A prefabricated large opening well and a construction method thereof

Abstract

The application discloses a prefabricated large-diameter well and a construction method, and belongs to the technical field of water conservancy construction. The prefabricated large-diameter well comprises well pieces, and a plurality of layers of the well pieces are connected in a top-down mode to form a well shaft; the lowermost layer of the well shaft is a blade foot piece; and a filter structure is arranged in the well piece and the blade foot piece in a penetrating mode from the inside to the outside. The application improves the construction efficiency of the large-diameter well, and the well body strength does not need to be waited on site, and a well wall filter layer does not need to be filled; the filter structure is produced and installed in a factory, the installation quality of filter material is ensured, and the loss of the filter material is avoided; complex construction in the later period is not needed, the efficiency is improved, and the operation and maintenance of the filter material in the later period are more favorable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water conservancy construction, and particularly relates to a prefabricated large-diameter well and a construction method. BACKGROUND

[0002] The large-diameter well is mainly composed of a well shaft, a well head and a water inlet part, has large water yield and the advantages of regulating water yield, can collect shallow groundwater and surface river bed seepage water, and is widely used in rural water supply. The large-diameter well is mostly made of cast-in-situ reinforced concrete structure, and the cast-in-situ large-diameter well needs to be supported and waited for structural strength every section. In addition, the water inlet part of the well body needs to be installed by workers after the well shaft is installed in place, which is high in labor intensity, slow in construction speed, and difficult to guarantee the filling quality of the filter layer, and is prone to filter material blockage and loss.

[0003] In recent years, there is also a construction technology of sinking a well by using a prefabricated reinforced concrete cylinder; however, the optimization of the well shaft water inlet is not considered in the prefabrication process. Generally, the filter layer is filled after the well wall is punched after sinking in place; the construction speed is slow, the construction environment is poor, and the safety risk is large. In addition, the filter layer of the well wall is difficult to compact and is prone to loss due to the narrow construction space.

[0004] In addition, when grouting resistance reduction is used in the previous well body assisted sinking method, a hole needs to be reserved or drilled to arrange the grouting hole; the grouting hole is small and is difficult to repair.

[0005] According to the related technologies, the inventors believe that at least the following defects exist:

[0006] The cast-in-situ large-diameter well is slow in construction speed; in the existing prefabricated assembly construction, there is no suitable special large-diameter well body, the filter layer of the well body is difficult to compact and is prone to loss; and the grouting hole of the assisted sinking is not flexible and is difficult to repair. SUMMARY

[0007] The present application aims to solve the problems of the large-diameter well structure and construction in the prior art, and provides a prefabricated large-diameter well and a construction method.

[0008] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0009] A prefabricated large-diameter well and a construction method, comprising a well piece, a plurality of layers of well pieces are spliced up and down to form a well shaft; the lowermost layer of the well shaft is a blade foot piece;

[0010] The filter structure is arranged inside and outside the well piece and the blade foot piece.

[0011] In some embodiments, the reverse filtration structure comprises an opening through the well piece, and a filter screen is arranged at the inner and outer sides of the opening, and the inner and outer filter screens are filled with filter material.

[0012] In some embodiments, the filter screen of the outer layer is embedded in the well piece.

[0013] The filter screen of the inner layer is installed through a connecting piece embedded in the well piece.

[0014] In some embodiments, the connecting piece is a pre-embedded hook or screw rod.

[0015] The filter screen is a stainless steel screen.

[0016] In some embodiments, a reserved grouting pipe is arranged in the reverse filtration structure.

[0017] In some embodiments, horizontal connecting ports are arranged at the upper and lower layer splicing positions of the well piece, and vertical connecting ports are arranged at the same layer splicing positions.

[0018] In some embodiments, flexible water stop pieces are arranged in the horizontal connecting ports and the vertical connecting ports.

