Method for determining upper threshold of groundwater level depth in water resources preservation during mining

Abstract

The invention belongs to the field of mining environmental engineering, and discloses a method for determining an upper threshold of a groundwater level depth in water resources preservation during mining, and the method comprises the following steps of obtaining parameters of a soil water characteristic curve: measuring a suction-moisture content relationship under the condition of soil dehumidification by a sand funnel method, and obtaining parameters of the soil water characteristic curve by using RETC software, wherein the parameters comprise the residual water rate thetar, saturated waterrate thetas, reciprocal alpha of an air entry value and shape parameter; calculating two limiting matrix suctions corresponding to the capillary action of ground water, that are, a value of air-entrysuction hb and a matrix force value hmax corresponding to the residual water rate; and calculating the minimum groundwater level depth LG=deltahcap=hmax-hb between the groundwater and topsoil when the liquid hydraulic connection is broken, wherein LG represents the upper threshold of the groundwater level depth in water resources preservation during mining. The method provided by the invention can determine the upper threshold of the mining groundwater level depth only requiring the measurement of hydraulic parameters of the soil indoors in advance, without carrying out large-scale regional surveys, thereby obviously reducing costs.

Description

technical field [0001] The invention belongs to the field of mining environment engineering, and relates to a method for determining the upper limit threshold value of buried depth of groundwater in water-conserving coal mining, and is a calculation method suitable for the minimum buried depth allowed to be reached by groundwater level in coal seam mining in arid and semi-arid areas. Background technique [0002] At present, the existing technology commonly used in the industry is as follows: through hydrogeological surveys, find out the distribution of the buried depth of the upper and lower groundwater levels in the area and the salinity content of the soil surface corresponding to each groundwater level, and then determine the occurrence of soil salinization through mathematical statistics. The critical water level buried depth. Not only is it time-consuming, labor-intensive, expensive, and the resolution is low, but the conclusions drawn generally cannot be promoted and ...

AI Technical Summary

Problems solved by technology

But so far, there has not been a general method to determine the critical water level through theoretical calculations, which has become a technical bottleneck for the protection of the ecological environment in mining areas.

[0005] To sum up, the problem existing in the existing technology is that the minimum threshold value of the buried depth of the groundwater table determined through the hydrogeological survey is only effective for the specific soil in the survey area, and cannot be widely used.

[0008] In the prior art, the determination of the upper threshold of the buried depth of the groundwater table through the statistical analysis of the regional survey results requires a large workload, cumbersome procedures, and unreliable results.

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