A construction method for building shaft walls using high-grade concrete freezing method.

Abstract

This application discloses a construction method for building a vertical shaft wall using high-strength concrete freezing. The construction method is as follows: S1, driving freezing pipes into freezing holes; S2, installing freezing stations; S3, introducing liquid nitrogen into the freezing pipes; S4, excavating a shaft wall pit at a predetermined location on the ground; S5, forming the bottom layer by pouring high-strength concrete; S6, pre-embedding the vertical reinforcement of the shaft wall steel skeleton into the bottom layer, and then pouring the shaft wall in sections using high-strength concrete; S7, tensioning the vertical reinforcement during the sectioned pouring of the shaft wall. High-strength concrete has ultra-high strength and good toughness, which is beneficial for reducing the thickness of the shaft wall. To ensure the uniformity of each section of the shaft wall, this application uses a sectioned pouring method to form the shaft wall. During the formation of the shaft wall, tensioning the vertical reinforcement generates prestress within the vertical reinforcement, making the shaft wall more resistant. This is beneficial for ensuring the stability of the shaft wall after reducing its thickness.

Description

Technical Field

[0001] This application relates to the field of vertical shaft wall construction technology, and in particular to a construction method for building vertical shaft walls using a high-grade concrete freezing method. Background Technology

[0002] With the technological development of the infrastructure industry, special well drilling technology has also made great progress. The technology of constructing vertical shaft walls using liquid nitrogen freezing has developed rapidly, forming a complete technical system including drilling, freezing, tunneling, and wall construction, and has become the main construction method for vertical shaft walls.

[0003] The main principle of liquid nitrogen freezing construction is to drill freezing holes on the ground to the expected freezing depth according to the design, and then to run freezing pipes into the freezing holes. The liquid nitrogen absorbs heat through vaporization in the freezing pipes to form a freezing curtain. Once the freezing curtain reaches the designed strength, the well casing can be excavated and lined under the protection of the freezing curtain.

[0004] For vertical shaft walls, the working conditions are characterized by high ground pressure and complex geological conditions. In order to ensure the stability of the shaft wall, it is necessary to increase the thickness of the wall. However, excessively thick walls not only lead to high excavation and lining costs, but are also a major cause of cracking.

[0005] Therefore, it is necessary to propose a construction method for building vertical shaft walls using high-grade concrete freezing, which reduces the thickness of the shaft wall while ensuring the structural stability of the shaft wall. This has become an important technical problem that urgently needs to be solved. Summary of the Invention

[0006] This application provides a construction method for building shaft walls using high-grade concrete freezing, aiming to solve the problem in existing technologies where shaft walls face high ground pressure and complex geological conditions, necessitating increased wall thickness to ensure stability. However, excessively thick walls not only lead to high excavation and lining costs but are also a major cause of shaft wall cracking.

[0007] To achieve the above objectives, this application proposes a construction method for building a vertical shaft wall using high-strength concrete freezing. The construction method is as follows: S1. Drill freezing holes at designated locations on the ground and insert freezing pipes into the freezing holes; S2. Install freezing stations and connect the freezing stations and freezing pipes; S3. Introduce liquid nitrogen into the freezing pipes, using the heat absorption of liquid nitrogen vaporization to rapidly freeze the soil layer; S4. Excavate a shaft wall pit at a designated location on the ground; S5. Pour high-strength concrete to the bottom of the shaft wall pit to form the bottom layer; S6. Embed the vertical reinforcement of the shaft wall steel reinforcement cage into the bottom layer, and pour high-strength concrete in sections to build the shaft wall, which includes the bottom section of the shaft wall and multiple sections of non-bottom section shaft wall; S7. Tension the vertical reinforcement during the sectioned pouring of the shaft wall.

[0008] In some embodiments, the method for pouring the bottom well wall in S6 above is as follows: S61, one end of the vertical reinforcement of the bottom well wall is pre-embedded in the bottom layer; S62, a pouring template for the bottom well wall is erected; S63, the other end of the vertical reinforcement of the bottom well wall is connected to a tensioning plate, and the vertical reinforcement of the bottom well wall is tensioned through the tensioning plate; S64, high-grade concrete is poured into the pouring template of the bottom well wall; S65, tensioning is stopped after the concrete strength of the bottom well wall reaches the preset value, and the bottom well wall is cured.

