Seepage-proofing structure design method suitable for sedimentation difference of soft soil foundation ash field reservoir areaTechnical Field
The invention relates to the technical field of gray field geotechnical engineering and foundation construction, in particular to an anti-seepage structure of a gray field soft soil foundation, and especially relates to an anti-seepage structure suitable for sedimentation difference of a gray field reservoir area of the soft soil foundation and a design method.
Background
With the development of design technology in recent years, the situation that a thermal power plant is built in a coastal area is more and more common, and a power plant matched gray field is often built on a coastal soft soil foundation.
When the ash field is built on the soft soil foundation, the special foundation treatment scheme is not generally adopted in the ash field warehouse due to large occupied area, and only the ground surface is cleaned, and an anti-seepage film is paved after a cushion layer is paved. After the ash field storage area starts to pile ash, the sequence of the ash pile in the storage is different, and different foundation conditions may exist in the ash field storage. The soft soil generates larger sedimentation difference under the action of load, and under the action of sedimentation difference, an impermeable film in a warehouse can be pulled apart, so that the risk of leakage of ash water in an ash field exists.
Therefore, the existing soft soil foundation structure of the gray field needs to be improved, and the impermeable structure of the gray field on the soft soil foundation should be optimized to avoid the stretch-breaking and breakage of the impermeable film, so that a more reasonable technical scheme is required to be provided, and the defects in the prior art are overcome.
Disclosure of Invention
In order to solve the defects in the prior art, the invention provides an anti-seepage structure suitable for sedimentation differences of a soft soil foundation ash field reservoir area and a design method thereof, and aims to ensure that an anti-seepage film is not pulled apart when sedimentation differences occur in the soft soil foundation ash field, so as to avoid leakage of ash water.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
The seepage-proofing structure suitable for the sedimentation difference of the soft soil foundation and the ash field reservoir area comprises a bottom cushion layer arranged on a raw soil foundation, wherein the bottom cushion layer is provided with a seepage-proofing layer which is provided with a fold structure vertical to the foundation plane; the anti-seepage layer is provided with a protective layer, and the protective layer completely covers the anti-seepage layer; the upper surface of the protective layer is provided with a lime stacking layer.
Above-mentioned disclosed seepage prevention structure through the fold structure that has set up the barrier layer, takes place to subside when poor, and protective layer and bed course structure take place dislocation deformation, and fold structure can provide sufficient deformation allowance, avoids regional subsidence to lead to the barrier layer to take place to drag deformation and appear even to draw the broken phenomenon of cracking to prevent the grey water seepage of grey field, improved waterproof, the water retention capacity of barrier structure.
Further, the base mat used in the present invention may be laid out from a variety of materials, which are not limited to only one of the possible choices that are optimized and exemplified herein: the bottom cushion layer comprises a sand cushion layer with the thickness of 200-400 mm. When the scheme is adopted, the sand cushion layer can adopt sand grains with uniform grain size, and also can adopt sand grains with various different grain sizes to carry out layered paving or mixed paving, and the top surface of the bottom cushion layer is leveled when paving.
Further, the barrier layer used in the present invention may take a variety of structures capable of achieving barrier and barrier, which are not limited only, and are optimized herein and one of the possible options is given: the impermeable layer comprises an impermeable film, and the thickness of the impermeable film is more than or equal to 1.5mm. With such an arrangement, the barrier film may be, but is not limited to, a HDPE (HIGH DENSITY Polyethylene) film.
Furthermore, the height of the fold structure is within a certain range, the deformation caused by the sedimentation difference between areas needs to be satisfied, the damage to the impermeable layer is avoided, and the method is optimized and a feasible choice is given here: the height of the fold structure is 100-200 mm.
Still further, when setting up the fold structure, can set up according to the differential settlement between the different regions, specifically, can adopt one kind of feasible selection after optimizing: the fold structures are criss-cross arranged in a cross shape on the bottom cushion layer, and the heights of the fold structures in different original soil foundation areas are different. By adopting the scheme, the structure with excessive folds can be avoided, and the dosage of the impermeable layer can be saved.
Still further, the protective layer sets up on the barrier layer, plays the effect of protection to the barrier layer, optimizes and gives up feasible scheme here: the protective layer comprises a clay layer with the thickness of 300-400 mm, and the thickness of the clay layer is increased along with the increase of the height of the fold structure.
