基于主成分分析法的膨胀土膨胀力预测

为探究引起膨胀土膨胀的内在因素与极限膨胀力的关系,以哈密地区膨胀土为试验材料,提取该地区膨胀土的蒙脱石含量、伊利石含量、阳离子交换量、自由膨胀率4个指标作为模型因子,采用主成分分析法(PCA)建立哈密地区膨胀土综合膨胀能力判定式Z值,并将Z值与极限膨胀力进行相关性分析,从而验证Z值准确性。分析结果表明:以上4个指标满足KMO与Bartlett检验,可进行主成分分析;Z值各项指标系数均为正值,Z值可以衡量膨胀土的膨胀能力;Z值与膨胀力满足显著相关性分析,sig值小于0.01,二者具有显著相关性;建立了Z值与膨胀力的函数关系式,Z值与膨胀力呈现正相关关系,在误差允许范围内,通过Z值可预测极限膨胀力大小。研究成果为膨胀土地区灾害防治提供一定理论支撑。

Principal component analysis-based prediction of swelling force of expansive soil

In order to explore the relationship between the intrinsic factor to cause the swelling of expansive soil and the ultimate expansion force，the expansive soil from Hami District is taken as the experimental material，from which four indexes，i. e. montmorillonite content，illite content，cation exchange capacity and free expansion rate，are selected as the factors for model， and then the Z value for discriminating the comprehensive expansion capacity of expansive soil in Hami District is established with the principal component analysis，while the correlative analysis between the Z value and the ultimate expansion force is made， thus the correctness of the Z value is verified. The analysis result shows that the four indexes mentioned above can meet KMOandBartlett’s test and then can be used for the principal component analysis. The coefficients of all the indexes for the Z value are positive，thus the Z value can be used for measuring the swelling capacity of the expansive soil. The Z value and the swelling force satisfy the significant correlative analysis and the sig value is less than 0. 01，thus a significant correlation is there between both of them. The function relation between Z value and swelling force is established，which presents a positive correlation within an allowable range of error. Z value can be used for predicting the magnitude of the ultimate expansion force，and then provide a certain theoretical support for the relevant disaster control within the region of expansion soil.