Double-pipe method with inner pipe drawdown for determining hydrogeological parameters of aquitard with outer pipe on site

Abstract

The invention discloses an inner tube drawdown double-tube method for determining the outer tube aquiclude hydrogeological parameter in site. According to the method, firstly, an inner tube drawdown double-tube test model with the determined outer tube aquiclude hydrogeological parameter is formed in site; on the basis of the double-tube test model, a flow rate formula analytic solution of the outer tube aquiclude unit level area under the conditions that an inner tube water head is reduced by a certain constant (the water level is not lower than the top surface of the aquiclude) but the underground water level at one side of an outer tube aquiclude post body keeps unchanged is deduced; then, experiment data based on measurement of the change of the flow rate of a Marriotte bottle at the upper part of the outer tube along with time is given; a wire fitting method is used for determining the aquiclude conduction coefficient, the seepage coefficient and the water storage rate. The method provided by the invention has the advantages that the operation is easy; the obtained parameters are many; the precision is high; the technical problem that the aquiclude hydrogeological parameter cannot be determined in situ in site in the prior art is solved; the defect of errors during test in laboratories after the sampling in site is overcome; good popularization and application values are realized.

Description

technical field [0001] The invention relates to a double-pipe method for determining the hydrogeological parameters of an aquitard on the spot with an inner pipe, in particular to a method for determining hydrogeological parameters such as conductivity, permeability coefficient and water storage rate of the aquitard on site. Background technique [0002] With the rapid development of society, the resource and environmental problems of land subsidence caused by the release of water from the aquitard are becoming more and more serious. In the Yangtze River Delta in China alone, the area of ​​land subsidence greater than 200 mm caused by groundwater overexploitation has accounted for one-tenth of the area, and the largest cumulative subsidence has reached 2.80 m, which has caused economic losses of 50 billion U.S. dollars. In addition, groundwater Pollution also spreads from the upper aquifer to the deep. All of these are closely related to the hydrogeological properties of th...

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Problems solved by technology

[0003] Although there have been many studies on the determination methods of hydrogeological parameters of aquifers, most of them are methods of field pumping (or water injection) tests, however, there are few studies on the determination methods of hydrogeological parameters of aquitards adjacent to aquifers , this aspect is because we have always considered the aquitard to be an aquitard or a relatively aquitard, and its contribution rate as a water resource is very small, so little special attention has been paid to it and necessary research has been obtained, and the aquitard is often regarded as Neglected or treated as a boundary; on the other hand, there is also a lack of an effective principle and method that can be used to directly determine these parameters on site. For example, the commonly used field pumping test to determine the hydrogeological parameters of aquifers is not applicable Aquitard

In addition, even if there is experimental research on determining the hydrogeological parameters of the aquitard, it is limited to indoor research. At present, there is no practice of experimental theory and methods for in-situ research on the determination of the hydrogeological parameters of the aquitard. Therefore, this paper The proposal of the invention can fill the blank of the technical method for determining the hydrogeological parameters of the aquitard on site, and has strong application value

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