Construction structure for constructing open caisson

Abstract

The open caisson comprises an open caisson cylinder wall sinking in a guide groove and a cement soil continuous wall arranged below the guide groove, and a guide hole extending in the vertical direction is formed in the open caisson cylinder wall; the construction structure comprises a steel pipe pile inserted into the cement soil continuous wall, a connecting beam is erected at the top of the steel pipe pile, a shaft control device is installed on the connecting beam, and the shaft control device is used for adjusting the sinking speed of a shaft of the open caisson wall. The shaft is formed by on-site casting in a shaft casting space between the connecting beam and the ground; the shaft can sink into the guide groove with the steel pipe pile as a guide rod, and after sinking of the shaft is completed, the steel pipe pile is pulled out, and the guide hole is backfilled. The guide groove is excavated firstly, then the shaft control device is used for sinking the shaft, and after shaft sinking is completed, earthwork is excavated, so that the problems of shaft inclination, collapse and the like are avoided, the manual excavation amount is reduced, the operation safety and the construction efficiency are improved, and the construction cost is saved.

Description

Technical Field

[0001] The utility model relates to a construction structure used for constructing a caisson. Background Art

[0002] At present, when constructing a caisson, the shaft is generally sunk into the ground first, and then the soil is excavated inside the shaft, and the caisson is sunk by its own weight or its own weight plus external force. In actual construction, the following problems may arise: due to the unevenness of the underground soil and uneven excavation, the shaft may sink and deflect; during the sinking process, the caisson may sink suddenly due to the complex strata and improper reaction force control; there may be problems of upward bulge and sudden surge of groundwater at the bottom; when encountering harder strata, the caisson may be difficult to sink or may not be able to sink; when sinking, the outer wall of the caisson has a significant dragging effect on the surrounding strata, which has a great impact on the surrounding environment.

[0003] Therefore, how to reduce the above-mentioned problems generated during the construction of caisson remains a technical problem that needs to be solved urgently by those skilled in the art. Utility Model Content

[0004] In order to solve at least one of the above-mentioned problems existing in caisson construction, the present application first proposes a construction structure for caisson construction, wherein the caisson comprises a caisson wall sunk in a guide groove and a cement soil continuous wall arranged below the guide groove, wherein the caisson wall comprises at least one shaft section, and has a guide hole extending in a vertical direction in the caisson wall, wherein the guide hole penetrates the top end surface and the bottom end surface of the caisson wall; the top end surface of the cement soil continuous wall is lower than the set elevation of the bottom surface of the foundation pit;

[0005] The construction structure includes steel pipe piles inserted downward into the cement soil continuous wall. After the steel pipe piles are inserted into the cement soil continuous wall, a connecting beam is erected on the top of the steel pipe piles, and a wellbore control device is installed on the connecting beam. The wellbore control device is used to adjust the sinking speed of the wellbore; the space between the connecting beam and the ground forms a wellbore casting space, and at least one wellbore section is cast on-site in the wellbore casting space, and the guide hole is sleeved on the steel pipe piles; the wellbore can be sunk into the guide groove with the steel pipe piles as guide rods. When all the wellbores in the caisson wall are sunk, the steel pipe piles are pulled out and recovered; when the steel pipe piles are pulled out and recovered, the guide hole is backfilled. In this application, the top surface of the cement soil continuous wall is preferably 0.2-2 meters lower than the set elevation of the bottom surface of the wellbore of the caisson wall. In this application, the foundation pit is the wellbore formed in the caisson when excavating the earth.

[0006] In the present application, the caisson includes at least two caisson sections connected together in a vertical direction, or the caisson includes only one caisson section.

[0007] When constructing the guide trough, equipment such as a double-wheel milling machine or a chain-type troughing machine (TRD) is used. The guide trough and the cement soil continuous wall can be completed continuously using the same equipment or different equipment. The cement soil continuous wall can also be constructed using equipment other than the double-wheel milling machine or the chain-type troughing machine, such as a double-axis or three-axis mixing pile driver and a rotary jet pile driver.

[0008] Since at least a portion of the shaft is cast in place within the shaft casting space, the bottom formwork is preferably a modular, assembled structure with holes for the steel pipe piles to pass through to facilitate removal. The connecting beams can be reinforced concrete or steel structures and can be fabricated on-site or prefabricated.

