A dehydration and consolidation device for treating slurry with geotextile tube bags and its working method

Abstract

The present invention discloses a dehydration and consolidation device for treating slurry with a geotextile tube bag, which includes a geotextile tube bag. A number of blind tubes are arranged along the length direction inside the geotextile tube bag. Both ends of the blind tubes extend out of the geotextile tube bag body. Both ends of the blind tubes are connected to one end of a branch pipeline through blind tube joints. The branch pipeline is connected to one end of a first main pipeline. A first valve is arranged on the first main pipeline. The other end of the first main pipeline is connected to an air compressor. The branch pipeline is connected to one end of a second main pipeline. A second valve is arranged on the second main pipeline. The other end of the second main pipeline is connected to a vacuum pump. The present invention also discloses a working method of the dehydration and consolidation device for treating slurry with a geotextile tube bag. The dehydration and consolidation device for treating slurry with a geotextile tube bag and its working method provided by the present invention effectively combine the pressurization and vacuum pumping methods and apply them at appropriate stages and time nodes during the dehydration and consolidation process of treating slurry with a geotextile tube bag, which can effectively promote the dehydration and consolidation speed of the slurry.

Description

Technical Field

[0001] The present invention relates to a dehydration and consolidation device for treating slurry with geotextile tube bags and a working method thereof, belonging to the technical field of slurry dehydration and consolidation. Background Art

[0002] In China, the amount of slurry to be treated every year is huge, including dredged slurry from rivers and lakes, construction waste slurry generated by underground shield and pile foundation drilling, tailing slurry generated by ore dressing, and industrial waste residues, etc. This kind of slurry has high water content, high clay particle content, huge volume, low bearing capacity and shear strength, and it is difficult to directly stack and utilize. It is necessary to first carry out dehydration, consolidation and volume reduction treatment on the slurry to reduce the volume of the slurry and improve its bearing capacity and shear strength.

[0003] At present, the traditional methods for slurry dehydration and consolidation treatment mainly include: natural drying method, mechanical dehydration method, sintering method, etc. The natural drying method means that the slurry is discharged to a certain storage yard and the free water in the slurry is removed by sunning, but this method is greatly affected by the weather and requires a sufficiently large site to stack and sun the slurry; the mechanical dehydration method means that the water in the slurry is discharged by means of dehydration machinery, but ordinary dehydration equipment is expensive and the dehydration efficiency is low; the sintering method means that the slurry is dried or treated at high temperature to make it dehydrated and consolidated, but this method requires specific equipment, the treatment capacity is limited, and the energy consumption is high and the cost is expensive. To sum up, these traditional slurry dehydration and consolidation treatment methods cannot treat slurry on a large scale, efficiently and environmentally friendly.

[0004] In the 1960s of the last century, geotextiles were first made into filled tube bags for revetment and plugging projects, which greatly reduced the project cost. In recent years, geotextiles have been continuously promoted and applied to the treatment of slurry, and a relatively mature technology - geotextile tube bag dehydration and consolidation method has been formed. This method mainly relies on the filtration characteristics of geotextiles to drain water while retaining most of the soil particles in the slurry.

[0005] In principle, the dehydration and consolidation of slurry by geotextile tube bags is divided into three stages: (1) Filling stage: The slurry is filled into the geotextile tube bag. There will be multiple fillings during the whole process until the final filling degree reaches more than 80%. (2) Rapid dehydration stage: After each filling, the water content of the slurry in the geotextile tube bag is relatively high. In this stage, the slurry inside the geotextile tube bag bears a large water pressure. Through the action of gravity and the tension of the bag wall, the water in the slurry is relatively easy to escape, but its dehydration rate will become slower and slower over time. (3) Consolidation stage: After rapid dehydration, the water content of the slurry in the geotextile tube bag decreases, and the slurry slowly changes from a saturated state to an unsaturated state. The pore water pressure is no longer continuous and the bag wall tension is very small. At this time, the slurry inside the tube bag only consolidates under its own dead weight stress, but the consolidation rate is slow.

