Prestressed concrete construction method for full-capacity low-temperature storage tank and low-temperature storage tank

Abstract

The invention discloses a full-capacity low-temperature storage tank prestressed concrete construction method and a low-temperature storage tank, and relates to the field of petrochemical engineering low-temperature storage tank construction.The full-capacity low-temperature storage tank prestressed concrete construction method comprises the steps that a medium pipeline is installed on a bearing platform reinforcing mesh, and a heat preservation medium is connected into the medium pipeline after bearing platform pouring is completed; the temperature control index of the bearing platform concrete is controlled in the solidification process of the bearing platform concrete; mounting a storage tank wall reinforcing mesh on the bearing platform, and mounting a positioning bracket and an embedded part on the positioning bracket on the storage tank wall reinforcing mesh; the storage tank wall is poured; and a dome steel vault mold located at the top of the storage tank wall is erected, and when dome concrete is poured, a closed space formed by the storage tank wall and the dome steel vault mold is controlled to be kept in a preset positive pressure state. The core temperature index in the concrete solidification process of the bearing platform can be controlled, and displacement of the embedded part during vibration is reduced through the positioning support.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of construction of petrochemical low-temperature storage tanks, and in particular to a prestressed concrete construction method for full-capacity low-temperature storage tanks and a low-temperature storage tank. BACKGROUND

[0002] In the construction of petrochemical low-temperature storage tanks, the original construction method takes "zoned control, modular construction, and special equipment support" as the core logic, and realizes the prestressed concrete construction of a full-capacity low-temperature storage tank (with a capacity of more than 100,000 m3, storing low-temperature medium such as LNG, LPG, and liquid ethane) by means of jump-pit pouring (interval ≥ 7 days) of the pile cap, ground precast modular hoisting of the wall steel reinforcement, wall formwork climbing form construction, steel dome + air pressure (9 KPa), and prestressed tendon tensioning and grouting, which meets the air tightness and structural pressure requirements of low-temperature medium storage.

[0003] However, the pile cap is made of C40 concrete (1.2 m thick and 88.4 m in diameter), and although the jump-pit method is used, it only relies on covering and curing. When pouring in summer, the central temperature rise value is easy to exceed 50℃, and the inside-outside temperature difference is easy to exceed 25℃, which is easy to produce harmful cracks. At the same time, during the pouring of the outer wall, the vertical and circumferential embedded parts of the outer wall are only fixed by iron wire binding + steel reinforcement bracing, and are easy to be affected by the displacement of the vibrating during pouring (allowable deviation: the center line of the inner embedded part ≤ 15 mm), which leads to the deviation of the connection between the inner lining plate and the embedded part. SUMMARY

[0004] The present application provides a prestressed concrete construction method for a full-capacity low-temperature storage tank and a full-capacity low-temperature storage tank, which can solve the technical problems in the prior art that the inside-outside temperature difference of the pile cap is large when pouring in summer, which is easy to produce harmful cracks, and at the same time, the vertical and circumferential embedded parts of the outer wall are only fixed by iron wire binding + steel reinforcement bracing, and are easy to be affected by the displacement of the vibrating during pouring, which leads to the deviation of the connection between the inner tank and the embedded part.

[0005] In a first aspect, an embodiment of the present application provides a prestressed concrete construction method for a full-capacity low-temperature storage tank, comprising: installing a medium pipeline on the pile cap steel reinforcement net, and connecting a heat preservation medium in the medium pipeline after the pile cap is poured to control the temperature control index of the pile cap during the solidification of the pile cap concrete; installing a tank wall steel reinforcement mesh on the pile cap, and installing a positioning support on the tank wall steel reinforcement mesh and a embedded part on the positioning support; pouring the tank wall, erecting a dome steel arch top mold at the top of the tank wall, and controlling the closed space formed by the tank wall and the dome steel arch top mold to maintain a predetermined positive pressure state when pouring the dome concrete.

[0006] In combination with the first aspect, in an implementation manner, before the medium pipeline is installed on the pile cap steel reinforcement net, the method further comprises: Construction support short column, and based on the bearing platform block pouring diagram, the bearing platform center cross axis and the bearing platform boundary line are set out; Based on the center cross axis and the bearing platform boundary line, the bearing platform vertical pole, the bearing platform horizontal pole and the continuous scissors support located at the top are erected on the ground between the support short columns to form the formwork support frame of the bearing platform.