The invention also discloses a design method of the seepage-proofing structure, which is specifically described, and is suitable for the sedimentation difference of a soft soil foundation ash field reservoir area, and comprises the following steps:
Determining a foundation treatment scheme and an operation plan of a soft soil foundation gray field;
establishing a numerical analysis model, calculating sedimentation values of each region of the gray field in different time periods, and determining sedimentation differences among the regions;
And determining the height of the fold structure and the single-area division size of the fold structure according to the sedimentation difference.
Further, in the method disclosed by the invention, the numerical analysis model comprises actual geological condition data of the gray field, seepage condition data, foundation treatment scheme data and operation planning data. When the scheme is adopted, the numerical analysis model is utilized to carry out operation simulation analysis on the gray field, and the sedimentation change after the operation of the gray field can be obtained through simulation calculation.
Further, since the sedimentation differences of different areas on the soft soil foundation are different, the height and the distance of the single fold structure need to be set according to the sedimentation differences of different areas, and specifically, the optimization is performed and one of the possible choices is given here: calculating the height of the fold structures according to the value of the sedimentation difference, and calculating the distance between adjacent fold structures according to the following rule:
Wherein,Spacing for the pleat formation; /(I)To calculate the region length; /(I)Calculating the sedimentation difference of the area; /(I)The length of the impermeable film is the length of the impermeable film after the influence of the sedimentation difference; /(I)The height of the folds is generally 100-200 mm; /(I)Is a safety factor.
Compared with the prior art, the invention has the following beneficial effects:
According to the invention, a numerical simulation model is established for the whole process from foundation treatment to stacking of ash in the ash fields, and after sedimentation differences of the ash fields in different areas are obtained through numerical analysis, the distances between the fold structures are calculated; after the impermeable layer is provided with the fold structure, when sedimentation difference occurs in a warehouse area, the length of the impermeable layer is increased through stretching of the fold structure, so that the impermeable layer is ensured not to be pulled apart, and the problem of influence of the sedimentation difference on the impermeable layer is solved; the anti-seepage structure has the advantages of easily available materials, low manufacturing cost, simple design method and great significance for environmental protection and safety.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic cross-sectional view of an impermeable structure.
FIG. 2 is a schematic illustration of the placement of a barrier structure.
FIG. 3 is a process schematic of the design method.
In the above figures, the meaning of each label is: 1. a raw soil foundation; 2. a bottom cushion layer; 3. an impermeable layer; 31. a pleated structure; 4. a protective layer; 5. and (5) a gray dike.
Detailed Description
The invention is further illustrated by the following description of specific embodiments in conjunction with the accompanying drawings.
It should be noted that the description of these examples is for aiding in understanding the present invention, but is not intended to limit the present invention. Specific structural and functional details disclosed herein are merely representative of example embodiments of the invention. This invention may, however, be embodied in many alternate forms and should not be construed as limited to the embodiments set forth herein.
Example 1
Aiming at the problem that the anti-seepage film is likely to be pulled apart after sedimentation difference occurs in the ash field reservoir area of the soft soil foundation at present, the embodiment discloses an anti-seepage structure of the soft soil foundation so as to solve the problem.
Specifically, the technical scheme adopted in this embodiment is as follows:
The seepage-proofing structure suitable for the sedimentation difference of a soft soil foundation ash field reservoir area comprises a bottom cushion layer 2 arranged on a raw soil foundation 1, wherein a seepage-proofing layer 3 is arranged on the bottom cushion layer 2, and a fold structure 31 vertical to a foundation plane is arranged on the seepage-proofing layer 3; the impermeable layer 3 is provided with a protective layer 4, and the protective layer 4 completely covers the impermeable layer 3; the upper surface of the protective layer 4 is provided with a dust layer.
According to the disclosed seepage-proofing structure, the gray dyke 5 is used as the original soil foundation 1, the fold structure 31 in the seepage-proofing layer 3 is arranged, when the sedimentation difference occurs, the structure of the protective layer 4 and the bottom cushion layer 2 are dislocated and deformed, the fold structure 31 can provide enough deformation allowance, the phenomenon that the seepage-proofing layer 3 is pulled and deformed or even broken due to pulling and cracking caused by the regional sedimentation difference is avoided, so that the gray water seepage of a gray field is prevented, and the waterproof and water-retaining capacities of the seepage-proofing structure are improved.