[0009] When sinking each wellbore, the following methods can be used: Method A: When one wellbore section is completely inserted into the guide groove, the next wellbore section is cast. As the next wellbore section sinks, the wellbore in the guide groove is pushed to continue sinking until all wellbores have completed sinking and reached the set position. Method B: When each wellbore section is sunk, it is sunk to its set position at once. The two methods can be used separately or simultaneously. When the above two methods are used simultaneously, the wellbore at the bottom can be sunk to its set position at once, while the upper wellbore is sunk using Method A.

[0010] In the present application, a guide groove is first excavated, and then a wellbore control device is used to sink the wellbore so that the wellbore sinks safely and evenly. After the wellbore is sunk, a foundation pit can be excavated in the wellbore to form a wellbore, thereby avoiding problems such as wellbore tilt caused by different underground soil qualities. At the same time, it also avoids safety problems caused by collapse of the lower part of the wellbore, thereby ensuring the safety of surrounding buildings. Since the wellbore can be excavated after the wellbore is sunk, large-scale construction machinery can be fully used for earth excavation, which minimizes the amount of manual excavation of earthwork, greatly improves the safety of the operation, improves construction efficiency, and saves construction costs. Specifically, after adopting this application, the following advantages are achieved during the construction of caissons:

[0011] 1. The reinforced concrete shaft and steel pipe piles form a combined structure. During the excavation process, the combined structure has high rigidity and strength, and small deformation during the excavation process. After the construction reaches zero, the steel pipe piles can be pulled out and reused, which is economical and environmentally friendly.

[0012] 2. The lower cement-soil continuous wall acts as a water-stop curtain to avoid the problem of the bottom bulging upward and the sudden surge of groundwater. When precipitation measures are adopted in the caisson, the impact on the surrounding environment is relatively small.

[0013] 3. The connection of the connecting beam increases the overall stability of the steel pipe piles. The steel pipe piles also serve as guide rods, enabling high-precision control of the sinking of the wellbore. The wellbore control device controls the sinking speed of the wellbore to avoid sudden sinking of the wellbore, avoiding the sudden sinking problem existing in the existing technology.

[0014] 4. The traditional caisson sinking construction method of digging and sinking has been changed. The original soil is fully mixed by double-wheel milling, TRD or multi-axis mixing pile driver, which greatly reduces the sinking resistance of the caisson and completely separates the side wall of the caisson from the surrounding soil. The geological conditions are relatively uniform, which solves the problems of sinking in hard strata, sudden sinking of the caisson and easy deviation of sinking, and greatly reduces the impact of the caisson sinking on the surrounding environment.

[0015] 5. The well shaft is cast in situ on the ground, with reliable construction quality, good integrity, impermeability and durability.

[0016] Furthermore, to reduce friction between the shaft and the steel pipe piles, an isolation membrane is provided on the outer circumference of the steel pipe piles. This membrane is used to reduce friction between the shaft and the steel pipe piles. The isolation membrane can be made of materials such as geotextiles and plastic film, or by applying an isolation paint film on the outer wall of the steel pipe piles.

[0017] Furthermore, to fully utilize the earth generated during the excavation of the guide trough, a slurry formed by mixing the underground soil is placed within the guide trough. This slurry is then pumped out during the sinking of the shaft. After the earth within the guide trough is mixed into the slurry, it protects the trough walls, preventing them from collapsing, and provides buoyancy for the shaft, ensuring even sinking.

[0018] The slurry is formed by mixing the earthwork in the guide trough during excavation. The slurry comprises, by weight, 70-90% water, 5-29% bentonite, and 1-5% binder. The binder can be carboxymethyl cellulose (CMC), polyacrylamide (PAM), or other similar binders. In specific embodiments, tests are conducted based on the different soil types in the construction area to determine the appropriate ratio. The slurry density is preferably 1.05-1.15 g / ml.

[0019] Furthermore, to facilitate smooth sinking, a pipe insertion hole is reserved axially along each shaft, with the pipe insertion holes on adjacent shafts connected axially. When sinking becomes difficult, a water jet tube can be inserted into the insertion hole and spray water through it toward the bottom of the lowest shaft section, impacting the mud below the first shaft section. When using the water jet tube to spray water downward, it is necessary to spray evenly along the circumference of the shaft to avoid over- or under-spraying in certain areas, which could cause the shaft to tilt. If the shaft tilts, the spray volume of each water jet tube must be adjusted promptly to correct the shaft.

