CN113668585B - Open caisson structure for deep and large water intaking in high-pressure water area and construction method - Google Patents
Open caisson structure for deep and large water intaking in high-pressure water area and construction method Download PDFInfo
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- 238000007789 sealing Methods 0.000 claims abstract description 22
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- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D23/00—Caissons; Construction or placing of caissons
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
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- E—FIXED CONSTRUCTIONS
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- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D23/00—Caissons; Construction or placing of caissons
- E02D23/08—Lowering or sinking caissons
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
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- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
- E21B33/138—Plastering the borehole wall; Injecting into the formation
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
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Abstract
The invention discloses a deep and large water intake open caisson in a high water pressure area and a construction method thereof, wherein the open caisson comprises a sealing bottom plate, a supporting short pile, a water intake pipe, outer concrete, a filling core material and a high-pressure rotary-jetting reinforcing body, the supporting short pile and the sealing bottom plate are used for providing vertical bearing capacity for the open caisson, the water intake pipe is used for taking water in the open caisson, the outer concrete and the filling core material are used for wrapping the water intake pipe so as to ensure long-term normal use of the water intake pipe, and the high-pressure rotary-jetting reinforcing body is used for carrying out cement high-pressure rotary-jetting reinforcement at the intersection of the water intake pipe and the side wall of the open caisson.
Description
Technical Field
The invention relates to the technical field of open caisson construction, in particular to a deep and large water intake open caisson in a high water pressure area and a construction method thereof.
Background
In recent years, along with the vigorous promotion of urbanization construction, the problem of shortage of water resource supply in cities and towns is more and more prominent, and the rapid development of long-distance pipe-jacking diversion engineering construction in China is promoted. As an important component of water diversion engineering, the open caisson structure is widely applied to water taking engineering and can be used as a jacking reaction force supporting structure and a water taking temporary receiving structure. Compared with the open caisson foundation adopted in the field of traditional foundation engineering, in the field of municipal water diversion engineering, the difference between the elevation of the water taking point and the elevation of the ground surface outside the water body is large, the downward penetration depth of the water taking jacking pipe is large, the open caisson depth is generally large, and the diameter of the open caisson is also large due to the requirement of meeting the space requirement of the jacking pipe reverse thrust operation. Therefore, the sinking resistance of the water intake open caisson structure is larger, and the problem of difficult sinking is easy to occur. For example, in the Yangtze river diversion project of the full-capacity water plant, in order to meet the water taking requirement, two circular open caissons are arranged in the dam of the Yangtze river to serve as starting wells of a water taking pipeline of the Yangtze river, the depth of each open caisson is about 48m, and the inner diameter of each open caisson is 15m, so that the open caisson is the deepest constructed open caisson in China at present. In addition, because the open caisson sets up the position and is nearer from the water intaking point, place groundwater often with the water intaking point surface water intercommunication, the water level is higher, the water pressure that the open caisson receives is great, at the in-process that sinks take place the soil body gushing easily, has great construction risk.
In the current engineering practice, in order to reduce the frictional resistance in the sinking process of the open caisson, a thixotropic slurry drag reduction method is usually adopted, but for municipal open caisson taking water with large depth, the construction requirement is often difficult to meet only by the thixotropic slurry. Particularly, when the stratum is a water-rich sand layer, the self-stability of sand is poor, and the sand is mixed into thixotropic slurry in the sinking process of the open caisson, so that the drag reduction effect of the slurry is greatly reduced, and the problem that the open caisson is difficult to sink is easily caused.
Disclosure of Invention
The invention aims to provide a deep and large water intake open caisson structure in a high-pressure water area and a construction method, which solve the problems mentioned in the technical background. In order to achieve the purpose, the invention provides the following technical scheme: the open caisson comprises an open caisson body, wherein the open caisson body comprises a sealing bottom plate, a supporting short pile, a water taking pipe, outsourcing concrete, a filling core material and a high-pressure rotary spraying reinforcing body, the supporting short pile and the sealing bottom plate are used for providing vertical bearing capacity of the open caisson, the water taking pipe is used for taking water in the open caisson, the outsourcing concrete and the filling core material are used for wrapping the water taking pipe so as to ensure long-term normal use of the water taking pipe, and the high-pressure rotary spraying reinforcing body is used for carrying out cement high-pressure rotary spraying reinforcement at the intersection of the water taking pipe and the side wall of the open caisson.
