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为了分析膨胀土地区路堤初始开裂行为,使用ABAQUS模拟了典型路基断面的路堤顶部张拉应力峰值和峰值位置的改变.模拟结果表明:基质吸力在膨胀土地基顶部呈凹形分布,并且引起了地基和路堤的不均匀变形.路堤顶部张拉应力峰值并非位于某一固定点,而是随着蒸发的持续逐渐朝路肩移动.蒸发强度越大,随着地表蒸发的进行,路堤顶面张拉应力峰值增大越快,其位置越靠近路肩;厚层膨胀土有助于路堤顶面张拉应力峰值快速到达其抗拉强度阈值,而膨胀土厚度小于1.5m时,地表蒸发30天,路堤不会开裂;路堤越高,路堤顶面张拉应力峰值越小,其位置越远离路肩.因此,薄层膨胀土土层上修筑较高路堤可以减少路堤裂缝的形成.
In order to analyze the initial cracking behavior of embankments in expansive soils, the change of peak tensile stress and peak position at the top of embankments of a typical embankment is simulated using ABAQUS. The simulation results show that the matrix suction is concavely distributed on the top of expansive soils, And the uneven deformation of the embankment.The tensile stress peak at the top of the embankment is not located at a fixed point, but gradually moves toward the shoulder as the evaporation continues.The larger the evaporation intensity, the higher the tensile stress of the embankment as the surface evaporates The faster the peak value increases, the closer its position to the shoulder. The thicker expansive soils can help the peak tensile stress at the top of the embankment reach the threshold value of tensile strength rapidly. When the expansive soil thickness is less than 1.5m, the surface evaporates for 30 days. Will crack. The higher the embankment, the smaller the peak tensile stress of the embankment is, and the farther the embankment is, the farther away from the shoulder. Therefore, the construction of high embankments on thin-layer expansive soil can reduce the formation of embankment cracks.