Method for installing and positioning unbonded prestressed tendon of underground continuous wall curve

Abstract

This invention provides a method for installing and positioning unbonded prestressed tendons in diaphragm walls. The method uses a pre-drawn linear installation and positioning diagram of the unbonded prestressed tendons in the diaphragm wall as the construction drawing for installation and positioning. Combined with corresponding construction steps, it ensures accurate installation and positioning of the unbonded prestressed tendons, effectively guaranteeing accurate and unchanged linear positioning of the unbonded prestressed tendons during installation, hoisting of the reinforcing cage into the trench, and underwater concrete pouring.

Description

Technical Field

[0001] This invention relates to the field of civil engineering technology, and in particular to a method for installing and positioning unbonded prestressed tendons for curved underground continuous walls. Background Technology

[0002] Diaphragm walls, as a common form of retaining wall for deep foundation pits, are widely used in the retaining structures of underground foundation pits in high-rise buildings and municipal engineering projects, especially in soft soil foundations, urban centers, and foundation pits requiring protection of adjacent buildings and underground pipelines. Diaphragm walls have become the preferred retaining method in these cases. However, as foundation pit excavations become deeper, the water and soil pressure on the retaining structure increases. To effectively control the deformation of the diaphragm wall structure, it is necessary to either increase the thickness of the diaphragm wall or reduce the spacing of the foundation pit supports. The former increases the cost of the retaining structure, while the latter increases the difficulty of foundation pit excavation. Prestressed technology, with its ability to effectively increase the stiffness of structural members and actively control the deformation of structural members under load, offers advantages such as material saving and improved structural performance, and has been widely used and developed in superstructures. Applying prestressed technology to diaphragm wall structures can improve the stiffness and crack resistance of the diaphragm wall structure, reduce the amount of steel reinforcement used in the wall, and reduce deformation under water and soil pressure, thereby achieving goals such as reducing project costs and accelerating construction progress, resulting in significant economic and social benefits.

[0003] There are two types of prestressing tendon layout schemes for cast-in-place diaphragm walls: one is a straight prestressing tendon layout, which requires placement along both the pit-facing and soil-facing sides of the diaphragm wall. This layout lacks specificity, resulting in poor prestressing effect on controlling diaphragm wall deformation, and also leads to a large amount of prestressing tendons and low economic efficiency. The other is a curved prestressing tendon layout, which is based on the stress and deformation characteristics of the cast-in-place diaphragm wall structure at each stage of construction, and is more specific. After applying prestress, it can achieve optimal deformation control of the diaphragm wall structure. Furthermore, using unbonded prestressing tendons can maximize the prestressing tendon sag and improve the prestressing effect, and it does not require grouting, offering advantages such as convenient construction and easy quality control. Therefore, using curved unbonded prestressing tendons is the optimal design scheme for cast-in-place diaphragm walls.

[0004] However, the installation and positioning of curved unbonded prestressed tendons in cast-in-place diaphragm walls faces numerous technical challenges: First, the reinforcement cages of diaphragm walls are typically densely reinforced, with only a few supporting trusses between the densely packed reinforcement bars on both sides. Furthermore, due to the depth of the diaphragm wall, the large length of the reinforcement cage, and the wide trench, accurately positioning the curved shape of the unbonded prestressed tendons within the densely reinforced, massive reinforcement cage is a key technical difficulty in installing curved prestressed tendons in diaphragm walls. Second, after the reinforcement cage and curved unbonded prestressed tendons are fabricated and installed on a horizontal platform, they still need to be hoisted and vertically inserted into the excavated diaphragm wall trench. During the hoisting process from horizontal to vertical, and during the insertion into the trench and concrete pouring, how to prevent the prestressed tendons from collapsing due to their own weight is a critical challenge. The key technical challenge in installing curved prestressed tendons for diaphragm walls is ensuring that the prestressed tendons maintain their accurate positioning and remain unchanged during dynamic construction, preventing slippage and sag. Third, cast-in-place diaphragm walls often suffer from defects in the density of underwater concrete pouring, which can easily lead to anchorage failure at the fixed ends deeply embedded in the concrete. Improving the reliability of the anchorage at the fixed ends of prestressed tendons in diaphragm walls is also a technical challenge in the construction of unbonded prestressed diaphragm walls. Fourth, because it is difficult to pour dense concrete at the top of the diaphragm wall, the concrete at the prestressing tensioning end needs to be removed and re-poured before tensioning. Effectively protecting the prestressed tendons in the tensioning end section during installation is also a problem that needs to be solved in the construction of prestressed diaphragm walls. Summary of the Invention