[0019] A construction method of a prefabricated large-diameter well, comprising the following steps:

[0020] S1, preparation: well piece prefabrication and transportation, measurement of defense line;

[0021] S2, blade foot piece splicing and installation;

[0022] S3, well shaft splicing and installation;

[0023] S4, earth excavation and sinking;

[0024] S5, sinking assistance;

[0025] Grouting or air curtain drag reduction method is adopted; through the reserved grouting pipe arranged in the reverse filtration structure, the grouting pipe is connected to the grouting pipe, and bentonite mud or air curtain is injected into the part where reduction is needed, so as to reduce the friction and assist sinking;

[0026] S6, final sinking;

[0027] S7, well bottom reverse filtration layer construction;

[0028] S8, water pumping test; repeated water pumping and cleaning until the sand content of the water body is qualified.

[0029] In some embodiments, in step S4, the earth excavation and sinking can be performed without drainage.

[0030] The earth excavation in the well should be performed according to the working face divided according to the center of the large-diameter well, and the earth excavation should be performed in layers, uniformly and symmetrically.

[0031] First, from the well middle, gradually dig to the four around, each layer of earthwork thickness is 0.4~0.5m, along the blade foot around 0.5m of earth embankment is reserved;

[0032] Then, again along the big mouth well wall every 2~3m a section to the blade foot direction layer by layer, symmetrically, uniformly thin soil layer, each time cut 5~10cm;

[0033] When the soil layer can not resist the extrusion of the blade foot and break, the big mouth well is extruded and sinks under the action of gravity.

[0034] In some embodiments, in step S7:

[0035] After precipitation, the small compactor is used to backfill and compact the filter layer at the well bottom layer by layer, and the blade foot part should be strengthened and assisted by artificial ramming;

[0036] Or, without precipitation, the geotextile is wrapped around the filter material layer by layer after compaction, and then hoisted to the well bottom, and the blade foot part is assisted by ramming.

[0037] Compared with the prior art, the present application provides a prefabricated assembly type big mouth well and a construction method, which has the following beneficial effects.

[0038] 1. The present application improves the construction efficiency of the big mouth well, and does not need to wait for the well body strength on site, and does not need to fill the filter layer of the well wall, only the installation and sinking of the well piece are needed.

[0039] 2. The present application sets the filter layer and the mortise and tenon connection mode of the well piece, guarantees the construction quality, and adapts to the non-dewatering construction operation condition; the filter structure is produced and installed in the factory, the filter screen is arranged in front and back, the installation quality of the filter material is guaranteed, and the loss of the filter material is avoided; through the self-provided filter structure, the complex construction in the later period is not needed, the efficiency is improved, and the quality of the filter layer can be fully guaranteed; the inner and outer filter screens are designed, the filler is convenient, and the operation and maintenance of the filter material in the later period are more favorable.

[0040] 3. The present application reserves the grouting pipe in the filter structure of the well wall, which is beneficial to grouting resistance reduction and auxiliary sinking of the well body.

[0041] 4. The present application sets the whole well body structure and the construction method, effectively avoids the complex operation in the limited space, improves the operation condition, and improves the safety guarantee rate of construction.

[0042] 5. The present application sets the flexible water stop part in the connecting port, matches the strip-shaped groove for clamping the flexible water stop part, prevents fine sand from entering the water well along the construction joint, and can guarantee that small particle sand and gravel naturally seal the construction joint in the later use process of the big mouth well.

[0043] 6、The invention, excavating sinking can not drain, dividing working face layering, uniform, symmetrically; along the blade foot around the reserved embankment thin soil layer, large well under the action of self-weight extruding soil sinking.

[0044] 7、The invention, well bottom filter construction can not be dewatering, on the ground to take geotextile wrapped filter material layering compaction after lifting to the well bottom, to the blade foot part auxiliary ramming.

[0045] Other advantages, objectives and features of the present invention will be in part apparent and in part pointed out hereinafter; and in part will be obvious to those skilled in the art from the following description, the appended claims, and the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 It is a structural schematic diagram of the present invention.

[0047] Figure 2 It is a sectional structure schematic diagram of the present invention.

[0048] Figure 3 It is Figure 2 The enlarged structure schematic diagram of A in the middle.

