阅读说明：本技术 一种室内模拟自然河道演变过程中侧向潜流交换的测量方法 (Measuring method for lateral undercurrent exchange in indoor simulation natural river course evolution process ) 是由 杜经纬 贾其萃 陈炳达 熊玉龙 方向元 袁越 陈孝兵 于 2019-08-08 设计创作，主要内容包括：本发明公开了一种室内模拟自然河道演变过程中侧向潜流交换的测量方法,包括以下步骤：根据实验方案绘制几何河道,并控制流量,连续冲刷一段时间后形成一定发展程度自然河道；改变河道中的水温,用红外热像仪拍摄侧向潜流交换的热图像,进行数据处理；每隔一段时间,对于形成的新的发展程度的河道,重复上述测量,直至河道形态稳定。本发明可连续测得高精度数据；用于室内试验,相对于传统野外测量方法,测量时间短,且易于操作；能够排除垂向潜流交换的干扰；仪器价格便宜、不易破损、寿命长且易于维修保养；测量灵敏,结果直观；可以获得河道演变过程中不同发展程度的河道中的侧向潜流交换特性,确定河道发展程度对侧向潜流交换的影响。(The invention discloses a measuring method for lateral undercurrent exchange in an indoor simulation natural river course evolution process, which comprises the following steps: drawing a geometric river channel according to an experimental scheme, controlling the flow, and continuously flushing for a period of time to form a natural river channel with a certain development degree; changing the water temperature in the river channel, shooting a thermal image of lateral subsurface flow exchange by using a thermal infrared imager, and performing data processing; at intervals, the measurements are repeated for newly developed watercourses until the river morphology is stable. The invention can continuously measure high-precision data; the method is used for indoor tests, has short measuring time and is easy to operate compared with the traditional field measuring method; the interference of vertical subsurface flow exchange can be eliminated; the instrument has low price, is not easy to damage, has long service life and is easy to maintain; the measurement is sensitive, and the result is visual; the method can obtain the lateral undercurrent exchange characteristics of the river in different development degrees in the river evolution process, and determine the influence of the river development degree on the lateral undercurrent exchange.)

1. A measuring method for lateral undercurrent exchange in an indoor simulation natural river course evolution process is characterized by comprising the following steps:

(1) drawing a geometric river channel in the water tank, and injecting normal-temperature water into the water tank;

(2) naturally washing the drawn river channel until the river channel is stable, and shooting the river channel forming process;

(3) changing the water temperature in the river channel, and shooting a thermal image of lateral subsurface flow exchange by using a thermal infrared imager;

(4) analyzing the interaction process of the river and the groundwater of the river banks on two sides according to the thermal image of the river bank underflow zone, and performing data processing;

(5) and (4) connecting the water tank with the normal-temperature water tank, and repeating the steps (2) to (4) until the river channel shape is stable.

2. The method for measuring the lateral undercurrent exchange in the indoor simulation natural river course evolution process according to claim 1, wherein the change mode of the river course water temperature in the step (3) is as follows: the water tank is connected with a constant temperature water tank.

3. The method for measuring the lateral undercurrent exchange in the indoor simulation natural river course evolution process according to claim 2, wherein a thermostat is arranged in the constant-temperature water tank.

4. The method for measuring the lateral undercurrent exchange in the indoor simulation natural river course evolution process according to claim 1, wherein the data processing process in the step (4) is as follows:

1) firstly, a threshold value T is given₀＝(T₁+T₂) 2, mixing T>T₀As a potential exchange effective area, determining key parameters, wherein T₀Exchanging the temperature threshold, T, for the undercurrent₁Initial temperature, T, of groundwater₂The water temperature of the river channel is communicated with the constant temperature water tank;

2) determining a migration path of the undercurrent exchange through the change process of the thermal image;

3) after the thermal image is substantially stabilized, the temperature T is determined by means of a thermal infrared imager>T₀The area of (A) is used as the influence range of the undercurrent exchange, and the area in the influence range of the undercurrent exchange is divided into a plurality of thin stripsThe area S of each strip-shaped area is approximately obtained according to the rectangular area_iObtaining the area S ═ S of the influence range of undercurrent exchange_i；

4) Recording the thermal image begins to change to a point where the temperature reaches T₀The maximum time of (d) is the residence time t.

