SU1633107A1 - Method of determining seepage factor of soils of aeration zone - Google Patents

Abstract

This invention relates to hydrogeology. The purpose of the invention is to improve the accuracy of determining the filtration coefficient. Before the beginning of the study, water is poured with increasing pressure in time into the gap between the inner and outer rings, which are buried in the ground and concentrically located, until the ground surface is completely soaked over the area of the inner ring. Filtering water with a constant pressure through both rings, measuring the flow rate of water along the inner ring, and determining a filtration coefficient of 1 or more.

Description

This invention relates to the field of hydrogeology.

The purpose of the invention is to improve the accuracy of determination.

The drawing shows a scheme for carrying out the method.

In the drawing, the following designations are accepted: soils 1 of the aeration zone, hole 2, inner ring 3, outer ring 4, quick-release cap 5 annular with branch pipe for connecting water supply pipes 6, flowmeter 7, device 8 for measuring water pressure (pressure), direction 9 of water movement under increasing pressure; direction 10 of movement of water under the bottom of the inner ring under the action of capillary suction.

For the implementation of the method, two different diameters of rings 3 and 4 are concentrically installed in hole 2 by pushing them to a certain depth to the bottom of hole 2 to a certain depth.

The outer 4 rings are initially attached on an airtight base to a rapidly removable ring head 5. having a threaded port at the top to which a water supply pipe of 6 dt is connected to the feed under increasing pressure of water, followed by filtration and lateral spreading. Under the influence of capillary suction, amplified by the increasing pressure of water filtering down over time, with diametrically opposite points of annular flow gradually coming closer to the depth, the pore water displaces the air from the first space from bottom to top, which completely displaces air bubbles from the pores of the soil. on the surface of the bottom of hole 2, under the inner ring 3, the injection of water into the water supply pipe 6 is stopped and waited

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water flow from it and the tip 5 then remove the tip 5 and begin to conduct the experiment according to the known technology with a separate supply of water at the same level into the space between the outer and inner rings and into the inner ring 3. At the end of the experiment, calculate the coefficient filtering Kf using the value of the cross-sectional area of the inner ring 3 and the flow rate of water passing through this section.

In the presence of highly dried soils, the aeration zone, and the water-repellent properties due to the wet hysteresis effect on them on the sandy zeoins, additionally add a third ring of larger diameter than ring 4 to the bottom of the hole 2. at the top of a new ring and ring 4, hermetically quick-detachable tip, similar in design to tip 5, and supply water with increasing pressure at the tubes connected to both ends, with a higher rate of compared with tip 5 and extra tip. After fully soaking the bottom of the hole under the inner ring, proceed to the operations described above.

In the case of the aeration zone in the upper part of the pound 1, there are possible small anomalies of the filtration properties of these soils, for example, water-repellent crys of sandy clayey rocks, micro-fractures, etc., to determine whether such anomalies contain both (or three) rings on the depth of intersection of at least two soil differences. Then, all operations and procedures are performed consistently that ensure the soaking of soils under the inner ring before the start of the experiment. After that, the top cap (head cap) is removed and the bottom of the hole is deepened over the entire surface to reach the normal depth above the bottom of the base of the rings, soil samples are taken for water filtration visual and laboratory observations and studies, after which, according to the established methodology, calculation of Kf of the main parameters, in parallel determined by selected samples visually and by laboratory means additional data. According to the results of the determination, the necessary computational corrections are made in the determination of Kf or the experiments are repeated to determine the main hydrogeological parameters.

Example Consider carrying out the invention using a third additional ring. For the basis we take two standard rings with a diameter of 500 and 250 mm, height 200 mm, design NS Nesterov. The third ring may be located outside the larger diameter of the ring, between the larger and smaller, and within the smaller one.

We choose the latter case from the calculation of the relatively small thickness of the rocks of the aeration zone, presented by sandy loams and loams

The value of the filtration coefficients for these rocks is 0.1-0.5 and 0.01-0.1 m / day, respectively; the rate of rise (advancement) of capillary waters at a height of 30-40 cm is 17-14 and 16 12 cm / h, and at a height of 50-100 cm, 9-3.1 and 5 0 2.8 cm / h, the highest ascent rate was noted at a height of 20-30 gm and was 31 17 and 26-16 cm / h.

The inner ring of the device considered as an example is 200 mm, the average 250 mm outer 500 mm; The height of each of the three rings is 200 mm. Before the start of the experiment, the rings are provided with a removable head that separates the space between the inner and middle rings of the middle and inner rings into two insulated chambers open below and the upper pipes that connect to the bottom of the feed tubes.