[0007] In an embodiment, the medium pipeline installed on the bearing platform reinforcement mesh specifically comprises: Based on the design drawing, the bearing platform bottom layer reinforcement mesh on the bearing platform protection layer cushion block is installed; The medium pipeline is bundled on the bearing platform bottom layer reinforcement mesh, and the two ends of the medium pipeline extend out of the bearing platform projection area; The bearing platform formwork, the bearing platform top layer reinforcement mesh located between the bearing platform bottom layer reinforcement mesh and the bearing platform top layer reinforcement mesh, and the bearing platform pouring are sequentially installed.

[0008] In an embodiment, after the bearing platform pouring is completed, the heat preservation medium is accessed into the medium pipeline to control the bearing platform temperature control index during the bearing platform concrete solidification process, specifically comprising: After the bearing platform pouring is completed, the temperature of the temperature monitoring point arranged on the bearing platform is measured, and the temperature of the temperature monitoring point is obtained, wherein the temperature monitoring point comprises an outer surface temperature monitoring point, a bottom surface temperature monitoring point and a center temperature monitoring point; The end of the medium pipeline extending out of the bearing platform projection area is connected with a circulating water pump, and the circulating water pump is controlled to access the heat preservation medium into the medium pipeline; Based on the temperature of the temperature monitoring point, the flow of the heat preservation medium in the medium pipeline is adjusted to make the bearing platform temperature control index within the allowable temperature difference range, wherein the bearing platform temperature control index comprises the bearing platform inner surface temperature difference, the cooling rate and the bearing platform surface and atmospheric temperature difference.

[0009] In an embodiment, the bearing platform wall body reinforcement mesh on the storage tank is installed, and the positioning support and the embedded part on the positioning support are installed on the bearing platform wall body reinforcement mesh, specifically comprising: The auxiliary wind-resistant column and the storage tank wall body reinforcement mesh are installed, and the storage tank wall body protection layer cushion block is installed on the storage tank wall body reinforcement mesh; The positioning support located on the storage tank wall body reinforcement mesh and the embedded part on the positioning support are installed, wherein the embedded part comprises a vertical embedded part and a ring-shaped embedded plate, the positioning support comprises a vertical positioning plate, an anchor bolt penetrating through both ends of the vertical positioning plate, and an adjusting steel plate located on the anchor bolt and capable of reciprocating along the anchor bolt.

[0010] In an embodiment, for the installation of the vertical embedded part, specifically comprising: The installation position of the vertical embedded part is set out on the storage tank wall body reinforcement mesh; The vertical embedded parts are temporarily tied to the steel mesh of the tank wall, and the installation position, elevation and verticality of the vertical embedded parts are verified. After verification, the vertical embedded parts and the steel mesh of the tank wall will be tied and fixed.

[0011] In one embodiment, the installation of the circumferential embedded plate specifically includes: Temporarily bind the circumferential embedded plate to the steel mesh of the tank wall, and install the vertical positioning plate on the circumferential embedded plate so that the through end of the anchor bolt abuts against the steel mesh of the tank wall; Verify the position of the circumferential embedded plate and weld the anchor bolts to the steel mesh of the tank wall; Rotate the adjusting steel plate until it abuts against the circumferential embedded plate.

[0012] In one embodiment, prior to the installation of the circumferential embedded plate, the method further includes: Install prestressed corrugated pipe ducts located within the steel mesh of the tank wall. The corrugated pipe ducts are connected by butt joints, and heat shrink tubing is fitted at the butt joints of the corrugated pipe ducts. After shrinking the heat shrink tubing, perform a ball-passing inspection on the corrugated pipe.

[0013] In one embodiment, the pouring of the tank wall involves erecting a dome-shaped steel arch mold located at the top of the tank wall, and during the pouring of the dome concrete, maintaining a predetermined positive pressure in the enclosed space formed by the tank wall and the dome-shaped steel arch mold, specifically including: A tank wall mold is erected along the steel mesh of the tank wall, and concrete is poured into the outer wall mold to form the tank wall; A ring beam is installed on the top of the tank wall after the concrete has solidified. A dome support system is then erected on the ring beam, and a welded skin plate is laid on the dome support system to form a dome steel arch mold. Install a pressure monitoring system and inflate the sealed space formed by the tank wall and the dome steel arch mold to achieve a predetermined positive pressure state in the sealed space. Concrete is poured into the dome steel arch mold. During the pouring process, the pressure monitoring system continuously monitors the air pressure in the sealed space. When the air pressure in the sealed space is lower than the preset air pressure value, an air replenishment action is performed to control the sealed space to maintain a predetermined positive pressure state.