5. The method for measuring the lateral undercurrent exchange in the process of simulating the evolution of a natural river channel indoors according to claim 1, wherein a water inlet is formed in one side of the water tank, a water outlet is formed in the other side of the water tank, the top of the water inlet is 5mm higher than the surface of quartz sand in the water tank, and the top of the water outlet is 1cm higher than the surface of the quartz sand.

6. The method for measuring the lateral undercurrent exchange in the indoor simulation natural river course evolution process according to claim 1, wherein a shooting rod is clamped on the side wall of the water tank, a thermal infrared imager and a camera are arranged at the top of the shooting rod, and the thermal infrared imager and the camera are over against the water tank.

7. The method for measuring the lateral subsurface flow exchange in the process of indoor simulation of natural river evolution of claim 6, wherein the thermal infrared imager is connected with a display through a data line.

Technical Field

The invention relates to the field of river undercurrent exchange, in particular to a lateral undercurrent exchange measurement method for simulating the evolution process of a natural river indoors.

Background

The undercurrent zone is a sediment layer with saturated water in the river bed of the river, is an area where river water and underground water interact, and has important significance for water environment pollution research and restoration of the ecological environment of the river. Therefore, in order to thoroughly solve the problems of water environment pollution in the eastern part of China, ensuring the health of a river ecosystem in the development of water resources in the western part of China and the like, deeper and more comprehensive understanding and understanding on underflow exchange and underflow are needed.

The river course evolution is a long process, and the river bed is always in continuous change under natural conditions. In the evolution process, the undercurrent characteristics of the riverway with different development degrees are different. The existing undercurrent exchange research is established in the existing riverway which develops to a certain degree, and the undercurrent exchange process in the riverbed at other development stages cannot be researched and analyzed. The transverse research of the undercurrent exchange characteristic at each stage is combined with the longitudinal research of the undercurrent exchange characteristic of the riverway with different development degrees in the evolution process, and the method has great significance for revealing the influence of the riverway evolution on the undercurrent exchange.

Currently, there is less research on lateral undercurrent exchange, and the undercurrent exchange mechanism is more researched by using the traditional field monitoring technology, such as: liquid specific gravity determination methods, underground solute tracer methods, and river tracer methods. The former two methods have the problem of arranging a net of pressure gauges; the latter method is very sensitive to the exchange between the active river and the vortex, and there is also a large uncertainty in using it to determine the underflow exchange. Most of tracer methods are semi-quantitative analysis of a river undercurrent exchange mode, cannot accurately depict the space-time distribution characteristics of a dynamic exchange process of a river undercurrent zone, and are high in cost and complex in operation, environmental tracers are widely distributed in a near-surface environment and easily interfere with a test process and a calculation result, and part of tracers possibly cause secondary pollution to the environment.

Therefore, it is urgently needed to develop a lateral undercurrent exchange measurement method for simulating riverways with different development degrees in the natural evolution process for indoor use, and to complete indoor simplification of measurement.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a lateral undercurrent exchange measurement method for simulating the evolution process of a natural river indoors, which is used for researching the lateral undercurrent exchange characteristics of the river with different development degrees and disclosing the influence of the development degree of the river on the undercurrent exchange.

The technical scheme is as follows: the invention comprises the following steps:

(1) drawing a geometric river channel in the water tank, and injecting normal-temperature water into the water tank;

(2) naturally washing the drawn river channel until the river channel is stable, and shooting the river channel forming process;

(3) changing the water temperature in the river channel, and shooting a thermal image of lateral subsurface flow exchange by using a thermal infrared imager;

(4) analyzing the interaction process of the river and the groundwater of the river banks on two sides according to the thermal image of the river bank underflow zone, and performing data processing;

(5) and (4) connecting the water tank with the normal-temperature water tank, and repeating the steps (2) to (4) until the river channel shape is stable.

The change mode of the river channel water temperature in the step (3) is as follows: the water tank is connected with a constant temperature water tank.

A thermostat is arranged in the constant-temperature water tank to heat and control the water in the water tank within a certain temperature range.

