CN111996993A - Method for forming impervious layer in cofferdam with sandy soil or silt as filler by utilizing straw degradation - Google Patents
Method for forming impervious layer in cofferdam with sandy soil or silt as filler by utilizing straw degradation Download PDFInfo
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- CN111996993A CN111996993A CN202010811811.5A CN202010811811A CN111996993A CN 111996993 A CN111996993 A CN 111996993A CN 202010811811 A CN202010811811 A CN 202010811811A CN 111996993 A CN111996993 A CN 111996993A
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- cofferdam
- injection pipe
- filler
- water injection
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B3/00—Engineering works in connection with control or use of streams, rivers, coasts, or other marine sites; Sealings or joints for engineering works in general
- E02B3/16—Sealings or joints
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B3/00—Engineering works in connection with control or use of streams, rivers, coasts, or other marine sites; Sealings or joints for engineering works in general
- E02B3/04—Structures or apparatus for, or methods of, protecting banks, coasts, or harbours
- E02B3/10—Dams; Dykes; Sluice ways or other structures for dykes, dams, or the like
- E02B3/106—Temporary dykes
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- General Engineering & Computer Science (AREA)
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- Environmental & Geological Engineering (AREA)
- Ocean & Marine Engineering (AREA)
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Abstract
The invention relates to a method for forming an impermeable layer in a cofferdam by utilizing straw degradation, which takes sandy soil or silt as filler.
Description
Technical Field
The invention relates to a method for forming an impermeable layer in a cofferdam taking sandy soil or silt as filler by utilizing straw degradation, belongs to civil engineering, and particularly relates to a method for forming an impermeable layer in a cofferdam taking soil with good water permeability as filler by utilizing straw degradation.
Background
A large amount of dredging sludge is generated by dredging the river channel in China every year, and in order to store the dredging sludge, temporary cofferdams need to be built along the bank of the river channel to be used as a storage yard of the dredging sludge. Because the water content of the dredged sludge is extremely high, the cofferdam of the sludge yard needs to block the sludge on one hand and have a good anti-seepage function on the other hand in the hydraulic filling process and 1-2 years after the hydraulic filling; because the water in the storage yard seeps in the cofferdam, after about 1-2 years, the silt in the storage yard is solidified under the dead weight, and the anti-seepage function of the cofferdam can be gradually cancelled.
For a traditional dredging mud storage yard, clay is often used as a main filling material of the cofferdam, and the clay has poor water permeability, so that an earth dam built by the clay generally has a good anti-seepage effect; however, in many areas, only silt or sandy soil exists in the local stratum, and the particles of the soil are relatively coarse, and the soil has strong water permeability, so that the soil is not suitable for being used as the filler of the cofferdam with the seepage-proofing requirement. Therefore, for the dam or the cushion layer using sand or silt as the filler, the anti-seepage problem is solved above all. Although there are many methods for cofferdam barrier, such as grouting, spreading barrier film, etc., these methods are relatively costly. In addition, a large amount of straws are generated in the crop production process every year in China, and the problems of environmental pollution caused by the burning, discarding and the like of the straws are more serious, so that governments at all levels vigorously promote the resource utilization of the straws; therefore, the cofferdam seepage-proofing method not only can solve the problem of cofferdam seepage-proofing, but also can provide a new way for recycling the waste straws.