Preferably, a circle of dewatering wells are arranged on the periphery of the open caisson and used for reducing the height of the underground water level in the sinking process of the open caisson and increasing the sinking load.
Preferably, the outer diameter of the open caisson is gradually reduced from bottom to top, and the outer wall of the open caisson is coated with wax.
Preferably, a gravel cushion layer is paved on the top of the open caisson, and the paving range of the cushion layer is more than 500mm larger than the outer diameter of the open caisson.
Preferably, floating platform on water includes a plurality of flotation tanks, polylith floating platform board, drawknot board and dead lever, a plurality of flotation tanks are used for adjusting floating platform's on water height, the drawknot board is used for connecting polylith floating platform board as a whole, the dead lever is used for drawknot floating platform on water and open caisson to guarantee floating platform board's stability.
Preferably, the platform plate is provided with a circumferential or longitudinal and transverse guide channel, and the guide channel is matched with the drill rod.
Preferably, the number of the supporting short piles is multiple.
Preferably, the position that intake pipe and open caisson intersect sets up the reservation hole, the hoop strengthening rib and the distribution strengthening rib are arranged to the hole periphery, just the distribution strengthening rib includes horizontal muscle and vertical muscle.
Preferably, the water intake pipe is arranged in a Z shape.
Preferably, the method comprises the following steps:
construction preparation: the construction site 'tee joint one-level' work is well done, measurement setting is carried out according to design requirements, the actual position of the open caisson is determined, a gravel cushion layer is laid on the construction site, the laying range of the cushion layer is larger than the outer diameter of the open caisson by more than 500mm, and a stable and reliable operation surface is provided for subsequent open caisson construction and material stacking;
and (3) dewatering well construction: arranging a circle of precipitation wells at the periphery of the open caisson, wherein the depth of the precipitation wells is greater than the maximum sinking depth of the open caisson, the bottommost part of the precipitation wells is provided with a precipitation pipe, the upper parts of the precipitation pipes are provided with filter pipes with holes, common well pipes are arranged on the precipitation pipes, the filter pipes and the open caisson, and the gaps among the precipitation pipes, the filter pipes and the open caisson are backfilled by using medium coarse sand;
and (3) open caisson pouring construction: the outer wall of the open caisson adopts a step-type design, the outer diameter of the bottommost end is largest, the outer diameter is gradually reduced along the depth, meanwhile, wax coating construction is carried out on the outer wall of the open caisson and thixotropic slurry drag reduction is matched, the construction process of the open caisson mainly comprises erecting an inner die, binding steel bars, erecting an outer die and pouring concrete, the excavation process in the open caisson is matched, the pouring work of the open caisson can be completed by repeating the processes, meanwhile, a reserved hole is arranged at the position where the water taking pipe and the open caisson intersect, the hole is blocked by a concrete thin plate, and annular reinforcing ribs and distributed reinforcing ribs are arranged at the periphery of the hole;
sinking construction of the open caisson: because the stratum where the water taking open caisson is located is generally high in underground water level and even if precipitation is adopted, the underground water level is difficult to completely reduce to below the designed depth, the water taking open caisson is generally required to carry out underwater open caisson sinking construction, then the construction of an overwater floating platform is adopted to carry out underwater well soil body excavation construction, the overwater floating platform is arranged on the inner side of the open caisson, the height of the overwater floating platform is adjusted by a lower water tank of the overwater floating platform, a high-pressure