Construction method for building vertical shaft wall through high-grade concrete freezing method

Abstract

The invention discloses a construction method for building a vertical shaft wall through a high-grade concrete freezing method. The construction method comprises the following steps that S1, freezing pipes are driven into freezing holes; s2, a freezing station is installed; s3, liquid nitrogen is introduced into the freezing pipe; s4, a well wall pit is excavated in a set position on the ground; s5, a bottom layer is formed through high-grade concrete pouring; s6, vertical ribs of the well wall steel reinforcement framework are pre-embedded into the bottom layer, and the well wall is poured in a segmented mode through high-grade concrete; and S7, in the process of pouring the well wall in sections, the vertical ribs are tensioned. The high-grade concrete has ultrahigh strength and good toughness, and is beneficial to reducing the thickness of the well wall. In order to ensure the uniformity of each section of the well wall, the well wall is formed in a segmented pouring mode. In the well wall forming process, the vertical ribs are tensioned, prestress is generated in the vertical ribs, and the resistance of the well wall is higher. And the stability of the well wall is ensured after the thickness of the well wall is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of shaft wall construction, and in particular to a construction method for building a shaft wall by using a high-grade concrete freezing method. Background Art

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

[0003] The main principle of liquid nitrogen freezing method construction is to drill freezing holes on the ground to the expected freezing depth according to the design, and then put freezing pipes in the freezing holes, using the vaporization of liquid nitrogen in the freezing pipes to absorb heat to form a freezing curtain. When the freezing curtain reaches the designed strength, the wellbore can be excavated under the protection of the freezing curtain.

[0004] For the shaft wall, the shaft wall faces high ground pressure and complex geological conditions. In order to ensure the stability of the shaft wall, the thickness of the shaft wall has to be increased. However, too thick a shaft wall will not only lead to high excavation costs, but is also the main cause of shaft wall cracking.

[0005] Based on this, it is necessary to propose a construction method for building the shaft wall using the high-grade concrete freezing method. On the basis of ensuring the stability of the shaft wall structure, reducing the thickness of the shaft wall has become an important technical problem that needs to be solved urgently. Summary of the invention

[0006] The present application provides a construction method for building a vertical shaft wall by using a high-grade concrete freezing method, aiming to solve the problem that the shaft wall in the prior art faces high ground pressure and complex geological conditions. In order to ensure the stability of the shaft wall, the thickness of the shaft wall has to be increased. However, an overly thick shaft wall not only leads to high excavation and masonry costs, but is also the main cause of shaft wall cracking.

[0007] To achieve the above-mentioned purpose, the present application proposes a construction method for constructing a vertical shaft wall by using a high-grade concrete freezing method, and the construction method is as follows: S1, drilling a freezing hole at a set position on the ground, and inserting a freezing pipe into the freezing hole; S2, installing a freezing station, and connecting the freezing station to the freezing pipe; S3, introducing liquid nitrogen into the freezing pipe, and quickly freezing the soil layer by absorbing heat through the gasification of liquid nitrogen; S4, digging a shaft wall pit at a set position on the ground; S5, casting the bottom surface of the shaft wall pit with high-grade concrete to form a bottom layer; S6, pre-embedding the vertical reinforcement of the shaft wall steel skeleton into the bottom layer, and casting the shaft wall in sections with high-grade concrete, the shaft wall including the bottom shaft wall and multiple sections of non-bottom shaft wall; S7, tensioning the vertical reinforcement during the process of casting the shaft wall in sections.

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

[0009] In some embodiments, the casting method of multiple sections of non-bottom well wall in the above S6 is as follows: S66, one end of the vertical reinforcement of the non-bottom well wall is connected to the vertical reinforcement of the upper section of the well wall through a connecting assembly; S67, building a casting template for the non-bottom well wall; S68, the other end of the vertical reinforcement of the non-bottom well wall is connected to the tensioning plate, and the vertical reinforcement of the non-bottom well wall is tensioned by the tensioning plate; S69, pouring high-grade concrete into the casting template of the non-bottom well wall; S610, stopping tensioning after the concrete strength of the non-bottom well wall reaches a preset value, and curing the non-bottom well wall; S611, repeating S66-S610 to form multiple sections of non-bottom well wall.