[0020] Furthermore, in order to increase the pile end resistance of the steel pipe pile in the cement soil continuous wall and improve the compressive capacity of the steel pipe pile, the bottom of the steel pipe pile is closed.

[0021] Specifically, the steel pipe piles are inserted into the cement-soil continuous wall to a depth of 5-10 meters. This design enables the steel pipe piles to generate sufficient friction in the cement-soil continuous wall to prevent them from sinking due to the friction of the wellbore during sinking, thus ensuring the stability of the steel pipe piles.

[0022] Specifically, the wellbore control device includes a lifting mechanism and a pressing mechanism, wherein the lifting mechanism is used to bear the weight of the wellbore and the pressing mechanism is used to push the wellbore downward. Specifically, the lifting mechanism is fixedly installed on the ground or fixedly installed on the connecting beam, and the pressing mechanism adopts a jack, which is arranged between the connecting beam and the wellbore to be sunk. The lifting mechanism can specifically adopt a winch or lifting machinery. When the lifting mechanism is installed on the ground, a pulley needs to be installed on the connecting beam to facilitate the arrangement of the lifting rope of the lifting mechanism. Specifically, the jack can adopt a mechanical jack or a hydraulic jack.

[0023] Alternatively, the wellbore control device includes a piston cylinder, the cylinder barrel of which is fixed to a connecting beam, and a piston rod of which extends downward and is detachably connected to the wellbore. Leveraging the piston cylinder's dual lifting and pressing capabilities, construction efficiency can be improved. The piston cylinder diameter can be either an electric or hydraulic piston cylinder for easier, unified control.

[0024] In order to further improve the stability of the wellbore during sinking, a number of steel pipe piles are set up, and each steel pipe pile is evenly spaced along the circumference of the caisson wall; and in the thickness direction of the wellbore, the steel pipe piles are located in the middle part of the wellbore. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a circular caisson made using the construction structure in this application.

[0026] Figure 2 yes Figure 1 Top view of .

[0027] Figure 3 It is a schematic diagram of the construction structure in this application.

[0028] Figure 4 yes Figure 3 Enlarged view of the middle AA direction.

[0029] Figure 5 It is a structural diagram of a wellbore control device that is a piston cylinder.

[0030] Figure 6 It is a schematic diagram of the local construction deployment of the wellbore.

[0031] Figure 7 It is a structural diagram of the bottom mold.

[0032] Figure 8 This is the construction flow chart of the caisson.

[0033] Figure 9 It is a top view of a rectangular caisson made using the construction structure in this application. DETAILED DESCRIPTION

[0034] The following first describes the structure of the caisson involved in this application. Figure 1 and Figure 2 The caisson includes a caisson wall 20 sunk in the guide groove 13 and a cement-soil continuous wall 31 arranged below the guide groove 13. The caisson wall is cylindrical. The caisson wall 20 specifically includes three sections of shafts. From bottom to top, the three sections of shafts are the first section 21, the second section 22 and the third section 23. The three sections of shafts are pressed against each other in the vertical direction. There is a guide hole 24 extending in the vertical direction in the caisson wall. The guide hole 24 passes through the top and bottom surfaces of the caisson wall. The guide hole 24 is formed by the guide sub-holes distributed in each shaft being connected to each other in the vertical direction. In this embodiment, according to conventional design, a blade foot 211 is provided at the lower end of the first section of shaft 21, and a groove 212 for clamping the bottom plate of the underground structure is provided on the inner wall of the lower end of the first shaft 21. It is understood that in other embodiments, the caisson wall may include only one shaft section, or two shaft sections, or may also include four, eight, or more shaft sections. The number of shaft sections is not limited and can be set according to specific construction requirements. The top surface of the cement-soil diaphragm wall is lower than the set elevation of the foundation pit bottom. In this application, the foundation pit is the wellbore 40 described below.

[0035] The following is an explanation of the construction structure of the above-mentioned caisson. Please also refer to Figure 3 The construction structure includes a plurality of steel pipe piles 14, each of which is inserted downward into the cement soil continuous wall. In order to improve the pile end resistance of the steel pipe pile, the bottom of the steel pipe pile is closed.

