An underground sewage interception and drainage system with integrated functions of pumping and gravity flow

Abstract

The present invention discloses an underground sewage interception and drainage system with integrated pump pumping and gravity flow functions, belonging to the technical field of underground sewage interception and drainage. The key points of its technical solution are as follows: it includes a slag interception dam, which is located upstream of the sewage reservoir and is an impermeable dam body; a water cutoff wall, which is located upstream of the slag interception dam and is an underground wall arranged below the ground with high sides and low middle at the bottom; a seepage guiding ditch, which is located upstream of the water cutoff wall and is a trench dug below the ground and connecting the waste dump and the water cutoff wall; and a collection and drainage well, which is erected at the low-lying area in the middle of the water cutoff wall. This kind of interception and drainage system no longer highly depends on pumping facilities, can effectively reduce the energy consumption of pumping facilities, and can also more comprehensively, quickly and efficiently achieve the collection of underground sewage.

Description

Technical Field

[0001] The present invention relates to the technical field of underground sewage interception and drainage, and particularly to an underground sewage interception and drainage system with an integrated function of pumping and gravity flow. Background Art

[0002] In metal mines, especially copper mines mainly for open-pit mining, a large amount of overburden and waste rock need to be stripped during the mining process and stacked in natural mountain valleys to form waste dumps. Due to the large floor area and the environmental protection requirements at that time, the bottoms of the early-built waste dumps were not waterproofed. The soil and stones in the waste dumps of copper mines generally contain relatively high levels of sulfides and heavy metals. After being exposed to the air for a long time and acted upon by oxidation and rainwater, acidic water containing heavy metals will seep down, ultimately causing groundwater pollution downstream of the waste dump.

[0003] Currently, the underground sewage interception and drainage system downstream of the mine waste dump mainly sets a vertical curtain downstream of the sewage reservoir, and sets a single infiltration well or a well group inside the vertical curtain to pump the sewage back to the upstream sewage reservoir by pumping, or sets an interception wall and a collection well inside the vertical curtain and also pumps the sewage back to the upstream sewage reservoir by pumping. However, the disadvantages of this method are relatively obvious:

[0004] 1. Highly dependent on pumping facilities. Once the pumping facilities fail or power outages occur, sewage pumping cannot be carried out, thus easily causing the spread of underground sewage;

[0005] 2. Only pumping sewage through pumping facilities, with high energy consumption;

[0006] 3. There is still a large room for improvement in the collection efficiency of underground sewage. Summary of the Invention

[0007] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide an underground sewage interception and drainage system with an integrated function of pumping and gravity flow. This kind of interception and drainage system combines the functions of pumping and gravity flow of sewage, and can choose to pump or drain sewage by gravity flow, no longer highly dependent on pumping facilities, and pumping and gravity flow sewage discharge can also be carried out simultaneously, thereby effectively reducing the energy consumption of pumping facilities. In addition, the water interception wall and the drainage ditch form a three-dimensional collection system, which can more comprehensively, quickly and efficiently realize the collection of underground sewage.

[0008] The above technical object of the present invention is achieved through the following technical solutions: An underground sewage interception and drainage system with integrated pumping and gravity flow functions is provided between the waste dump and the sewage reservoir, including a slag retaining dam, which is located upstream of the sewage reservoir and is an impermeable dam body; a cut-off wall, which is located upstream of the slag retaining dam and is an underground wall below the ground with high sides and low middle at the bottom; a drainage ditch, which is located upstream of the cut-off wall and is a trench dug below the ground to connect the waste dump and the cut-off wall; a collection and drainage well, which is vertically arranged at the low-lying place in the middle of the cut-off wall, and a perforated hole for communicating with the cut-off wall is opened on the side wall of the collection and drainage well. A sewage pump is also provided in the collection and drainage well, and the output end of the sewage pump leads to the sewage reservoir through a pipeline; a drainage pipe, one end of which is connected to the collection and drainage well, and the other end passes through the slag retaining dam and leads to the sewage reservoir.

[0009] In some embodiments, an impermeable membrane that is integrally connected is laid on the surface of the slag retaining dam and the bottom of the sewage reservoir.

[0010] In some embodiments, one end of the impermeable membrane away from the sewage reservoir is buried and anchored below the toe of the slag retaining dam, and the impermeable membrane is also provided with an anchor point at the position of the top of the slag retaining dam.

[0011] In some embodiments, when the drainage pipe passes through the slag retaining dam, it also passes through the impermeable membrane, and a through hole is left on the impermeable membrane. The through hole and the outer wall of the drainage pipe are sealed and connected through a sleeve.