Disclosure of Invention
The invention provides a method for forming an impermeable layer in a cofferdam taking sandy soil or silt as filler by utilizing straw degradation.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a method for forming an impervious layer in a cofferdam taking sandy soil or silt as filler by utilizing straw degradation comprises the following steps:
firstly, crushing waste straws, and sieving the crushed straws to obtain straw powder;
secondly, mixing and stirring the filler for burying the cofferdam and the crushed and sieved straw powder, wherein the weight of the straw powder accounts for 0.1-0.6% of the weight of the filler;
thirdly, rolling and burying the filler containing the straw powder after mixing and stirring to manufacture a cofferdam;
fourthly, covering geotechnical filter cloth on one side of the cofferdam;
fifthly, inserting the water injection pipe into the cofferdam, wherein the open end of the water injection pipe extends out of the cofferdam;
sixthly, injecting water into the cofferdam through a water injection pipe every 2-3 days;
seventhly, after 30 days, continuously injecting water into the cofferdam through a water injection pipe, keeping the hydraulic gradient range to be 3-5, enabling degraded products of the straw powder and the degraded straw powder to migrate to one side where the geotechnical filter cloth is laid under the action of the hydraulic gradient, forming an impermeable layer at a position close to the geotechnical filter cloth in the cofferdam, and gradually enlarging the volume of the impermeable layer;
eighthly, carrying out seepage flow on the water injected into the water injection pipe in the cofferdam, and gradually reducing the permeability coefficient of the cofferdam until no water flows out of the side wall of the cofferdam, and stopping injecting water into the water injection pipe at the moment;
as a further preferred aspect of the present invention, in the first step, the crushed straw is sieved by a 0.5mm sieve to obtain straw powder with a particle size of less than 0.5 mm;
as a further optimization of the invention, in the fourth step, the geotechnical filter cloth is covered on one side of the cofferdam, and the equivalent aperture is smaller than 0.1 mm;
as a further preferred aspect of the present invention, the water injection pipe is inserted into the cofferdam, and the bottom end of the water injection pipe is closed and perpendicular to the ground, and the water injection pipe is located at a side of the cofferdam far away from the geotextile filter cloth;
as a further preferred aspect of the present invention, a plurality of water injection nozzles are uniformly arranged on the side wall of the water injection pipe, and the water injection nozzles face to one side where the geotextile filter cloth is laid.
Through the technical scheme, compared with the prior art, the invention has the following beneficial effects:
1. the method fully utilizes the characteristic that the waste straws can be degraded to generate fine-grain degradation products, and the seepage water can be generated after the fine-grain degradation products are mixed with the clear water;
2. the cofferdam takes sandy soil or silt as the filler, the characteristic that pores exist among the sandy soil or silt inside the cofferdam is utilized, and fine-grained degradation products are blocked in the pores in the seepage process of seepage water to form an impermeable layer.
Drawings
The invention is further illustrated with reference to the following figures and examples.
Fig. 1 is a schematic structural diagram of a preferred embodiment provided by the present invention.
In the figure: 1 is cofferdam, 2 is water injection pipe, 3 is water jet, 4 is geotechnical filter cloth.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.
In the prior art, various methods for preventing seepage of cofferdams exist, such as grouting or paving an anti-seepage film, but the former method has higher cost, and the latter method is aged due to long-term use and combines a large amount of waste straws generated in the production process of crops every year in China at present.
Example (b):
the method for forming the impermeable layer in the cofferdam 1 with sandy soil or silt as the filler by using straw degradation mainly has the principle that fine-grained degradants formed after straw degradation migrate under the action of water power and are silted up in the silt or sandy soil cofferdam 1 to form the impermeable layer, and finally the purpose of reducing the water permeability of the impermeable layer is achieved;
the method of barrier layer specifically comprises the steps of:
firstly, crushing waste straws, and sieving the crushed straws by a 0.5mm sieve to obtain straw powder with the particle size of less than 0.5 mm;
secondly, mixing and stirring the filler (sand or silt) for burying the cofferdam 1 and the crushed and sieved straw powder, wherein the weight of the straw powder accounts for 0.1-0.6% of the weight of the filler;
thirdly, rolling and burying the filler containing the straw powder after mixing and stirring to manufacture the cofferdam 1;
fourthly, covering a geotextile filter cloth 4 with an equivalent aperture O on one side of the cofferdam 195(95% of the pore diameter in the geotechnical filter cloth 4 is smaller than the equivalent pore diameter) is smaller than 0.1 mm;
