Variable water head sectional permeation coefficient measuring equipment and measuring method

Abstract

The invention provides variable water head sectional permeation coefficient measuring equipment which comprises a falling head micro-water testing device, a double-plug blocking device and a probe, wherein the micro-water testing device comprises a measuring cylinder and a water leakage shock tube which are connected though a water guide tube; the double-plug blocking device comprises a high-pressure air cylinder, a one-way valve, a pressure gauge, a first plug and a second plug which are connected through a gas guide tube from top to bottom in sequence; a gas valve is further arranged between the one-way valve and the pressure gauge; and the first plug, the water leakage shock tube and the second plug are arranged inside the probe from top to bottom in sequence. The invention further provides a method for measuring the sectional permeation coefficient by using the equipment. The equipment is simple in structure, low in cost and convenient to use; and the first plug and the second plug are swelled to block and isolate a section of drilling holes by compressing air using the high-pressure air cylinder, the permeation coefficient of a water-bearing layer near the drilling holes at the sealed section can be measured by using the micro-water testing device, and the measurement result is accurate.

Description

technical field [0001] The invention belongs to the field of geotechnical engineering parameter detection, and in particular relates to a variable water head segmented seepage coefficient measuring device, and also relates to a method for measuring the seepage coefficient by using the device. Background technique [0002] Water injection method or water pumping method are generally used to measure the permeability coefficient of aquifers by using boreholes. Both methods measure the average permeability of the formations exposed by boreholes. However, due to the complexity of geological conditions, the permeability coefficients of formations at different depths are not the same, and some even differ by several orders of magnitude; therefore, these two methods cannot reflect the inhomogeneity of permeability. [0003] At present, the hydraulic pressure method is usually used to measure the segmented permeability coefficient of boreholes, for example, "Drilling Water Pressure T...

AI Technical Summary

Problems solved by technology

However, due to the different construction techniques of drilling and the complex and changeable geological conditions, it is difficult for many drilling holes to meet the above requirements

At the same time, due to the high water pressure in the pressurized water method, it is generally divided into three pressure values ​​(0.3MPa, 0.6MPa, 1.0MPa), so the sealing performance of the plug is very high. For example, the length of the plug required in the above regulations reaches 7.5 times the borehole diameter, that is, the length of the plugging plug required for a borehole with a borehole diameter of 1dm reaches 7.5dm; however, even this is difficult to achieve a good plugging effect

In addition, the pressure water method takes a long time to measure and the cost is high, so it is not practical for projects that are eager to obtain the permeability coefficient of rock and soil

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