[0009] In some embodiments, the method for pouring multiple sections of non-bottom-end well wall in S6 is as follows: S66, one end of the vertical reinforcement of the non-bottom-end well wall is connected to the vertical reinforcement of the previous section of well wall through a connecting component; S67, a pouring template for the non-bottom-end well wall is erected; S68, the other end of the vertical reinforcement of the non-bottom-end well wall is connected to a tensioning plate, and the vertical reinforcement of the non-bottom-end well wall is tensioned through the tensioning plate; S69, high-grade concrete is poured into the pouring template of the non-bottom-end well wall; S610, tensioning is stopped after the concrete strength of the non-bottom-end well wall reaches a preset value, and the non-bottom-end well wall is cured; S611, S66-S610 are repeated to form multiple sections of non-bottom-end well wall.

[0010] In some embodiments, the components of the high-grade concrete in S5 and S6 above include: cement, mineral powder, admixtures, sand, crushed stone, water, and polycarboxylate superplasticizer, wherein the admixtures include steel fibers.

[0011] In some embodiments, in S1 above, the ground is provided with outer ring freezing holes, middle ring freezing holes and inner ring freezing holes. The outer ring freezing holes, middle ring freezing holes and inner ring freezing holes each include a plurality of freezing holes arranged at intervals along the circumference, and freezing holes are drilled in the freezing holes.

[0012] In some embodiments, the connecting assembly includes: a reinforcing bar sleeve, one end of which is provided with a head, and a first cavity for the vertical reinforcing bar to pass through, the inner diameter of the first cavity being smaller than the diameter of the thickest part of the head; and a connecting sleeve, the other end of which is provided with an external threaded section, the connecting sleeve having a threaded hole, the external threaded section being screwed into the connecting sleeve, and the reinforcing bar sleeve having a second cavity for the connecting sleeve to be inserted into, the connecting sleeve being screwed into the second cavity.

[0013] In some embodiments, the connecting assembly includes: a lock nut, which is screwed onto the external thread section and abuts against the connecting sleeve; an anti-loosening agent, wherein the end of the rebar sleeve facing the connecting sleeve is provided with an anti-loosening groove, the connecting sleeve is provided with an anti-loosening protrusion adapted to the anti-loosening groove, and the anti-loosening agent is provided between the rebar sleeve and the connecting sleeve.

[0014] In some embodiments, the rebar sleeve further includes:

[0015] Curved face, curved face adapted to pier head.

[0016] In some embodiments, the rebar sleeve further includes:

[0017] The third cavity has an inner diameter smaller than that of the second cavity. The connection between the third cavity and the second cavity forms a limiting surface, which is used to limit the screwing depth of the connecting sleeve.

[0018] A grouting groove is installed on the reinforcing bar sleeve and connects to the third cavity.

[0019] In some embodiments, arc-shaped grooves are provided at the top of both the bottom well wall and the top of the multiple non-bottom well walls.

[0020] This application proposes a construction method for building shaft walls using high-strength concrete freezing. The construction method is as follows: S1. Drill freezing holes at designated locations on the ground and insert freezing pipes into the holes; S2. Install freezing stations and connect the freezing stations and freezing pipes; S3. Introduce liquid nitrogen into the freezing pipes, using the heat absorption of liquid nitrogen vaporization to rapidly freeze the soil layer; S4. Excavate a shaft wall pit at a designated location on the ground; S5. Pour high-strength concrete to the bottom of the shaft wall pit to form the bottom layer; S6. Embed the vertical reinforcement of the shaft wall steel reinforcement cage into the bottom layer, and pour high-strength concrete in sections to build the shaft wall, including the bottom section and multiple sections of non-bottom section shaft wall; S7. Tension the vertical reinforcement during the sectioned construction of the shaft wall. This application uses three rings of freezing pipes arranged around the excavation area to ensure the freezing speed and strength of the soil layer, effectively improving construction efficiency and ensuring the safety of subsequent tunneling construction. High-grade concrete is selected for pouring. High-grade concrete possesses ultra-high strength and good toughness, which helps reduce the size and weight of the well wall, improving its seismic performance. This achieves the effect of reducing the wall thickness, which in turn helps reduce the diameter of the freezing ring in the well casing. A smaller freezing ring diameter reduces the number of freezing pipes and the amount of excavation, increasing the excavation speed. To ensure the uniformity of each section of the well wall and prevent premature setting of some high-grade concrete leading to uneven strength distribution and affecting the stability of the well wall, a segmented pouring method is adopted in this application. During the well wall forming process, the vertical reinforcement is tensioned, generating prestress within it. When soil pressure acts on the well wall, this prestress can offset or reduce the tensile stress generated by the soil pressure, increasing the stiffness of the well wall, delaying the appearance of cracks, increasing durability, and reducing vibration and elastic deformation. This significantly improves the elastic strength of the well wall, making it more resistant to damage. This helps ensure the stability of the well wall after reducing its thickness. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0022] Figure 1 This is a technical roadmap of a construction method for building a vertical shaft wall using a high-grade concrete freezing method, as described in one embodiment of this application.