[0005] The purpose of this invention is to provide a method for installing and positioning curved unbonded prestressed tendons in diaphragm walls, in order to solve the following technical problems: the problem of inaccurate installation and positioning of curved prestressed tendons in cast-in-place diaphragm walls within densely reinforced steel cages; the problem of curved prestressed tendons slipping due to their own weight during dynamic hoisting and trenching construction, thus failing to maintain the designed curved shape; the problem of ensuring the anchorage reliability of the fixed end of the prestressed tendons in the face of defects in the compaction of underwater concrete in cast-in-place diaphragm walls; and the problem of how to economically and efficiently protect the prestressed tendons in the section of diaphragm wall where the top concrete has been removed and recast.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for installing and positioning unbonded prestressed tendons for curved diaphragm walls, the method comprising:

[0007] S1: Draw the installation and positioning diagram of the curved unbonded prestressed tendons for the diaphragm wall. The installation and positioning diagram of the curved unbonded prestressed tendons includes: a plan view of the prestressed tendons, an elevation view of the prestressed tendons, an elevation view of the prestressed tendons, the sag of the prestressed tendons at the linear control points, and a structural diagram of the tensioning end and the fixed end.

[0008] S2: Cut the prestressed tendons according to the design curve length of the unbonded prestressed tendons for the diaphragm wall, the tensioning operation length at the tensioning end, and the anchorage structure requirements at the fixed end. Then, fabricate the anchorage structure at the fixed end of each unbonded prestressed tendon and insert each unbonded prestressed tendon into a plastic corrugated pipe. Complete the fabrication of the prestressed tendons required for each diaphragm wall in batches according to the project progress. The anchorage structure is a double-anchor combination anchorage structure, including: an embossed anchor at the end of the unbonded prestressed tendon and an extrusion anchor above the embossed anchor.

[0009] S3: After the non-prestressed tendons and the steel bars of the steel cage erecting truss on the pit-facing side of the underground continuous wall are tied and welded, according to the above-mentioned curve unbonded prestressed tendon linear installation positioning diagram, mark the sag of the prestressed tendons at each control point on the diagonal steel bars of the steel cage erecting truss, and weld the prestressed tendon linear positioning bracket steel bars at each marked position.

[0010] S4: According to the prestressed tendon plan layout diagram and the prestressed tendon elevation line positioning diagram, lay all the prestressed tendons on the prestressed tendon line positioning bracket steel bars in sequence, and lay all the prestressed tendons from the bottom of the steel cage to the top of the steel cage.

[0011] S5: After verifying the results of steps S3 and S4 against the curve of the unbonded prestressed tendon linear installation positioning diagram, tie and fix the prestressed tendon to the prestressed tendon linear positioning bracket steel bar.

[0012] S6: According to the curve of the unbonded prestressed tendon linear installation positioning diagram, tie and weld part of the steel bars on the soil-facing side of the steel cage to form the first grid-shaped steel bar support and the second grid-shaped steel bar support, which respectively fix the plastic corrugated pipe at the top tensioning end of the prestressed tendon and the extrusion anchor at the bottom fixing end of the prestressed tendon.

[0013] S7: Tie the remaining non-prestressed steel bars on the soil-facing side of the steel cage to complete the fabrication and installation of the entire steel cage.

[0014] S8: Carry out the hoisting and placement of the steel reinforcement cage into the trench for the underground continuous wall and the underwater concrete pouring construction.