[0036] After the steel pipe piles are inserted into the cement soil continuous wall, a connecting beam 15 is erected on the top of the steel pipe piles. A shaft control device 16 is installed on the connecting beam to adjust the sinking speed of the shaft. Specifically in this embodiment, the shaft control device 16 includes a lifting mechanism and a pressing mechanism. The lifting mechanism is used to bear the weight of the shaft, and the pressing mechanism is used to push the shaft downward. Figure 4In this embodiment, the lifting mechanism is an electric hoist 161. A bracket 168 is installed on the upper side of the connecting beam 15, and the electric hoist is installed on the lower side of the bracket 168. A rope hole 151 is provided on the connecting beam, and the lifting rope 162 of the electric hoist is freely passed through the rope hole 151 and is installed with a hook 163. The pressing mechanism specifically adopts a jack, which can be a mechanical jack or a hydraulic jack. There are no special requirements for the structural form of the jack, and other forms of jacks can also be used. In this embodiment, a hydraulic jack is specifically used, and the hydraulic jack is arranged between the connecting beam and the shaft to be sunk.

[0037] It can be understood that in another implementation, the electric hoist can be installed on the ground, and then the lifting rope can be passed through the pulley installed on the bracket and then hooked on the wellbore. Of course, in other embodiments, the lifting mechanism can also use a winch, and the winding machine can be specifically installed on the connecting beam or the ground. Of course, other lifting equipment can also be used.

[0038] The space between the connecting beam and the ground forms a wellbore casting space. In this embodiment, all wellbores are cast on-site in the wellbore casting space, and at the same time, guide holes are formed on the steel pipe piles. During the wellbore casting process, the wellbore is wrapped around the outer peripheral surface of the steel pipe pile. In order to reduce the friction between the wellbore and the steel pipe pile during the sinking process, an isolation membrane is provided on the outer peripheral surface of the steel pipe pile to reduce the friction between the wellbore and the steel pipe pile. Specifically, in this embodiment, the isolation membrane is made of plastic film. It is understood that in another embodiment, geotextile can be used to replace the plastic film, or isolation paint can be applied to the outer wall of the steel pipe pile, and the paint film formed by the isolation paint forms an isolation membrane. When casting each section of the wellbore, it is necessary to re-set the isolation membrane on the outer wall of the steel pipe pile to avoid damage to the isolation membrane due to friction.

[0039] After each section of the shaft is poured and the concrete reaches the set strength, steel pipe piles can be used as guide rods to sink into the guide groove. To ensure the smooth sinking of the shaft, mud mixed from the underground soil is placed in the guide groove, and this mud is pumped out during the sinking process. During the construction of the guide groove, water is sprayed into the guide groove to stir the underground soil into mud. The buoyancy of the mud is used to ensure the stability of the shaft during sinking. When all the shafts are sunk, the steel pipe piles are pulled out and recycled; after the steel pipe piles are pulled out and recycled, the guide hole is backfilled.

[0040] In this embodiment, all wellbores are constructed by on-site casting. It can be understood that in other implementations, wellbores can also be produced in a prefabricated manner. The lowest one or two sections of the wellbores can be prefabricated first, and after sinking into the guide groove, steel pipe piles are inserted, and the remaining wellbores are constructed by on-site casting. Since there is mud in the guide groove, a lifting device is required to sink the wellbores into the guide groove, which will complicate the construction and reduce the safety of the construction. Therefore, it is recommended that all wellbores be constructed by on-site casting.

[0041] In order to ensure the smooth descent of each wellbore, the plurality of steel pipe piles are evenly spaced along the circumference of the caisson wall; and in the thickness direction of the wellbore, the steel pipe piles are located in the middle of the wellbore.

[0042] See also Figure 6 A pipe hole 29 is reserved axially on each wellbore, and the pipe holes on adjacent wellbores are connected axially. When the wellbore is difficult to sink, the water jet tube can be inserted into the pipe hole and spray water through the water jet tube to the bottom of the lowest section of the wellbore to impact the mud below the first section of the wellbore, so that the wellbore can sink smoothly.