[0023] Figure 2 This is a schematic diagram of the arrangement of the freezing holes in one embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the steel reinforcement skeleton structure of the well wall in one embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the construction structure of the non-bottom well wall in one embodiment of this application;

[0026] Figure 5 for Figure 4 Enlarged view of part A in the middle;

[0027] Figure 6 for Figure 4 Enlarged view of part B in the middle;

[0028] Figure 7 This is a three-dimensional structural diagram of the vertical rib in one embodiment of this application;

[0029] Figure 8 This is a three-dimensional structural diagram of the steel bar sleeve in one embodiment of this application;

[0030] Figure 9 This is a cross-sectional view of a steel bar sleeve in one embodiment of this application.

[0031] In the diagram: Outer ring freezing hole 1, Middle ring freezing hole 2, Inner ring freezing hole 3, Temperature measuring hole 4, Excavation area 5, Reinforcing steel cage 6, Vertical reinforcement 61, Pier head 611, External threaded section 612, Circumferential reinforcement 62, Non-bottom end well wall 7, Well wall pit 8, Lifting beam 9, Main lifting point 10, Sub-lifting point 11, Tensioning plate 12, Stepped threaded hole 121, Casting template 13, Reinforcing steel sleeve 14, Limiting surface 141, Arc surface 142, Grouting groove 143, Anti-loosening groove 144, First cavity 145, Second cavity 146, Third cavity 147, Connecting sleeve 15, Locking nut 16. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0033] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0034] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0035] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0036] See Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, this application proposes a construction method for building shaft walls using high-grade concrete freezing method. The construction method is as follows:

[0037] S1. Drill freezing holes at designated locations on the ground and insert freezing pipes into the freezing holes. The arrangement of freezing holes is a key factor in the trend of soil temperature change. The arrangement of freezing holes can affect not only the freezing time of the soil layer but also the freezing intensity of the soil layer. The freezing time of the soil layer affects the construction efficiency, and the freezing intensity of the soil layer affects the safety of the construction. Therefore, the arrangement of freezing holes is crucial. In this embodiment, a three-ring freezing pipe arrangement is adopted, consisting of an outer ring of freezing holes 1, a middle ring of freezing holes 2, and an inner ring of freezing holes 3. The three rings of freezing holes are arranged around the excavation area 5 to ensure the freezing speed and freezing intensity of the soil layer, effectively improve the construction efficiency, and ensure the safety of subsequent tunneling construction.

[0038] S2. Install the freezing station and connect the pipeline between the freezing station and the freezing pipe; S3. Introduce liquid nitrogen into the freezing pipe. The liquid nitrogen absorbs heat through vaporization to quickly freeze the soil layer. The liquid nitrogen is produced in a factory and transported to the construction site by truck or train tanker. It is then injected into the liquid nitrogen supply pipe in the freezing station. The liquid nitrogen vaporizes within the freezing pipe, absorbing heat from the surrounding soil and freezing it. After absorbing heat through vaporization, the liquid nitrogen escapes from the freezing pipe and is vented through the nitrogen discharge pipeline. As the liquid nitrogen vaporizes, evaporates, and new liquid nitrogen is continuously supplied to the freezing pipe, a frozen soil wall meeting design requirements is formed, at which point excavation can begin. During the excavation process, a small amount of liquid nitrogen continues to be supplied to maintain the strength of the frozen soil wall. Several temperature measuring holes 4 need to be excavated on the ground. These holes are used to measure the soil temperature. Subsequent excavation work can proceed once the soil temperature and freezing strength reach the preset values.

