恰拉水库周边土壤盐渍化分析及防治措施初探

为探究治理平原水库周边盐渍化问题的措施,以恰拉水库为例,在非饱和土力学理论的基础上,利用ABAQUS有限元软件分别模拟水库完善防渗体系前后坝体坝基的稳定渗流形态,获得了大坝下游的地下水埋藏深度,并将其与地下水临界深度进行对比,以确定土壤盐渍化的范围。结果表明,水库改建前,防渗体系较差,坝后地下水位很高,水库下游土壤盐渍化的范围距大坝2 290m处;水库改建后,完善了坝体坝基的防渗体系,坝后地下水位有所降低,水库下游土壤盐渍化的范围距大坝1 350m处。可见改善水库防渗体系对降低坝后地下水位、减小盐渍化范围的效果明显,可作为防治平原水库周边土壤盐渍化问题的措施。

Analysis of Qiala Reservoir Soil Salinization and Study of Its Prevention Measures

In order to explore the ways for salinization control of soil around plain reservoir, we took the Qiala reservoir for an example. Based on the theory of unsaturated soil mechanics, the FEM software ABAQUS was used to simulate the steady seepage performances before and after improving impervious system of the whole dam separately. And then the buried depth of ground water at downstream of the reservoir was obtained. Finally, the range of soil salinization was determined by comparing with the critical depth of ground water. The results show that before reconstruction of the dam, the impervious system of the reservoir is poor; the groundwater table behind the dam is very high, and the range of soil salinization at the downstream is about 2 290 m from the dam. While after reconstruction, the impervious system of the whole dam has been improved; the groundwater table behind the dam is lower, and the range of soil salinization at the downstream reduces to 1 350 m. As a result, improving the impervious system of reservoir has obvious effects, especially on lowering the groundwater table behind dam and reducing the range of salinization, which can be measures for preventing soil salinization around plain reservoir.