rotary spraying power device is arranged on the platform, a high-pressure rotary spraying drill rod is connected below the platform and extends into a soil body to be excavated of the open caisson, the soil body on the inner side of the open caisson is quickly crushed and cut by high-pressure air and high-pressure liquid sprayed by the drill rod, the crushed soil body is further extracted by a mud suction device, the drill rod is moved on the overwater floating platform through a guide channel, the omnibearing crushing and cutting of the soil body in the open caisson is realized, and the soil body in the open caisson is completely excavated, the smooth sinking of the deep and large open caisson is ensured;
and (3) bottom sealing and water intake pipe hole high-pressure rotary spraying reinforcement: when the open caisson is sunk to the designed depth, firstly removing sludge at the bottom of the open caisson, driving a series of supporting short piles to improve the overall vertical bearing capacity of the open caisson, determining the number and the arrangement positions of the supporting short piles according to the design requirements, further laying a concrete sealing bottom plate reinforcing mesh and carrying out underwater concrete sealing bottom plate construction, after the open caisson bottom plate is poured, carrying out cement high-pressure rotary spraying reinforcement at the intersection of a water intake pipe and the open caisson wall, wherein the reinforcement range of the cement high-pressure rotary spraying is determined according to the design requirements;
and (3) communicating and constructing a water intake pipe: breaking a thin plate at the opening of the water taking pipe, connecting a water taking top pipe with a water taking pipe in the open caisson, connecting an upper water taking top pipe and a lower water taking top pipe in the open caisson by adopting a Z-shaped pipe, and directly conveying the two top pipes to a water plant through the water taking pipe for further treatment;
backfilling an open caisson core filling material and recovering a field: after the water intake pipe is communicated, firstly, plain concrete filler is adopted to wrap the Z-shaped water intake pipe along the depth direction to form a first protective layer of the water intake pipe, further, filling core material is filled outside the concrete wrapping layer to compact and fill the inner wall of the whole open caisson, a second protective layer of the water intake pipe is formed, after the open caisson core material is backfilled, original state recovery is carried out on the open caisson construction site, protection work of the open caisson structure is carried out, and the open caisson and the water intake pipe are prevented from being damaged during use.
In conclusion, the invention has the following beneficial effects:
according to the deep and large water taking open caisson structure in the high-pressure water area and the construction method, the step type deep and large water taking open caisson structure in the high-water pressure area can greatly reduce the frictional resistance applied to the sinking construction of the well body, meanwhile, the water taking pipe in the well body is provided with sufficient protection measures, and the long-term normal use of the water taking pipe in the well body can be effectively guaranteed; the construction method reduces the height of the underground water level in the sinking process of the open caisson by arranging a circle of dewatering wells at the periphery of the wall of the open caisson pipe, can effectively increase the sinking load, adopts an above-water platform type excavation mode, and crushes and cuts the soil body on the inner side of the open caisson through a high-pressure rotary jet drill rod, thereby greatly improving the sinking efficiency of the open caisson and reducing the risk of underwater excavation construction.
Drawings
FIG. 1 is a schematic view of a structure of a water intake open caisson;
FIG. 2 is a flow chart of water intake open caisson construction
FIG. 3 is a schematic view of a dewatering well arrangement;
FIG. 4 is a schematic diagram of soil excavation in a well of an over-water floating platform;
FIG. 5 is a schematic plan view of the water flotation platform;
fig. 6 is a schematic diagram of the arrangement of reinforcing ribs of the reserved holes.