[0012] In some embodiments, the elevation of the outlet of the drainage pipe is higher than the elevation of the bottom plate of the spillway of the sewage reservoir.

[0013] In some embodiments, the cut-off wall is filled with water-permeable filler, and the drainage ditch is also filled with the water-permeable filler.

[0014] In some embodiments, clay is laid on the water-permeable filler of the cut-off wall and the drainage ditch.

[0015] In some embodiments, the water-permeable filler is completely wrapped by an anti-filter and water-permeable geotextile material.

[0016] In some embodiments, a drainage pipe is buried in the water-permeable filler in the drainage ditch. The drainage pipe connects the waste dump and the collection and drainage well, and perforated holes are opened on the side wall of the drainage pipe.

[0017] In some embodiments, the elevation of the bottom of the collection and drainage well is lower than that of the cut-off wall, and the elevation of the top is higher than that of the clay.

[0018] In summary, the present invention has the following beneficial effects:

[0019] Compared with the prior art, an underground sewage interception and drainage system with integrated pumping and gravity flow functions provided by the present invention can form a three-dimensional underground sewage collection system through seepage guiding ditches and water cutoff walls, significantly improving the collection efficiency of underground sewage. In addition to conventional pumping facilities, the system can also drain underground sewage to the downstream sewage reservoir by gravity flow. It can optionally pump or drain by gravity, and can also pump and drain by gravity simultaneously. This not only reduces energy consumption but also has a high guarantee rate, and the entire system no longer highly depends on pumping facilities, greatly reducing the risk of underground sewage spreading downstream. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a top view layout diagram of the underground sewage interception and drainage system with integrated pumping and gravity flow functions in the first embodiment of the present invention downstream of the mine waste dump;

[0021] Figure 2 It is a sectional view along line A-A in the figure;

[0022] Figure 3 It is a sectional view along line B-B in the figure;

[0023] Figure 4 It is a sectional view along line C-C in the figure;

[0024] Figure 5 It is a sectional view layout diagram of the underground sewage interception and drainage system with integrated pumping and gravity flow functions in the second embodiment of the present invention downstream of the mine waste dump;

[0025] Figure 6 For Figure 5 The sectional view along line D-D therein.

[0026] In the figure: 1. slag retaining dam; 10. waste dump; 11. anti-seepage membrane; 2. water cutoff wall; 20. sewage reservoir; 3. seepage guiding ditch; 30. water guiding filler; 31. seepage guiding pipe; 4. collection and drainage well; 40. anti-filter and water-permeable geotechnical material; 5. drainage pipe; 50. clay; 60. sewage pump. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0028] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "upstream", "downstream", "bottom", "top" and similar expressions used herein are only for the purpose of illustration.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs. The terms used in the specification of this invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0030] Embodiment 1

[0031] Figures 1 to 4 Shown is an underground sewage interception and drainage system with integrated pumping and gravity flow functions in Embodiment 1 of the present invention. In this embodiment, there is no siltation reservoir upstream of the slag interception dam 1, the siltation reservoir has been filled with the sediment and stone slag flowing down from the waste dump 10, and the waste dump is about to be closed for greening (as Figure 2 shown). In this embodiment, the interception and drainage system is arranged between the waste dump 10 and the sewage reservoir 20 and is used to intercept and drain the underground sewage downstream of the mine waste dump 10, including a slag interception dam 1, a water cutoff wall 2, a drainage ditch 3, a drainage well 4 and a drainage pipe 5.

[0032] As Figure 2 shown, the slag interception dam 1 is located upstream of the sewage reservoir 20 and is made of cohesive soil to form an impervious dam body for intercepting slag and blocking water. For anti-seepage, an anti-seepage membrane 11 that is integrally connected can be laid on the surface of the slag interception dam 1 and the bottom of the sewage reservoir 20. The anti-seepage membrane 11 can be a 2.0 mm thick HDPE geomembrane. In order to anchor the anti-seepage membrane 11, the end of the anti-seepage membrane 11 away from the sewage reservoir 20 (i.e., the end of the anti-seepage membrane 11 at the bottom of the upstream slope of the slag interception dam 1) can be buried and anchored below the toe of the slag interception dam 1 and at least 1 m below the bottom of the drainage well 4, preferably 1 m, to achieve more sufficient anti-seepage and at the same time reduce the excavation work volume. An anchor point can also be set at the position of the anti-seepage membrane 11 on the top of the slag interception dam 1.

