values and impacts given by inhomogeneity of the soil under the wave velocity tests on the results from wave velocity tests and indoor tests are also discussed in this paper. The analysis results indicate that the density values and the inhomeqeneity of the soil are the main influence factors, and the consolidation ration is the secondary. The research results show that the density values of the sample preparation are close to the actual soil layer, and the experiment values are close to the test values obtained from the field.

     

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