[0039] S4. Excavate the well wall pit 8 at the designated location on the ground; S5. Pour high-grade concrete to form the bottom layer of the well wall pit 8; Excavate the well wall pit 8 in the excavation area 5 on the ground using excavation equipment; After the well wall pit 8 is formed, lay the ground steel reinforcement structure on the bottom surface of the well wall pit 8 and pour high-grade concrete to form the bottom layer. The bottom layer is the foundation for subsequent construction. The high-grade concrete and the internal steel reinforcement structure help to enhance the structural strength of the bottom layer, thereby enhancing the stability of the well wall.

[0040] S6. The vertical reinforcing bars 61 of the well wall steel reinforcement skeleton 6 are pre-embedded in the bottom layer, and the well wall is poured in sections using high-grade concrete. The well wall includes the bottom well wall and multiple sections of non-bottom well wall 7. During the pouring process, a sectioned pouring method is adopted. The bottom well wall is poured based on the bottom layer, and the non-bottom well walls 7 are poured based on the bottom well wall or the previous section of non-bottom well wall 7, thus forming the entire well wall. High-grade concrete is used for pouring. High-grade concrete has ultra-high strength and good toughness, which helps to reduce the size of the well wall, reduce the self-weight of the well wall, and improve the seismic performance of the well wall. This achieves the effect of reducing the thickness of the well wall, and reducing the thickness of the well wall helps to reduce the diameter of the freezing ring in the well shaft. Reducing the diameter of the freezing ring in the well shaft helps to reduce the number of freezing pipes and reduce the amount of well shaft excavation, thereby increasing the excavation speed. However, since high-grade concrete has a high viscosity, the segmented pouring method is adopted in this application. This method helps to ensure the uniformity of each section of the well wall and avoids uneven strength distribution of the well wall caused by premature setting of some high-grade concrete, which would affect the stability of the well wall.

[0041] S7. During the segmented casting of the well wall, the vertical reinforcement bars 61 are tensioned. A steel reinforcement cage 6 is installed inside the bottom well wall and each non-bottom section. The steel reinforcement cage 6 includes vertical reinforcement bars 61 and circumferential reinforcement bars 62, which are connected by lap splices to form the steel reinforcement cage 6. During the forming of the bottom well wall and each non-bottom well wall section 7, the vertical reinforcement bars 61 are tensioned, generating prestress within them. When soil pressure acts on the well wall, the prestress within the vertical reinforcement bars 61 can offset or reduce the tensile stress generated by the soil pressure, improving the stiffness of the well wall, delaying the appearance of cracks, increasing the durability of the well wall, and reducing vibration and elastic deformation. This significantly improves the elastic strength of the well wall, making it more resistant. It is beneficial to ensure the stability of the well wall after reducing its thickness.

[0042] Specifically, this application employs a three-ring freezing pipe arrangement around the excavation area 5 to ensure the freezing speed and strength of the soil layer, effectively improving construction efficiency and ensuring the safety of subsequent tunneling. High-grade concrete is selected for pouring, as it possesses ultra-high strength and good toughness, which helps reduce the size of the well wall, lightens its self-weight, and improves its seismic performance. This achieves the effect of reducing the thickness of the well wall, which in turn helps reduce the diameter of the freezing ring, thus reducing the number of freezing pipes and the amount of tunneling, thereby increasing the tunneling speed. To ensure the uniformity of each section of the well wall and avoid uneven strength distribution due to premature setting of some high-grade concrete, which would affect the stability of the well wall, this application adopts a segmented pouring method to form the well wall. During the well wall forming process, the vertical ribs 61 are tensioned, generating prestress within them. When soil pressure acts on the well wall, this prestress can offset or reduce the tensile stress generated by the soil pressure, increasing the stiffness of the well wall, delaying the appearance of cracks, increasing its durability, and reducing vibration and elastic deformation. This significantly improves the elastic strength of the well wall, making it more resistant to damage. It also helps ensure the stability of the well wall after its thickness is reduced.

[0043] In some embodiments, the pouring method of the bottom well wall in S6 above is as follows: S61, one end of the vertical reinforcement 61 of the bottom well wall is pre-embedded in the bottom layer; during the pouring of the bottom well wall, it is necessary to base it on the bottom layer, and the external thread end of the vertical reinforcement 61 of the bottom well wall is pre-embedded in the bottom layer to form a connection with the steel reinforcement structure in the bottom layer, so as to ensure the connection strength between the bottom well wall and the bottom layer.

