南疆盐渍土路基盐分迁移特性及阻盐技术研究

摘要

In order to research the characteristics of salt migration from urban road subgrade in the process of operation in saline soil area southern Xinjiang, long-term monitoring experiment of salt migration was carried out under the condition of natural environment.This experiment relied on the typical test section of JunKen Road exten-sion project in Alar.Analysis the salt infitrative way to subgrade and pavement, and put forward targeted measures on the basis of measured data.The experimental results showed that salt migrated from both sides of road to road center in the transverse direction and reached the dynamic balance finally.And salt migrated from top to bottom in the vertical direction,and salt gathered in different materials boundaries.The first layer of salt was situated in gra-ded gravel supply.The second layer of salt was situated in natural graded gravel cushion.The third layer of salt was situated in up road bed.To do this, the paper put forward the measures of cutting off salt and controlling salt, and made numerical simulation by ANSYS.The specific measures were that concrete water retaining wall was set be-tween both sides of road and green belts, in order to stop water of green belts from infiltrating pavement structure layer.At the same time separation layer constituted aeolian sand was set on the top surface of subgrade soil, in or-der to stop capillary water from infiltrating pavement structure layer.%为研究南疆盐渍土地区城市道路在工后运营过程中路基盐分运移特性，依托阿拉尔市军垦大道延伸段工程，选取有代表性的试验路段，进行了自然环境条件下路基盐分迁移长期监测试验。基于实测数据，分析了盐分渗入路基路面的途径，提出了相应的隔断措施。试验结果表明：在横断面方向，即同一埋深不同水平距离位置的盐分由路两侧向路中心逐渐迁移，最后达到一种动态平衡；在竖直方向，即同一水平距离不同埋深位置的盐分由下向上迁移，并且在不同材料分界处出现聚盐区域。自上而下依次为，第一层处于级配砾石下基层中，第二层处于天然级配砂砾垫层中，第三层处于路基土上路床中。为此，提出双向截盐控盐的隔断措施，并通过ANSYS进行数值模拟，即在道路两侧与林带之间设置混凝土挡水墙阻断林带水携盐渗入路面结构层，在路基土顶面采用风积沙隔断层抑制毛细水携盐渗入路面结构层。