[0049] Figure 4 It is a sectional structure schematic diagram of the filter structure.

[0050] Figure 5 It is a structure schematic diagram of the inside filter screen.

[0051] Figure 6 It is a structure schematic diagram of the horizontal connection port.

[0052] Figure 7 It is a structure schematic diagram of the vertical connection port.

[0053] In the figure:

[0054] 1, well piece;

[0055] 2, blade foot piece;

[0056] 3, filter structure;

[0057] 4, filter screen;

[0058] 5, filter material;

[0059] 6, reserved grouting pipe;

[0060] 7, grouting pipe;

[0061] 8, horizontal connection port;

[0062] 9, vertical connection port;

[0063] 10. Flexible waterstop. DETAILED DESCRIPTION

[0064] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application.

[0065] Reference Figures 1-7 A prefabricated large-diameter well and a construction method, comprising well pieces 1, and a plurality of layers of the well pieces 1 are spliced to form a well shaft.

[0066] Each layer can be formed by one well piece 1, or a plurality of well pieces 1 are spliced to form a layer; that is, when the well diameter is small (less than three meters), a single-layer well piece can be set as a whole prefabricated section, and when the diameter is large (greater than three meters), the well is prefabricated in sections and spliced to form a layer.

[0067] Generally, the large-diameter well has a large size, and is set in a mode of a plurality of well pieces 1 spliced to form a layer.

[0068] It should be noted that when a plurality of well pieces 1 are spliced to form a layer, the well pieces 1 of the upper and lower layers are spliced in a staggered manner to form a well shaft.

[0069] The lowermost layer of the well shaft is a blade foot piece 2, so as to facilitate sinking.

[0070] The well piece 1 and the blade foot piece 2 are provided with a filter structure 3 penetratingly arranged inside and outside; by being provided with the filter structure 3, complex post-construction is not needed, efficiency is improved, and the quality of the filter layer can be fully ensured.

[0071] It should be noted that the filter structure 3 on the blade foot piece 2 is optionally arranged; if the height of the blade foot piece 2 is small, the filter structure 3 can not be arranged; generally, the height of the blade foot piece 2 is consistent with the height of the ordinary well piece 1, and the filter structure 3 is arranged.

[0072] In some embodiments, the filter structure 3 comprises an opening penetrating the well piece 1, and filter screens 4 are arranged at the inner and outer positions of the opening, and filter material 5 is filled between the inner and outer filter screens 4.

[0073] The opening is preferably a circular hole; of course, it can also be arranged in the form of a square hole, an oval hole, etc.; relatively, the circular hole has higher structural strength; at the same time, the circular hole is also more conducive to filling the filter material 5, and can well control the filling quality of the filter material 5.

[0074] It can be understood that the pore size of the filter screen 4 should be smaller than the minimum particle size of the filter material 5, so as to ensure that the filter material 5 is not lost, and the operation and maintenance in the later period is facilitated.

[0075] In addition, it should be noted that:

[0076] The filter material 5 in the filter structure 3 is filled and compacted in the prefabrication yard after the well piece 1 is completed, so as to fully ensure the quality of the filter layer and ensure the filtering effect.

[0077] The filter material 5 is generally divided into 2-3 layers, and the particle size ratio of adjacent filter layers is 2-4.

[0078] In some embodiments, the outer layer of the filter screen 4 is pre-embedded in the well piece 1; and the inner layer of the filter screen 4 is installed through the connecting piece pre-embedded in the well piece 1.

[0079] In production, the filter screen 4 on the outside of the well is directly installed when the well body is prefabricated and is poured and fixed in the well piece 1; similarly, the connecting piece on the inside of the well is prefabricated and poured and fixed in the well piece 1; after the filter material 5 is filled, the filter screen 4 on the inside is installed on the well piece 1 through the connecting piece.

[0080] It can be understood that the filter screen 4 is pre-installed on one side and post-installed on the other side, so as to facilitate the filling and later maintenance.