[0015] Optionally, in the method for installing and positioning unbonded prestressed tendons for diaphragm wall curves, step S2 further includes the following step:

[0016] The embossed anchors of two adjacent prestressed tendons are staggered in the longitudinal direction.

[0017] Optionally, in the aforementioned method for installing and positioning unbonded prestressed tendons for diaphragm walls, step S3, the process of welding the prestressed tendon linear positioning bracket reinforcement at each marked position, includes the following steps:

[0018] The linear positioning bracket steel bars are horizontally inserted through the diaphragm wall steel cage and welded to the vertical truss, and the linear positioning bracket steel bars are perpendicular to the longitudinal non-prestressed main bars of the diaphragm wall and the vertical truss.

[0019] Optionally, in the installation and positioning method of the unbonded prestressed tendons of the underground continuous wall curve, the plastic corrugated pipe is a flat plastic corrugated pipe.

[0020] Optionally, in the aforementioned method for installing and positioning unbonded prestressed tendons for diaphragm walls, in step S2, the fabrication process of each prestressed tendon includes the following steps:

[0021] A predetermined number of unbonded prestressed tendons are grouped together to form a prestressed bundle;

[0022] A plastic corrugated pipe is fitted onto the outside of each prestressed tendon.

[0023] Optionally, in the method for installing and positioning unbonded prestressed tendons for diaphragm wall curves, the predetermined number ranges from 3 to 5 tendons.

[0024] Optionally, in the aforementioned method for installing and positioning unbonded prestressed tendons for diaphragm walls, step S4, which involves sequentially laying all prestressed tendons onto the reinforcing bars of the prestressed tendon linear positioning bracket, includes the following steps:

[0025] All prestressed tendons are laid on the prestressed tendon linear positioning support steel bars at predetermined intervals.

[0026] Optionally, in the installation and positioning method of the unbonded prestressed tendons for the underground continuous wall curve, in S5, the prestressed tendons are tied and fixed to the prestressed support reinforcement based on the reinforcement clips.

[0027] Optionally, in the method for installing and positioning unbonded prestressed tendons for diaphragm wall curves, in step S6, after forming the first grid-shaped reinforcement support and the second grid-shaped reinforcement support, the following step is further included:

[0028] Seal the top port of the plastic corrugated pipe of each prestressed tendon with waterproof tape;

[0029] Seal the bottom port of the plastic corrugated pipe of each prestressed tendon with waterproof tape.

[0030] Optionally, in the installation and positioning method of the unbonded prestressed tendons of the underground continuous wall, the diameter range of the prestressed tendon linear positioning bracket reinforcement is 18-20mm.

[0031] In the installation and positioning method of unbonded curved prestressed tendons for diaphragm walls provided by this invention, a pre-drawn linear installation and positioning diagram of unbonded curved prestressed tendons for diaphragm walls is used as the construction drawing for the installation and positioning of unbonded curved prestressed tendons. The corresponding construction method is adopted to carry out the precise installation and positioning of unbonded curved prestressed tendons for cast-in-place diaphragm walls. This method can achieve accurate and reliable linear positioning of unbonded curved prestressed tendons during the construction of cast-in-place prestressed diaphragm walls. On the one hand, processing the curved unbonded prestressed tendons into prestressed strands and then attaching plastic corrugated pipes to the prestressed strands not only effectively prevents the prestressed tendons from slipping due to their own weight during the dynamic process of hoisting and placing the steel cage into the trench, ensuring the accuracy of the linear installation and positioning of the curved unbonded prestressed tendons, but also protects the unbonded prestressed tendons in the sections where the concrete at the tensioning end needs to be removed and recast. In addition, the anchorage structure at the fixed end of each unbonded prestressed tendon is a double anchorage structure of extrusion anchor and embossed anchor, which effectively improves the reliability of the anchorage at the fixed end of the unbonded prestressed tendons, solves the problem of prestressed tendon anchorage quality caused by the density defects of underwater concrete pouring in cast-in-place diaphragm walls, and is convenient, economical and efficient in construction.