[0033] As Figures 1 - 4As shown in the figure, the cut-off wall 2 is located upstream of the sediment retention dam 1. In this embodiment, it is preferably arranged parallel to the dam axis of the sediment retention dam 1. It is a strip-shaped underground wall located below the ground, with high sides and a low middle at the bottom, and is used to intercept underground sewage. The slopes formed on both sides of the bottom of the cut-off wall 2 are 2%. The thickness of the cut-off wall 2 is 0.6 - 1 m, preferably 0.8 m in this embodiment, and the depth is 3 - 5 m, preferably 4 m in this embodiment. The cut-off wall 2 is arranged at a position 3 m vertically away from the upstream dam toe of the sediment retention dam 1. The cut-off wall 2 is filled from top to bottom with 50 layers of compacted clay and 30 layers of water-permeable filler. Among them, the clay layer 50 is 1 m thick and flush with the ground elevation, and the compaction degree is 0.9. The clay layer 50 is used to prevent surface water from entering the cut-off wall 2, reducing the generation amount of underground sewage. At the same time, it also reduces the burden on the interception and drainage system. The water-permeable filler layer 30 is 3 m thick. The water-permeable filler 30 can be composed of gravel with a particle size of 20 - 50 mm, and it is wrapped by an anti-filter water-permeable geotextile 40, preferably a non-woven geotextile of 200 g / m 2 to play an anti-filter role and prevent fine particles from being brought into the cut-off wall or blind ditch to cause blockage and affect the sewage drainage effect.

[0034] As Figure 1 , Figure 2 and Figure 4 shown, the seepage guiding ditch 3 is located upstream of the cut-off wall 2. It is a linear groove dug below the ground, connecting the waste dump 10 and the cut-off wall 2 along the longitudinal slope direction, and is used to collect and guide the underground seepage water. The longitudinal slope of the seepage guiding ditch 3 is 2%. In this embodiment, there are three seepage guiding ditches 3. The three seepage guiding ditches 3 gradually converge into one in the path of guiding and draining towards the cut-off wall 2, and are arranged in a trident shape or a "fishbone" shape as a whole (as Figure 1 shown). The width of the seepage guiding ditch 3 is 0.6 - 1 m, preferably 1 m in this embodiment, and the depth is 1 - 2 m, preferably 2 m in this embodiment. Inside the seepage guiding ditch 3, there are 50 layers of compacted clay and 30 layers of filled water-permeable filler from top to bottom. Among them, the thicknesses of both the clay layer 50 and the water-permeable filler layer 30 are 1 m. The compaction degree of the clay layer 50 is 0.9 and it is flush with the ground elevation. The clay layer 50 is used to prevent surface water from entering the seepage guiding ditch 3, reducing the generation amount of underground sewage. At the same time, it also reduces the burden on the interception and drainage system. The water-permeable filler 30 can be composed of gravel with a particle size of 20 - 50 mm, and it is wrapped by an anti-filter water-permeable geotextile 40, preferably a non-woven geotextile of 200 g / m 2The non-woven geotextile is used to play a role in filtration, preventing fine particles from entering the cut-off wall or blind ditch and causing siltation, which affects the sewage drainage effect. To accelerate the sewage drainage, a drainage pipe 31 can be buried in the water-conducting filler 30 in the drainage ditch 3, and the drainage pipe 31 is connected to the spoil ground 10 and the collection and drainage well 4. The drainage pipe 31 can be made of HDPE pipe with a diameter of DN200 - DN315. In this embodiment, the HDPE pipe with a diameter of DN315 is preferably selected, and perforations are provided on the side wall of the drainage pipe 31. The aperture of the perforations is 6mm - 10mm, preferably 10mm (as Figure 2 and Figure 4 shown). The drainage pipe 31 and the collection and drainage well 4 are preferably connected by welding with good sealing performance. Before welding, a welding hole needs to be opened on the collection and drainage well 4, and the aperture of the welding hole is selected to be 315mm, which is the same as the diameter of the drainage pipe 31.

