Inner tube drawdown double tube method of determining hydrogeological parameters of aquitard of inner tube on site

Abstract

The invention discloses an inner tube drawdown double tube method of determining hydrogeological parameters of an aquitard of an inner tube on site. The method comprises the following steps: firstly, forming an inner tube drawdown double tube testing model of determining the hydrogeological parameters of the aquitard of the inner tube on site, and deducing a flow formula analytical solution of a unit horizontal area of the aquitard of the inner tube under a condition that the water head of the aquitard of the inner tube is reduced by a certain constant (the water level is not lower than the top surface of the aquitard) while the underground water level on one side of the outer tube is maintained unchanged based on the double tube testing model; and giving out measured time-dependent experimental data of a flow of a water pump of the inner tube, and determining the conductivity coefficient, osmotic coefficient and water storage rate of the aquitard by means of a fitting curve method. The method disclosed by the invention is easy to operate, more in acquired parameters and high in precision, solves the key technical problem that the hydrogeological parameters of the aquitard cannot be determined in situ at present, overcomes the error due to testing in a laboratory after field sampling, and has good promotion and application values.

Description

technical field [0001] The invention relates to an inner pipe drawdown double-pipe method for determining the hydrogeological parameters of the inner pipe aquitard on site, in particular to a method for determining the hydrogeological parameters such as the 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 hydrogeologica...

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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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