[0043] In this embodiment, the wellbore control device has a lifting mechanism and a pressing mechanism, wherein the lifting mechanism is used to bear the weight of the wellbore, and the pressing mechanism is used to push the wellbore downward. Figure 5 In another embodiment, the lifting and pressing mechanisms can be combined into a single mechanism, directly employing a piston cylinder 17. When using the piston cylinder 17 as the wellbore control device, its barrel 171 is fixed to the top of the connecting beam 15, and corresponding piston holes 152 are provided in the connecting beam to allow the piston rod 172 of the piston cylinder to extend downward through the piston hole and, after freely passing through the piston hole, be detachably connected to the wellbore. The piston cylinder is preferably an electric or hydraulic piston cylinder for ease of unified control.

[0044] The following describes the construction method for constructing a caisson using the construction structure in this embodiment. Figure 8 , the mark 100 in the accompanying drawings represents the ground, and the steps of the construction method are as follows:

[0045] (1) Please refer to Figure 8 (a) A guide wall 11 is constructed in the sunken area of ​​the caisson wall. The guide wall includes an inner guide wall and an outer guide wall which are sleeved together.

[0046] (2) Please refer to Figure 8(b) A guide groove 13 is constructed downwardly along the area between the inner and outer guide walls, and a cement-soil continuous wall 31 is formed at the lower portion of the guide groove. The top surface of the cement-soil continuous wall 31 is 1 meter lower than the set elevation of the bottom surface of the caisson wall. It is understood that in other embodiments, the top surface of the cement-soil continuous wall 31 can be 0.2 meter, 0.5 meter, 1.5 meter, 2 meter, or another distance between 0.2 and 2 meters lower than the set elevation of the bottom surface of the caisson wall.

[0047] When constructing the guide groove, slurry is sprayed into the guide groove at the same time to stir the earth in the guide groove into mud. In this embodiment, a double-wheel milling machine is specifically used to construct the guide groove. It can be understood that in other embodiments, a chain-type groove forming machine (TRD) and other equipment can also be used to construct the guide groove. The cement-soil continuous wall 31 serves as a water-stop curtain to avoid the problem of the bottom of the caisson wall bulging upward and the sudden surge of groundwater due to the external pressure of the caisson wall. When precipitation measures are adopted in the caisson wall, the groundwater outside the caisson wall has less impact on the surrounding environment due to the barrier effect of the cement-soil continuous wall.

[0048] The slurry is specifically made by mixing the following components by mass percentage: 85% clean water, 12% bentonite, and 3% binder. The density of the slurry is controlled between 1.06-1.08 g / ml. It will be understood that in other embodiments, the composition of the slurry can also be 70% clean water, 25% bentonite, and 5% binder, or 90% clean water, 6% bentonite, and 4% binder, or 83% clean water, 16% bentonite, and 1% binder, or 90% clean water, 5% bentonite, and 5% binder. The density of the slurry can also be 1.05-1.06 g / ml, 1.08-1.11 g / ml, or 1.12-1.15 g / ml. The specific density is determined based on factors such as the convenience of construction.

[0049] (3) Insert the steel pipe pile 14 into the guide groove 13, and insert the lower end of the steel pipe pile 14 into the cement soil continuous wall. The depth of the steel pipe pile inserted into the cement soil continuous wall is 6 meters. It is understood that in other embodiments, the depth of the steel pipe pile inserted into the cement soil continuous wall can also be 5 meters, 7 meters, 9 meters, 10 meters, or other values ​​between 5 and 10 meters.

[0050] In this embodiment, in order to increase the pile end resistance of the steel pipe pile, the bottom of the steel pipe pile is closed.

[0051] (4) Please refer to Figure 8(c) Connecting beams 15 are constructed on top of the steel pipe piles 14. Connecting beams 15 connect the steel pipe piles into a single unit. The space between connecting beams 15 and the ground forms the wellbore casting space. Wellbore control devices 16 are then installed on the connecting beams. In this embodiment, to improve operational efficiency, the connecting beams are prefabricated steel beams. It is understood that in another embodiment, connecting beams can be constructed on-site using section steel. The connecting beams can also be constructed using reinforced concrete. When using reinforced concrete, prefabricated beams or cast-in-place beams can be selected as needed.

