季冻区低路堤土基强度与影响因素相关性

对吉林省高等级低路堤公路填土高度与最大冻深进行了调研,该地区低路堤填土高度为0.0~2.2m,钻孔数据表明路基最大冻深为距路表1.6~2.4m。选取3种不同塑性指数的路基土,采用正交表L16(45)进行了试验设计,应用静力成型法,使得土体在设定的含水率和压实度的水平下成型,并经历不同的冻融循环次数后,分别测试土体的无侧限抗压回弹模量。试验结果表明:1)对同一种土质,影响因素的大小排序为:含水率冻融次数压实度。2)随着含水率增大,土基强度接近线性减小;随着冻融次数的增加,土基强度逐渐减小,前2次冻融影响较大,之后幅度变小趋于稳定;随着压实度的增大,土基强度逐渐增大,增大幅度较小。3)采用指数函数对3种土的室内试验数据进行多元非线性拟合,拟合结果较好。

Influencing Factors of Low Embankment Soil Subgrade Strength in Seasonally Frozen Region

Through the investigation of filling height and freezing depth of the low embankment high-grade highway soil in Jilin Province,the filling height of the low embankment is found in the range of 0.0 m to 2.2 m in the investigated region.The maximum frozen soil depth is 1.6 m to 2.4 m based on the drilling data.Three kinds of embankment soils with different plasticity indices were selected from seasonal frozen soil regions.The testing schedules were made with the method of orthogonal design (L1 6 (4 5 )).By using the static molding method,the soil samples were compacted differently in its different moisture contents and compactness. After setting freeze-thaw cycles,the unconfined compressive resilient modulus of the soil samples were tested respectively.For the same kind of soil under the different influencing conditions,the experiment results show that the influence of different factors are as following:moisture content > freeze-thaw cycles > compactness.With the increase of themoisture content,the embankment soil strength decreases linearly;with the increase of freeze-thaw cycles,the embankment soil strength decreases,the first and second cycles create a greater impact on embankment soil strength.With the increase of compactness,the embankment soil strength increases, but increasing percentage is small.According to the indoor experiment data,the exponential function is adopted for multiple nonlinear fitting that deliver good results.