Rings fitted with a tip are set into the bottom of a hole specially prepared for the experiment to a depth of more than half the height of the rings for an example of 175 mm. Both chambers are filled with water, including water-supply pipes connected to the pipes, which in turn are connected with two independent pumping systems, equipped with regulators and pressure and flow sensors.

With the same pressure head, the flow rate of water passing through the annular gap between the outer and middle rings is 7.3 times higher than that between the middle and inner rings. When increasing the relative annular clearance of the outer annular gap relative to the internal COLTED gap, for example, twice the flow rate the external gap also doubles and exceeds 1.6 times the flow rate in the internal gap; The kinetic energy of the first flow is 29.2 times the kinetic energy of the second. Due to this, the boundary between the internal and external flows deviates in axial flow and the deviation in the angle of penetration reaches the full value of the angle, ish 6 °

the inner boundary of the inner annular flow, this angle will reach 9 °.

Starting from the latter, the opposite streams of flow (in diametrically cut) are connected according to the calculation at a depth of 0.63 m,

Taking into account the specific values of the diameters of the inner and middle ring (200 and 250 mm, 25 mm clearance) and the depth of the rings (175 mm), the maximum length of the capillary channel to the surface of the earth is 200 mm. The complete passage of capillary water along the path this length should be somewhat longer than the time of filtration of water in the inner annular gap until the opposite jets are completely closed (depth 0.63 m).

We take as an example the filtration of water in loams - Kf 0 1 m / day (fraction 0.01-0.005 mm). The estimated filtration time for this case should be (capillary speed of 0.125 cm / h) not more than 5 hours. With a hydraulic slope of 1, the time required for filtration to a depth of 0.63 m is at least 6 days. To ensure a value of not more than 5 hours, it is necessary to create a hydraulic slope correspondingly equal to Kin m of an excess water column. The excess / PVH f p. Below the gap between the Hapv and the inner rings should be in the internal gap of 1 7 3, g sweat, completely exclude w / wi, m, II, ea flow on its border with uiieimuv; i orot This corresponds in the external HI to the rank of excessive aspiration i.

The pressure build-up,, ode podody in the external and internal - zazs, j lead at the same time to the narpsts ,,, oy4sg-. Hepe, approvals of the indicated values are in and 0-piped water column in the first and second kgpc PM gaps, not allowing sharp bridges, r-bits and its increase or decrease. and Vider "and wa predominance of pressure on the outside: h; m gap

After the occurrence, the entire surface of the inner ring 01 is covered over the entire surface of the water supply and the water supply to both chambers of the sigilant is repaired by the water supply pipes and the openings, opening the access to the bottom of the hole between the inner and outer shafts; the bottom of the hole is deepened inside the inner ring of the inner ring and between the inside and the middle and also with a large variability of the lithological composition of loams in the area between the middle and large remaining area of the hole bottom (to study the nature of the variability of the composition a vertically) to a depth of 0 75 m to study

lithological heterogeneity of rocks, degree of soaking, and (idrofilnosti take samples of rocks along the meridional section and send them to the laboratory for relevant studies, the number of samples and the place of their selection are selected based on specific conditions; equip the inner ring of the inner ring and between the inner and middle rings regulators for water supply, for example, with Mariotta vessels, the bottom of the middle and inner rings are covered with sand or fine gravel with a layer of 1-2 cm, include regulators and support the inner ring and between the inner and the average height of the water layer 10 cm; experience leads to stabilization of water flow through the inner ring; to improve the accuracy of calculations, it is recommended to measure the infiltration rate by the rate of drop in the pit with the power off for the measurement time, for each such measurement a reduction in the level of 2–4 cm is sufficient. There are several ways to process the loading data in the pits based on the Darcy Nerebrega law with capillary pressure, which introduces an error in the definition of e 20% and in the process taking a long pressure infiltration c Plizknm unit filgrerp coefficient can onptT- pi i s c at a known flow FPI pass fast i and python by formulas;

Q

Kf

W

where v CKPC is CTL, t is dichichnin water but inner ring

W area internal K1l & tsa (pps-shchdt filterg.tsii1

G1 - the standard of the HIT i

So, in RChs (, r-honored gaimer-s with

0- 0.003 m3 / s; KSSTR-IT 0.095 m / day.

Claims (1)

The invention of the method of dividing io -fiqe.nta Soil drainage eo.ch1 aeration including filtrats to, water with a post: with a different pressure through agrofounding into the soil t centrically located at the center; and the filtering submitted a study of the filtration coefficient, differing in that. that, in order to improve the determination accuracy, before On the first step of the study, water is poured with a time-increasing ng-gap in the gap between the inner and outer rings until the ground surface is soaked ia of the area of the inner ibua