The base mat 2 used in this embodiment may be laid from a variety of materials, not limited to, in some embodiments, fine sand, non-sharp filter particles, etc., which are optimized and selected from one of the possible choices: the bottom cushion layer 2 comprises a sand cushion layer with the thickness of 200-400 mm. When the scheme is adopted, the sand cushion can adopt sand grains with uniform grain size, and also can adopt sand grains with various different grain sizes to carry out layered paving or mixed paving, and the top surface of the bottom cushion 2 is leveled when paving.
The impermeable layer 3 may be of various structures capable of achieving isolation and impermeable, and is not limited to only, and may be made of waterproof materials such as waterproof cloth and waterproof film in some embodiments, and the embodiments are optimized and adopt one of the possible choices: the impermeable layer 3 comprises an impermeable film, and the thickness of the impermeable film is more than or equal to 1.5mm.
Preferably, the impermeable film in this example is a HDPE (HIGH DENSITY Polyethylene) film.
The height of the fold structure 31 provided in this embodiment is within a certain range, which needs to meet the deformation caused by the inter-zone differential settlement, avoiding damage to the impermeable layer 3, and is optimized and selected as possible: the height of the fold structure 31 is 100-200 mm.
Preferably, when the fold structure 31 is provided, the arrangement can be performed according to the sedimentation differences between different areas, specifically, after optimization, the following possible selection is adopted: the fold structures 31 are arranged on the base cushion layer 2 in a crisscross manner in a cross shape, and the heights of the fold structures 31 in different areas of the original soil foundation 1 are different. By adopting such a scheme, the provision of excessive fold structures 31 can be avoided, and the amount of the impermeable layer 3 can be saved.
The protective layer 4 is arranged on the impermeable layer 3, plays a role in protecting the impermeable layer 3, optimizes and gives out a feasible scheme: the protective layer 4 includes a clay layer having a thickness of 300 to 400mm, the thickness of which increases as the height of the corrugated structure 31 increases.
Example 2
The content of the above embodiment discloses an impermeable structure of a soft soil foundation, and this embodiment discloses a design method of the impermeable structure, and specific explanation will be made, and the design method of the impermeable structure suitable for sedimentation differences of ash fields and reservoirs of the soft soil foundation includes:
s01: determining a foundation treatment scheme and an operation plan of a soft soil foundation gray field;
s02: establishing a numerical analysis model, calculating sedimentation values of each region of the gray field in different time periods, and determining sedimentation differences among the regions;
S03: and determining the height of the fold structure and the single-area division size of the fold structure according to the sedimentation difference.
In the method disclosed in this embodiment, the numerical analysis model includes actual geological condition data, seepage condition data, foundation treatment plan data, and operation planning data of the gray field. When the scheme is adopted, the numerical analysis model is utilized to carry out operation simulation analysis on the gray field, and the sedimentation change after the operation of the gray field can be obtained through simulation calculation.
Because the sedimentation differences of different areas on the soft soil foundation are different, the size of a single fold structure needs to be set according to the sedimentation differences of different areas, and in particular, the size is optimized and one of the possible choices is given here: calculating the height of the fold structures according to the value of the sedimentation difference, and calculating the distance between adjacent fold structures according to the following rule:
Wherein,Spacing for the pleat formation; /(I)To calculate the region length; /(I)Calculating the sedimentation difference of the area; /(I)The length of the impermeable film is the length of the impermeable film after the influence of the sedimentation difference; /(I)The height of the folds is generally 100-200 mm; /(I)As a safety factor, in the present embodiment/>Has a value of 2.
In the embodiment, the foundation treatment scheme of the soft soil foundation gray field is determined according to geological conditions of the region and arrangement of the gray field, and the foundation can be treated by adopting a natural foundation, a filled foundation, a composite foundation or a drainage consolidation method, and the like, and the operation planning of the gray field is determined according to annual ash gypsum amount, storage capacity of the gray field and operation requirements; in step S2, the numerical analysis model is consistent with the actual geological conditions, seepage conditions, foundation treatment scheme and the ash stacking sequence in the running period of the ash field; the calculation software uses the Geo-studio Sigma/w module.
The above is an embodiment exemplified in this example, but this example is not limited to the above-described alternative embodiments, and a person skilled in the art may obtain various other embodiments by any combination of the above-described embodiments, and any person may obtain various other embodiments in the light of this example. The above detailed description should not be construed as limiting the scope of the present embodiments, which is defined in the claims and the description may be used to interpret the claims.