[0006] The geotube dewatering and consolidation method has the advantages of simple construction and low cost, and can dewater and consolidate slurry on a large scale. However, for slurries with a high clay content, the dewatering and consolidation speed is slow, resulting in an excessively long slurry treatment period and too high time cost. Before the present invention, CN111088790A, CN110777773A, and CN110451760A all proposed a dewatering method for treating slurry by combining vacuum pumping with geotubes, that is, drainage boards are pre-arranged inside the geotubes or filter trough hole pipes are inserted into the upper cuffs of the geotubes, and vacuum pumping is carried out through a vacuum pump to quickly dewater and consolidate the slurry. The above patent methods can indeed accelerate the dewatering rate of the slurry and reduce the construction period in principle, but their main disadvantages are as follows: The drainage boards or filter trough hole pipes arranged inside the geotubes are all ordinary drainage materials and are extremely easy to be blocked during the vacuum filtration process, thereby reducing the promoting effect of the vacuum method on the dewatering and consolidation speed of the slurry. In addition, the dewatering of the slurry by geotubes involves multiple filling operations, and the dewatering and consolidation principles in the above three different stages are different. For example, in the rapid dewatering stage, the dewatering principle mainly relies on the internal water pressure of the slurry to promote the rapid discharge of water bodies. At this time, applying vacuum pumping will instead reduce the water pressure, resulting in poor dewatering effect. It shows that the vacuum pumping method can effectively improve the dewatering and consolidation speed only when it is adopted at the appropriate time point during the implementation process. However, none of the methods proposed in the above patents describe at which stage or time node during the implementation process the vacuum pumping method is adopted to accelerate the dewatering and consolidation. Therefore, the above patent methods cannot effectively guide the construction of on-site geotube slurry dewatering projects and cannot be truly popularized and applied in engineering practice. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a staged accelerated dewatering and consolidation device and its working method that effectively combines the pressurization and vacuum pumping methods and applies them at the appropriate stage and time node during the dewatering and consolidation process of treating slurry with geotubes, and can effectively promote the dewatering and consolidation speed of the slurry; further, the present invention provides a staged accelerated dewatering and consolidation device and its working method that can avoid the problem that the drainage materials arranged inside the geotubes are extremely easy to be blocked during the vacuum filtration process and ensure the promoting effect of the vacuum pumping method on the dewatering and consolidation speed of the slurry.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0009] A dehydration and consolidation device for treating slurry with a geotextile tube bag, comprising a geotextile tube bag. A number of blind tubes are arranged along the length direction inside the geotextile tube bag. Both ends of the blind tubes extend out of the geotextile tube bag body. Both ends of the blind tubes are connected to one end of a branch pipeline through a blind tube joint. The other ends of a number of branch pipelines are connected in parallel through a pipeline joint. The branch pipeline on one side of the geotextile tube bag is connected to one end of a first main pipeline. A first valve is arranged on the first main pipeline. The other end of the first main pipeline is connected to an air compressor. The branch pipeline on the other side of the geotextile tube bag is connected to one end of a second main pipeline. A second valve is arranged on the second main pipeline. The other end of the second main pipeline is connected to a vacuum pump. By connecting both ends of a number of blind tubes inside the geotextile tube bag in parallel through a pipeline joint and detachably connecting them to an air compressor and a vacuum pump respectively, the present invention can perform pressurization or vacuum pumping operations on the geotextile tube bag at an appropriate time, effectively promoting the dehydration and consolidation speed of the slurry and shortening the construction period of the slurry dehydration project.

[0010] A layer of anti-silting composite geotextile is wrapped outside the blind tube. The anti-silting composite geotextile includes a spun geotextile layer arranged on the inner layer and a non-woven geotextile layer arranged on the outer layer. The effective aperture O 95 of the anti-silting composite geotextile is in the range of 0.08 - 0.15 mm. During the slurry dehydration and consolidation process, the excellent filter-backwashing characteristics of the anti-silting composite geotextile are utilized to keep the blind tube always have good water permeability, avoiding the problem that the promotion effect of the vacuum pumping accelerated dehydration method on slurry dehydration is reduced due to the silting of the blind tube.

