提出了坝基深厚覆盖层密度辨识的基本方法,对大渡河双江口水电站河床覆盖层进行了8孔、106点的现场旁压试验,在对其进行统计分析的基础上建立了威布尔分布模型,依据试验数据对模型的参数进行了最小二乘估计,并对威布尔分布进行了拟合优度检验。依据现场勘查所得的级配曲线,通过20组室内模型试验探讨了旁压模量与模型密度和上覆压力的对应关系,得出了旁压模量与模型密度间服从对数关系的规律。在此基础上对深厚覆盖层的密度进行随机模拟,得到了覆盖层各亚层密度的模拟值,通过与勘探结果的对比,证明了该方法的实用性。
Density identification method of dam foundation deep overburden is put forward. The Weibull distribution model is established based on 8 holes, 106 points field pressuremeter tests in dam foundation deep overburden of Shuangjiangkou Hydropower Station. Parameters of the distribution are estimated by least-squares method based on the test results above; and the goodness-of-fit of Weibull distributions is tested. The corresponding relations among pressuremeter modulus, density and pressure are investigated by 20 sets of model tests using the givengrading curve acquired in field exploration. The exponential relation of pressuremeter modulus and density is determined by model tests. Based on those above, the authors carry out randomly numerical simulation of the density of dam foundation deep overburden. The simulated density of second-overburden is obtained and its practicability is proved through comparing with exploration results.