[0010] In some embodiments, the ingredients of the high-grade concrete in S5 and S6 above include: cement, mineral powder, admixture, sand, crushed stone, water and polycarboxylate water reducer, and the admixture includes steel fiber.

[0011] In some embodiments, in the above S1, the ground is provided with an outer circle freezing holes, a middle circle freezing holes and an inner circle freezing holes, and the outer circle freezing holes, the middle circle freezing holes and the inner circle freezing holes all include a plurality of freezing holes arranged at intervals along the circumferential direction, and freezing holes are drilled at the freezing holes.

[0012] In some embodiments, the connecting assembly includes: a steel sleeve, a pier head is provided at one end of the vertical reinforcement, a first cavity is provided in the steel sleeve for the vertical reinforcement to pass through, and the inner diameter of the first cavity is smaller than the diameter of the thickest part of the pier head; a connecting sleeve, an external thread section is provided at the other end of the vertical reinforcement, the connecting sleeve is provided with a threaded hole, the external thread section is screwed to the connecting sleeve, the steel sleeve is provided with a second cavity for the connecting sleeve to be inserted, and the connecting sleeve is screwed to the second cavity.

[0013] In some embodiments, the connecting assembly includes: a locking nut, which is threaded on the external thread section and abuts against the connecting sleeve; an anti-loosening agent, an anti-loosening groove is provided at one end of the steel sleeve facing the connecting sleeve, the connecting sleeve is provided with an anti-loosening protrusion adapted to the anti-loosening groove, and an anti-loosening agent is provided between the steel sleeve and the connecting sleeve.

[0014] In some embodiments, the steel sleeve further comprises: Arc surface, the arc surface is suitable for the pier head.

[0015] In some embodiments, the steel sleeve further comprises: A third cavity, wherein the inner diameter of the third cavity is smaller than the inner diameter of the second cavity, and a limiting surface is formed at the connection between the third cavity and the second cavity, and the limiting surface is used to limit the screwing depth of the connecting sleeve; A grouting groove is arranged on the steel sleeve and is connected to the third cavity.

[0016] In some embodiments, arc grooves are provided at the tops of the bottom well wall and the multiple sections of non-bottom well walls.

[0017] The technical solution of this application proposes a construction method for building a vertical shaft wall by using a high-grade concrete freezing method. The construction method is as follows: S1. Drill a freezing hole at a set position on the ground, and insert a freezing pipe into the freezing hole; S2. Install a freezing station, and connect the freezing station to the freezing pipe; S3. Introduce liquid nitrogen into the freezing pipe, and quickly freeze the soil layer by absorbing heat through the gasification of liquid nitrogen; S4. Dig a shaft wall pit at a set position on the ground; S5. Cast the bottom surface of the shaft wall pit with high-grade concrete to form a bottom layer; S6. Pre-embed the vertical reinforcement of the shaft wall steel skeleton into the bottom layer, and cast the shaft wall in sections with high-grade concrete, the shaft wall including the bottom shaft wall and multiple sections of non-bottom shaft wall; S7. In the process of casting the shaft wall in sections, tension the vertical reinforcement. This application adopts three circles of freezing pipes arranged around the excavation area to ensure the freezing speed and freezing strength of the soil layer, effectively improve the construction efficiency and ensure the safety of subsequent excavation construction. High-grade concrete is selected for pouring. High-grade concrete has ultra-high strength and good toughness, which is conducive to reducing the size of the well wall, reducing the deadweight of the well wall, and improving the seismic performance of the well wall. The effect of thinning the well wall thickness is achieved, and thinning the well wall thickness is conducive to reducing the diameter of the wellbore freezing circle. Reducing the diameter of the wellbore freezing circle is conducive to reducing the number of freezing pipes and can reduce the amount of wellbore excavation, thereby increasing the excavation speed. In order to ensure the uniformity of each section of the well wall, avoid the premature solidification of some high-grade concrete, resulting in uneven strength distribution of the well wall, and affect the stability of the well wall, the well wall is formed by segmented casting in this application. In the process of well wall forming, the vertical reinforcement is tensioned to generate prestress in the vertical reinforcement. When the soil layer pressure acts on the well wall, the prestress in the vertical reinforcement can offset or reduce the tensile stress generated by the soil layer pressure, increase the stiffness of the well wall, delay the time for the appearance of cracks in the well wall, increase the durability of the well wall, and reduce the vibration and elastic deformation of the well wall. The elastic strength of the well wall is significantly improved, making the well wall more resistant. It is helpful to ensure the stability of the well wall after thinning the well wall thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work, among which: Figure 1 A technical roadmap for a construction method for constructing a vertical shaft wall using a high-grade concrete freezing method in an embodiment of the present application; Figure 2 This is a schematic diagram of the arrangement of freezing holes in one embodiment of the present application; Figure 3 This is a schematic diagram of the steel bar skeleton structure of the shaft wall in one embodiment of the present application; Figure 4 This is a schematic diagram of the construction structure of the non-bottom well wall in one embodiment of the present application; Figure 5 for Figure 4 A partial enlarged view of the middle A part; Figure 6 for Figure 4 A partial enlarged view of the middle B part; Figure 7 This is a schematic diagram of the three-dimensional structure of the vertical ribs in one embodiment of the present application; Figure 8 This is a schematic diagram of the three-dimensional structure of a steel bar sleeve in one embodiment of the present application; Fig. 9 It is a cross-sectional view of a steel sleeve in one embodiment of the present application.