[0014] Secondly, this application provides a fully containment cryogenic storage tank, which is constructed using the aforementioned prestressed concrete construction method for fully containment cryogenic storage tanks.

[0015] The beneficial effects of the technical solutions provided in this application include: 1. By pre-embedding medium pipes inside the foundation and dynamically introducing insulation medium, the temperature difference between the inside and outside of the large-volume concrete during the solidification process is precisely controlled. This method can directly control key temperature control indicators such as the temperature difference between the inside and outside of the foundation and the cooling rate, thereby significantly reducing the risk of harmful cracks when pouring the foundation in high-temperature summer conditions, thus ensuring the integrity of the foundation structure and its long-term safety. 2. By setting up a special positioning bracket that is integrated with the steel mesh of the tank wall and fixing the embedded parts to the rigid bracket, the isolated embedded parts are connected and fixed in a stable and integral rigid frame. When the concrete flows and the impact load generated by the vibrator acts on a certain embedded part, the load will be quickly distributed and transferred to the entire support system through the bracket and borne by the multi-point support of the bracket, thus avoiding the movement of the embedded parts due to local stress. 3. By injecting and maintaining a predetermined air pressure into the sealed space formed by the tank wall, dome mold and foundation, the air pressure provides uniform vertical support to the dome mold and the wet concrete above. It can dynamically maintain stable air pressure throughout the pouring and curing process, and can automatically compensate for minor pressure fluctuations caused by temperature changes and concrete shrinkage, thus avoiding the impact of sudden pressure changes on the unhardened concrete structure. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0017] Figure 1 A schematic diagram of a prestressed concrete construction method for a fully containment cryogenic storage tank is provided for this application; Figure 2 A schematic diagram of the fixed support structure in a prestressed concrete construction method for a fully containment cryogenic storage tank provided in this application.

[0018] In the diagram: 1. Vertical positioning plate; 2. Anchor bolts; 3. Adjusting steel plate. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0020] Firstly, this application provides a prestressed concrete construction method for a full-containment cryogenic storage tank, which can solve the technical problems existing in the prior art where the temperature difference between the inside and outside of the foundation is large during summer pouring, which easily leads to harmful cracks. At the same time, the external wall vertical and the embedded parts are only fixed by wire binding and steel bar support, which are easily affected by vibration during concrete pouring, resulting in the connection deviation between the inner tank and the embedded parts.

[0021] Figure 1 A prestressed concrete construction method for a fully containment cryogenic storage tank, provided in this application embodiment, specifically includes: S1: Install medium pipelines on the reinforcing mesh of the foundation and connect the insulation medium to the medium pipelines after the foundation is poured to control the temperature index of the foundation during the concrete solidification process; before the foundation is poured, the medium pipelines are tied to the reinforcing mesh of the foundation. After the foundation concrete is poured, the insulation medium, which is circulating water, is connected to the medium pipelines. Then, during the concrete solidification process, the preset temperature monitoring points on the foundation are monitored regularly. By observing the temperature at the temperature monitoring points, the temperature difference is calculated, and the flow rate of the circulating water in the medium pipelines is controlled to ensure that the temperature difference of each part of the foundation is within the design range, thereby reducing the risk of foundation cracking. S2: Install the steel mesh of the tank wall on the foundation, and install the positioning bracket and the embedded parts on the steel mesh of the tank wall. After the foundation concrete has solidified and stabilized, install the steel mesh of the tank wall, and install the positioning bracket and the embedded parts on the upper part of the embedded parts as required.

[0022] S3: The tank wall is poured, and a dome-shaped steel arch mold is erected at the top of the tank wall. During the pouring of the dome concrete, the sealed space formed by the tank wall and the dome-shaped steel arch mold is maintained at a predetermined positive pressure. First, the tank wall construction is completed and reaches the design strength. At the top of the tank wall, the dome-shaped steel arch mold is installed. Positive pressure air is injected into the sealed space formed by the tank wall, the dome-shaped steel arch mold, and the tank bottom to counteract the downward loads from the concrete, formwork, and reinforcing steel during pouring, ensuring the entire system is in a state of stress balance. During pouring, the pressure in the sealed space is continuously monitored. When the pressure in the sealed space falls below the preset pressure, air is automatically replenished through a pre-set pressure-maintaining system.

