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选取柴达木盆地大柴旦盐湖采卤区作为试验区,对区内地层剖面盐渍土的基本类型进行划分,即通过测定Na+、Mg2+、Cl-等易溶盐离子的方法,得出区内采卤区地层剖面盐渍土的主要类型是以亚氯盐渍土为主。在此基础上,对盐渍土进行扰动试样的室内直剪试验研究,以获取抗剪强度指标粘聚力c值与内摩擦角φ值。试验结果表明,该区盐渍土的含盐量由地表开始向下呈逐渐降低趋势,即由地表的6.89%降到地下4.5 m处的1.11%。粘聚力c值主要受试样含水量大小的影响,表现出随着含水量的增加,粘聚力c值呈降低现象,即当含水量由19.8%上升至23.3%时,粘聚力c值由35.4 k Pa下降至24.9 k Pa,下降率约为29.7%;而当含水量由23.3%下降至17.4%时,粘聚力c值则由24.9 k Pa上升至34.1 k Pa,上升率约为36.9%。内摩擦角φ值则受试样粒径影响相对较为明显,随着试样中粘粒含量的增多,粗粒含量相对减少,内摩擦角呈逐渐增大的趋势,即由24.1°上升至33.3°,增加率约为37.3%。随着试样中含盐量的增加,粘聚力c值和内摩擦角φ值均呈线性增加趋势。该研究成果将有助于进一步探讨含水量、颗粒大小以及含盐量对盐渍土试样抗剪强度变化的影响,且对区内盐田及其相应的基础设施建设有一定的理论指导意义。
This paper chooses the mining area of Dachaidan salt lake in the Qaidam Basin as the experimental area, and divides the basic types of the saline soil in the stratigraphic section of the Qaidam Basin, that is, by measuring the soluble salt ions such as Na +, Mg2 + and Cl-, The main type of salinized soil in the lithofacies profiles is chlorous saline soil. On this basis, the indoor direct shear tests on the disturbed samples of saline soils were conducted to obtain the values of cohesion c and internal friction angle φ of the shear strength index. The results show that the salt content of saline soils in this area decreases gradually from the surface to the bottom, from 6.89% of the surface to 1.11% of the ground at 4.5 m. Cohesion c value is mainly affected by the size of the water content of the sample, showing that as the water content increases, the cohesion c value decreased, that is, when the moisture content increased from 19.8% to 23.3%, the cohesion c The value decreased from 35.4 kPa to 24.9 kPa, and the rate of decrease was about 29.7%. When the water content decreased from 23.3% to 17.4%, the cohesion c increased from 24.9 kPa to 34.1 kPa, 36.9%. The value of the internal friction angle φ is affected by the particle size of the sample obviously. With the increase of the clay content in the sample, the content of the coarse particles decreases and the internal friction angle gradually increases, from 24.1 ° to 33.3 °, the increase rate is about 37.3%. With the increase of salt content in the sample, the cohesion value c and the internal friction angle φ value all showed a linear increase. The research results will help to further explore the effect of water content, particle size and salt content on the shear strength of saline soil samples, and provide some theoretical guidance for the construction of Yantian and its corresponding infrastructure.