[0019] In the figure: outer circle freezing hole position 1, middle circle freezing hole position 2, inner circle freezing hole position 3, temperature measuring hole 4, excavation area 5, steel skeleton 6, vertical rib 61, pier head 611, external thread section 612, annular rib 62, non-bottom well wall 7, well wall pit 8, lifting beam 9, total hanging point 10, branch hanging point 11, tensioning plate 12, stepped threaded hole 121, casting formwork 13, 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 DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0021] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0022] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0023] In addition, the descriptions of "first", "second", etc. in this application are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0024] See also Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the present application proposes a construction method for constructing a shaft wall by using a high-grade concrete freezing method. The construction method is as follows: S1. Drill freezing holes at set positions on the ground, and drive freezing pipes into the freezing holes. The arrangement of freezing holes is a key factor in the temperature change trend of the soil layer. The arrangement of freezing holes can not only affect the freezing time of the soil layer, but also affect the freezing strength of the soil layer. The freezing time of the soil layer affects the construction efficiency, and the freezing strength of the soil layer affects the safety of the construction. Therefore, the arrangement of freezing holes is very important. In this embodiment, a three-circle freezing pipe arrangement of outer circle freezing hole position 1, middle circle freezing hole position 2 and inner circle freezing hole position 3 is adopted. The three circles of freezing hole positions are arranged around the excavation area 5 to ensure the freezing speed and freezing strength of the soil layer, effectively improve the construction efficiency and ensure the safety of subsequent excavation construction. S2. Install the freezing station and connect the pipes between the freezing station and the freezing pipe; S3. Introduce liquid nitrogen into the freezing pipe, and quickly freeze the soil layer by absorbing heat through the vaporization of liquid nitrogen; liquid nitrogen is produced in the factory, transported to the construction site by tank trucks of cars or trains, and injected into the liquid nitrogen supply pipe in the freezing station, where it vaporizes in the freezing pipe space, absorbs heat from the surrounding soil, and freezes the soil. After the liquid nitrogen vaporizes and absorbs heat, it escapes from the freezing pipe and is discharged through the nitrogen exhaust pipe. As the liquid nitrogen vaporizes and evaporates, and new liquid nitrogen is continuously supplied to the freezing pipe, until a frozen soil wall that meets the design requirements is formed, excavation and construction 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. It is also necessary to dig a number of temperature measuring holes 4 on the ground. The temperature measuring holes 4 are used to measure the temperature of the soil layer. When the temperature of the soil layer reaches a preset value and the freezing strength of the soil layer reaches a preset value, subsequent excavation work can be carried out; S4, digging a well pit 8 at a set position on the ground; S5, pouring high-grade concrete on the bottom surface of the well pit 8 to form a bottom layer; digging the well pit 8 in the digging area 5 on the ground by using an excavation device; after the well pit 8 is formed, laying a ground steel structure on the bottom surface of the well pit 8, and pouring high-grade concrete to form a bottom layer, which is the basis for subsequent construction. The high-grade concrete and the internal steel structure are conducive to enhancing the structural strength of the bottom layer, thereby enhancing the stability of the well wall; S6. The vertical ribs 61 of the well wall steel skeleton 6 are embedded in the bottom layer, and the well wall is cast in sections with high-grade concrete. The well wall includes the bottom well wall and multiple sections of non-bottom well wall 7. In the casting process of the well wall, a segmented casting method is adopted. The bottom well wall is cast based on the bottom layer, and the non-bottom well wall 7 is cast based on the bottom well wall or the upper section of the non-bottom well wall 7, so as to form the entire well wall. In the casting process, high-grade concrete is selected for casting. High-grade concrete has ultra-high strength and good toughness, which is conducive to reducing the size of the well wall, reducing the deadweight of the well wall, and improving the seismic performance of the well wall. The effect of thinning the well wall thickness is achieved, and thinning the well wall thickness is conducive to reducing the diameter of the wellbore freezing circle. Reducing the diameter of the wellbore freezing circle is conducive to reducing the number of freezing pipes and can reduce the wellbore excavation amount, thereby increasing the excavation speed. However, due to the high viscosity of high-grade concrete, the segmented casting method adopted in this application is conducive to ensuring the uniformity of each section of the well wall and avoiding the premature solidification of some high-grade concrete, which will lead to uneven strength distribution of the well wall and affect the stability of the well wall.

