变质软岩路堤填料湿化变形规律研究

采用双线法,对十堰—天水高速公路安康西段的变质软岩路堤填料,在两种密度条件下进行了大型三轴试验,同一竖向偏应力下饱和与风干状态填料应变的差值即为湿化引起的应变,对其变化规律进行分析,结果表明:填料的湿化变形发展呈两个阶段,临界湿化应变的大小与竖向偏应力和围压的比值密切相关,同一密度、不同围压条件下的各曲线变化点的湿化应变值较为一致;填料密度增大,则变化点的湿化应变值增加,说明密度和围压不仅影响湿化变形的大小,还影响其发展规律。根据3种围压条件下的试验结果,对两种密度的填料,分别建立了填料湿化变形发展规律的公式,并用新的第4种围压条件下的试验结果进行校核,吻合程度较好。该公式可用于分析高速公路施工中路堤湿化变形的大小及发展规律。

Large-scale triaxial tests on metamorphic soft rock embankment filler for wetting deformation characteristics

Large-scale triaxial tests on metamorphic soft rock embankment filler at Ankang west section of Shiyan-Tianshui expressway are conducted with double lines method respectively and under two kinds of densities. Variation of wetting strains (i.e., the differences between strains of dry and saturated states under the same vertical deviatoric stress) is analyzed. Results show that, there are two development stages of filler wetting strain curves. The positions of the change points of the two stages are closely related to the ratio of vertical deviatoric stress and confining pressure. Values of the wetting strain at change points on the curves of fillers with same density under different confining pressures are comparably consistent. They can become larger as the filler density increases. This indicates that the density and confining pressure have effects on both the magnitude and the rules of wetting deformation. Empirical formulas of wetting deformations and vertical deviatoric stress are put forward using the test results of three kinds of confining pressures. and the formulas are then verified with the test results of a new kind of confining pressures. These formulas can be applied to analyzing the laws of embankment wetting deformation in highway construction.