The data processing process in the step (4) is as follows:

1) firstly, a threshold value T is given₀＝(T₁+T₂) 2, mixing T>T₀As a potential exchange effective area, determining key parameters, wherein T₀Exchanging the temperature threshold, T, for the undercurrent₁Initial temperature, T, of groundwater₂The water temperature of the river channel is communicated with the constant temperature water tank;

2) determining a migration path of the undercurrent exchange through the change process of the thermal image;

3) after the thermal image is substantially stabilized, the temperature T is determined by means of a thermal infrared imager>T₀The area of (A) is used as the influence range of the undercurrent exchange, the area in the influence range of the undercurrent exchange is divided into a plurality of thin strip-shaped areas, and the area S of each strip-shaped area is approximately obtained according to the rectangular area_iObtaining the area S ═ S of the influence range of undercurrent exchange_i；

4) Recording the thermal image begins to change to a point where the temperature reaches T₀The maximum time of (d) is the residence time t.

The water tank is characterized in that a water inlet is formed in one side of the water tank, a water outlet is formed in the other side of the water tank, the top of the water inlet is 5mm higher than the surface of quartz sand in the water tank, the top of the water outlet is 1cm higher than the surface of the quartz sand, and the height of the water inlet is higher than that of the water outlet, so that smooth flowing of water is guaranteed, and water accumulation is avoided.

The side wall of the water tank is clamped with a shooting rod, the top of the shooting rod is provided with a thermal infrared imager and a camera, and the thermal infrared imager and the camera are right opposite to the upper part of the water tank and shoot thermal images of underflow exchange in the process of forming a river channel and in a hot water state.

The thermal infrared imager is connected with the display through a data line to display thermal images and data.

Has the advantages that: the invention can continuously measure high-precision data; the method is used for indoor tests, has short measuring time and is easy to operate compared with the traditional field measuring method; the interference of vertical subsurface flow exchange can be eliminated; the instrument has low price, is not easy to damage, has long service life and is easy to maintain; the measurement is sensitive, and the result is visual; the method can obtain the lateral undercurrent exchange characteristics of the river in different development degrees in the river evolution process, and determine the influence of the river development degree on the lateral undercurrent exchange.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

Detailed Description

The invention will be further explained with reference to the drawings.

Fig. 1 shows a measuring device used in the present invention, which includes a water tank 4 made of organic glass and having a height not too high to eliminate the influence of vertical subsurface flow exchange, and having the dimensions: the length is 1.2m, the width is 80cm, the height is 10cm, and a shooting rod 11 is clamped on the side wall of the downstream of the water tank 4. A clay layer 2 with the thickness of 3mm is laid at the bottom of the water tank 4, a quartz sand layer 3 with the thickness of 7cm is laid above the clay layer 2, and the clay layer 2 is used for keeping the stability of quartz sand and preventing the quartz sand from being washed away by water. The left side of the water tank 4 is provided with a water inlet, the right side of the water tank is provided with a water outlet, the water inlet is connected with a water inlet conduit 9, the water outlet is connected with a water outlet conduit 10, the inner diameters of the water inlet and the water inlet conduit 9 of the water tank are both 15mm, and the inner diameters of the water outlet and the water outlet conduit 10 are 30 mm. The top of the water inlet is higher than the surface of the quartz sand by about 5mm, the top of the water outlet is higher than the surface of the quartz sand by about 1cm, the water inlet and the water outlet are respectively connected with the head and the tail of a drawn river channel, the inner diameters of the water outlet and the water outlet pipe 10 are larger than the inner diameters of the water inlet and the water inlet pipe 9, and the height of the water inlet is higher than that of the water outlet, so that the smooth flow of water is ensured, and water.

The bottom in basin 4 upper reaches is fixed with expansion bracket 1, and expansion bracket 1 and inlet conduit 9 lie in basin 4 with one side, and the adjustable height of expansion bracket 1 is 0 ~ 10cm to control basin slope size. The telescopic frame 1 adopts a retractable X-shaped lifting frame, is made of aluminum alloy and has the advantages of good bearing capacity and strong pressure resistance. The connecting part of the top end of the telescopic frame 1 and the water tank 4 is provided with an anti-slip mat to prevent the water tank 4 from slipping off. The water inlet pipe 9 is sequentially provided with a valve 8 and a flowmeter 7 for controlling the flow of the artificial river and accurately measuring through the flowmeter 7, the tail end of the water inlet pipe 9 is connected with a water pump 6, and the tail end of the water inlet pipe 9, together with the water pump 6, and the water outlet pipe 10 are placed in the same water tank. The water tank comprises a constant temperature water tank 5 and a normal temperature water tank 17, wherein a thermostat 16 is placed in the constant temperature water tank 5 to heat and control water in the water tank to be kept in a certain temperature range (higher than room temperature). The water pump 6 is placed in the constant-temperature water tank 5 or the constant-temperature water tank 17, the water pump 6 adopts a direct-current micro submersible pump, the maximum lift is 5m, and the maximum flow is 4L/min. The water pump 6 is connected with the flowmeter 7, the valve 8 and the water inlet in sequence through the water inlet conduit 9. The joints of the water inlet conduit 9, the water pump 6, the flowmeter 7 and the valve 8 and the joints of the water outlet conduit 10 and the water outlet are provided with anti-seepage rubber pads, so that water leakage is prevented, and good sealing performance is kept.