[0044] S62. Construct the bottom well wall casting template 13; the casting template 13 can be a wooden template or a metal template, and there is no specific restriction here. The casting template 13 and the well wall together form the forming space of the bottom well wall. High-grade concrete is poured into the forming space to form the concrete structure of the bottom well wall.

[0045] S63. The other end of the vertical reinforcement 61 of the bottom well wall is connected to the tensioning plate 12, and the vertical reinforcement 61 of the bottom well wall is tensioned through the tensioning plate 12; S64. High-grade concrete is poured into the casting formwork 13 of the bottom well wall; S65. Tensioning is stopped after the concrete strength of the bottom well wall reaches the preset value, and the bottom well wall is cured. Tensioning the vertical reinforcement 61 of the bottom well wall before pouring the high-grade concrete creates prestress within the vertical reinforcement 61. When soil pressure acts on the bottom well wall, the prestress within the vertical reinforcement 61 can offset or reduce the tensile stress generated by the soil pressure, improving the stiffness of the bottom well wall, delaying the appearance of cracks in the bottom well wall, increasing the durability of the bottom well wall, and reducing the vibration and elastic deformation of the bottom well wall. It significantly improves the elastic strength of the bottom well wall, making the well wall more resistant. This is beneficial for ensuring the stability of the well wall after reducing its thickness. After the concrete of the bottom well wall is formed, it is subjected to early curing, and tensioning is stopped after the concrete strength of the bottom well wall reaches the preset value, and the concrete of the bottom well wall is subjected to later curing.

[0046] In some embodiments, the method for casting the multiple non-bottom end well wall sections 7 in S6 above is as follows:

[0047] S66. One end of the vertical rib 61 of the non-bottom well wall 7 is connected to the vertical rib 61 of the upper section of the well wall through a connecting component; the non-bottom well wall 7 is based on the bottom well wall or the upper section of the non-bottom well wall 7; S67. Construct the pouring template 13 of the non-bottom well wall 7; the pouring template 13 of the non-bottom well wall 7 is the same as the pouring template 13 of the bottom well wall;

[0048] S68, the other end of the vertical rib 61 of the non-bottom well wall 7 is connected to the tension plate 12, and the vertical rib 61 of the non-bottom well wall 7 is tensioned by the tension plate 12; one end of the vertical rib 61 is connected to the vertical rib 61 of the previous section of the well wall, and the other end is connected to the tension plate 12. Prestress can be formed in the vertical rib 61 by applying tension through the tension plate 12.

[0049] S69. Pour high-grade concrete into the casting template 13 of the non-bottom well wall 7; S610. Stop tensioning after the concrete strength of the non-bottom well wall 7 reaches the preset value, and cure the non-bottom well wall 7; S611. Repeat S66-S610 to form multiple sections of the non-bottom well wall 7.

[0050] In some embodiments, the components of the high-grade concrete in S5 and S6 above include: cement, mineral powder, admixtures, sand, crushed stone, water, and polycarboxylate superplasticizer, wherein the admixtures include steel fibers. The preferred grade of high-grade concrete is C100, but it can also be higher. In this embodiment, a cost composition of high-grade concrete is provided. In 1 cubic meter of high-grade concrete, the weight of cement is 395 kg, the weight of mineral powder is 100 kg, the weight of admixture is 120 kg, the weight of sand is 660 kg, the weight of crushed stone is 1100 kg, the weight of water is 105 kg, and the weight of polycarboxylate superplasticizer is 29 kg. The admixture includes steel fiber and fly ash. Of course, other admixtures can also be added according to actual needs. The proportion of each material in the admixture can be selected according to actual needs. Steel fiber can effectively inhibit the expansion of microcracks inside the well wall and the formation of macrocracks, significantly improving the tensile, bending, impact and fatigue resistance of the well wall, which is beneficial to maintaining the reliability of the well wall after reducing the thickness of the well wall.