In the figure: 1. sinking a well; 2. taking a water pipe; 3. sealing the bottom plate; 4. supporting the short piles; 5. concrete is coated outside; 6. filling a core material; 7. high-pressure rotary spraying to reinforce the body; 8. a settling tube; 9. medium coarse sand; 10. cohesive soil filler; 11. a well pipe; 12. a filter tube; 13. dewatering wells; 14. a drill stem; 15. a buoyancy tank; 16. a soil body; 17. a high-pressure rotary jet power device; 18. a drawknot plate; 19. fixing the rod; 20. a floating platform deck; 21. a guide channel; 22. circumferential reinforcing ribs; 23. a hole; 24. and reinforcing ribs are distributed.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1 to 6, the open caisson for deep and large water intake in high water pressure areas and the construction method thereof comprise an open caisson 1, wherein the open caisson 1 comprises a sealing bottom plate 3, a supporting stub 4, a water intake pipe 2, an outer concrete 5, a filling core material 6 and a high-pressure rotary spraying reinforcing body 7, the supporting stub 4 and the sealing bottom plate 3 are used for providing vertical bearing capacity of the open caisson 1, the water intake pipe 2 is used for taking water in the open caisson 1, the outer concrete 5 and the filling core material 6 are used for wrapping the water intake pipe 2 so as to ensure long-term normal use of the open caisson, the high-pressure rotary spraying reinforcing body 7 is used for carrying out cement high-pressure rotary spraying reinforcement at the junction of the water intake pipe 2 and the side wall of the open caisson 1, the long-term durability of the water intake pipe 2 can be effectively improved through the outer concrete 5 and the filling core material 6, the corrosion and deformation of the water intake pipe 2 in the use process are avoided, the outer diameter of the open caisson 1 is gradually reduced from bottom to top, the outer wall of the open caisson 1 is coated with wax. An overwater floating platform is arranged in the open caisson 1, a high-pressure rotary spraying power device 17 is arranged on the overwater floating platform, and the high-pressure rotary spraying power device 17 sprays high-pressure air and high-pressure liquid through a drill rod 14 to quickly break and strip soil bodies on the inner side of the open caisson and extract the broken soil bodies. The floating platform on water includes a plurality of flotation tanks 15, polylith floating platform board 20, drawknot board 18 and dead lever 19, a plurality of flotation tanks 15 are used for adjusting floating platform's on water height, drawknot board 18 is used for connecting polylith floating platform board 20 as an organic whole, dead lever 19 is used for drawknot floating platform on water and open caisson 1 to guarantee floating platform board 20's stability. The floating platform plate 20 is provided with a circumferential or longitudinal and transverse guide channel 21, and the guide channel 21 is matched with the drill pipe 14. The number of the support stub 4 is multiple. The position that intake pipe 2 and open caisson 1 intersect sets up and reserves hole 23, hoop strengthening rib 22 and distribution strengthening rib 24 are arranged to the hole 23 periphery, just the distribution strengthening rib includes horizontal muscle and vertical muscle. The water intake pipe 2 is arranged in a Z shape, a water source is led out of the open caisson 1 through the Z-shaped water intake pipe 2, and the height value of the water floating platform can be adjusted by filling box pressing water with different volumes into the floating box 15, so that cutting and pumping drainage of soil bodies on the inner side of the open caisson 1 with different depths can be realized, and the construction operation efficiency is improved. In order to ensure that the heavy water intake open caisson can smoothly sink to a designed position in a high water pressure area, a circle of precipitation wells are arranged on the periphery of the pipe wall of the open caisson 1 so as to reduce the height of the underground water level in the sinking process of the open caisson 1 and increase the sinking load; further, in order to improve the sinking rate of the open caisson 1, an overwater platform type excavation mode is adopted, and the soil body on the inner side of the open caisson 1 is broken and stripped by arranging the high-pressure rotary spraying drill rod 14 on the platform, so that the excavation rate on the inner side of the open caisson 1 can be greatly improved, and meanwhile, the danger of traditional underwater operation construction can also be avoided. The invention can effectively enhance the construction efficiency of the open caisson for deep and large water intake in high water pressure areas, avoid the problem that the open caisson is difficult to sink, and meanwhile, the open caisson structure has stronger protection effect on the prop of the water intake pipe 2, thereby meeting the long-term normal use requirement of the water intake pipe 2
Construction preparation: the construction site 'tee joint leveling' work is well done, the measurement and setting-out are carried out according to the design requirements, the actual construction position of the open caisson 1 is determined, and a gravel or plain concrete cushion (the preferable strength is not lower than C20) is laid on the construction site, so that the ground surface forms a certain supporting strength, the stability of the sinking process of the open caisson 1 is ensured, and the over-allowable differential settlement is avoided; the thickness of the cushion layer is more than 200mm, the laying range is more than 500mm of the outer diameter of the open caisson, and a stable and reliable operation surface is provided for the subsequent open caisson construction and material stacking;