[0032] On the other hand, the use of flat corrugated pipes in plastic corrugated pipes effectively increases the lever arm and effect of prestressing tendons. Attached Figure Description

[0033] The above and other objects, features and advantages of this disclosure will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0034] Figure 1 This is an elevation view of the unbonded prestressed tendons of a diaphragm wall in one embodiment of the present invention.

[0035] Figure 2 This is a schematic elevation view of the fixed end of the unbonded prestressed tendon of the underground continuous wall curve in one embodiment of the present invention.

[0036] Figure 3 This is a vertical alignment diagram of the unbonded prestressed tendon in one embodiment of the present invention;

[0037] Figure 4 yes Figure 3 Cross-sectional view of the fixed end;

[0038] Figure 5 yes Figure 3 Cross-sectional view along the AA direction;

[0039] Figure 6 yes Figure 3 Cross-sectional view along the BB direction;

[0040] Figure 7 It is a cross-sectional schematic diagram of the installation of the steel cage truss and curved unbonded prestressed tendons for the underground continuous wall.

[0041] Figure 8 It is a three-dimensional schematic diagram of the installation of the steel cage truss and curved unbonded prestressed tendons for the underground continuous wall;

[0042] Figure 9 This is a flowchart of a method for installing and positioning unbonded prestressed tendons for a continuous underground wall curve, according to an embodiment of the present invention.

[0043] In the picture:

[0044] 1-Diaphragm wall; 2-Unbonded prestressed tendon; 3-Plastic corrugated pipe; 4-Extrusion anchor; 5-Embossed anchor; 6-Prestressed tendon linear positioning support reinforcement; 7-Reinforced cage truss; 8-Prestressed tendon. Detailed Implementation

[0045] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a method for installing and positioning unbonded prestressed tendons for curved diaphragm walls according to the present invention. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0046] Please refer to Figures 1 to 9 The installation and positioning method for the unbonded prestressed tendons of the underground continuous wall curve includes the following steps:

[0047] First, such as Figure 1 , Figure 2 and Figure 3 As shown, step S1 is executed to draw the linear installation and positioning diagram of the unbonded prestressed tendons of the underground continuous wall 1. The linear installation and positioning diagram of the unbonded prestressed tendons includes: a planar layout diagram of the prestressed tendons, an elevation layout diagram of the prestressed tendons, a linear positioning diagram of the prestressed tendons on the elevation, a sag diagram of the prestressed tendons at the linear control points, a structural diagram of the tensioning end, and a structural diagram of the fixing end.

[0048] Next, as Figure 3 , Figure 5 and Figure 6 As shown, in step S2, materials are cut according to the design curve length, tensioning operation length at the tensioning end, and anchorage requirements at the fixed end of the unbonded prestressing tendons 2 of the diaphragm wall 1. Then, the anchorage structures at the fixed ends of the unbonded prestressing tendons 2 are fabricated one by one, and each unbonded prestressing tendon is inserted into a plastic corrugated pipe. The fabrication of the prestressing tendons 8 required for each diaphragm wall is completed in batches according to the project progress; where, as... Figure 2 and Figure 4As shown, the anchoring structure is a double-anchor combination anchoring structure, including: a embossed anchor 5 located at the end of the unbonded prestressing tendon 2 and a squeeze anchor 4 located above the embossed anchor 5. The embossed anchors of two adjacent prestressing tendons are staggered in the longitudinal direction to facilitate construction operations and to ensure the compaction of the ground wall concrete.

[0049] To address the issue of insufficient compaction in underwater concrete pouring for cast-in-place diaphragm walls, this invention employs a double-anchor structure (double insurance) for the fixed end of the unbonded prestressing tendons, using an extrusion anchor 4 and a embossed anchor 5. The embossed anchor is located at the end of the unbonded prestressing tendon, while the extrusion anchor is positioned above it. This not only effectively improves the reliability of the anchorage at the fixed end of the unbonded prestressing tendons in the cast-in-place diaphragm wall, thus ensuring the construction quality of the curved unbonded prestressing tendons in the diaphragm wall, but also facilitates construction and operation, resulting in significant economic and social benefits.