[0052] (5) Please refer to Figure 8 (d) Cast the first section of the shaft 21 in the shaft casting space, with the wall of the first section of the shaft wrapped around the steel pipe pile. Figure 6 and Figure 7 When pouring the first section of the wellbore 21, a bottom formwork 51 is first laid on the ground. To facilitate the removal of the bottom formwork 51, the bottom formwork adopts a block-assembled structure. Specifically, in this embodiment, the bottom formwork 51 is divided into an inner bottom formwork 53 and an outer bottom formwork 54 as a whole, and the inner bottom formwork is divided into several inner sub-bottom forms 531, and the outer bottom formwork 54 is divided into several outer sub-bottom forms 541. A bottom formwork hole 52 is opened on the bottom formwork for the steel pipe pile to pass through, and the outer semicircle of the bottom formwork hole is located on the outer bottom formwork, and the inner semicircle is located on the inner bottom formwork. Figure 7 This is only to illustrate the structure of the bottom mold, not a specific implementation example. During actual construction, the inner and outer sub-bottom molds need to be specifically designed and cut according to the needs of removing the bottom mold.

[0053] After the bottom formwork 51 is laid, the steel cage 26 is tied to the bottom formwork, and the inner and outer formworks are supported. The support of the inner and outer formworks and the tying of the steel cage can be constructed in accordance with existing technology, and there are no special requirements. Finally, the concrete 27 is poured. After the concrete reaches the design strength, the first section of the shaft 21 is formed. In order to facilitate hooking, a lifting lug 28 is embedded in the top of the first section of the shaft. In order to avoid the lifting lug affecting the sinking of the upper shaft, it is preferred to set the lifting lug to a sinking type so that the top of the lifting lug does not exceed the top surface of the first section of the shaft. If it is necessary to make the top surface of the lifting lug exceed the top surface of the first section of the shaft, before sinking the second section of the shaft, the lifting lug on the first section of the shaft needs to be cut off, or a receiving cavity for accommodating the lifting lug needs to be set at the bottom of the second section of the shaft. This method is used in the subsequent pouring construction of other shafts and will not be described in detail.

[0054] A hook is installed on the lifting rope 162 of the electric hoist in this embodiment, so a lifting ear is set at the top of the wellbore. It can be understood that in other embodiments, other forms of hanging components can be set as needed. For example, an internal threaded pipe can be embedded in the top of the wellbore, and the hook can be replaced with a bolt. When sinking the wellbore, the bolt is screwed onto the internal threaded pipe.

[0055] When constructing a wellbore, steel pipe piles are used to naturally form guide holes in the wellbore.

[0056] (6) Please refer to Figure 8 (e) After the concrete of the first section of the shaft 21 reaches the designed strength, the hook of the shaft control device is hung on the lifting lug of the first section of the shaft, and the first section of the shaft is sunk into the guide groove using the steel pipe pile as a guide rod. The sinking speed of the first section of the shaft is adjusted using the shaft control device.

[0057] During the sinking process of the first section of the wellbore, the sinking is mainly completed by the deadweight of the first section of the wellbore. When sinking only by its deadweight, if it cannot sink or the sinking speed is too slow, the jack as the downward pressure mechanism will be arranged between the first section of the wellbore and the connecting beam, and the jack will be used to provide auxiliary sinking force.

[0058] (7) Please also refer to Figure 8 (f) and see Figure 8 (g) Repeat steps (5) and (6) until all the shafts are sunk and adjacent shafts are connected up and down to form a shaft wall 20. Figure 8 In (f), the second section of the wellbore 22 has sunk into the ground, and the third section of the wellbore 23 has been cast. During the sinking of the wellbore, the mud in the guide groove is pumped out by a mud pump.

[0059] (8) Please also refer to Figure 8 (h) and Figure 8 (i) Earth is excavated in the caisson wall to form a well hole 40 in the caisson wall. In this embodiment, while excavating earth, a purlin 41 is synchronously erected on the inner surface of the caisson wall.

[0060] (9) Please refer to Figure 8 (j) Lay a cushion layer in the wellbore and construct the bottom plate 61, middle plate and top plate of the underground structure 60.

[0061] (10) Please continue to participate Figure 8 (j) After the underground structure 60 is constructed to zero, the steel pipe piles 14 are removed and recycled, and the holes left by the removed steel pipe piles are filled with concrete.

[0062] In this embodiment, when one wellbore section is completely inserted into the guide groove, the next wellbore section is cast. As the next wellbore section sinks, it pushes the wellbores in the guide groove to continue sinking until all wellbores have been sunk and reached the set position. It is understood that in another embodiment, each wellbore section can be sunk to its set position at once.