[0025] S7. During the process of casting the well wall in sections, the vertical ribs 61 are tensioned. The bottom well wall and each section not at the bottom are provided with a steel skeleton 6, which includes vertical ribs 61 and annular ribs 62. The vertical ribs 61 and annular ribs 62 are connected as a whole by tying to form a steel skeleton 6. During the forming process of the bottom well wall and each section not at the bottom well wall 7, the vertical ribs 61 are tensioned to generate prestress in the vertical ribs 61. When the soil pressure acts on the well wall, the prestress in the vertical ribs 61 can offset or reduce the tensile stress generated by the soil pressure, increase the rigidity of the well wall, delay the time for the occurrence of cracks in the well wall, increase the durability of the well wall, and reduce the vibration and elastic deformation of the well wall. The elastic strength of the well wall is significantly improved, making the well wall more resistant. It is beneficial to ensure the stability of the well wall after the thickness of the well wall is thinned.

[0026] Specifically, the present application uses three circles of freezing pipes arranged around the excavation area 5 to ensure the freezing speed and freezing strength of the soil layer, effectively improve the construction efficiency and ensure the safety of subsequent excavation construction. High-grade concrete is selected for pouring. High-grade concrete has ultra-high strength and good toughness, which is conducive to reducing the size of the well wall, reducing the deadweight of the well wall, and improving the seismic performance of the well wall. The effect of thinning the well wall thickness is achieved, and thinning the well wall thickness is conducive to reducing the diameter of the wellbore freezing circle. Reducing the diameter of the wellbore freezing circle is conducive to reducing the number of freezing pipes and can reduce the amount of wellbore excavation, thereby increasing the excavation speed. In order to ensure the uniformity of each section of the well wall, avoid premature solidification of some high-grade concrete, resulting in uneven strength distribution of the well wall, and affect the stability of the well wall, the well wall is formed by segmented casting in the present application. During the forming process of the well wall, the vertical ribs 61 are tensioned to generate prestress in the vertical ribs 61. When the soil pressure acts on the well wall, the prestress in the vertical ribs 61 can offset or reduce the tensile stress generated by the soil pressure, improve the rigidity of the well wall, delay the appearance of cracks in the well wall, increase the durability of the well wall, and reduce the vibration and elastic deformation of the well wall. The elastic strength of the well wall is significantly improved, making the well wall more resistant. It is beneficial to ensure the stability of the well wall after the thickness of the well wall is thinned.