and (3) dewatering well construction: as shown in fig. 3, a circle of precipitation well 13 is arranged on the periphery of the open caisson 1 by a drilling machine, and the depth of the precipitation well 13 is larger than the maximum designed sinking depth of the open caisson 1 so as to ensure that the underground water level in the open caisson 1 can be effectively reduced; the distance between the dewatering well 13 and the outer wall of the open caisson is not more than 3m, so that the dewatering efficiency of the dewatering well 13 is improved. As shown in fig. 1, the precipitation well 13 mainly comprises a settling pipe 8, a filter pipe 12 and a common well pipe, wherein the settling pipe 8 is arranged at the bottommost part and is used for preventing impurities and foreign matters in the precipitation process from clogging the precipitation well 13; the upper part of the settling pipe 8 is provided with a filter pipe 12 with a hole (the diameter of the filter hole is preferably larger than 3mm and is wrapped by filter cloth), which is the main water pumping part of a dewatering well 13, and the upper part of the settling pipe is provided with a common well pipe 11 (the well wall is not provided with a water pumping hole); the depth value of the filter pipe 12 is mainly related to the permeability of the soil body of the field stratum, the filter pipe 12 can take a small value in the sandy soil stratum, and otherwise, the depth value of the filter pipe 12 in the viscous soil stratum can take a large value. Correspondingly, the gap parts of the settling pipe 8, the filter pipe 12 and the open caisson 1 hole are backfilled by medium coarse sand 9, and the gap parts of the common well pipe 11 and the open caisson 1 hole can be backfilled by common cohesive soil filling materials;
pouring construction of the open caisson 1: in order to reduce the frictional resistance in the sinking process of the deep and large open caisson, the outer wall of the open caisson 1 is designed in a step mode, the outer diameter of the bottom end is largest, the outer diameter is gradually reduced upwards along the depth, and the heights of all sections and the heights of the steps are determined according to the stratum characteristics and the design depth. Under the condition of meeting the design condition, the preferred segmental height is not less than 6m, and the step width is not less than 20 mm. Meanwhile, wax coating construction is carried out on the outer wall of the open caisson 1, and thixotropic slurry is matched for resistance reduction, so that the well wall friction resistance value is further reduced; further, drainage construction is carried out through the dewatering well 13 on the outer side of the open caisson, the underground water level height in the open caisson 1 is reduced, the effective weight of the structure is increased, and the sinking load of the open caisson is effectively improved. The construction process of the side wall of the open caisson 1 mainly comprises erecting an internal mold, binding steel bars, erecting an external mold and pouring concrete; and (5) the pouring work of the open caisson can be completed by matching with the excavation process in the open caisson and repeating the above processes. As shown in fig. 6, in order to ensure that the water intake pipe 2 can smoothly pass through the borehole wall, a reserved hole 23 is arranged at the intersection position of the water intake pipe 2 and the open caisson 1, the hole 23 is sealed by a concrete thin plate, and a circumferential reinforcing rib 22 and a distributed reinforcing rib 24 (the distributed reinforcing ribs comprise a transverse rib and a longitudinal rib) are arranged at the periphery of the hole 23;
sinking construction of the open caisson 1: since the stratum where the water taking open caisson 1 is located is generally high in ground water level, even if precipitation is performed by the precipitation well 13, it is difficult to completely reduce the ground water level to below the designed depth, and therefore the water taking open caisson 1 generally needs to be constructed by sinking the open caisson 1. The construction of the overwater floating platform is preferably adopted for soil body excavation construction in the underwater open caisson 1, so that the construction efficiency is improved, and the construction risk is reduced. As shown in fig. 4, the water floating platform comprises buoyancy tanks 15, a floating platform plate 20, tie plates 18 and fixing bars 19. An above-water floating platform is arranged on the inner side of the open caisson 1, and the height of the platform is adjusted by a floating platform plate 20 through a lower floating box 15 of the floating platform plate. As shown in fig. 5, the tie plates 18 essentially connect a plurality of floating platform plates 20 together as a unit; further, the platform is tied with the wall of the open caisson 1 through the fixing rods 19, so that the stability of the platform plate is guaranteed. As shown in fig. 4, a high-pressure jet grouting power device 17 is arranged on a floating platform plate 20, a high-pressure jet grouting drill pipe 14 is connected below the high-pressure jet grouting power device, and the drill pipe 14 is provided with a high-pressure nozzle and extends into a soil body 16 to be excavated in the open caisson 1; the soil 16 inside the open caisson 1 is quickly crushed and cut by the high-pressure air and high-pressure liquid sprayed out through the drill pipe 14, and the crushed soil 16 is further pumped out through a mud suction device.
