采用HYDRUS模拟采煤沉陷地裂缝区土壤水盐运移规律

Simulation of soil water and salt movement in mining ground fissure zone based on HYDRUS

煤炭的开采带来经济快速发展的同时也会带来一系列的生态环境问题,其中采煤沉陷产生的地裂缝是最直观的一种,其分布广、对土地破坏性大、对周边植物生长影响严重。西部矿井水矿化度较高,极易产生次生盐碱化,裂缝区的水盐运移对于该区域植物生长具有潜在的影响。为探究采煤沉陷地裂缝对土壤中水盐运移规律的影响,通过室内模拟试验,研究不同土壤盐浓度条件下,裂缝区土壤水盐分布特征,并运用数值模拟方法,建立采煤地裂缝土壤水盐运移模型,采用HYDRUS 2D软件进行模拟,将模拟值与实测值对比,结果表明:HYDRUS模拟数值与实测值呈现出相同的规律,满足精度要求,说明HYDRUS能够较好的模拟裂缝区域内的水盐运移。在56 d的模拟试验中,裂缝区土壤含水量在前3周为快速下降期,4~5周为中速下降期,5周之后为稳定期。越靠近地裂缝处土壤含水量下降越快,对于台阶为20 cm的地裂缝,其水盐含量影响范围约为水平距离裂缝45 cm处,地裂缝区域内土壤盐分运移趋势与水分基本一致,遵循盐随水行的运移规律,裂缝区含盐量有向下迁移的趋势,具有减轻次生盐碱化发生的潜力。

Coal mining brings rapid economic development and also results in a series of ecological and environmental problems.Among them,the ground fissures produced by coal mining subsidence are the most intuitive one.They are widely distributed,destructive to land,and impacting on the growth of surrounding plants.The impact is severe.The salinity of the western mine water is relatively high,and secondary salinization is easy to occur.The water and salt migration in the fracture zone has a potential impact on plant growth in the area.In order to study the effect of mining ground fissures on the water and salt transport in soil,this paper used simulated fissure experiments in the laboratory to study the artificial simulation of soil water and salt distribution in the ground fissure area under the different soil salt solubility conditions features.In addition,the numerical simulation software HYDRUS 2D was applied to establish the soil water and salt transport model under the condition of mining ground fissures.The simulation was carried out by using the simulation to compare the measured values with the simulated values.The research results show that HYDRUS simulation values and measured values show the same rules,which meet the accuracy requirements,indicating that HYDRUS can better simulate the water and salt migration in the fracture area.In the 56-day simulation test,the soil water content in the cracked area showed a rapid decline period in the first 3 weeks,a moderate-speed decline period in 4 to 5 weeks,and a stable period after 5 weeks.The closer to the ground fissure,the faster the soil water content decreases.The ground fissures can reduce the surrounding soil moisture content and accelerate the loss of soil water.For ground fissures with 20 cm steps,the impact range is about 45 cm away from the fissures.The soil salt movement trend in the ground fissure area is basically consistent with the water trend,following the law of salt moving with water movement.This research has certain reference value and scientific significance for the ecological management of coal mining subsidence areas.