[0035] In order to enable the sewage accumulated in the cut-off wall 2 to flow naturally into the collection and drainage well 4, the collection and drainage well 4 needs to be erected at the low-lying area in the middle of the cut-off wall 2, and perforations for communicating with the cut-off wall 2 are provided on the side wall of the collection and drainage well 4. The distribution position of the perforations coincides with the position of the water-conducting filler 30 layer. The perforations are preferably arranged in a plum blossom pattern, and the aperture of the perforations is 10 - 16mm, preferably 16mm. The collection and drainage well 4 is a vertical pipe well for water collection and drainage, and it can be made of HDPE pipe with a diameter of DN630 - DN1000. The HDPE pipe with a diameter of DN630 is preferably selected. For safety and to prevent natural rainwater from flowing into the collection and drainage well 4, the collection and drainage well 4 is equipped with a locked manhole cover. A sewage pump 60 with an automatic start-stop function and a liquid level control function is also provided at the bottom of the collection and drainage well 4. It is preferably required that the selected sewage pump 60 has acid and corrosion resistance. A pipeline is connected to the output end of the sewage pump 60, and the pipeline extends out of the collection and drainage well 4 and leads to the sewage reservoir 20. The bottom elevation of the collection and drainage well 4 is lower than that of the cut-off wall 2, and the top elevation is higher than that of the clay 50. Specifically, the depth of the collection and drainage well 4 below the ground is 4 - 8m, and the top elevation exposed above the ground is not less than 0.5m. The bottom elevation is not less than 1m lower than the lowest point of the bottom of the cut-off wall 2. As a preferred solution in this embodiment, the overall height of the collection and drainage well 4 is 6m, including a depth of 5m below the ground and 1m exposed above the ground, and the bottom elevation is 1m lower than the lowest point of the bottom of the cut-off wall 2 (as Figure 3As shown in the figure, the bottom of the sewage collection and drainage well 4 is always set lower than the elevation of the lowest point at the bottom of the water cutoff wall 2, so that the sewage in the water cutoff wall 2 can seep and gather in the sewage collection and drainage well 4 more thoroughly under the action of gravity, preventing a large amount of sewage from accumulating in the water cutoff wall 2 due to the inability to be discharged in time. In addition, the top of the sewage collection and drainage well 4 is set higher than the ground surface to prevent surface rainwater from flowing into the sewage collection and drainage well 4. Since the main function of this system is to treat underground sewage, if surface rainwater also enters the system, it will not only increase the amount of sewage but also bring an additional burden to the operation of the system. Therefore, the top of the sewage collection and drainage well 4 needs to be set higher than the ground surface to prevent surface rainwater from flowing into the sewage collection and drainage well 4.

[0036] As Figure 1 and Figure 2 shown, a drain pipe 5 is also connected to the sewage collection and drainage well 4. The drain pipe 5 can be made of HDPE pipe with a diameter of DN200 - DN400, without holes on its pipe body, and the longitudinal slope is not less than 1%. In this embodiment, the drain pipe 5 can be made of DN315 HDPE pipe, and its longitudinal slope can be set at 2%. The sewage collection and drainage well 4 and the drain pipe 5 are preferably connected by welding with good sealing performance. Before welding, a welding hole needs to be opened on the sewage collection and drainage well 4, and the opening diameter of the welding hole is selected as 315mm, which is the same as the diameter of the drain pipe 5. The drain pipe 5 can be buried in the clay layer 50. One end of the drain pipe 5 is connected to the sewage collection and drainage well 4, and the other end passes through the slag retaining dam 1 and leads to the sewage reservoir 20. When the drain pipe 5 passes through the slag retaining dam 1, it also passes through the anti-seepage membrane 11, and a through hole is left on the anti-seepage membrane 11. The space between the through hole and the outer wall of the drain pipe 5 can be sealed by a sleeve, that is, a sleeve is sleeved on the drain pipe 5, and the sleeve and the anti-seepage membrane 11 are thermally welded to achieve the sealing connection. The sleeve can be made of 2.0mm thick HDPE material. In order to prevent sewage backflow, the elevation of the outlet of the drain pipe 5 should be higher than the elevation of the spillway floor of the sewage reservoir 20.

[0037] Through the above technical solution, the sewage seeping into the ground from the upstream waste dump 10 is gradually diverted to the water cutoff wall 2 under the diversion and confluence effects of multiple seepage guiding ditches 3. Among them, the seepage guiding ditches 3 can quickly divert the underground sewage away, preventing the sewage from further penetrating deeper, thus playing a role in pre-intercepting and discharging. The seepage guiding pipes 31 in the seepage guiding ditches 3 provide a high-speed diversion channel, which can directly introduce the sewage into the collection and drainage well 4, further accelerating the interception and discharge of the sewage. The seepage guiding ditches 3 are horizontally linearly collected, and the water cutoff wall 2 is vertically collected. The two together constitute a three-dimensional underground sewage collection and interception system. After the sewage seeps into the water cutoff wall 2, it will gradually gather in the collection and drainage well 4 under the action of gravity. At this time, the sewage in the collection and drainage well 4 can be pumped to the sewage reservoir 20 through the sewage pump 60, or as the water level in the collection and drainage well 4 rises, the sewage can be discharged to the sewage reservoir 20 by gravity through the drainage pipe 5. Compared with the prior art, this system can form a three-dimensional underground sewage collection system through the seepage guiding ditches 3 and the water cutoff wall 2, significantly improving the collection efficiency of underground sewage. In addition to conventional pumping facilities, the underground sewage can also be drained to the downstream sewage reservoir 20 by gravity. It is possible to choose either pumping or gravity drainage for sewage discharge, and of course, pumping and gravity drainage can also be carried out simultaneously. This not only has low energy consumption but also high guarantee rate, and the entire system no longer highly depends on pumping facilities, greatly reducing the risk of underground sewage spreading downstream.