[0051] See Figure 2 As shown, in some embodiments, in S1 above, the ground is provided with outer ring freezing holes 1, middle ring freezing holes 2, and inner ring freezing holes 3. Each of the outer ring freezing holes 1, middle ring freezing holes 2, and inner ring freezing holes 3 includes several freezing holes arranged at intervals along the circumference, and freezing holes are drilled at these freezing holes. The three-ring freezing pipe arrangement of outer ring freezing holes 1, middle ring freezing holes 2, and inner ring freezing holes 3 surrounds the excavation area 5, ensuring the freezing speed and freezing strength of the soil layer, effectively improving construction efficiency and ensuring the safety of subsequent tunneling construction. The diameter of the outer ring freezing holes 1, middle ring freezing holes 2, and inner ring freezing holes 3, and the spacing between adjacent freezing holes, can be selected according to actual working conditions and are not specifically limited here.

[0052] See Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 9As shown, in some embodiments, the connecting assembly includes: a rebar sleeve 14, one end of the vertical rebar 61 having a head 611, and the rebar sleeve 14 having a first cavity 145 for the vertical rebar 61 to pass through, the inner diameter of the first cavity 145 being smaller than the diameter of the thickest part of the head 611; the head 611 at one end of the vertical rebar 61 includes a gradually expanding portion and a gradually contracting portion, the expanding portion being connected to the vertical rebar 61, and the contracting portion being connected to the expanding portion; the rebar sleeve 14 is fitted onto the vertical rebar 61 from the other end of the vertical rebar 61, due to the first cavity 145 being smaller than the diameter of the thickest part of the head 611; the head 611 at one end of the vertical rebar 61 includes a gradually expanding portion and a gradually contracting portion, the expanding portion being connected to the vertical rebar 61, and the rebar sleeve 14 being fitted onto the vertical rebar 61 from the other end of the vertical rebar 61, due to the first cavity 145 being smaller than the diameter of the thickest part of the head 611; the head 611 at one end of the vertical rebar 61 has a first cavity 145 for the vertical rebar 61 to pass through, the first cavity 145 having a first cavity 145 for the vertical rebar 61 to pass through, the first cavity 145 having a first cavity 145 being smaller than the diameter of the thickest part of the vertical rebar 61; the head 611 at one end of the vertical rebar 61 includes a gradually expanding portion and a gradually contracting portion, the first cavity 145 being smaller than the diameter of the thickest part of the vertical rebar 61, the first cavity 145 being smaller than the diameter of the thickest part of the vertical rebar 61, the first cavity 145 being smaller than the diameter of the thickest part of the vertical rebar 6 The inner diameter of cavity 145 is smaller than the diameter of the thickest part of the pier head 611, causing the rebar sleeve 14 to abut against the pier head 611 and unable to disengage from the vertical reinforcement 61. However, the rebar sleeve 14 can rotate relative to the vertical reinforcement 61. The connecting sleeve 15 has an externally threaded section 612 at the other end of the vertical reinforcement 61, and a threaded hole. The externally threaded section 612 is screwed onto the connecting sleeve 15. The rebar sleeve 14 has a second cavity 146 for insertion into which the connecting sleeve 15 is screwed. The connecting sleeve 15 is screwed onto the externally threaded section 612 of the vertical reinforcement 61, and has external threads on its outer side. The second cavity 146 of the rebar sleeve 14 has internal threads that match the external threads of the connecting sleeve 15. The rebar sleeve 14 can be screwed onto the connecting sleeve 15 to form a connection between the rebar sleeve 14 and the connecting sleeve 15.

[0053] In this embodiment, the outer circumferential surface of the rebar sleeve 14 is provided with external threads, and the tensioning plate 12 is provided with stepped threaded holes 121. The rebar sleeve 14 is screwed into the stepped threaded holes 121 of the tensioning plate 12. One end of the vertical bar 61 is connected to the upper section of the well wall through the rebar sleeve 14 of the connecting sleeve 15 and the vertical bar 61 of the upper end of the well wall. The other end of the vertical bar 61 is connected to the tensioning plate 12 through its own rebar sleeve 14. The tensioning structure also includes a main lifting point 10. The main lifting point 10 is connected to the power mechanism through a wire rope. The main lifting point 10 is connected to a lifting beam 9. Multiple sub-lifting points 11 are provided on the lifting beam 9. The sub-lifting points 11 are connected to the tensioning plate 12 through fasteners. When the power mechanism outputs tension, the tension can be transmitted to the tensioning plate 12. During the connection process, the lifting beam 9 drives the tension plate 12, thereby moving the steel reinforcement cage 6 to the preset position. At this time, the connection between the vertical reinforcement 61 of the upper section of the well wall and the vertical reinforcement of the current section of the well wall is achieved through the steel sleeve 14 on the upper section of the well wall vertical reinforcement 61. In addition to connecting the tension plate 12, the lifting beam 9 can also connect other structures, such as the casting formwork 13.