[0011] The spun geotextile layer and the non-woven geotextile layer are formed into a whole by thermal bonding or needling or gluing, and the bonding effect between the spun geotextile layer and the non-woven geotextile layer is better.

[0012] The distance between the blind tube and the geotextile tube bag body is not greater than 30 cm, and the distance between two adjacent blind tubes is not greater than 60 cm. In the present invention, a series of blind tubes are arranged along the length direction inside the geotextile tube bag, and the distance between adjacent blind tubes is strictly set, increasing the dehydration channels of the slurry, effectively reducing the drainage distance, and realizing simultaneous drainage in multiple directions inside and outside the geotextile tube bag, thereby realizing accelerated dehydration.

[0013] A working method of a dehydration and consolidation device for treating slurry with a geotextile tube bag includes the following steps:

[0014] S01, filling the slurry into the geotextile tube bag through a slurry pump. During the filling process, adding a flocculant to the mud conveying pipeline and ensuring that the flocculant and the slurry can be fully mixed and reacted;

[0015] S02, after the geotextile tube bag is filled with slurry, connecting the air compressor to the first main pipeline, unscrewing the first valve, tightening the second valve on the second main pipeline, turning on the air compressor, and pressurizing the blind tube through the branch pipeline.

[0016] S03. After the slurry in the geotextile tube bag is dehydrated under high pressure conditions and the volume of the slurry drops to 60-70% of the maximum capacity of the geotextile tube bag, repeat S01 and S02. This stage belongs to the rapid dehydration stage, and its dehydration principle mainly relies on the internal water pressure of the slurry to promote the rapid discharge of water. At this time, increasing the internal pressure of the geotextile tube bag can promote the rapid dehydration effect of the slurry. In the prior art, there is no clear pressure treatment in this stage.

[0017] S04. When the volume of the slurry in the geotextile tube bag is more than 80% of the maximum capacity of the geotextile tube bag and there is no water seeping out from the wall of the geotextile tube bag under high pressure conditions, close the air compressor and the first valve, connect the vacuum pump to the second main pipeline, slightly open the second valve, open the first valve, and turn on the vacuum pump to evacuate the blind pipe through the branch pipeline. This stage belongs to the consolidation stage of slurry dehydration. At this time, the moisture content of the slurry in the geotextile tube bag decreases, and the slurry slowly changes from a saturated state to an unsaturated state. The pore water pressure is no longer continuous, and the wall tension of the bag is very small. At this time, the slurry inside the tube bag only consolidates under its own self-weight stress, but the consolidation rate is slow. It is not suitable to pressurize the geotextile tube bag anymore in this stage. In the present invention, the geotextile tube bag is evacuated through the vacuum pump and the control of two valves in this stage, which can reduce the internal pressure of the geotextile tube bag, adapt to the dehydration of the slurry in the unsaturated state, and can accelerate the dehydration process of the slurry.

[0018] S05. When there is no water flowing out of the first main pipeline, turn off the vacuum pump.

[0019] Advantages of the present invention: The present invention provides a device and its working method for dehydrating and consolidating slurry using a geotextile tube bag. In different stages of dehydrating and consolidating the slurry using the geotextile tube bag, by pressurizing and evacuating the blind pipe, the dehydration and consolidation speed of the slurry is effectively promoted, shortening the construction period of the slurry dehydration project; and the anti-siltation composite geotextile wrapped on the blind pipe can effectively prevent the blind pipe from being silted up, making the pressurization and evacuation more effective in promoting the dehydration and consolidation speed and effect of the slurry. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of an accelerating dehydration and consolidation device for treating slurry using a geotextile tube bag according to the present invention;

[0021] Figure 2 is Figure 1 the A-A sectional view of

[0022] Figure 3 is a cross-sectional view of the blind pipe structure in the present invention.

[0023] The markings in the figure are as follows: 1-geotextile tube bag; 2-perforated pipe; 3-filling port; 4-slurry; 5-perforated pipe joint; 6-pipeline joint; 7-branch pipeline; 8-first valve; 9-first main pipeline; 10-second valve; 11-second main pipeline; 12-vacuum pump; 13-air compressor; 14-drainage layer; 15-ground surface; 16-woven geotextile layer; 17-non-woven geotextile layer. Specific implementation mode

[0024] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and cannot be used to limit the protection scope of the present invention.