Soil mass crushing and cutting need to be matched with deformation monitoring data of the open caisson 1 in real time, and the crushing and cutting position and speed are adjusted according to the inclination condition of the open caisson 1. Referring to fig. 5, the preferred method is to provide a series of circumferential or longitudinal/transverse guide channels 21 on the floating platform plate 20, and to move the drill pipe 14 through the guide channels 21 to the area to be excavated and to perform soil body breaking and cutting according to the real-time monitoring data of the inclination of the open caisson. By reasonably arranging the guide channel 21, the stable sinking of the open caisson 1 can be ensured, the soil in the open caisson 1 can be crushed and cut in all directions, the soil 16 in the wall of the open caisson 1 is completely excavated, and the smooth sinking of the deep and large open caisson 1 is ensured;
1, bottom sealing of the open caisson and high-pressure rotary spraying and reinforcing of the water intake pipe 2 pipeline opening: after the open caisson 1 sinks to the designed depth, firstly removing sludge at the bottom of the open caisson, pouring bottom sealing concrete, and driving a series of supporting short piles 4 (figure 1), wherein the number and the arrangement positions of the supporting short piles 4 are determined according to the design requirements; further, 3 reinforcing meshes of the concrete sealing bottom plate are arranged, the underwater concrete sealing bottom plate 3 is constructed, and the underwater concrete pouring preferably adopts a conduit method to ensure that the poured concrete sealing bottom plate 3 does not have fillers such as segregation and silt, and the construction quality of the sealing bottom plate 3 is influenced. After the sealing plate 3 of the open caisson 1 is poured, cement high-pressure rotary spraying reinforcement is carried out at the intersection of the water taking pipe 2 and the wall of the open caisson 1, the reinforcement range of the high-pressure rotary spraying reinforcement body 7 is determined according to design requirements, and the preferable suggestion is that the diameter of the water taking pipe 2 is more than 3 times. The high-pressure rotary spraying is preferably constructed by adopting triple-tube equipment, the pressure of high-pressure water is between 30 and 35MPa, the pressure of compressed air is between 0.6 and 0.8MPa, the pressure of cement slurry is between 25 and 30MPa, the cement is more than 32.5 common portland cement, the dosage of the cement per linear meter is more than 300kg, and the diameter of the formed high-pressure rotary spraying pile is more than 800mm so as to improve the water stopping and water resisting effects;
and (3) communicating and constructing a water taking pipe 2: and breaking the thin plate at the hole 23, and connecting the water taking jacking pipe with the water taking pipe 2. As shown in figure 1, a Z-shaped water taking pipe 2 is connected with a top pipe, so that the problem that the water taking top pipe is easily clogged by impurities in water under the action of self weight in the traditional water taking mode of the artesian well is solved; the Z-shaped water taking pipe 2 is connected with the water taking jacking pipe in a welding mode, and the quality of a welding seam needs to be ensured so as to ensure the reliability of pipeline connection under the impact of water flow pressure.
Backfilling a core filling material of the open caisson 1 and recovering a field: after the water taking pipe 2 is communicated, firstly, the Z-shaped water taking pipe 2 is wrapped by adopting outer concrete 5 along the depth direction, and the wrapping thickness is more than 20 cm; and when the filler is wrapped by the concrete 5 for pouring, a mold is required to be erected outside the water intake pipe 2, and corresponding pouring is carried out. Further, filling core material 6 is filled outside the outer concrete 5, and the filling core material 6 can preferably adopt cohesive soil with the compactness of more than 95%. Through the double protection measures, the long-term durability of the water taking pipe 2 can be effectively improved, and the water taking pipe 2 is prevented from being corroded and deformed in the using process. After the filling of the core material 6 of the open caisson 1 is completed, the construction site of the open caisson 1 is restored to the original state, the structure of the open caisson 1 is well protected, and the open caisson 1 and the water intake pipe 2 are prevented from being damaged in the using period.