[0081] In some embodiments, the connecting piece is a pre-embedded hook or screw connecting structure; preferably, the filter screen 4 is a stainless steel screen, which ensures the quality and prolongs the service life.

[0082] In some embodiments, the filter structure 3 is provided with a reserved grouting pipe 6.

[0083] Correspondingly, in construction, the reserved grouting pipe 6 is connected to the external grouting pipeline 7.

[0084] It should be noted that the number of reserved grouting pipes 6 is planned according to the diameter of the well shaft, the number and position of the filter structure 3, so as to be appropriate for assisting; it is not necessary to set a reserved grouting pipe 6 in each filter structure 3, and generally, the reserved grouting pipes 6 are arranged at intervals.

[0085] By setting the reserved grouting channel in the well wall filter layer, the demand for post-grouting of the well wall is met, the sinking is assisted, and grouting can be performed at different heights.

[0086] When sinking is difficult, the grouting pipeline 7 of the mud system is connected to the reserved grouting pipe 6, and bentonite mud or an air curtain is injected to reduce the resistance behind the wall. By accurately controlling the position with large friction, the well piece 1 is ensured to sink smoothly and the relative position of the well piece 1 is adjusted; the well piece 1 can be prevented from being disconnected due to excessive local friction.

[0087] It should be noted that the reserved grouting pipe 6 should be promptly plugged after sinking in place.

[0088] In addition, the reserved grouting pipe 6 arranged at intervals by the filter structure 3 does not need to be repaired later and does not affect the use function of the filter structure 3.

[0089] In some embodiments, the connecting port of the large well well piece 1 is a horizontal connecting port 8, a vertical connecting port 9.

[0090] Specifically, the horizontal connecting port 8 is arranged at the upper and lower layer splicing position of the well piece 1, and the vertical connecting port 9 is arranged at the same layer splicing position.

[0091] Among them, the horizontal connecting port 8 and the vertical connecting port 9 are a few Chinese character-shaped grooves and protrusions matched with each other; the few Chinese character-shaped grooves are connected between the rings and radially.

[0092] It should be further explained that:

[0093] Since the main function of the large well is to collect water, it is not necessary to set a complex connecting mode, so as to avoid construction difficulties and affect the construction speed.

[0094] In some embodiments, a flexible water stop 10 is arranged in the horizontal connecting port 8 and the vertical connecting port 9.

[0095] Preferably, the flexible water stop 10 is a rubber ring.

[0096] Further, a strip-shaped groove for clamping the flexible water stop 10 is arranged at the corresponding position of the few Chinese character-shaped grooves and protrusions.

[0097] It should be further explained that:

[0098] The connecting seam between the well pieces 1 of the large well is embedded by the rubber ring; the main function is to prevent fine sand from entering the water well along the construction seam; at the same time, the flexible waterproof material can ensure that the small particle sand can naturally seal the construction seam in the later use process of the large well.

[0099] A construction method of a prefabricated assembly type large well, comprising the following steps.

[0100] S1, preparation work: well piece prefabrication and transportation, measurement of defense line.

[0101] Well piece prefabrication and transportation: according to the well diameter and depth, the corresponding well piece 1 is prefabricated;

[0102] Among them, the diameter less than 3m can be prefabricated in whole section, and the diameter greater than 3m is prefabricated in section; when prefabricating, the filter screen 4 at the outer side of the well wall is installed firmly and reliably, and the connecting piece of the filter screen 4 at the inner side of the well wall is pre-buried.

[0103] It should be noted that the well piece 1 of the prefabricated large well can be lifted when the strength reaches 75%, and can be transported when the strength reaches 100%.

[0104] Measurement of defense line: set up the measurement control network and the level base point according to the design general drawing and the large well plane layout requirements, carry out positioning and line laying, and determine the center axis and contour line of the large well.

[0105] It should be noted that when there are buildings and underground pipelines nearby, settlement observation points are set on the original buildings, and periodic settlement observations are carried out.

[0106] S2, blade foot piece 2 splicing installation.