[0025] As Figure 1 and Figure 2 shown, the present invention provides a dehydration and consolidation device for treating slurry with a geotextile tube bag, including a geotextile tube bag 1. A number of perforated pipes 2 are arranged along the length direction inside the geotextile tube bag 1, and both ends of the perforated pipes 2 extend out of the bag body of the geotextile tube bag 1. The arrangement of the perforated pipes 2 should meet the following two requirements: a) the distance between the perforated pipe 2 and the bag body of the geotextile tube bag 1 is not greater than 30 cm; b) the distance between two adjacent perforated pipes 2 is not greater than 60 cm. In the present invention, a series of perforated pipes 2 are arranged along the length direction inside the geotextile tube bag 1, and the distance between adjacent perforated pipes 2 is strictly set, which increases the dehydration channels of the slurry, effectively reduces the drainage distance, realizes simultaneous drainage in multiple directions inside and outside the geotextile tube bag 1, and thus realizes accelerated dehydration.

[0026] As Figure 3 shown, a layer of anti-silting composite geotextile is wrapped outside the perforated pipe 2. The anti-silting composite geotextile is formed by laminating a layer of non-woven geotextile layer 17 and a layer of woven geotextile layer 16 through thermal bonding or needle punching or adhesive bonding to form an integral body. The woven geotextile layer 16 is inside and the non-woven geotextile layer 17 is outside. The effective aperture O 95 of the anti-silting composite geotextile is in the range of 0.08 - 0.15 mm. During the dehydration and consolidation process of the slurry, the excellent filtration characteristics of the anti-silting composite geotextile are used to keep the perforated pipe always have good water permeability, avoiding the problem that the promotion effect of the vacuum pumping accelerated dehydration method on slurry dehydration is reduced due to the silting of the perforated pipe.

[0027] As Figure 1As shown in the figure, both ends of the blind pipe 2 are connected to one end of the branch pipeline 7 through the blind pipe joint 5, and the other ends of several branch pipelines 7 are connected in parallel through the pipeline joint 6 to gather several branch pipelines 7 together. The branch pipeline 7 on one side of the geotextile tube bag 1 is connected to one end of the first main pipeline 9. A first valve 8 is arranged on the first main pipeline 9, and the other end of the first main pipeline 9 is connected to an air compressor 13. The branch pipeline 7 on the other side of the geotextile tube bag 1 is connected to one end of the second main pipeline 11. A second valve 10 is arranged on the second main pipeline 11, and the other end of the second main pipeline 11 is connected to a vacuum pump 12.

[0028] The present invention provides a working method for a dehydration and consolidation device for treating slurry with a geotextile tube bag, including the following steps:

[0029] Step 1: Arrange a drainage layer 14 on a relatively flat ground 15, and lay the geotextile tube bag 1 with the blind pipe 2 and pipelines arranged thereon on the drainage layer 14 to prepare for the filling of slurry.

[0030] Step 2: Connect the slurry pump to the filling port 3 through the sludge pipeline, open the slurry pump to fill the slurry into the geotextile tube bag 1. During the filling process, add an appropriate amount of flocculant to the sludge pipeline at a certain distance from the filling port 3 to ensure that the flocculant and the slurry can fully mix and react.

[0031] Step 3: After the geotextile tube bag 1 is filled with slurry 4, connect the air compressor 13 to the first main pipeline 9, unscrew the first valve 8, tighten the second valve 10, and open the air compressor 13 to pressurize the blind pipe 2 through the pipeline. During the rapid dehydration stage, pressurize the blind pipe through the air compressor to make the slurry in the geotextile tube bag in a high-pressure state, which can effectively promote the dehydration speed of the slurry in this stage.

[0032] Step 4: After the slurry 4 in the geotextile tube bag 1 is dehydrated under high-pressure conditions and the volume of the slurry 4 drops to 60 - 70% of the maximum capacity of the geotextile tube bag 1, repeat Step 2 and Step 3.