[0027] In some embodiments, the casting method of the bottom well wall in the above S6 is as follows: S61, one end of the vertical rib 61 of the bottom well wall is pre-buried in the bottom layer; during the casting of the bottom well wall, the bottom layer needs to be used as the basis, and the external threaded end of the vertical rib 61 of the bottom well wall is pre-buried in the bottom layer to form a connection with the steel bar structure in the bottom layer to ensure the connection strength between the bottom well wall and the bottom layer; S62, constructing a casting template 13 for the bottom shaft wall; the casting template 13 can be a wooden template or a metal template, and is not specifically limited here. The casting template 13 and the shaft wall are combined to form a forming space for the bottom shaft wall, and high-grade concrete is poured into the forming space to form a concrete structure of the bottom shaft wall; S63, the other end of the vertical rib 61 of the bottom well wall is connected to the tensioning plate 12, and the vertical rib 61 of the bottom well wall is tensioned through the tensioning plate 12; S64, high-grade concrete is poured into the casting template 13 of the bottom well wall; S65, the tensioning is stopped after the concrete strength of the bottom well wall reaches the preset value, and the bottom well wall is maintained. Before pouring the high-grade concrete, the vertical rib 61 of the bottom well wall is tensioned to form prestress in the vertical rib 61. When the soil pressure acts on the bottom well wall, the prestress in the vertical rib 61 can offset or reduce the tensile stress generated by the soil pressure, improve the rigidity of the bottom well wall, delay the time for the cracks in the bottom well wall to appear, increase the durability of the bottom well wall, and reduce the vibration and elastic deformation of the bottom well wall. The elastic strength of the bottom well wall is significantly improved, making the well wall more resistant. It is beneficial to ensure the stability of the well wall after the thickness of the bottom well wall is thinned. After the concrete of the bottom shaft wall is formed, early curing is performed on it, and after the concrete strength of the bottom shaft wall reaches a preset value, the tensioning is stopped, and the concrete of the bottom shaft wall is subjected to later curing.

[0028] In some embodiments, the casting method of the multiple sections of the non-bottom well wall 7 in S6 is as follows: 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 well wall through a connecting assembly; the non-bottom well wall 7 is based on the bottom well wall or the upper non-bottom well wall 7; S67, build a casting template 13 for the non-bottom well wall 7; the casting template 13 of the non-bottom well wall 7 is the same as the casting template 13 of the bottom well wall; S68, the other end of the vertical rib 61 of the non-bottom well wall 7 is connected to the tensioning plate 12, and the vertical rib 61 of the non-bottom well wall 7 is tensioned by the tensioning plate 12; one end of the vertical rib 61 is connected to the vertical rib 61 of the upper well wall, and the other end is connected to the tensioning plate 12, and the tension is applied by the tensioning plate 12 to form prestress in the vertical rib 61; S69, pouring high-grade concrete into the casting formwork 13 of the non-bottom well wall 7; S610, stopping tensioning after the concrete strength of the non-bottom well wall 7 reaches a preset value, and curing the non-bottom well wall 7; S611, repeating S66-S610 to form multiple sections of the non-bottom well wall 7.

[0029] In some embodiments, the ingredients of the high-grade concrete in S5 and S6 above include: cement, mineral powder, admixture, sand, crushed stone, water and polycarboxylate water reducer, and the admixture includes steel fiber. The grade of high-grade concrete is preferably C100, and the grade of high-grade concrete may also be greater than C100. 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, the weight of polycarboxylic acid water-reducing agent is 29 kg, the admixture includes steel fiber, and the admixture also includes fly ash. Of course, other admixtures can 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 hinder the expansion of microcracks inside the well wall and the formation of macrocracks, significantly improve the tensile, bending, impact and fatigue resistance of the well wall, and is beneficial to maintain the reliability of the well wall after the thickness of the well wall is thinned.

[0030] See also Figure 2 As shown, in some embodiments, in the above S1, the ground is provided with an outer circle freezing hole 1, a middle circle freezing hole 2 and an inner circle freezing hole 3, and the outer circle freezing hole 1, the middle circle freezing hole 2 and the inner circle freezing hole 3 all include a plurality of freezing holes arranged at intervals along the circumferential direction, and freezing holes are drilled in the freezing holes. A three-circle freezing pipe arrangement of the outer circle freezing hole 1, the middle circle freezing hole 2 and the inner circle freezing hole 3 is adopted, and the three circles of freezing pipes are arranged around the excavation area 5 to ensure the freezing speed and freezing strength of the soil layer, effectively improve the construction efficiency and ensure the safety of subsequent excavation construction. The diameters of the outer circle freezing hole 1, the middle circle freezing hole 2 and the inner circle freezing hole 3 and the distance between two adjacent freezing holes can be selected according to the actual working conditions, and are not specifically limited here.