[0107] Before installing the blade foot piece 2, lay a sand cushion layer on the blade foot foundation to level and compact in layers; according to the construction site and the size of the well piece 1, select a car crane to install the well piece 1; strictly control the linearity, joint, and perpendicularity, and connect the grouting pipe 7.

[0108] S3, well shaft splicing installation.

[0109] The upper and lower well pieces 1 should be installed with wrong joints;

[0110] The well piece 1 needs to be hoisted according to the alignment of the joint (the mu structure of several characters); after installation, accurate alignment and perpendicularity adjustment are carried out.

[0111] It should be noted that after the well piece 1 is transported to the site, it is assembled and installed by hoisting the well piece 1 to connect the horizontal joint 8 and the vertical joint 9, and the flexible water stop 10 is installed in advance.

[0112] S4, excavate and sink.

[0113] S5, assist sinking.

[0114] Grouting or air curtain resistance reduction method is adopted;

[0115] Through the reserved grouting pipe 6 in the filter structure 3, the grouting pipe 7 is connected to inject bentonite slurry or air curtain to the part needing resistance reduction, and the friction force is reduced to assist sinking;

[0116] S6, final sinking.

[0117] The large well mainly corrects deviation in the final sinking stage, and is basically corrected when it sinks to 1m above the design elevation; the final sinking ends with a self-sinking speed control of not more than 10mm / 8h;

[0118] S7, construction of well bottom filter layer.

[0119] S8, test pumping.

[0120] Through repeated pumping and cleaning, until the sand content of the water body is qualified; generally, the sand content of the water body is required to be less than or equal to 1 / 200000 (volume ratio).

[0121] In some embodiments, in step S4: the excavating and sinking can be without drainage.

[0122] The excavation in the well should be divided into working faces according to the center of the large well, and the excavation should be carried out in layers, uniformly and symmetrically;

[0123] First, gradually dig from the middle of the well to the four sides, and the thickness of each layer of soil is 0.4-0.5m, and a 0.5m soil embankment is reserved around the blade foot;

[0124] Then, the soil layer is thinned layer by layer, symmetrically and uniformly along the well wall of the large well to the blade foot direction every 2-3m, and each time the soil layer is thinned by 5-10cm;

[0125] When the soil layer is broken under the pressure of the blade foot, the large well sinks under the action of its own weight.

[0126] In some embodiments, in step S8:

[0127] After dewatering, the small compactor is used to backfill and compact each layer of filter material of the filter layer at the bottom of the well; the blade foot part should be strengthened and assisted by artificial ramming;

[0128] Or, without dewatering, after the geotextile is wrapped around the filter material and the filter material is layered and compacted on the ground, the blade foot part is assisted by ramming.

[0129] The scheme has been applied to a rural centralized water supply project and an urban and rural integrated water supply project in a certain city, and is used for village water supply stations, shallow rivers in mountainous areas and areas rich in shallow groundwater; The construction of the prefabricated large well improves the construction efficiency, reduces the construction difficulty and reduces the construction cost.

[0130] The present application can improve the construction efficiency of the large well, and the well body strength does not need to be waited on site, and the well wall filter layer does not need to be filled, only the installation and sinking of the well piece 1 are needed; The setting of the filter layer and the mortise and tenon connection mode of the well piece guarantee the construction quality and adapt to the non-dewatering construction operation conditions; The filter structure is produced and installed in the factory, the filter screen is arranged in front and back, the installation quality of the filter material 5 is guaranteed, and the loss of the filter material 5 is avoided; Through the self-provided filter structure 3, complex construction in the later period is not needed, the efficiency is improved, and the quality of the filter layer can be fully guaranteed; The inner and outer filter screens 4 are designed, the filler is convenient, and the operation and maintenance of the filter material 5 in the later period are more beneficial; In addition, the grouting pipe is reserved in the well wall filter structure, which is beneficial to the grouting resistance reduction and auxiliary sinking of the well body; In addition, the setting of the whole well body structure and the construction method effectively avoid complex operations in limited space, improve the operation conditions, and improve the safety guarantee rate of construction.

