SU1548334A1 - Method of stabilizing ground water level - Google Patents

Abstract

The invention relates to land reclamation and can be used mainly in the conditions of the humid zone in the presence of precipitation and evaporation. The goal is to simplify the stabilization process. GWM measurements are made over the entire range of its possible changes and at the same time the rate of GWG changes is measured, and the controlling change in the water level in the regulating network is determined by the dependence ΔН _к = -K (ΔН + T _y U), where ΔН _К is the controlling change of water level in the regulatory network, m

K is the gain of the control device; dimensionless quantity

ΔH is the deviation of the GWL in the middle between the regulating channels from the desired position, m

U - rate of change of GWL under the action of precipitation and evaporation, m / day

T _y - the time of anticipation of the disturbing effect of precipitation or evaporation

T _y = δ ² / 4K _f M day, where δ is the porosity of the soil, dimensionless value

B - distance between the channels of the regulating network, m

K _f - the filtration coefficient of the aquifer, m / day

M is the average power of the groundwater flow, m. The method provides compensation for the effects on the GWM and precipitation, and evaporation, and keeps the GWL at a predetermined level. 2 Il.

Description

The invention relates to land reclamation and can be used to maintain an optimum water regime of the soil under conditions of precipitation and evaporation.

The purpose of the invention is to simplify the stabilization process.

Fig. 1 is a functional diagram of a system performing automatic stabilization of the groundwater level; Fig. 2 shows diagrams for explaining the process of stabilization of the groundwater level.

The system contains a master device (memory) 1, the signal at the output of which corresponds to the specified value

groundwater level (GWL), feedback link (OS) 2, including a GWG sensor with an output proportional to the current GWL value, comparing element 3, which compares the current and set value of GWG, while output signal & h from the element 3 enters the gain link B with the gain K, the differentiation link 5 with the output is connected to the multiplication unit 6. 5 V Link Output

W 2S rate of change of GWL. On

at the second input of block 6 multiply PSP

4i

EO

with so

four.

a Tu signal is given - a preemptive time of the disturbing effect of evaporation or precipitation. Link 7 is the inter-channel space of a meliorative object. The GWM sensor is located in it in the middle of the distance between the channels.

The lead time TC is calculated by the formula

Јв2

(.uP

Ltf

de 0 is the coefficient of water return when lowering groundwater and free porosity when raising the surface of groundwater, the proportion of a unit of ground volume j B is the distance between the channels

regulatory network, m, 20 K - filtration coefficient of the aquifer, m / day; w - average power flow

groundwater within the change of the surface of the groundwater 5 m,

The control action of the level in the regulatory network is determined by the formula

DN k -K (Ah + V Tu).

The method is carried out as follows.

In the absence of precipitation and evaporation, the groundwater surface is at a constant predetermined depth h0 (Fig. 2). The surface of the water in the regulating channel is also located at a constant depth of Nco. In this case, Nku BER: L0, where BER is the enhancement factor of the meliorative object, which takes into account continuously acting perturbations.

Under the action of precipitation or evaporation, the equilibrium of the system is disturbed. For example, under the action of evaporation, the GWL begins to decrease along convoy 3 (Fig. 2). The negative value Db increases. When GWH reaches the lower limit of the insensitivity range, at the output of link 3, the signal DL h - h0 appears, and at the output

Link k - signal D Nk AIK, & Nk2 (curve 2). At the same time, the GWL varies along curve 1, remaining within the limits of the allowable values of D. d0 Кри Curve k reflects the fraction of HHK, and in the total value of the control & Hk. & Hk - the proportion of the control level change in the channel

0

five

0

50

50

The le, proportional to the deviation of Δh, kH -KDb, and D.Nk2 - the proportion of the controlling change in the water level in the channel, is proportional to the speed V of the variation of the deviation, LL "r -Kluv.

As soon as an initial deviation of & h | synchronously, but in the opposite direction, a control change & H K (water level in the regulating network LH – L (L,)), where K is the gain of the control device. The level change in the channel AhV stops as soon as the change in In the end, the system comes to equilibrium — the inflow from the regulating channel to the groundwater zone becomes equal to the outflow from the groundwater zone to evaporation. The GWL stabilizes. At the same time, the resulting deviation of & h (, the more than the bol This is the flow rate (intensity) of evaporation (similarly, the intensity of precipitation P).

In order to exclude an increase in this deviation in conditions of significant disturbances, the controlling change in the level of water in the regulating channel & NK is carried out in proportion to the deviation of DL, as well as the speed of its measurement.

V h, where & h is the initial deviation arising, ut is the time of its occurrence, In the limit V

D1k dh

-Ahno (& t} - dtExample. In order to save energy, the system operates intermittently h & 0,1, V 90 m, Kp 10 m / day; n 10 m; VMC, KC 0.1 m / day; &; h Dog1 0.1 m, K 2.

The frequency of switching on the system

u o ylop 12 c

VMOKC System Lead Time:

2,

v -2 days

those. a possible change in the GWI is foreseen in 2 days. The controlling change in the level of water in the regulating network, & Hk is 0.5 m. At the same time, h is within the limits of LODG1, and the LNC value is 0.1 m and & Nkg is 0.4 m.

Claims (1)

Invention Formula Method for stabilization of groundwater level, including level 5 5 measurement groundwater and changes in the level of water in the regulating network, characterized in that, in order to simplify the method, the level of groundwater is measured over the entire range of its changes possible under the action of precipitation and evaporation, and the rate of change in the level of groundwater the change in water level in the regulatory network is determined by the dependence & NK –K (Ah + V iy, where & NK is the controlling change in the water level in the channel of the regulating network, m; K is the gain of the control device, a dimensionless quantity; Ah - deviation of the groundwater level in the middle between the regulating channels from the predetermined position to the upper Ofch) or lower (-Ah) Ron MI - the rate of change of the groundwater level under the action of precipitation or evaporation, - the time of anticipation of the disturbing effect of precipitation or evaporation, E2 t Hz5 days " where 8 is the coefficient of water loss when lowering groundwater and free porosity when raising the surface of groundwater, the proportion of a unit volume of soil; distance between the channels of the regulating network, m; aquifer filtration coefficient, m / day; average groundwater flow rate within the range of groundwater surface change, m In K (p m J /  V with Sh % Surface marks ei / w Editor N.Rogulich Tehred M. Khodanych Order 119 Circulation 531 Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, “-35, Raushsk nab., T / 5 - -.- ".-.-.-. --- .-. - - - - - - - - - - - - - ---- - - - ---- - .. Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 FIG. g Proofreader S. Shekmar