[0023] Specifically, before installing the media pipelines on the steel reinforcement mesh of the foundation, the following steps are also included: Construction supports short columns, and based on the block casting diagram of the foundation, the central cross axis and edge lines of the foundation are laid out; Based on the central cross axis and the edge line of the foundation, foundation uprights, foundation horizontal bars, and continuous scissor bracing at the top are erected on the ground between the supporting short columns to form the formwork support frame for the foundation.

[0024] The foundation is an elevated structure, erected above the reinforced concrete supporting columns of the lower structure. According to the block pouring diagram of the foundation, the central cross axis and edge line of the foundation are marked on the concrete floor. The formwork support system is erected according to the safety calculation parameters. The formwork support system is mainly used to replace the supporting columns to bear pressure during construction and is dismantled after construction is completed, so that the fulcrum is converted into supporting columns.

[0025] In one implementation, the uprights are made of Q355 material with a standard φ48×3.2mm wheel buckle plate. The maximum spacing is 900mm horizontally and 900mm vertically. When the column edge does not meet the erection spacing, the erection spacing of the uprights is reduced to 600mm or 300mm according to the actual situation. A pad is placed at the bottom of each upright. The horizontal bars are connected by buckle plates. Continuous scissor bracing is set at the top, with a scissor bracing interval of 6 steps. The panel is made of 15mm thick plywood. During installation, the gaps and misalignments between the panels are controlled. The panels are laid in sections according to the area. After completion, the counterweight of the tower crane is used to perform a counterweight pressure test on the panel. The test counterweight is 120% of the load on the area of ​​the counterweight block in contact with the panel. After 24 hours of pressure test, the settlement is observed to be less than 2mm (excluding measurement error), which meets the specification requirements. After acceptance, the next process is carried out. Of course, in addition to the above components, it also includes adjustable supports, main and secondary keels and panels, which are all commonly used components in the existing support system, and will not be described in detail here.

[0026] Furthermore, the installation of the medium pipeline in S1 specifically includes: S101: Based on the design drawings, install the foundation protective layer pad block and the bottom steel mesh of the foundation on the foundation protective layer pad block; S102: Tie the medium pipeline to the bottom steel mesh of the foundation, and make the two ends of the medium pipeline extend beyond the projected area of ​​the foundation. S103: Install the foundation formwork, the stirrups between the bottom and top reinforcement meshes of the foundation, and the top reinforcement mesh of the foundation in sequence, and then pour the foundation.

[0027] Before processing, the reinforcing bars are prepared according to the design drawings and current specifications. They are then centrally processed and prefabricated at the prefabrication yard, transported to the site for installation and binding. The protective layer spacers for the foundation are made of 1:2 cement mortar, with a length of 150~250mm, a width of 25~35mm, and a thickness according to the design drawings. The foundation has multiple layers of reinforcing mesh, with reinforcing bar supports between the upper and lower layers of mesh, spaced 1.5m apart, arranged in a quincunx pattern. Multiple media pipes are pre-embedded between the layers of reinforcing mesh in the foundation, spaced 1.5m apart, and arranged in a quincunx pattern. The media pipes extend 500mm beyond the foundation at both ends and are connected to the circulating water pump. The media pipes are fixed to the reinforcing mesh of the foundation with tie wire. Subsequently, the foundation formwork is arranged and the foundation is poured. The foundation is divided into five areas and poured using the skip-pour method. The time interval between concrete pours in adjacent areas is no less than 7 days, and the temperature of the poured concrete is controlled below 30℃.

[0028] Furthermore, before the foundation is poured, adjustable U-shaped steel bars are welded onto the stirrups. The elevation of the bottom of the U-groove is measured using a level, and the height of the screw rods is adjusted to make the bottom elevation of the U-groove consistent. Galvanized square steel is laid on the U-shaped steel bars as a leveling reference for the concrete. The upper surface of the galvanized square steel is the finished surface of the concrete pouring. According to the layout of the stirrups, the square steel is arranged at 3m intervals along the entire length to ensure that the overall flatness of the foundation concrete meets the design and specification requirements.