[0131] The flexible water stop 10 is arranged in the connecting port, and is matched with the strip-shaped groove for clamping the flexible water stop 10, so that fine sand is prevented from entering the well, and small particle sand can be naturally blocked in the construction joint in the later use of the large well; the soil excavation and sinking can be carried out without drainage, and the working surface is divided into layers, is uniform and symmetrical; the soil layer is thinned after the soil embankment is reserved around the blade foot, the large well is sunk by extruding soil under the action of the self weight, the construction of the bottom filter layer can be carried out without drainage, and the blade foot part is assisted by ramming after the geotextile is wrapped around the filter material on the ground and is hoisted to the bottom.

[0132] The above merely describes preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical scheme and the inventive concept of the present application within the technical scope disclosed by the present application, which should be covered by the protection scope of the present application.

[0133] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0134] Although the embodiments of the present application have been shown and described above, it should be understood that the above-described embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A construction method of a prefabricated large-diameter well, characterized in that it comprises a prefabricated large-diameter well comprising well pieces (1), a plurality of layers of well pieces (1) being spliced together to form a well shaft; the lowermost layer of the well shaft is a blade foot piece (2); the well pieces (1) and the blade foot piece (2) are provided with a filter structure (3) penetrating inwards and outwards; the filter structure (3) comprises an opening penetrating the well piece (1), filter screens (4) are arranged at the inner and outer positions of the opening, and filter material (5) is filled between the inner and outer filter screens (4); the filter material (5) is filled and compacted in the prefabrication yard after the well piece (1) is completed; the filter material (5) is divided into 2-3 layers, and the particle size ratio of adjacent filter layers is 2-4; the filter screen (4) of the outer layer is embedded in the well piece (1); the filter screen (4) of the inner layer is installed through a connecting piece embedded in the well piece (1); the connecting piece is a pre-embedded hook or screw rod; the filter screen (4) is a stainless steel screen; a reserved grouting pipe (6) is arranged in the filter structure (3); in construction, the reserved grouting pipe (6) is connected to an external grouting pipeline (7); horizontal connecting openings (8) are arranged at the splicing positions of the upper and lower layers of the well piece (1), and vertical connecting openings (9) are arranged at the splicing positions of the same layer; flexible water-stopping pieces (10) are arranged in the horizontal connecting openings (8) and the vertical connecting openings (9); it comprises the following steps: S1, preparation: well piece prefabrication and transportation, and measurement of the defense line; S2, blade foot piece splicing and installation; S3, well shaft splicing and installation; S4, earth excavation and sinking; S5, sinking assistance; grouting or air curtain resistance reduction method; through the reserved grouting pipe (6) arranged in the filter structure (3), the grouting pipeline (7) is connected, and bentonite mud or air curtain is injected into the position requiring resistance reduction, so as to reduce the friction and assist sinking; S6, final sinking; S7, construction of the bottom filter layer of the well; S8, water pumping test; repeated water pumping and cleaning until the sand content of the water body is qualified; in step S4: the earth excavation and sinking can be performed without drainage; the earth excavation in the well should be performed according to the division of working faces based on the center of the large-diameter well, and the earth excavation should be performed in layers, uniformly and symmetrically; first, the earth excavation is performed from the middle of the well to the periphery, the thickness of each layer is 0.4-0.5 m, and a 0.5 m soil embankment is reserved around the blade foot; then, the soil layer is gradually thinned in layers, fully, symmetrically and uniformly along the well wall of the large-diameter well every 2-3 m to the blade foot direction, and the soil layer is thinned by 5-10 cm each time; when the soil layer is broken under the extrusion of the blade foot, the large-diameter well sinks under the action of its own weight; in step S7: after precipitation, a small compactor is used to backfill and compact the bottom filter layer in layers; the blade foot part should be reinforced and assisted by artificial tamping; or, without precipitation, the filter material is wrapped with geotextile, hoisted to the bottom of the well after being compacted in layers, and the blade foot part is assisted by tamping.

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