[0031] See also Figure 4 , Figure 5 , Figure 6 , Figure 7 and Fig. 9As shown, in some embodiments, the connection assembly includes: a steel sleeve 14, a pier head 611 is provided at one end of the vertical rib 61, a first cavity 145 is provided in the steel sleeve 14 for the vertical rib 61 to pass through, and the inner diameter of the first cavity 145 is smaller than the diameter of the thickest part of the pier head 611; the pier head 611 at one end of the vertical rib 61 includes a gradually expanding portion and a gradually contracting portion, the gradually expanding portion is connected to the vertical rib 61, and the gradually contracting portion is connected to the gradually expanding portion, and the steel sleeve 14 is sleeved on the vertical rib 61 from the other end of the vertical rib 61. Due to the first cavity The inner diameter of the cavity 145 is smaller than the diameter of the thickest part of the pier head 611, so that the steel sleeve 14 is against the pier head 611 and cannot be removed from the vertical rib 61, but the steel sleeve 14 can rotate relative to the vertical rib 61; the connecting sleeve 15, the other end of the vertical rib 61 is provided with an external thread section 612, the connecting sleeve 15 is provided with a threaded hole, the external thread section 612 is screwed to the connecting sleeve 15, the steel sleeve 14 is provided with a second cavity 146 for the connecting sleeve 15 to be inserted, and the connecting sleeve 15 is screwed to the second cavity 146. The connecting sleeve 15 is screwed to the external thread section 612 of the vertical rib 61, and the outer side of the connecting sleeve 15 is provided with an external thread, and the second cavity 146 of the steel sleeve 14 is provided with an internal thread adapted to the external thread of the connecting sleeve 15, and the steel sleeve 14 can be screwed onto the connecting sleeve 15 to form a connection between the device and the connecting sleeve 15.

[0032] In this embodiment, the outer peripheral surface of the steel sleeve 14 is provided with an external thread, and the tensioning plate 12 is provided with a stepped threaded hole 121. The steel sleeve 14 is screwed into the stepped threaded hole 121 of the tensioning plate 12. One end of the vertical reinforcement 61 is connected to the upper section of the well wall through the connecting sleeve 15 and the steel sleeve 14 of the vertical reinforcement 61 of the upper end of the well wall. The other end of the vertical reinforcement 61 is connected to the tensioning plate 12 through its own steel sleeve 14. The tensioning structure also includes a total hanging point 10, which is connected to the power mechanism through a steel wire rope. The total hanging point 10 is connected to the lifting beam 9, and a plurality of branch hanging points 11 are provided on the lifting beam 9. The branch hanging points 11 are connected to the tensioning plate 12 through fasteners. The power mechanism outputs tension, which can transfer the tension to the tensioning plate 12. During the connection process, the lifting beam 9 drives the tensioning plate 12 and thus drives the steel frame 6 to move to the preset position. At this time, the steel sleeve 14 on the vertical reinforcement 61 of the upper section of the well wall is used to realize the connection between the vertical reinforcement 61 of the upper section of the well wall and the vertical reinforcement of this section of the well wall. In addition to connecting the tensioning plate 12, the lifting beam 9 can also be connected to other structures, such as a casting formwork 13.

[0033] See also Figure 4 , Figure 5 , Figure 6 , Figure 7 and Fig. 9As shown, in some embodiments, the connection assembly includes: a locking nut 16, the locking nut 16 is threaded on the external thread section 612, and the locking nut 16 abuts against the connecting sleeve 15; the locking nut 16 locks the locking nut 16 through the friction between the locking nut 16 and the connecting sleeve 15 to prevent the thread from loosening during the tensioning process and affecting the tensioning effect. Anti-loosening agent, an anti-loosening groove 144 is provided at one end of the steel sleeve 14 facing the connecting sleeve 15, and the connecting sleeve 15 is provided with an anti-loosening protrusion adapted to the anti-loosening groove 144, and an anti-loosening agent is provided between the steel sleeve 14 and the connecting sleeve 15, and the anti-loosening agent is pre-applied on the steel sleeve 14, and then the steel sleeve 14 is screwed onto the connecting sleeve 15. The cooperation of the anti-loosening groove 144 and the anti-loosening protrusion can increase the contact area between the steel sleeve 14 and the connecting sleeve 15, thereby enhancing the anti-loosening effect.