[0054] See Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 9As shown, in some embodiments, the connecting assembly includes: a locking nut 16, which is screwed onto the external thread section 612 and abuts against the connecting sleeve 15; the locking nut 16 locks itself in place by friction with the connecting sleeve 15, preventing the threads from loosening during tensioning and affecting the tensioning effect. An anti-loosening agent is also included; the end of the rebar sleeve 14 facing the connecting sleeve 15 has an anti-loosening groove 144, and the connecting sleeve 15 has an anti-loosening protrusion that matches the anti-loosening groove 144. An anti-loosening agent is placed between the rebar sleeve 14 and the connecting sleeve 15. The rebar sleeve 14 is pre-applied with the anti-loosening agent before being screwed onto the connecting sleeve 15. The cooperation between the anti-loosening groove 144 and the anti-loosening protrusion increases the contact area between the rebar sleeve 14 and the connecting sleeve 15, thereby enhancing the anti-loosening effect.

[0055] See Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 9 As shown, in some embodiments, the rebar sleeve 14 further includes an arc-shaped portion 142, which is adapted to the pier head 611. The arc-shaped portion 142 is adapted to the gradually widening portion on the end of the rebar. During tensioning, the arc-shaped portion 142 helps to increase the contact area between the rebar sleeve 14 and the vertical reinforcement 61, thus preventing damage to the rebar sleeve 14 during tensioning.

[0056] See Figure 8 and Figure 9As shown, in some embodiments, the rebar sleeve 14 further includes: a third cavity 147, the inner diameter of which is smaller than the inner diameter of the second cavity 146; a limiting surface 141 is formed at the connection between the third cavity 147 and the second cavity 146, the limiting surface 141 being used to limit the screw-in depth of the connecting sleeve 15; the third cavity 147 is an enlarged diameter portion, the inner diameter of the second cavity 146 being larger than the inner diameter of the third cavity 147; due to the difference in inner diameter, the limiting surface 141 is formed at the connection between the third cavity 147 and the second cavity 146, the limiting surface 141 effectively limiting the screw-in depth of the connecting sleeve 15; and a grouting groove 143, which is disposed in the rebar sleeve 14 and communicates with the third cavity 147. The grouting groove 143 is located on the outer wall of the third cavity 147. Due to the high viscosity of the high-strength concrete, to ensure that the high-strength concrete can flow into the rebar sleeve 14, expel the air inside the rebar sleeve 14, and improve the corrosion resistance of the rebar sleeve 14, the inflow of high-strength concrete also helps to improve the connection strength between the rebar sleeve 14 and the connecting sleeve 15. The grouting groove 143 is an arc-shaped groove. Of course, the grouting groove 143 can also be multiple arc-shaped grooves, which is not specifically limited here. In order to avoid the impact of the grouting groove 143 on the strength of the rebar sleeve 14, the grouting groove 143 is specifically located in the enlarged diameter third cavity 147 to avoid the grouting groove 143 weakening the rigidity of the rebar sleeve 14, which would cause the rebar sleeve 14 to be pulled apart during tensioning.

[0057] See Figure 4 As shown, in some embodiments, arc-shaped grooves are provided at the top of both the bottom well wall and the top of the multiple non-bottom well wall segments 7. The arc-shaped grooves help to increase the connection area between the bottom well wall and the non-bottom well wall segments 7, as well as the connection area between two adjacent non-bottom well wall segments 7, thereby enhancing the connection strength between the bottom well wall and the non-bottom well wall segments 7 and between two adjacent non-bottom well wall segments 7.