The right side of the water tank 4 is provided with a shooting rod 11, and the shooting rod 11 is 1.5m in height and can be clamped at the downstream of the water tank 4. The camera 12 and the thermal infrared imager 13 are fixed at the tail end of the shooting rod 11, the camera 12 and the thermal infrared imager 13 are vertically fixed above the water tank 4, the camera 12 is used for vertically shooting the river channel forming process, the thermal infrared imager 13 is used for shooting the undercurrent exchange process under the action of warm water and is connected with the display 15 through the data line 14, and the thermal image in the water tank 4 is collected.

The measuring method of the invention comprises the following steps:

(1) controlling the geometry and flow control of the river channel according to an experimental scheme:

according to research needs, selecting proper initial wavelength and amplitude, drawing a plurality of characteristic points on a quartz sand layer according to a sine function shape, connecting the characteristic points by a square column, drawing a river channel on the quartz sand layer 3 to form the river channel with an initial rectangular section and a fixed river width, wherein a water inlet conduit 9 and a water outlet conduit 10 are both communicated with a normal-temperature water tank 17; the regulating valve 8 controls the flow of water, so that the reading of the flowmeter 7 is stabilized at a certain flow and then the flow is read.

(2) Simulating the natural evolution process of the river:

under the flow, the drawn river channel is naturally washed by connecting the water inlet conduit 9 with the normal-temperature water tank 17. River channel form can change under the washing of rivers, river channel camber can increase gradually, slowly become the river channel that accords with actual shape, different states can appear at this in-process, these different states are called the river channel of different development degree, then every certain interval, repeat step (3) - (4), accomplish the experiment under this state, the time interval is decided by river channel form change and research demand (generally between several hours to tens of hours), until the river channel is stable, use camera 12 to shoot river channel formation process simultaneously.

(3) Changing the water temperature of the river:

under the condition of a river channel at a certain development stage, the water inlet guide pipe 9 is communicated with the constant temperature water tank 5, the water outlet guide pipe 10 is communicated with the normal temperature water tank 17, the thermostat 16 in the constant temperature water tank 5 is opened to keep the temperature within the range of 70 +/-0.2 ℃, warm water is injected into the water tank 4, the thermostat 16 in the constant temperature water tank 5 keeps the temperature of water in the constant temperature water tank 5 at a certain temperature, and the shooting rod 11 can present and record a thermal image of undercurrent exchange in a hot water state shot by the thermal infrared imager 13 through the display 15.

(4) Data processing:

according to the thermal image of the river bank underflow zone, the interaction process of the river and the groundwater of the river banks on the two sides is analyzed, and parameters such as migration path, influence range, retention time and the like are determined.

The method comprises the following specific steps:

1) firstly, a threshold value T is given₀＝(T₁+T₂) 2, mixing T>T₀As a potential exchange effective area, determining key parameters, wherein T₀Exchanging the temperature threshold, T, for the undercurrent₁Initial temperature, T, of groundwater₂The water temperature of the river channel is communicated with the constant temperature water tank;

2) determining a migration path of the undercurrent exchange through the change process of the thermal image;

3) after the thermal image is substantially stabilized, the temperature T is determined by means of a thermal infrared imager>T₀The area of (A) is used as the influence range of the undercurrent exchange, the area in the influence range of the undercurrent exchange is divided into a plurality of thin strip-shaped areas, and the area S of each strip-shaped area is approximately obtained according to the rectangular area_iObtaining the area S ═ S of the influence range of undercurrent exchange_i；

4) Recording the thermal image begins to change to a point where the temperature reaches T₀The maximum time of (d) is the residence time t.

(5) And (4) connecting the water inlet guide pipe 9 with the normal-temperature water tank 17, and repeating the steps (2) to (4) until the river channel shape is stable.