fifthly, inserting the water injection pipe 2 into the cofferdam 1, wherein the water injection pipe 2 is a steel pipe made of iron, the opening end of the water injection pipe extends out of the cofferdam 1, the bottom end of the water injection pipe is closed and is vertical to the ground, one side of the water injection pipe 2, which is far away from the geotechnical filter cloth 4, is arranged, and meanwhile, a plurality of water spray nozzles 3 are uniformly arranged on the side wall of the water injection pipe 2, and the water spray nozzles 3 face one side of the geotechni;
sixthly, injecting water into the cofferdam 1 through the water injection pipe 2 every 2-3 days to keep the soil body of the cofferdam 1 moist and promote the degradation of the straw powder;
seventhly, after 30 days, continuously injecting water into the cofferdam 1 through the water injection pipe 2, keeping the hydraulic gradient range to be 3-5 (the ratio of the height of a water head after the water is injected into the water injection pipe 2 to the width of the bottom of the cofferdam 1), transferring degraded products of the straw powder and the degraded straw powder to one side where the geotechnical filter cloth 4 is laid under the action of the hydraulic gradient, forming an impermeable layer at a position close to the geotechnical filter cloth 4 in the cofferdam 1, and gradually enlarging the volume of the impermeable layer;
and eighthly, carrying out seepage on the water injected into the water injection pipe 2 in the cofferdam 1, gradually reducing the permeability coefficient of the cofferdam 1 until no water flow flows out from the side wall of the cofferdam 1, and stopping injecting water into the water injection pipe 2 at the moment.
In the provided preferred embodiment, in order to manufacture muddy water with optimal seepage-proofing effect, the mixing amount of the straw powder accounts for 0.1-0.6% of the mass of the dry soil, and the seepage water formed by combining the generated mixed powder and the clear water achieves the optimal effect of blocking the pores in the cofferdam 1;
when inserting water injection pipe 2, it keeps away from the one side of laying geotechnological filter cloth 4, like this in cofferdam 1, can form great space between water injection pipe 2 and the one side of laying geotechnological filter cloth 4 of cofferdam 1, when letting in the clear water in water injection pipe 2, because water jet 3 is towards the one side of laying geotechnological filter cloth 4, the product that takes place to degrade after straw powder combines with the clear water so, can be under hydraulic gradient's effect, to the one side migration of laying geotechnological filter cloth 4, because the space is great between one side of water injection pipe 2 and cofferdam 1, can progressively become silted up in this space and form the barrier layer, it is full of the silted up position until whole space.
The utility model provides an ingenious straw with smashing formation straw powder, both solved the renewable utilization of abandonment straw, solved the seepage water mixture problem of adoption simultaneously, form the fine grain degradation thing after utilizing the straw degradation and take place the migration under the hydraulic action to the siltation forms the barrier layer in cofferdam 1, has finally realized reducing the mesh of cofferdam 1 ability of permeating water.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The meaning of "and/or" as used herein is intended to include both the individual components or both.
The term "connected" as used herein may mean either a direct connection between components or an indirect connection between components via other components.
In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (5)
1. A method for forming an impervious layer in a cofferdam taking sandy soil or silt as filler by utilizing straw degradation is characterized in that: the method comprises the following steps:
firstly, crushing waste straws, and sieving the crushed straws to obtain straw powder;
secondly, mixing and stirring the filler for burying the cofferdam and the crushed and sieved straw powder, wherein the weight of the straw powder accounts for 0.1-0.6% of the weight of the filler;
thirdly, rolling and burying the filler containing the straw powder after mixing and stirring to manufacture a cofferdam;
fourthly, covering geotechnical filter cloth on one side of the cofferdam;
fifthly, inserting the water injection pipe into the cofferdam, wherein the open end of the water injection pipe extends out of the cofferdam;
sixthly, injecting water into the cofferdam through a water injection pipe every 2-3 days;
seventhly, after 30 days, continuously injecting water into the cofferdam through a water injection pipe, keeping the hydraulic gradient range to be 3-5, enabling degraded products of the straw powder and the degraded straw powder to migrate to one side where the geotechnical filter cloth is laid under the action of the hydraulic gradient, forming an impermeable layer at a position close to the geotechnical filter cloth in the cofferdam, and gradually enlarging the volume of the impermeable layer;
and eighthly, carrying out seepage flow on the water injected into the water injection pipe in the cofferdam, and gradually reducing the permeability coefficient of the cofferdam until no water flow flows out from the side wall of the cofferdam, and stopping injecting water into the water injection pipe at the moment.