[0034] See also Figure 4 , Figure 5 , Figure 6 , Figure 7 and Fig. 9 As shown, in some embodiments, the steel sleeve 14 further includes: an arc portion 142, and the arc portion 142 is adapted to the pier head 611. The arc portion 142 is adapted to the gradually expanding portion on the end of the steel bar. During the tensioning process, the setting of the arc portion 142 is conducive to increasing the contact area between the steel sleeve 14 and the vertical rib 61, thereby avoiding damage to the steel sleeve 14 during the tensioning process.

[0035] See also Figure 8 and Fig. 9As shown, in some embodiments, the steel sleeve 14 further includes: a third cavity 147, the inner diameter of the third cavity 147 is smaller than the inner diameter of the second cavity 146, and a limiting surface 141 is formed at the connection between the third cavity 147 and the second cavity 146, and the limiting surface 141 is used to limit the screw-in depth of the connecting sleeve 15; the third cavity 147 is an expanded diameter portion, and the inner diameter of the second cavity 146 is larger than the inner diameter of the third cavity 147. Due to the difference in inner diameters, a limiting surface 141 is formed at the connection between the third cavity 147 and the second cavity 146, and the limiting surface 141 can effectively limit the screw-in depth of the connecting sleeve 15. A grouting groove 143, the grouting groove 143 is provided in the steel sleeve 14, and is connected to the third cavity 147. The grouting groove 143 is opened on the outer wall of the third cavity 147. Due to the high viscosity of high-grade concrete, in order to ensure that the high-grade concrete can flow into the steel sleeve 14, the air in the steel sleeve 14 is discharged, and the anti-corrosion ability of the steel sleeve 14 is improved. The inflow of high-grade concrete is also conducive to improving the connection strength between the steel sleeve 14 and the connecting sleeve 15. The grouting groove 143 is a segment of arc groove. Of course, the grouting groove 143 can also be a multi-segment arc groove without specific restrictions. In order to avoid the influence of the opening of the grouting groove 143 on the strength of the steel sleeve 14, the grouting groove 143 is opened to the expanded third cavity 147 to avoid the opening of the grouting groove 143 to weaken the rigidity of the steel sleeve 14, causing the steel sleeve 14 to be broken during the tensioning process.

[0036] See also Figure 4 As shown, in some embodiments, arc grooves are provided at the tops of the bottom well wall and the multiple sections of non-bottom well walls 7. The provision of the arc grooves is conducive to increasing the connection area between the bottom well wall and the non-bottom well wall 7, and the connection area between two adjacent sections of non-bottom well walls 7, thereby increasing the connection strength between the bottom well wall and the non-bottom well wall 7, and between two adjacent sections of non-bottom well walls 7.

[0037] The above description is only a partial or preferred embodiment of the present application. Neither the text nor the drawings can limit the scope of protection of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the overall concept of the present application, or direct / indirect application in other related technical fields are included in the scope of protection of the present application.

Claims

1. A construction method for building a shaft wall using a high-grade concrete freezing method, characterized in that: The construction method is as follows: S1. Drilling a freezing hole at a set position on the ground, and inserting a freezing pipe into the freezing hole; S2, installing a freezing station and connecting the freezing station to the freezing pipe; S3, introducing liquid nitrogen into the freezing pipe to quickly freeze the soil layer by absorbing heat through the vaporization of the liquid nitrogen; S4, digging a well wall pit at a set position on the ground; S5, pouring high-grade concrete on the bottom surface of the well wall pit to form a bottom layer; S6, embedding the vertical reinforcement of the well wall steel skeleton into the bottom layer, and casting the well wall in sections with high-grade concrete, the well wall including the bottom well wall and multiple sections of non-bottom well wall; S7. During the segmented casting of the well wall, the vertical reinforcement is tensioned.