The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present invention.
Claims (6)
1. The utility model provides a deep big water intaking open caisson structure in high pressure water area which characterized in that: the open caisson comprises an open caisson, wherein a circle of dewatering well is arranged on the periphery of the open caisson, the dewatering well is used for reducing the height of an underground water level in the sinking process of the open caisson and increasing the sinking load, the open caisson comprises a sealing bottom plate, a supporting short pile, a water taking pipe, outsourcing concrete, a filling core material and a high-pressure rotary spraying reinforcing body, the supporting short pile and the sealing bottom plate are used for providing the vertical bearing capacity of the open caisson, the water taking pipe is used for taking water in the open caisson, the outsourcing concrete and the filling core material are used for wrapping the water taking pipe to ensure long-term normal use of the water taking pipe, and the high-pressure rotary spraying reinforcing body is used for carrying out cement high-pressure rotary spraying reinforcement at the junction of the water taking pipe and the side wall of the open caisson;
a reserved hole is formed in the position where the water taking pipe and the open caisson intersect, annular reinforcing ribs and distributed reinforcing ribs are arranged on the periphery of the hole, and the distributed reinforcing ribs comprise transverse ribs and longitudinal ribs;
an overwater floating platform is arranged in the open caisson, a high-pressure rotary spraying power device is arranged on the overwater floating platform, and the high-pressure rotary spraying power device is used for quickly crushing and stripping soil bodies on the inner side of the open caisson by spraying high-pressure air and high-pressure liquid through a drill rod and extracting the crushed soil bodies;
the utility model discloses a floating platform, including floating platform on water, including a plurality of flotation tanks, polylith floating platform board, drawknot board and dead lever, a plurality of flotation tanks are used for adjusting floating platform's on water height, the drawknot board is used for connecting polylith floating platform board as a whole, the dead lever is used for floating platform and open caisson drawknot on water to guarantee floating platform board's stability, be equipped with the hoop on the floating platform board or indulge horizontal direction passageway, direction passageway with drilling rod looks adaptation.
2. The open caisson structure for deep and large water intaking in high-pressure water area according to claim 1, wherein: the outer diameter of the open caisson is gradually reduced from bottom to top, and the outer wall of the open caisson is coated with wax.
3. The open caisson structure for deep and large water intaking in high-pressure water area according to claim 2, wherein: and a gravel cushion is laid on the top of the open caisson, and the laying range of the cushion is more than 500mm larger than the outer diameter of the open caisson.
4. The open caisson structure for deep and large water intaking in high-pressure water area according to claim 3, wherein: the number of the supporting short piles is multiple.
5. The open caisson structure for deep and large water intaking in high-pressure water area according to claim 4, wherein: the water intake pipe is arranged in a Z shape.
6. The construction method of the open caisson structure for deep and large water intaking in the high-pressure water area according to claim 5, characterized in that: the method comprises the following steps:
construction preparation: the three-way leveling work of a construction site is well done, the measurement and setting-out are carried out according to the design requirements, the actual position of the open caisson is determined, a gravel cushion layer is laid on the construction site, the laying range of the cushion layer is more than 500mm larger than the outer diameter of the open caisson, and a stable and reliable operation surface is provided for the subsequent open caisson construction and material stacking;
and (3) construction of a dewatering well: arranging a circle of precipitation well around the open caisson, wherein the depth of the precipitation well is greater than the maximum sinking depth of the open caisson, the bottommost part of the precipitation well is a precipitation pipe, the upper part of the precipitation pipe is a filter pipe with a hole, the upper part of the precipitation pipe is a common well pipe, the gap part of the precipitation pipe, the filter pipe and the open caisson is backfilled by medium coarse sand, and the gap part of the common well pipe and the open caisson is backfilled by common cohesive soil filling materials;
