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为了对安康膨胀土地区拟建机场工程设计提供必要的基础参数,特在该场地建立了填方边坡稳定性的现场物理试验模型;跟踪测试了边坡在降雨-蒸发循环作用下的一系列变形,进而分析了其演化规律与成因机制。结果显示:(1)新建填方边坡的雨水入渗过程由自由入渗、冲刷入渗及稳定入渗3个阶段组成。在本次试验中;雨水入渗过程大部分处于冲刷入渗阶段,导致其入渗深度有限。(2)对于完整均匀的填方边坡,其变形的发展受到土体膨胀变形的主导作用;在坡顶主要表现为竖直向的胀缩变形;坡面则主要表现为水平向的累积变形;随着深度的加大、降雨次数的增加,变形速率急剧降低。(3)边坡的变形与降雨-蒸发作用密切相关,降雨作用是导致变形陡增的主要因素;蒸发作用是变形发展的必要前提条件。(4)防止边坡在降雨-蒸发作用下的变形破坏应从两方面着手:一是有效减弱其在边坡表层影响范围内土体湿度的变化,二是防止径流对坡面的冲刷、侵蚀作用。
In order to provide the necessary basic parameters for the design of the proposed airport in the expansive soil area of Ankang, a field physical test model for filling slope stability was established at this site. A series of experiments were carried out to test the slope stability under the action of rainfall-evaporation cycles Deformation, and then analyzed its evolution and genesis mechanism. The results show that: (1) The infiltration process of the new fill slope is composed of three stages of free infiltration, infiltration infiltration and steady infiltration. In this experiment, most of the rainfall infiltration process is in the infiltration and infiltration stage, resulting in a limited infiltration depth. (2) For a complete and uniform filled slope, the development of deformation is dominated by the expansion and deformation of the soil; at the top of the slope, the vertical expansion and contraction deformation is mainly manifested; while the slope surface is mainly characterized by horizontal cumulative deformation With the increase of depth and the increase of rainfall times, the deformation rate decreases sharply. (3) The deformation of the slope is closely related to the rainfall-evaporation. Rainfall is the major factor leading to the sharp increase of the deformation. The evaporation is the necessary prerequisite for the development of the deformation. (4) Prevention of deformation and failure of slope under rainfall-evaporation should proceed from two aspects: firstly, it can effectively reduce its change of soil moisture within the influence range of slope surface; secondly, prevent runoff from scouring and erosion on slope surface .