[0029] Furthermore, the specific control of the temperature control index of the foundation in S1 includes: S104: After the foundation is poured, the temperature monitoring points arranged on the foundation are measured and the temperature of the temperature monitoring points is obtained. The temperature monitoring points include the outer surface temperature monitoring point, the bottom surface temperature monitoring point and the center temperature monitoring point. S105: The end of the medium pipeline extending beyond the projected area of ​​the foundation is connected to a circulating water pump, and the circulating water pump is controlled to enter the insulation medium into the medium pipeline. S106: Based on the temperature of the temperature monitoring point, adjust the flow rate of the insulation medium in the medium pipeline so that the temperature control index of the foundation is within the allowable temperature difference range. The temperature control index of the foundation includes the temperature difference between the inner and outer surfaces of the foundation, the cooling rate of the foundation, and the temperature difference between the surface of the foundation and the ambient temperature.

[0030] After the foundation is poured, select external temperature measurement points, bottom temperature measurement points, and center temperature measurement points on the foundation surface. The external temperature measurement points are located on the outer surface of the foundation concrete, directly in contact with the environment. The bottom temperature measurement points can be pre-arranged before pouring. They are located at the bottom of the foundation, close to the base or cushion layer, embedded 5-10 cm above the bottom of the foundation, or fixed to the bottom reinforcement. The center temperature measurement point can also be pre-arranged. It is located at the geometric core and thermal center of the foundation concrete, at 1 / 2 the height of the foundation thickness, in the central area of ​​the plane position, to monitor the highest temperature inside the concrete.

[0031] After the foundation is poured, 20°C circulating water is immediately introduced into the medium channel. Temperature parameters such as the center temperature, surface-to-interior temperature difference, cooling rate, and temperature difference with the environment are monitored using a thermometer. In one possible implementation, the center temperature rise should be ≤50°C, the surface-to-interior temperature difference ≤25°C, and the cooling rate ≤2.0°C / day. The initial water flow rate in the medium channel is set to 1.5 m³ / h. Temperature measurement begins 12 hours after concrete pouring, and temperature curves are plotted. In one implementation, the temperature is measured and recorded every 2 hours for 1-3 days, every 4 hours for 4-7 days, every 8 hours for 7-10 days, and every 12 hours thereafter until the insulation covering is removed. The water flow rate in the medium channel is adjusted based on the monitored surface-to-interior temperature difference and cooling rate of the foundation concrete.

[0032] Furthermore, step S2 specifically includes: S201: Install auxiliary wind-resistant columns and tank wall steel mesh, and install concrete pads on the tank wall steel mesh. The tank wall steel mesh is tied on site. The tank wall steel mesh is orthogonally arranged with vertical and circumferential steel bars. Starting from the second layer, every two layers are made and installed together until the 10th layer. Each tank wall steel mesh is equipped with 3 wind-resistant columns, one on each side of the same steel mesh, shared with adjacent steel meshes, and another wind-resistant column is set in the middle. After the tank wall steel mesh is installed, the buttress column steel bars are installed. First, the vertical steel bars are tied, then the spacing of the horizontal steel bars is marked on the vertical steel bars, and finally the horizontal steel bars are tied to form the buttress column steel bars. The spacing of the tank wall protective layer pads is arranged at a circumferential spacing of 1.5m and a vertical spacing of 1m.

[0033] S202: Install the positioning brackets and embedded parts on the steel reinforcement mesh of the storage tank wall, wherein the embedded parts include vertical embedded parts and circumferential embedded plates, wherein... Figure 2 A schematic diagram of the fixed support structure in the prestressed concrete construction method for a fully containment cryogenic storage tank provided in this application is shown below. Figure 2 As shown, in one possible implementation, the positioning bracket includes a vertical positioning plate 1, anchor bolts 2 penetrating both ends of the vertical positioning plate 1, and an adjusting steel plate 3 located on the anchor bolts 2 and capable of reciprocating along the anchor bolts 2. The ends of the anchor bolts 2 that penetrate the vertical positioning plate 1 are folded back to facilitate hooking back the steel mesh of the tank wall. After assembly, the vertical positioning plate 1 is fitted to the outer periphery of the circumferential embedded plate, and the two anchor bolts 2 are located at the top and bottom of the circumferential embedded plate, respectively, and the hooked ends of the anchor bolts 2 are welded to the steel mesh of the tank wall.