2. The method for forming the impervious layer in the cofferdam taking sandy soil or silt as the filler by utilizing the straw degradation as the claim 1 is characterized in that: in the first step, the crushed straws are sieved by a 0.5mm sieve to obtain straw powder with the particle size of less than 0.5 mm.
3. The method for forming the impervious layer in the cofferdam taking sandy soil or silt as the filler by utilizing the straw degradation as the claim 1 is characterized in that: and in the fourth step, the geotechnical filter cloth is covered on one side of the cofferdam, and the equivalent aperture of the geotechnical filter cloth is less than 0.1 mm.
4. The method for forming the impervious layer in the cofferdam taking sandy soil or silt as the filler by utilizing the straw degradation as the claim 1 is characterized in that: the water injection pipe is inserted in the cofferdam, the bottom end of the water injection pipe is closed and vertical to the ground, and the water injection pipe is far away from one side, covered with the geotechnical filter cloth, in the cofferdam.
5. The method for forming the impervious layer in the cofferdam taking sandy soil or silt as the filler by utilizing the straw degradation as the claim 4 is characterized in that: and a plurality of water spraying nozzles are uniformly arranged on the side wall of the water injection pipe, and face to one side where the geotechnical filter cloth is laid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010811811.5A CN111996993B (en) | 2020-08-13 | 2020-08-13 | Method for forming impervious layer in cofferdam with sandy soil or silt as filler by utilizing straw degradation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010811811.5A CN111996993B (en) | 2020-08-13 | 2020-08-13 | Method for forming impervious layer in cofferdam with sandy soil or silt as filler by utilizing straw degradation |
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| Publication Number | Publication Date |
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| CN111996993A true CN111996993A (en) | 2020-11-27 |
| CN111996993B CN111996993B (en) | 2022-04-22 |
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| CN202010811811.5A Active CN111996993B (en) | 2020-08-13 | 2020-08-13 | Method for forming impervious layer in cofferdam with sandy soil or silt as filler by utilizing straw degradation |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003306921A (en) * | 2002-04-12 | 2003-10-31 | Shibata Ind Co Ltd | Rubble mound, its construction method and high specific- gravity rubber granular material used for it |
| CN103938643A (en) * | 2014-04-28 | 2014-07-23 | 润峰电力有限公司 | Photovoltaic power station base construction process achieved through sand falling under action of water |
| CN104153380A (en) * | 2014-04-11 | 2014-11-19 | 中国水利水电第十一工程局有限公司 | Anti-seepage cofferdam structure and construction process |
| CN210002342U (en) * | 2019-04-12 | 2020-01-31 | 中交天航滨海环保浚航工程有限公司 | Coating type plain soil cofferdam structure of kinds of dredging engineering |
-
2020
- 2020-08-13 CN CN202010811811.5A patent/CN111996993B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003306921A (en) * | 2002-04-12 | 2003-10-31 | Shibata Ind Co Ltd | Rubble mound, its construction method and high specific- gravity rubber granular material used for it |
| CN104153380A (en) * | 2014-04-11 | 2014-11-19 | 中国水利水电第十一工程局有限公司 | Anti-seepage cofferdam structure and construction process |
| CN103938643A (en) * | 2014-04-28 | 2014-07-23 | 润峰电力有限公司 | Photovoltaic power station base construction process achieved through sand falling under action of water |
| CN210002342U (en) * | 2019-04-12 | 2020-01-31 | 中交天航滨海环保浚航工程有限公司 | Coating type plain soil cofferdam structure of kinds of dredging engineering |
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| CN111996993B (en) | 2022-04-22 |
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