[0050] Specifically, the fabrication process of each prestressed tendon 8 includes the following steps:

[0051] S21: A predetermined number of unbonded prestressing tendons 2 are grouped together to form a prestressed bundle; preferably, the predetermined number is 3 to 5 tendons, and in this embodiment, the predetermined number is preferably 3 tendons, that is, a prestressed bundle includes three unbonded prestressing tendons 2.

[0052] S22: A plastic corrugated pipe 3 is sleeved on the outside of each prestressed tendon to ensure accurate linear positioning of the unbonded prestressed tendon 2 and meet design requirements, while preventing sagging and slippage due to the self-weight of the unbonded prestressed tendon 2 during subsequent hoisting and placement of the reinforcing cage. Preferably, to increase the lever arm and effect of the prestressed tendon, the plastic corrugated pipe 3 is a flat plastic corrugated pipe, and correspondingly, a flat anchor is used for anchoring at the tensioning end. In addition, the flat plastic corrugated pipe sleeved on each prestressed tendon can also effectively protect the unbonded prestressed tendon 2 in the section where the concrete at the tensioning end needs to be removed and re-poured.

[0053] Next, as Figure 3 , Figure 7 and Figure 8 As shown, in step S3, after the non-prestressed tendons of the diaphragm wall's steel cage facing the pit and the steel cage frame 7 are tied and welded, according to the curved unbonded prestressed tendon linear installation positioning diagram, the sag of the prestressed tendons at each control point is marked on the diagonal steel bars of the steel cage frame 7, and the prestressed tendon linear positioning bracket steel bars 6 are welded at each marked position. The specific welding process is as follows: the linear positioning bracket steel bars are horizontally inserted through the diaphragm wall steel cage and welded to the vertical truss, and the linear positioning bracket steel bars are perpendicular to the longitudinal non-prestressed main reinforcement of the diaphragm wall and the vertical truss.

[0054] In this embodiment, the diameter of the prestressed tendon linear positioning bracket steel bar 6 is preferably in the range of 18-20mm, and the steel bar type is HRB400 hot-rolled steel bar.

[0055] Next, as Figure 1 , Figure 5 and Figure 6 As shown, in step S4, according to the prestressed tendon plan layout diagram and the prestressed tendon elevation alignment positioning diagram, all prestressed tendons are laid on the prestressed tendon alignment positioning bracket reinforcement. All prestressed tendons are laid from the bottom to the top of the reinforcement cage. The process of laying all prestressed tendons on the prestressed tendon alignment positioning bracket reinforcement includes the following steps:

[0056] like Figure 1 As shown, all prestressed tendons 8 are laid on the prestressed tendon linear positioning bracket reinforcement at predetermined intervals a; wherein, predetermined interval a is determined by design calculations; each prestressed tendon is threaded from bottom to top of the reinforcement cage of the diaphragm wall 1, and each prestressed tendon is laid and installed according to the prestressed tendon elevation linear positioning diagram. Since the position of the prestressed tendon linear positioning bracket reinforcement is the position of the curved positioning point, all prestressed tendons laid and fixed on the prestressed tendon linear positioning bracket reinforcement exhibit a curved distribution.

[0057] Next, step S5 is executed. After verifying the results of steps S3 and S4 against the installation positioning diagram of the unbonded prestressed tendon curve (i.e., verifying the planar position of the prestressed tendon and the sag of each control point of the elevation curve with the installation positioning diagram of the unbonded prestressed tendon curve to ensure that the installation results meet the design requirements), the prestressed tendon is tied and fixed to the prestressed support reinforcement. In this embodiment, the prestressed tendon and the prestressed support reinforcement are tied and fixed based on the reinforcement clips. The reinforcement clips are actually tied to the plastic corrugated pipe 3 covering the prestressed tendon, indirectly tying and fixing the prestressed tendon and the prestressed support reinforcement to achieve a stable connection between the two.

