高速铁路地基膨胀土膨胀变形试验研究

摘要

以兰新铁路第2双线一处典型原状膨胀土为对象,通过进行厚度为5,10,15和20 cm不同含水率下膨胀量试验,得出原状膨胀土在不同厚度及不同含水率下过程膨胀量,研究含水率和厚度对原状膨胀土过程膨胀量的影响.试验结果表明:厚度一定时,含水率越小原状膨胀土的过程膨胀量越大,含水率越大原状膨胀土的过程膨胀量越小;含水率较低时,厚度对原状膨胀土的过程膨胀量影响较大,含水率较高时,厚度对原状膨胀土过程膨胀量影响较小,通过对试验数据的进一步分析发现,在厚度一定时,含水率和原状膨胀土的过程膨胀量呈良好的对数关系,依据不同厚度对公式参数进行拟合,建立含水率和厚度耦合作用下原状膨胀土过程膨胀量计算模型,模型计算结果与实测数据吻合较好,为今后膨胀土地区的工程建设提供一定的理论支撑.%The effect of moisture content and thickness for the process expansion of undisturbed expansive soil was studied under the second line of Lanzhou to Xinjiang Railway. Through swelling quantity tests for thickness of 5, 10, 15 and 20 cm under different moisture content, the process expansion of undisturbed expansive soil with different thickness and different water content was concluded. Test results show that when the thickness is constant, the larger the water content is, the larger the expansion process of undisturbed expansive soil is, the smaller the water content is, the smaller the expansion process of undisturbed expansive soil is. When the moisture content is low, the thickness has a great influence on the expansion process of undisturbed expansive soil. When the water content is higher, the thickness of the expansive soil has little influence on the expansion process of undisturbed expansive soil. It is found that the expansion process of the undisturbed expansive soil has a good logarithmic relationship with moisture contentin the case of a certain thickness through further analysis of the test data. According to the parameters of the formula, the calculation model of expansive soil under the coupling action of water content and thickness is established. The calculated results agree well with the measured data, which provides some theoretical support for the project construction of the expansive soil area in the future.