[0034] Specifically, step S202 includes the following construction procedures for vertical embedded parts: S202a1: Lay out the installation positions of the vertical embedded parts on the steel mesh of the tank wall; S202a2: Temporarily tie the vertical embedded parts to the steel mesh of the tank wall, and verify the installation position, elevation and verticality of the vertical embedded parts; S202a3: After verification, the vertical embedded parts and the steel mesh of the tank wall will be tied and fixed.

[0035] First, use wire to temporarily tie the vertical embedded parts to the steel reinforcement mesh of the tank wall at the corresponding position. Then, use a total station to accurately locate and adjust the position, elevation and verticality of the vertical embedded parts to ensure that the deviation meets the design and specification requirements. When the vertical embedded parts conflict with the steel reinforcement mesh of the tank wall, the position of the steel reinforcement at the conflicting part can be adjusted appropriately to prioritize the installation accuracy of the embedded parts. After completion, weld and fix the vertical embedded parts to the corresponding steel reinforcement mesh of the tank wall.

[0036] Furthermore, the installation of the circumferential embedded plate in step S202 specifically includes: S202b1: Based on the design location, temporarily tie the circumferential embedded plate to the predetermined position of the steel mesh of the tank wall, and install the vertical positioning plate 1 on the circumferential embedded plate so that the vertical positioning plate 1 fits against the surface of the circumferential embedded plate, and the through end of the anchor bolt 2 hooks back into the steel mesh of the tank wall. S202b2: Verify the position of the circumferential embedded plate. After temporary fixing, use a total station to accurately measure the elevation and position of the circumferential embedded plate. Adjust it according to the design requirements to meet the design and specification requirements. Then weld the anchor bolts 2 to the steel mesh of the tank wall. S202b3: Rotate the adjusting steel plate 3 until it abuts against the circumferential embedded plate to complete the fixing of the circumferential embedded plate.

[0037] Furthermore, prior to the installation of the circumferential embedded plate, the following also includes: Prestressed corrugated pipe ducts are installed within the steel mesh of the tank wall. The corrugated pipe ducts are connected by butt joints, and heat shrink tubing is fitted at the joints. Prestressed ducts are pre-reserved within the concrete structure of the tank wall to facilitate tensioning and anchoring of prestressing tendons, thereby applying circumferential compressive stress to the tank wall to counteract the tensile force generated by the internal liquid. The corrugated pipes serve as the channels for the prestressing tendons, which are tied to the steel mesh of the tank wall and permanently embedded in the concrete after pouring. Their end joints are tightly butt-jointed. Shrink the heat shrink tubing and use a hot air gun to heat it from the middle to both ends until it is completely shrunken and tightly fitted, thus forming a physical barrier at the interface between the corrugated pipe and the prestressed duct.

[0038] After completing the above sealing treatment and before pouring concrete, use a rubber or plastic ball with a diameter slightly smaller than the inner diameter of the corrugated pipe. Insert it into one end of the corrugated pipe and lead it out from the other end to ensure that the heat does not cause the corrugated pipe to be locally flattened or deformed when the heat shrink tubing is heated. Also, confirm that the corrugated pipe is undamaged, not punctured by steel bars, and does not have inward rolling blockage at the joints.

[0039] Furthermore, step S3 specifically includes: S301: Erect tank wall molds along the steel mesh of the tank wall, pour concrete into the outer wall molds to form the tank wall. Before erecting the tank wall molds, auxiliary systems such as support climbing system, support system, and anchoring system are also installed. Existing common construction methods can be used, and they will not be described in detail here. The tank wall molds include inner molds and outer molds. After being hoisted and fixed by a hoisting system, conventional pouring and tensioning are carried out to finally form the tank wall. S302: Install a ring beam on the top of the solidified tank wall, and erect a dome support system on the ring beam. Lay a welded skin plate on the dome support system to form a dome steel arch mold. After the tank wall reaches the required hardness, construct the ring beam and the dome steel arch mold sequentially. The dome support system in the dome steel arch mold is formed by reinforcing steel binding. The steel reinforcement construction is divided into two main stages from bottom to top. In the first stage, the reinforcing steel is arranged radially towards the center of the dome at 50mm intervals along the circumference. In the second stage, the reinforcing steel is arranged horizontally and vertically at 150mm intervals along the axis. The reinforcing steel in the two stages overlaps by 1500mm. The upper and lower layers of reinforcing steel are supported by stirrups at 1500mm intervals. Concrete spacers are used to ensure the thickness of the protective layer for the reinforcing steel. The number of spacers should be 1 per square meter. Subsequently, a sealed skin plate is welded to the outer perimeter of the dome support system to form a hollow dome steel arch mold.