[0058] Next, please refer to Figure 1 , Figure 3 and Figure 4In step S6, according to the curved unbonded prestressed tendon linear installation positioning diagram, some of the reinforcing bars on the soil-facing side of the reinforcing cage are tied and welded to form a first grid-shaped reinforcing bar support and a second grid-shaped reinforcing bar support, respectively fixing the plastic corrugated pipe at the top tensioning end of the prestressed tendon and the extrusion anchor at the bottom fixing end of the prestressed tendon. Specifically, the plastic corrugated pipe at the tensioning end is fixed by the first grid-shaped reinforcing bar support to ensure that the position of the prestressed tendon at the tensioning end does not shift during concrete pouring. Then, the top port of the plastic corrugated pipe of each prestressed tendon is sealed / closed with waterproof tape. The extrusion anchor 4 at the bottom fixing end of the prestressed tendon is fixed by the second grid-shaped reinforcing bar support to ensure that the position of the fixing end meets the design requirements and does not shift during concrete pouring. Then, the bottom port of the plastic corrugated pipe of each prestressed tendon is sealed / closed with waterproof tape.

[0059] Next, proceed to step S7 to tie the remaining non-prestressed steel bars on the soil-facing side of the steel cage and complete the fabrication and installation of the entire steel cage.

[0060] Next, step S8 is executed to hoist the underground continuous wall reinforcement cage into the trench and carry out underwater concrete pouring.

[0061] It should be noted that, for the sake of simplicity, the aforementioned method embodiments are described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps may be performed in other orders or simultaneously.

[0062] Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by this application.

[0063] In summary, the installation and positioning method for unbonded curved prestressed tendons in a diaphragm wall provided by this invention uses a pre-drawn linear installation and positioning diagram of the unbonded curved prestressed tendons in the diaphragm wall as the construction drawing for the installation and positioning of the unbonded curved prestressed tendons. Combined with corresponding construction steps, this method ensures accurate installation and positioning of the unbonded curved prestressed tendons, effectively guaranteeing that the linear positioning of the unbonded curved prestressed tendons in the diaphragm wall is accurate and remains unchanged during installation, hoisting of the reinforcing cage into the trench, and underwater concrete pouring.

[0064] On the other hand, the unbonded curved prestressed tendons are processed into prestressed strands, and flat plastic corrugated pipes are attached to the prestressed strands to effectively prevent the prestressed tendons from slipping due to their own weight during the hoisting and placement of the steel cage. This not only ensures the accuracy of the linear installation and positioning of the unbonded curved prestressed tendons, but also increases the lever arm and effect of the prestressed tendons.

[0065] On the other hand, the anchorage structure at the fixed end of each unbonded prestressed tendon is a double anchorage structure including extrusion anchor and embossed anchor, which effectively improves the reliability of the anchorage at the fixed end of the unbonded prestressed tendon and solves the problem of the compactness defect of underwater concrete pouring in cast-in-place diaphragm walls.