[0058] The above description is only a part or preferred embodiment of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. A construction method for building a vertical shaft wall using a high-grade concrete freezing method, characterized in that, The construction method is as follows: S1. Drill freezing holes at predetermined locations on the ground and insert freezing tubes into the freezing holes; S2. Install the freezing station and connect the freezing station to the freezing pipe; S3. Liquid nitrogen is introduced into the freezing pipe to rapidly freeze the soil layer by absorbing heat through the vaporization of liquid nitrogen. S4. Excavate a well wall pit at the designated location on the ground; S5. The bottom of the well wall pit is formed by pouring high-grade concrete; S6. The vertical reinforcement bars of the well wall steel reinforcement skeleton are pre-embedded in the bottom layer, and the well wall is poured in sections with high-grade concrete. The well wall includes the bottom well wall and multiple sections of non-bottom well wall. S7. During the segmented casting of the well wall, tension the vertical reinforcement bars; The casting method for the bottom well wall in S6 above is as follows: S61. One end of the vertical rib of the bottom well wall is pre-embedded in the bottom layer; S62. Construct the bottom well wall casting template; S63. The other end of the vertical rib of the bottom well wall is connected to a tensioning plate, and the vertical rib of the bottom well wall is tensioned through the tensioning plate. S64. Pour high-grade concrete into the casting template of the bottom well wall; S65. After the concrete strength of the bottom well wall reaches the preset value, stop tensioning and cure the bottom well wall. The pouring method for the non-bottom end well wall sections mentioned in S6 above is as follows: S66. One end of the vertical rib of the non-bottom well wall is connected to the vertical rib of the upper section of the well wall through a connecting component. S67. Construct the non-bottom end well wall casting template; S68. The other end of the vertical rib of the non-bottom well wall is connected to the tensioning plate, and the vertical rib of the non-bottom well wall is tensioned through the tensioning plate. S69. Pour high-grade concrete into the casting template of the non-bottom well wall; S610. After the concrete strength of the non-bottom well wall reaches the preset value, stop tensioning and cure the non-bottom well wall. S611, Repeat S66-S610 to form multiple sections of the non-bottom end well wall; The connection component includes: A rebar sleeve, wherein one end of the vertical rebar is provided with a head, and the rebar sleeve is provided with a first cavity for the vertical rebar to pass through, wherein the inner diameter of the first cavity is smaller than the diameter of the thickest part of the head; The connecting sleeve has an external threaded section at one end of the vertical reinforcing bar, a threaded hole in the connecting sleeve, and the external threaded section screwed into the connecting sleeve. The reinforcing bar sleeve has a second cavity for the connecting sleeve to be inserted into, and the connecting sleeve is screwed into the second cavity.

2. The construction method for constructing the shaft wall using the high-grade concrete freezing method according to claim 1, characterized in that, The high-grade concrete mentioned in S5 and S6 above comprises: cement, mineral powder, admixtures, sand, crushed stone, water, and polycarboxylate superplasticizer, wherein the admixtures include steel fibers.

3. The construction method for constructing the shaft wall using the high-grade concrete freezing method according to claim 1, characterized in that, In the above S1, the ground is provided with outer ring freezing holes, middle ring freezing holes and inner ring freezing holes. The outer ring freezing holes, middle ring freezing holes and inner ring freezing holes each include a number of freezing holes arranged at intervals along the circumference, and freezing holes are drilled in the freezing holes.

4. The construction method for constructing the shaft wall using high-grade concrete freezing method according to claim 1, characterized in that, The connection component includes: A locking nut is screwed onto the external thread section and abuts against the connecting sleeve; The anti-loosening agent is provided at one end of the rebar sleeve facing the connecting sleeve, the connecting sleeve is provided with an anti-loosening protrusion that matches the anti-loosening groove, and the anti-loosening agent is provided between the rebar sleeve and the connecting sleeve.

5. The construction method for constructing the shaft wall using the high-grade concrete freezing method according to claim 1, characterized in that, The steel bar sleeve also includes: The curved surface is adapted to the pier head.

6. The construction method for constructing the shaft wall using the high-grade concrete freezing method according to claim 1, characterized in that, The steel bar sleeve also includes: The third cavity has an inner diameter smaller than that of the second cavity. The third cavity forms a limiting surface at the connection point with the second cavity. The limiting surface is used to limit the screwing depth of the connecting sleeve. A grouting groove is provided in the reinforcing bar sleeve and communicates with the third cavity.

7. The construction method for constructing the shaft wall using the high-grade concrete freezing method according to claim 1, characterized in that, The bottom end well wall and the top of the multiple sections of the non-bottom end well wall are all provided with arc-shaped grooves.

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