济南市富水地层基坑降水与回灌理论计算及试验研究

发布时间：2018-11-09 14:59

【摘要】：济南地区地下水资源丰富,给济南轨道交通建设带来了巨大的困难和挑战。基坑工程降水影响周边环境,不利于济南市的泉水保护,因此考虑采用地下水回灌技术,把抽取的地下水原位回灌到含水层中,保证基坑外一定范围内地下水位不发生明显变化,尽量减少对周边环境的不利影响,同时又可以补给地下水。但目前有关回灌计算理论及相关试验的研究较少且不成熟,缺乏完善的理论计算体系,为此开展基坑降水与回灌理论计算及相关试验研究具有深远的现实意义。本文依托济南轨道交通R1线基坑工程,通过理论分析、模型试验、现场试验和数值模拟相结合的研究方法,对富水地层基坑降水回灌计算理论进行了研究,并通过模型试验和现场试验对计算理论进一步完善,最后将研究结果应用到实际工程中。主要研究工作和相关结果如下:(1)系统地下水回灌计算理论研究。在前人研究的基础上,通过建立地下水回灌的数学模型并进行求解和分析,对单井回灌理论计算公式进行补充完善,并确定回灌影响半径的计算方法。在此基础上,根据水流叠加原理,进一步推求多井抽水、多井回灌、抽水回灌同时进行工况下的稳定流和非稳定流计算公式,此外,根据映象法推导了边界附近的回灌计算公式,进一步完善了现有地下水抽水回灌计算理论。(2)济南市典型砂卵石地层的室内回灌模型试验研究。模型试验真实模拟管井回灌过程,得到地下水渗流场随时间的变化规律,通过对试验数据进行整理分析,验证了管井回灌非稳定流计算理论。(3)现场回灌试验规律性分析及对计算理论的修正。根据济南地区现场回灌试验现象和试验数据,探讨济南地区管井回灌规律,分析回灌效果。针对各种原因引起的实际回灌效率低于理论值的问题,提出降低计算公式中渗透系数的方法。结果表明,实际地层回灌的渗透系数比原地层渗透系数降低2/3～3/4。(4)济南轨道交通R1线沿线某深基坑工程降水回灌方案设计。将回灌计算理论应用到实际基坑降水与回灌方案设计中,通过数值分析软件模拟基坑降水与回灌引起的地下水位变化,优化基坑降水回灌方案。通过对数值计算结果与理论计算结果的对比分析证明了基坑降水回灌设计方案的可行性,同时也验证了抽灌结合计算理论,为实际工程施工提供了借鉴和指导作用。
[Abstract]:Jinan is rich in groundwater resources, which brings great difficulties and challenges to the construction of Jinan rail transit. The dewatering of foundation pit works affects the surrounding environment and is not conducive to the protection of spring water in Jinan. Therefore, considering the use of groundwater recharge technology to recharge the extracted groundwater in situ into the aquifer, It is ensured that the underground water level does not change obviously in a certain range outside the foundation pit, and the adverse effects on the surrounding environment are minimized as far as possible, and the groundwater can be recharged at the same time. However, there are few and immature researches on the theory of recharge calculation and related experiments, and there is no perfect theoretical calculation system. Therefore, it is of great practical significance to carry out theoretical calculation of foundation pit dewatering and recharge and related experiments. Based on the foundation pit engineering of Jinan rail transit line R1, this paper studies the theory of dewatering and recharge calculation of foundation pit in water-rich layer by combining theoretical analysis, model test, field test and numerical simulation. The calculation theory is further improved by model test and field test. Finally, the research results are applied to practical engineering. The main research work and related results are as follows: (1) theoretical study of groundwater recharge calculation. On the basis of previous studies, the mathematical model of groundwater recharge is established, solved and analyzed, the theoretical calculation formula of recharge in single well is supplemented and perfected, and the calculating method of influence radius of recharge is determined. On this basis, according to the principle of superposition of water flow, the formulas for calculating steady and unsteady flow in multi-well pumping, multi-well recharge and pumping recharge simultaneously are derived. Based on the mapping method, the calculation formula of recharge near the boundary is derived, and the existing calculation theory of groundwater pumping and recharge is further improved. (2) the indoor recharge model test of typical sand pebbles in Jinan. The model test is used to simulate the recharge process of pipe wells, and the variation law of groundwater seepage field with time is obtained, and the experimental data are analyzed by sorting out and analyzing the experimental data. The calculation theory of the unsteady flow of recharge in pipe well is verified. (3) the regularity analysis and modification to the calculation theory of the in-situ recharge test. According to the phenomenon and data of recharge test in Jinan area, the recharge rule of tube well in Jinan area is discussed, and the effect of recharge is analyzed. Aiming at the problem that the actual recharge efficiency is lower than the theoretical value caused by various reasons, a method to reduce the permeability coefficient in the calculation formula is put forward. The results show that the permeability coefficient of the actual formation recharge is 2 / 3 / 3 / 4 lower than that of the original formation. (4) the design of the dewatering recharge scheme of a deep foundation pit project along the R1 line of Jinan Rail Transit. The theory of recharge calculation is applied to the design of dewatering and recharge scheme of actual foundation pit. The groundwater level change caused by dewatering and recharge of foundation pit is simulated by numerical analysis software, and the dewatering and recharging scheme of foundation pit is optimized. The feasibility of the design scheme of dewatering and recharge of foundation pit is proved by comparing the results of numerical calculation and theoretical calculation. At the same time, the theory of combined pumping and irrigation calculation is verified, which provides reference and guidance for practical engineering construction.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU753.66

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