[0033] Step 5: When the volume of the slurry 4 in the geotextile tube bag 1 is more than 80% of the maximum capacity of the geotextile tube bag 1 and under high-pressure conditions, and almost no water seeps out from the wall of the geotextile tube bag 1, turn off the air compressor 13, disconnect the air compressor 13 from the first main pipeline 9, connect the vacuum pump 12 to the second main pipeline 11, unscrew the second valve 10, slightly unscrew the first valve 8 to allow air and water to slowly flow into or out of the first main pipeline 9, and open the vacuum pump 12 to evacuate the blind pipe 2 through the pipeline. When the wall of the geotextile tube bag no longer drains water during the consolidation stage, evacuate the blind pipe through the vacuum pump, which can effectively improve the consolidation speed and effect of the slurry in this stage.

[0034] Step 6: When almost no water flows out from the first main pipeline 9, turn off the vacuum pump 12.

[0035] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A dehydration and consolidation device for treating slurry with a geotextile tube bag, characterized in that: It includes a geotextile tube bag (1), and a number of blind pipes (2) are arranged along the length direction inside the geotextile tube bag (1). Both ends of the blind pipes (2) extend out of the bag body of the geotextile tube bag (1). Both ends of the blind pipes (2) are connected to one end of a branch pipeline (7) through blind pipe joints (5). The other ends of a number of the branch pipelines (7) are connected in parallel through a pipeline joint (6). The branch pipeline (7) on one side of the geotextile tube bag (1) is connected to one end of a first main pipeline (9). A first valve (8) is arranged on the first main pipeline (9). The other end of the first main pipeline (9) is detachably connected to an air compressor (13). The branch pipeline (7) on the other side of the geotextile tube bag (1) is connected to one end of a second main pipeline (11). A second valve (10) is arranged on the second main pipeline (11). The other end of the second main pipeline (11) is detachably connected to a vacuum pump (12). The blind pipes (2) are wrapped with an anti-silting composite geotextile. The anti-silting composite geotextile includes a spun geotextile layer (16) arranged on the inner layer and a non-woven geotextile layer (17) arranged on the outer layer. The effective aperture O 95 of the anti-silting composite geotextile is in the range of 0.08 - 0.15 mm. The distance between the blind pipes (2) and the bag body of the geotextile tube bag (1) is not greater than 30 cm, and the distance between two adjacent blind pipes (2) is not greater than 60 cm.

2. The dehydration and consolidation device for treating slurry with a geotextile tube bag according to claim 1, characterized in that: The woven geotextile layer (16) and the non-woven geotextile layer (17) are formed into an integral body by thermal bonding, needling or gluing.

3. A working method of a dehydration and consolidation device for treating slurry with a geotextile tube bag, based on the dehydration and consolidation device for treating slurry with a geotextile tube bag according to claim 1 or 2, characterized in that: It includes the following steps: S01, Fill the slurry into the geotextile tube bag (1) through a slurry pump. During the filling process, add a flocculant to the mud conveying pipeline and ensure that the flocculant and the slurry can be fully mixed and reacted; S02, After the geotextile tube bag (1) is filled with slurry (4), connect the air compressor (13) to the first main pipeline (9), unscrew the first valve (8), tighten the second valve (10) on the second main pipeline (11), turn on the air compressor (13), and pressurize the blind tube (2) through the branch pipeline (7); S03, After the slurry in the geotextile tube bag (1) is rapidly dehydrated under high pressure and the slurry volume drops to 60-70% of the maximum capacity of the geotextile tube bag (1), repeat S01 and S02; S04, When the volume of the slurry in the geotextile tube bag (1) is more than 80% of the maximum capacity of the geotextile tube bag (1) and there is no water seeping out from the wall of the geotextile tube bag (1) under high pressure, turn off the air compressor (13) and the first valve (8), disconnect the connection between the air compressor (13) and the first main pipeline (9), connect the vacuum pump (12) to the second main pipeline (11), unscrew the second valve (10), slightly unscrew the first valve (8), turn on the vacuum pump (12), and evacuate the blind tube (2) through the branch pipeline (7); S05, When there is no water flowing out of the first main pipeline (9), turn off the vacuum pump (12).

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