[0040] S303: Install a pressure monitoring system and inflate the sealed space formed by the tank wall and the dome steel arch mold to achieve a predetermined positive pressure in the sealed space. S304: Pour concrete into the dome steel arch mold, and during the pouring process, the pressure monitoring system continuously monitors the air pressure in the sealed space. When the air pressure in the sealed space is lower than the preset air pressure value, the system performs an air replenishment action to control the sealed space to maintain a predetermined positive pressure state.

[0041] The pressure monitoring system includes an inflation component, a monitoring component, and a replenishment component. The inflation component is primarily used to inflate the sealed space formed by the tank wall and the dome's steel arch mold before pouring, creating a high-pressure environment to counteract the downward loads from the concrete, formwork, and reinforcing steel during subsequent pouring, thus maintaining the entire system in a state of stress balance. The monitoring component continuously monitors the pressure within the sealed space throughout the pouring process. The replenishment component performs replenishment when the pressure in the sealed space falls below a predetermined value. In one possible implementation, the predetermined positive pressure state means that the sealed space is always maintained between 8.5 kPa and 9.5 kPa. When the pressure in the sealed space falls below 8.5 kPa, it automatically replenishes air to between 9 kPa and 9.5 kPa. When it exceeds 9.5 kPa, an alert is issued, and construction personnel release the air. After the dome construction is completed, curing and acceptance procedures are carried out according to standard procedures.

[0042] Secondly, this application provides a cryogenic storage tank, which is constructed using the aforementioned prestressed concrete construction method for a fully containment cryogenic storage tank.

[0043] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0044] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0045] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for constructing a prestressed concrete structure for a fully containment cryogenic storage tank, characterized in that, include: Medium pipes are installed on the reinforcing mesh of the foundation, and insulation medium is introduced into the medium pipes after the foundation is poured, so as to control the temperature control index of the foundation concrete during the solidification process. Install the steel mesh of the tank wall on the pier, and install the positioning bracket and the embedded parts on the positioning bracket on the steel mesh of the tank wall; The tank wall is poured, and a dome steel arch mold is erected on top of the tank wall. When pouring the dome concrete, the sealed space formed by the tank wall and the dome steel arch mold is kept under a predetermined positive pressure.

2. The prestressed concrete construction method for a full-containment cryogenic storage tank as described in claim 1, characterized in that, Before installing the medium pipeline on the steel reinforcement mesh of the foundation, the method further includes: Construction supports short columns, and based on the block casting diagram of the foundation, the central cross axis and edge lines of the foundation are laid out; Based on the central cross axis and the edge line of the foundation, foundation uprights, foundation horizontal bars, and continuous scissor bracing at the top are erected on the ground between the supporting short columns to form the formwork support frame for the foundation.

3. The prestressed concrete construction method for a full-containment cryogenic storage tank as described in claim 2, characterized in that, The medium pipeline installed on the steel reinforcement mesh of the foundation specifically includes: Based on the design drawings, install the foundation protective layer pads and the bottom steel mesh of the foundation on the foundation protective layer pads; The medium pipeline is tied to the bottom steel reinforcement mesh of the foundation, and both ends of the medium pipeline extend beyond the projected area of ​​the foundation. Install the foundation formwork, the stirrups between the bottom and top reinforcement meshes of the foundation, and the top reinforcement mesh of the foundation in sequence, and then pour the foundation.

