【作者】 周迅；

【导师】 姜月华；

【作者基本信息】 中国地质科学院 ， 地质工程， 2007， 硕士

【摘要】 加油站地下储油罐的渗漏,造成土壤及地下水的污染。国内目前对这一现象的关注程度还不高,且尚未有比较高效率的探测手段。地质雷达作为一种物探手段,应用于环境地质调查已有若干年历史,但在地下水及土壤的有机污染调查方面,特别是轻质石油烃的污染调查,国内尚未见诸报道。作为一种尝试,笔者使用地质雷达对苏南地区一些加油站进行了调查,并分析了影响渗漏概率和污染物扩散的条件。验证了地质雷达在苏南地区的适用性,为推广地质雷达的适用范围和对该问题的后续研究提供了参考经验。同时也对苏南地区加油站渗漏污染的现状和趋势进行了调查估算,为相关部门对这一问题的管理和决策提供了资料和依据研究显示,大多数老旧加油站存在不同程度的渗漏,在29个被调查对象中,有21座存在不同程度的渗漏,占被调查加油站总数的72.4%;渗漏特征较为典型的有18座,占总数的62.1%。15年以上的20座加油站中,12座存在渗漏,且均为典型渗漏。即在具有典型渗漏特征的加油站中,15年以上的老旧加油站占2/3。所有被调查的加油站中,15年以上的共有20座,这类老旧加油站发生渗漏的概率约为60%。已开展地质雷达工作表明,在砂泥互层的地质条件下,地质雷达能够比较准确的探测深度范围在0.5～15米的土壤及地下水中的的有机污染。污染场地的水样分析证实了雷达探测结果。虽然粘土的高导电性虽然会降低雷达的探测深度,但却能增大背景与有机污染物之间的雷达特征差异,从而使雷达的探测准确性上升。污染羽在雷达图像上基本显示高阻的强反射特征,反映了污染物是以液态的形式存在的。对场地背景条件的分析则显示,加油站建设历史、包气带岩性、含水层渗透性、地下水位、油罐容积、场地荷载、地面覆盖程度对油罐的渗漏概率,污染的扩散速度都有影响,且存在相互联系。其中,建设历史是影响渗漏发生的主要因素,而包气带岩性、含水层渗透性则是影响污染扩散速度的主要因素。加油站历史越久,渗漏发生概率越高,包气带和含水层渗透性越好,污染扩散速度越快。值得注意的是,污染物浓度的变化将导致其雷达图像特征的变化,如何将这种浓度变化和雷达数据进行定量关联,将是一个值得研究的方向,这将有助于使用地质雷达快速监测污染物的衰减和降解过程。更多还原

【Abstract】 The leakage of underground oil storage tank leads to the contamination of soil and groundwater. There is no high concentration on the phenomenon and no high efficiency method to detect the leakage contamination. Ground penetrating radar(GPR),has been used as a geophysic method in environment geology investigation for several years, but it hasn’t been reported in china as a method in groundwater and soil organic contamination investigation especially the petroleum-derived hydrocarbons contamination.As a trying, the author investigated several gas station in South Jiangsu province by GPR and analysis the conditions which affect the probability of leakage and diffiusion. The applicability of the GPR in south Jiangsu province were certified, which provide the experience to the popularilize the GPR and research the problem further. The situation and the trend of the leakage contamination of gas station in South Jiangsu province were also estimated, which provide the government imformations and basis to make dicision and administrate.The research shows that most of the old gas station has the problem of leakage. Leakage was detected in 21gas station. It means 72.4% of the 29 gas station which was investigated were detected to leak. Typical leakage character were found in 18 gas station and these station dominate 62.1% of all the 34 cases.12 gas station which have typical leakage character are older than 15 years age. It means that 2/3 of those gas station with typical leakage character are old ones. That is to say the probability of leakage in old gas station is 60%.The result of GPR survey shows that GPR can detect the organic contaminant disributing from 0.5 meter to 15 meter beaneth the ground under the conditions of sand-water interlayer. High electronical conductivity of clay can reduce dephth of the GPR detection but can increase the difference of the conductivity between the background and organic contaminant, which can increase the accuracy of the GPR. The analysis to the sample from the ground in which contamination were deteced certified the result of GPR survey. Strong reflection character indicated high electronical resistance were observed in the GPR image of contamination plume, which indicates that the contaminant exist in liquid state.The analysis to the environment and geology conditions of these gas stations shows that the history, the lithology of the unsaturated zone, the permittivity of the acquifer, the water table, capacity of the UST, the load to the ground, and the cover of the ground can affect the probability of the leakage and the speed of expansion of the contaminants. These facters are also affect each other. In all these facters history is the main facter to the leakage probability. In the other hand the lithology of the unsaturated zone and the permittivity of the acquifer dorminant the speed of contaminant’s expansion. The older the gas station is, the high leakage probability will be and the high the permittivity of unsaturated zone and the acquifer is, the high the speed of contaminant’s expansion will be.It is worthile to attention that the variety of the contaminant concentration will lead the variety of the Character of the GPR image. It is necessary to relate the variety of the concentration to the data of the GPR quantificaitonally, which is hepful to surpervise the process of the attenuation and biodegradation of the contaminants.更多还原