气候边缘区膨胀土抗剪强度影响因子显著性研究

Study on the Significance of Factors Influencing Shear Strength of Expansive Soils in Climatic Marginal Zones

目的确定工程设计中气候边缘区膨胀土抗剪强度关键影响因子。方法基于不同初始状态气候边缘区膨胀土三轴试验数据,采用显著性分析理论研究初始状态对气候边缘区膨胀土抗剪强度的影响。结果当压实系数为0.90时,冻融循环次数及初始湿度显著性分析结果为Ⅰ级;最优含水率状态(w=20%)下,压实系数显著性分析结果为Ⅱ级。结论周期性冻融作用下不同初始状态膨胀土黏聚力整体呈衰减趋势,而内摩擦角却呈现出一定的增长趋势,其中冻融循环次数、初始湿度为影响膨胀土内摩擦角和黏聚力的关键因子。

There are many factors affecting the shear strength of expansive soils in the climatic fringe zone,and the strength of soils in different initial states has large variability,so it is necessary to determine the key influencing factors in engineering design.Based on the triaxial test data of swelling soil in the climate edge area with different initial states,the effect of initial state on the shear strength of swelling soil in the climate edge area was studied by using the theory of significance analysis.The results show that the cohesive force of swelling soil in different initial states under the action of periodic freezing and thawing shows an overall decreasing trend,while the internal friction angle shows a certain increasing trend.When the compaction coefficient is 0.90,the number of freeze-thaw cycles and initial humidity are the key factors affecting the internal friction angle and cohesion of expansive soils,and the significance analysis results are grade I.Under the optimum moisture content condition(w=20%),the compaction coefficient has the second most important effect on the internal friction angle and cohesion after the effect of freeze-thaw cycles,and the significance level isⅡ;while the freezing temperature only has a certain effect on the cohesion,and has almost no effect on the internal friction angle.