[0066] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method for installing and positioning unbonded prestressed tendons for curved diaphragm walls, characterized in that, include: S1: Draw the installation and positioning diagram of the curved unbonded prestressed tendons for the diaphragm wall. The installation and positioning diagram of the curved unbonded prestressed tendons includes: a plan view of the prestressed tendons, an elevation view of the prestressed tendons, an elevation view of the prestressed tendons, a sag of the prestressed tendons at the linear control points, a tensioning end structure view, and a fixing end structure view. S2: Based on the design curve length, tensioning operation length at the tensioning end, and anchorage requirements at the fixed end of the unbonded prestressed tendons for the diaphragm wall, the tendons are cut to size. Then, the anchorage structures at the fixed ends of each unbonded prestressed tendon are fabricated, and each tendon is inserted into a corrugated plastic pipe. The fabrication of the prestressed tendons required for each diaphragm wall is completed in batches according to the project schedule. The anchorage structure is a double-anchor combination, including: an embossed anchor at the end of the unbonded prestressed tendon and an extrusion anchor above the embossed anchor. The fabrication process for each prestressed tendon includes the following steps: A predetermined number of unbonded prestressed tendons are grouped together to form a prestressed bundle; A plastic corrugated pipe is fitted onto the outside of each prestressed tendon; S3: After the non-prestressed tendons and the steel bars of the steel cage erecting truss on the pit-facing side of the underground continuous wall are tied and welded, according to the above-mentioned curve unbonded prestressed tendon linear installation positioning diagram, mark the sag of the prestressed tendons at each control point on the diagonal steel bars of the steel cage erecting truss, and weld the prestressed tendon linear positioning bracket steel bars at each marked position. S4: According to the prestressed tendon plan layout diagram and the prestressed tendon elevation line positioning diagram, lay all the prestressed tendons on the prestressed tendon line positioning bracket steel bars in sequence, and lay all the prestressed tendons from the bottom of the steel cage to the top of the steel cage. S5: After verifying the results of steps S3 and S4 against the curve of the unbonded prestressed tendon linear installation positioning diagram, tie and fix the prestressed tendon to the prestressed tendon linear positioning bracket steel bar. S6: According to the curve of the unbonded prestressed tendon linear installation positioning diagram, tie and weld part of the steel bars on the soil-facing side of the steel cage to form the first grid-shaped steel bar support and the second grid-shaped steel bar support, which respectively fix the plastic corrugated pipe at the top tensioning end of the prestressed tendon and the extrusion anchor at the bottom fixing end of the prestressed tendon. S7: Tie the remaining non-prestressed steel bars on the soil-facing side of the steel cage to complete the fabrication and installation of the entire steel cage. S8: Carry out the hoisting and placement of the reinforcement cage into the trench for the underground continuous wall and the underwater concrete pouring construction.

2. The installation and positioning method for unbonded prestressed tendons of a diaphragm wall as described in claim 1, characterized in that, S2 also includes the following steps: The embossed anchors of two adjacent prestressed tendons are staggered in the longitudinal direction.

3. The installation and positioning method for unbonded prestressed tendons of a diaphragm wall as described in claim 1, characterized in that, In S3, the process of welding the prestressed tendon linear positioning bracket reinforcement at each marked location includes the following steps: The linear positioning bracket steel bars are horizontally inserted through the diaphragm wall steel cage and welded to the vertical truss, and the linear positioning bracket steel bars are perpendicular to the longitudinal non-prestressed main bars of the diaphragm wall and the vertical truss.

4. The installation and positioning method for unbonded prestressed tendons of a diaphragm wall as described in claim 1, characterized in that, The plastic corrugated pipe is a flat plastic corrugated pipe.

5. The installation and positioning method for unbonded prestressed tendons of a diaphragm wall as described in claim 1, characterized in that, The predetermined quantity ranges from 3 to 5 pieces.

6. The method for installing and positioning unbonded prestressed tendons for curved diaphragm walls as described in claim 1, characterized in that, In S4, the process of sequentially laying all prestressed tendons on the prestressed tendon linear positioning support reinforcement includes the following steps: All prestressed tendons are laid on the prestressed tendon linear positioning support steel bars at predetermined intervals.

7. The installation and positioning method for unbonded prestressed tendons of a diaphragm wall as described in claim 1, characterized in that, In S5, the prestressed tendons are tied and fixed to the prestressed support reinforcement based on the rebar clips.

8. The method for installing and positioning unbonded prestressed tendons for curved diaphragm walls as described in claim 1, characterized in that, In S6, after forming the first grid-shaped rebar support and the second grid-shaped rebar support, the following steps are also included: Seal the top port of the plastic corrugated pipe of each prestressed tendon with waterproof tape; Seal the bottom port of the plastic corrugated pipe of each prestressed tendon with waterproof tape.

9. The method for installing and positioning unbonded prestressed tendons for curved diaphragm walls as described in any one of claims 1 to 8, characterized in that, The diameter range of the prestressed tendon linear positioning support steel bar is 18-20mm.

Images