[0038] Embodiment 2

[0039] Figure 5 and Figure 6 The figure shows the underground sewage interception and drainage system with the integrated function of pumping and gravity drainage in Embodiment 2 of the present invention. In this embodiment, there is a siltation storage capacity upstream of the slag retaining dam 1, and the sediment and stone slag flowing down from the waste dump 10 have not yet filled it up. After it is filled up in the future, it will be closed and greened (as shown in Figure 5 ). The difference between this embodiment and Embodiment 1 is that in this embodiment, no clay 50 is laid on the water guiding filler 30 of the water cutoff wall 2 and the seepage guiding ditches 3. In this embodiment, a large amount of clay 50 is not laid upstream of the slag retaining dam 1, providing sufficient siltation space for the sediment and stone slag flowing down from the waste dump 10. At the same time, it can quickly collect the surface sewage generated between the waste dump 10 and the slag retaining dam 1 to prevent these sediment and stone slag from flowing around with the rainwater beyond the effective action range of this sewage interception and drainage system.

[0040] It should be noted that for the device provided in Embodiment 2 of the present invention, its implementation principle and some technical effects are the same as those of the first embodiment. For the sake of brief description, for the parts not mentioned in this embodiment, reference can be made to the corresponding content in the first embodiment.

[0041] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. An underground sewage interception and drainage system with integrated pumping and gravity flow functions is provided between a waste dump (10) and a sewage reservoir (20), and is characterized in that, Comprising: A slag retaining dam (1), which is located upstream of the sewage reservoir (20) and is an impervious dam body; A cut-off wall (2), which is located upstream of the slag retaining dam (1) and is an underground wall provided below the ground with a middle part lower than both sides at the bottom; A seepage guiding ditch (3), which is located upstream of the cut-off wall (2) and is a trench dug below the ground to connect the waste dump (10) and the cut-off wall (2); A collecting and draining well (4), which is vertically arranged at the low-lying part in the middle of the cut-off wall (2). A perforated hole for communicating with the cut-off wall (2) is opened on the side wall of the collecting and draining well (4). A sewage pump (60) is also arranged in the collecting and draining well (4), and the output end of the sewage pump (60) leads to the sewage reservoir (20) through a pipeline; A drainage pipe (5), one end of which is connected to the collecting and draining well (4), and the other end passes through the slag retaining dam (1) and leads to the sewage reservoir (20).

2. The underground sewage interception and drainage system with the integrated functions of pumping and gravity flow according to claim 1, characterized in that: The elevation of the water outlet of the drainage pipe (5) is higher than the elevation of the spillway floor of the sewage reservoir (20).

3. The underground sewage interception and drainage system with the integrated function of pumping and gravity flow according to claim 1, wherein: The cut-off wall (2) is filled with a water guiding filler (30), and the water guiding filler (30) is also filled in the seepage guiding ditch (3).

4. The underground sewage interception and drainage system with the integrated function of pumping and gravity flow according to claim 3, characterized in that: Clay (50) is laid on the water guiding filler (30) of the cut-off wall (2) and the seepage guiding ditch (3).

5. A subsurface sewage interception and drainage system with integrated pumping and gravity flow functions according to any one of claims 3-4, characterized in that: A seepage guiding pipe (31) is buried in the water guiding filler (30) in the seepage guiding ditch (3). The seepage guiding pipe (31) connects the waste dump (10) and the collecting and draining well (4), and perforated holes are opened on the side wall of the seepage guiding pipe (31).

6. The underground sewage interception and drainage system with the integrated functions of pumping and gravity flow according to claim 4, characterized in that: The bottom elevation of the collecting and draining well (4) is lower than that of the cut-off wall (2), and the top elevation is higher than that of the clay (50) and the water guiding filler (30).

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