2. The construction method for constructing a shaft wall by using a high-grade concrete freezing method according to claim 1 is characterized in that: The casting method of the bottom well wall in the above S6 is as follows: S61, one end of the vertical reinforcement of the bottom well wall is embedded in the bottom layer; S62, constructing 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 by the tensioning plate; S64, pouring high-grade concrete into the casting template of the bottom well wall; S65, stopping tensioning after the concrete strength of the bottom shaft wall reaches a preset value, and performing maintenance on the bottom shaft wall.

3. The construction method for constructing a shaft wall by using a high-grade concrete freezing method according to claim 2 is characterized in that: The casting method of the non-bottom well wall described in the above S6 is as follows: S66, one end of the vertical reinforcement of the non-bottom well wall is connected to the vertical reinforcement of the upper well wall through a connecting component; S67, constructing the non-bottom well wall casting template; S68, the other end of the vertical reinforcement of the non-bottom well wall is connected to the tensioning plate, and the vertical reinforcement of the non-bottom well wall is tensioned by the tensioning plate; S69, pouring high-grade concrete into the casting template of the non-bottom well wall; S610, stopping tensioning after the concrete strength of the non-bottom shaft wall reaches a preset value, and performing maintenance on the non-bottom shaft wall; S611, repeat S66-S610 to form multiple sections of the non-bottom well wall.

4. The construction method for constructing a shaft wall by using a high-grade concrete freezing method according to claim 1 is characterized in that: The components of the high-grade concrete in S5 and S6 above include: cement, mineral powder, admixture, sand, crushed stone, water and polycarboxylate water-reducing agent, and the admixture includes steel fiber.

5. The construction method for constructing a shaft wall by using a high-grade concrete freezing method according to claim 1 is characterized in that: In the above S1, the ground is provided with an outer circle freezing holes, a middle circle freezing holes and an inner circle freezing holes, and the outer circle freezing holes, the middle circle freezing holes and the inner circle freezing holes all include a plurality of freezing holes arranged at intervals along the circumferential direction, and the freezing holes are drilled at the freezing holes.

6. The construction method for constructing a shaft wall by using a high-grade concrete freezing method according to claim 3 is characterized in that: The connection component comprises: A steel sleeve, wherein one end of the vertical reinforcement is provided with a pier head, and a first cavity for the vertical reinforcement to pass through is provided in the steel sleeve, and the inner diameter of the first cavity is smaller than the diameter of the thickest part of the pier head; A connecting sleeve, the other end of the vertical reinforcement is provided with an external thread section, the connecting sleeve is provided with a threaded hole, the external thread section is screwed to the connecting sleeve, the steel bar sleeve is provided with a second cavity for inserting the connecting sleeve, and the connecting sleeve is screwed to the second cavity.

7. The construction method for constructing a shaft wall by using a high-grade concrete freezing method according to claim 6 is characterized in that: The connection component comprises: A locking nut, the locking nut being threadedly connected to the external thread section and abutting against the connecting sleeve; An anti-loosening agent, wherein an anti-loosening groove is arranged at one end of the steel sleeve facing the connecting sleeve, and the connecting sleeve is provided with an anti-loosening protrusion adapted to the anti-loosening groove, and the anti-loosening agent is arranged between the steel sleeve and the connecting sleeve.

8. The construction method for constructing a shaft wall by using a high-grade concrete freezing method according to claim 6 is characterized in that: The steel sleeve also includes: The arc surface portion is adapted to the pier head.

9. The construction method for constructing a shaft wall by using a high-grade concrete freezing method according to claim 6 is characterized in that: The steel sleeve also includes: a third cavity, wherein the inner diameter of the third cavity is smaller than the inner diameter of the second cavity, and a limiting surface is formed at the connection between the third cavity and the second cavity, and the limiting surface is used to limit the screwing depth of the connecting sleeve; A grouting groove is provided in the steel sleeve and is connected to the third cavity.

10. The construction method for constructing a shaft wall by using a high-grade concrete freezing method according to claim 1, characterized in that: The bottom well wall and the tops of the multiple sections of the non-bottom well walls are all provided with arc grooves.

Images