[0063] In this embodiment, a pipe insertion hole 29 is reserved along the axial direction of each wellbore. The pipe insertion holes in adjacent wellbores are connected along the axial direction. When the wellbore is difficult to sink, a water jet tube is inserted into the pipe insertion hole and sprayed through the water jet tube toward the bottom of the first wellbore section, impacting the mud below the first wellbore section. The downward pressure mechanism and the water jet tube can be used simultaneously or separately, depending on the specific construction situation. The water jet tube is specifically made of steel pipe. After all wellbores are sunk, the pipe insertion holes are filled and sealed.

[0064] Since the wall of the caisson is circular in this embodiment, the steel pipe piles are evenly spaced along the circumference of the caisson wall, and the steel pipe piles are located in the middle of the caisson in the wall thickness direction. It is understood that in another embodiment, the caisson wall can also be rectangular, for details, please refer to Figure 9 Of course, the caisson wall can also be other regular or irregular shapes.

[0065] It can be understood that when the caisson only includes one section of the shaft, after completing step (6), the first section of the caisson is formed into the caisson shaft wall, and then the construction enters step (8) without step (7).

Claims

1. A construction structure for constructing a caisson, characterized in that: The caisson includes a caisson wall sunk in a guide groove and a cement-soil continuous wall arranged below the guide groove. The caisson wall includes at least one shaft section and has a guide hole extending in a vertical direction in the caisson wall. The guide hole penetrates the top end surface and the bottom end surface of the caisson wall. The top end surface of the cement-soil continuous wall is lower than the set elevation of the bottom surface of the foundation pit. The construction structure includes steel pipe piles inserted downward into the cement soil continuous wall. After the steel pipe piles are inserted into the cement soil continuous wall, a connecting beam is erected on the top of the steel pipe pile, and a wellbore control device is installed on the connecting beam. The wellbore control device is used to adjust the sinking speed of the wellbore; the space between the connecting beam and the ground forms a wellbore casting space, at least one wellbore section is cast on-site in the wellbore casting space, and a guide hole is sleeved on the steel pipe pile; the wellbore can sink into the guide groove with the steel pipe pile as a guide rod, and when all the wellbores of the caisson wall have completed sinking, the steel pipe piles are pulled out and recovered; when the steel pipe piles are pulled out and recovered, the guide hole is backfilled.

2. The construction structure according to claim 1, characterized in that: An isolation membrane is provided on the outer peripheral surface of the steel pipe pile, and the isolation membrane is used to reduce the friction between the wellbore and the steel pipe pile.

3. The construction structure according to claim 1, characterized in that: The guide groove contains mud stirred from underground soil, which is pumped out during the sinking of the shaft.

4. The construction structure according to claim 3, characterized in that: A pipe insertion hole is reserved axially on each wellbore. When it includes at least two wellbore sections, the pipe insertion holes on the upper and lower adjacent wellbores are connected axially. When the wellbore is difficult to sink, the water jet tube can be inserted into the pipe insertion hole and water is sprayed through the water jet tube to the bottom of the lowest wellbore section to impact the mud below the first wellbore section.

5. The construction structure according to claim 1, characterized in that: The bottom of the steel pipe pile is closed.

6. The construction structure according to claim 1, characterized in that: The depth of steel pipe piles inserted into the cement soil continuous wall is 5-10 meters.

7. The construction structure according to claim 1, characterized in that: The wellbore control device includes a lifting mechanism and a pressing mechanism, wherein the lifting mechanism is used to bear the weight of the wellbore, and the pressing mechanism is used to push the wellbore downward.

8. The construction structure according to claim 7, characterized in that: The hoisting mechanism is fixedly installed on the ground or on a connecting beam, and the pressing mechanism adopts a jack, which is arranged between the connecting beam and the wellbore to be sunk.

9. The construction structure according to claim 1, characterized in that: The wellbore control device comprises a piston cylinder, a cylinder barrel of the piston cylinder is fixed on a connecting beam, and a piston rod of the piston cylinder can extend downward and be detachably connected to the wellbore.

10. The construction structure according to claim 1, characterized in that: A plurality of steel pipe piles are provided, and each steel pipe pile is evenly spaced along the circumference of the caisson wall; and in the thickness direction of the caisson, the steel pipe piles are located in the middle of the caisson.

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