4. The prestressed concrete construction method for a full-containment cryogenic storage tank as described in claim 3, characterized in that, After the foundation concrete is poured, an insulating medium is introduced into the medium pipeline to control the temperature index of the foundation during the concrete solidification process. Specifically, this includes: After the foundation is poured, the temperature of the temperature monitoring points arranged on the foundation is measured and the temperature of the temperature monitoring points is obtained. The temperature monitoring points include the outer surface temperature monitoring point, the bottom surface temperature monitoring point and the center temperature monitoring point. The end of the medium pipeline extending beyond the projected area of ​​the foundation is connected to a circulating water pump, which controls the circulating water pump to flow into the medium pipeline to receive the insulation medium. Based on the temperature at the temperature monitoring point, the flow rate of the insulation medium in the medium pipeline is adjusted so that the temperature control index of the foundation is within the allowable temperature difference range. The temperature control index of the foundation includes the temperature difference between the inner and outer surfaces of the foundation, the cooling rate, and the temperature difference between the surface of the foundation and the ambient temperature.

5. The prestressed concrete construction method for a fully containment cryogenic storage tank as described in claim 1, characterized in that, The installation of the steel mesh of the tank wall on the mounting platform, and the installation of positioning brackets and embedded parts on the steel mesh of the tank wall, specifically includes: Install auxiliary wind-resistant columns and steel mesh for the tank wall, and install tank wall protective layer pads on the steel mesh for the tank wall; The positioning bracket and the embedded parts on the steel mesh of the tank wall are installed. The embedded parts include vertical embedded parts and circumferential embedded plates. The positioning bracket includes a vertical positioning plate (1), anchor bolts (2) penetrating both ends of the vertical positioning plate (1), and an adjusting steel plate (3) located on the anchor bolts (2) and capable of reciprocating along the anchor bolts (2).

6. The prestressed concrete construction method for a fully containment cryogenic storage tank as described in claim 5, characterized in that, The installation of vertical embedded parts specifically includes: Lay out the installation positions of the vertical embedded parts on the steel mesh of the tank wall; The vertical embedded parts are temporarily tied to the steel mesh of the tank wall, and the installation position, elevation and verticality of the vertical embedded parts are verified. After verification, the vertical embedded parts and the steel mesh of the tank wall will be tied and fixed.

7. The prestressed concrete construction method for a fully containment cryogenic storage tank as described in claim 5, characterized in that, The installation of the circumferential embedded plate specifically includes: Temporarily bind the circumferential embedded plate to the steel mesh of the tank wall, and install the vertical positioning plate (1) on the circumferential embedded plate so that the through end of the anchor bolt (2) abuts against the steel mesh of the tank wall; Verify the position of the circumferential embedded plate and weld the anchor bolts (2) to the steel mesh of the tank wall; Rotate the adjusting steel plate (3) until the adjusting steel plate (3) abuts against the circumferential embedded plate.

8. The prestressed concrete construction method for a fully containment cryogenic storage tank as described in claim 7, characterized in that, Before the installation of the circumferential embedded plate, the following is also included: Install prestressed corrugated pipe ducts located within the steel mesh of the tank wall. The corrugated pipe ducts are connected by butt joints, and heat shrink tubing is fitted at the butt joints of the corrugated pipe ducts. After shrinking the heat shrink tubing, perform a ball-passing inspection on the corrugated pipe.

9. A prestressed concrete construction method for a fully containment cryogenic storage tank as described in claim 1, characterized in that, The process of pouring the tank wall involves erecting a dome-shaped steel arch mold at the top of the tank wall, and maintaining a predetermined positive pressure in the enclosed space formed by the tank wall and the dome-shaped steel arch mold during the pouring of the dome concrete. Specifically, this includes: A tank wall mold is erected along the steel mesh of the tank wall, and concrete is poured into the tank wall mold to form the tank wall. A ring beam is installed on the top of the tank wall after the concrete has solidified. A dome support system is then erected on the ring beam, and a welded skin plate is laid on the dome support system to form a dome steel arch mold. Install a pressure monitoring system and inflate the sealed space formed by the tank wall and the dome steel arch mold to achieve a predetermined positive pressure state in the sealed space. Concrete is poured into the dome steel arch mold. During the pouring process, the pressure monitoring system continuously monitors the air pressure in the sealed space. When the air pressure in the sealed space is lower than the preset air pressure value, an air replenishment action is performed to control the sealed space to maintain a predetermined positive pressure state.

10. A cryogenic storage tank, characterized in that, The cryogenic storage tank is constructed using the prestressed concrete construction method for a full-containment cryogenic storage tank as described in any one of claims 1 to 9.

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