and (3) open caisson pouring construction: the outer wall of the open caisson adopts a step-type design, the outer diameter of the bottommost end is largest, the outer diameter is gradually reduced along the depth, meanwhile, wax coating construction is carried out on the outer wall of the open caisson and thixotropic slurry drag reduction is matched, the construction process of the open caisson mainly comprises erecting an inner die, binding steel bars, erecting an outer die and pouring concrete, the excavation process in the open caisson is matched, the pouring work of the open caisson can be completed by repeating the processes, meanwhile, a reserved hole is arranged at the position where the water taking pipe and the open caisson intersect, the hole is blocked by a concrete thin plate, and annular reinforcing ribs and distributed reinforcing ribs are arranged at the periphery of the hole;
sinking construction of the open caisson: because the stratum where the water taking open caisson is located is generally high in underground water level and even if precipitation is adopted, the underground water level is difficult to completely reduce to below the designed depth, the water taking open caisson is generally required to carry out underwater open caisson sinking construction, then the construction of an overwater floating platform is adopted to carry out underwater well soil body excavation construction, the overwater floating platform is arranged on the inner side of the open caisson, the height of the overwater floating platform is adjusted by a lower water tank of the overwater floating platform, a high-pressure rotary spraying power device is arranged on the platform, a high-pressure rotary spraying drill rod is connected below the platform and extends into a soil body to be excavated of the open caisson, the soil body on the inner side of the open caisson is quickly crushed and cut by high-pressure air and high-pressure liquid sprayed by the drill rod, the crushed soil body is further extracted by a mud suction device, the drill rod is moved on the overwater floating platform through a guide channel, the omnibearing crushing and cutting of the soil body in the open caisson is realized, and the soil body in the open caisson is completely excavated, ensuring smooth sinking of the deep and large open caisson;
bottom sealing at the shaft bottom and water intake pipe hole high-pressure jet grouting reinforcement: after the open caisson is sunk to the designed depth, firstly removing sludge at the bottom of the open caisson, driving a series of supporting short piles to improve the overall vertical bearing capacity of the open caisson, determining the number and the arrangement positions of the supporting short piles according to the design requirements, further laying a concrete sealing bottom plate reinforcing steel mesh and carrying out underwater concrete sealing bottom plate construction, after the open caisson bottom plate is poured, carrying out cement high-pressure rotary spraying reinforcement at the junction of a water intake pipe and the open caisson wall, wherein the reinforcement range of the cement high-pressure rotary spraying is determined according to the design requirements;
water intake pipe communication construction: breaking a thin plate at the opening of the water taking pipe, connecting a water taking top pipe with a water taking pipe in the open caisson, connecting an upper water taking top pipe and a lower water taking top pipe in the open caisson by adopting a Z-shaped pipe, and directly conveying the two top pipes to a water plant through the water taking pipe for further treatment;
backfilling of open caisson core filling materials and site recovery: after the water intake pipes are communicated, firstly, the Z-shaped water intake pipes are wrapped by plain concrete filler along the depth direction to form a first protective layer of the water intake pipes, further, core filling materials are filled outside the concrete wrapping layers to compact and fill the inner wall of the whole open caisson to form a second protective layer of the water intake pipes, after the open caisson core filling materials are backfilled, original state recovery is carried out on the open caisson construction site, protection work of the open caisson structure is well carried out, and damage to the open caisson and the water intake pipes during use is prevented.
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| JP3326465B2 (en) * | 1993-11-18 | 2002-09-24 | 株式会社竹中工務店 | Open caisson method |
| CN101994319A (en) * | 2010-05-06 | 2011-03-30 | 中交第二公路工程局有限公司 | Land oversized open caisson subsidence construction method |
| CN107100183B (en) * | 2017-04-19 | 2019-08-16 | 张士普 | Open caisson builds engineering method |
| CN206706792U (en) * | 2017-04-28 | 2017-12-05 | 高创建设股份有限公司 | Deep foundation pit precipitation well construction |
| CN109210288A (en) * | 2018-11-01 | 2019-01-15 | 上海康识食品科技有限公司 | A kind of diversion pipeline |
| CN110284547A (en) * | 2019-05-13 | 2019-09-27 | 中国华冶科工集团有限公司 | The construction method of intake pipe |
| CN110485468B (en) * | 2019-08-08 | 2021-04-16 | 南方工程检测修复技术研究院 | Permanent circular working well with water-rich stratum preset jacking pipe door opening and construction method thereof |
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