A processing method suitable for super-long non-retractable joint in special environment

Abstract

The application discloses a processing method suitable for super-long non-expansion joint in special environment, and relates to the technical field of railway construction.The processing method suitable for super-long non-expansion joint in special environment comprises the following steps: S1, preparing double-expansion gradient concrete; S2, laying an intelligent post-pouring belt system; S3, foundation segmental pouring and maintenance; S4, data-driven post-pouring belt closing dynamic decision; S5, post-pouring belt interface activation treatment; and S6, post-pouring belt intelligent pouring and maintenance.Through the above steps, the application solves the comprehensive technical problem that the super-long foundation in special environment is difficult to simultaneously meet the requirements of seismic integrity, crack resistance, seepage prevention and construction period, eliminates the many disadvantages caused by expansion joints, transforms the traditional weak link of the post-pouring belt into a reliable structural part, and realizes seamless, intelligent and high-durability construction of the super-long foundation.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and more specifically, to a method for treating extra-long structures without expansion joints in special environments. Background Technology

[0002] Expansion joints are structural joints installed along the construction joint direction of a building or structure to prevent cracks or damage caused by changes in climate temperature (thermal expansion and contraction) and uneven settlement of the foundation. Traditional expansion joint construction typically employs a reverse grooving process: pre-laying out the groove → cutting the pre-reserved groove → adjusting the embedded reinforcement of the expansion joint → removing debris from the groove → installing the expansion device → tying the reinforcement → setting up formwork → pouring concrete. This method of releasing stress by creating physical joints is widely used in conventional buildings, is technically mature, and convenient to construct.

[0003] With the acceleration of urbanization, the number of super high-rise buildings, large stadiums, and complexes with extremely long structures is increasing, and the limitations of traditional expansion joints are becoming increasingly apparent. On the one hand, expansion joints themselves are expensive, and the waterproofing process requires high precision; improper handling can easily lead to leakage. On the other hand, under complex geological conditions or extreme climates, expansion joints are prone to failure due to uneven foundation settlement or temperature changes. Especially in areas with high seismic fortification, expansion joints can easily become weak points during earthquakes, resulting in impact damage; in areas with large temperature differences, repeated expansion and contraction of expansion joints can cause the waterproofing strips to age and crack; and in environments with high salt spray corrosion, the metal components of expansion joints suffer from significant corrosion. Furthermore, the installation of expansion joints compromises the integrity of the building facade and the overall structural integrity, leading to high maintenance costs in the later stages.

[0004] To address the aforementioned issues, various methods for treating foundations without expansion joints have emerged in existing technologies. For example, ECC deformation bands combined with servo control devices can release stress through active mechanical means; or PTFE sliding layers can be installed to allow the main structure to slide relative to each other and release temperature stress; or expansion reinforcement bands can be installed in areas of significant shrinkage to compensate for shrinkage with locally high-expansion concrete; or seismic isolation temperature shrinkage bands can be used to completely disconnect the foundation to form multi-tower units, which are then mechanically joined together later. However, these methods still have their own drawbacks: ECC deformation bands and servo devices are complex to construct and expensive, and their long-term reliability needs to be verified; sliding layers may experience slippage and instability in seismic zones; expansion reinforcement bands can only compensate for shrinkage stress and cannot solve differential settlement problems; completely disconnecting the foundation weakens the overall structural integrity and is detrimental to seismic resistance. More importantly, existing methods cannot perceive the state of post-cast strips in real time, dynamically decide when to close them, or achieve chemical bonding between the new and old concrete interfaces.

[0005] Therefore, there is a need to provide a method for handling ultra-long, expansion joint-free structures in special environments. Summary of the Invention

[0006] The purpose of this invention is to provide a treatment method for ultra-long, expansion joint-free structures in special environments, in order to solve the problem that existing technologies cannot achieve real-time sensing and dynamic control of post-cast strips, which remain high-risk areas for cracking and leakage.

[0007] To achieve the above objectives, the present invention provides a method for treating ultra-long, expansion-free joints suitable for special environments, comprising the following steps: S1. Preparation of double-expansion gradient concrete: Using silicate low-heat hydration cement, with the addition of an expansion agent, the foundation concrete and post-cast strip concrete are prepared to achieve the restricted expansion rate of the foundation concrete. The restricted expansion rate of the post-cast strip concrete is 0.015% to 0.020%. The resistivity ranges from 0.025% to 0.030%, forming an expansion gradient; the post-cast concrete contains conductive phase material to enable real-time monitoring of resistivity changes. S2. Deployment of intelligent post-pouring strip system: Set up a post-pouring strip every 25m to 35m within the construction range of the ultra-long foundation. The longitudinal and transverse steel bars in the post-pouring strip are continuous throughout. Distributed strain sensors and temperature and humidity sensors are preset on both sides of the post-pouring strip interface. Electrode arrays are pre-embedded in the concrete of the post-pouring strip to form an intelligent sensing network. S3. Segmented pouring and curing of foundation: The foundation concrete prepared by S1 is poured in segments. The temperature of the concrete mixture when it is poured into the formwork is controlled at 5℃~30℃. After pouring, it is kept warm and moist for no less than 14 days. During this period, the strain development data and temperature data of the foundation concrete are collected in real time through the aforementioned sensor. S4. Data-driven dynamic decision-making for post-tensioning strip closure: Based on the real-time data collected in S3, a prediction model for the shrinkage strain development of the foundation concrete is established, and the model parameters are dynamically updated through a filtering algorithm. When the predicted future cumulative shrinkage increment is less than the set threshold, and the relative displacement rate of the interfaces on both sides of the post-tensioning strip is continuously lower than the limit, and the ambient temperature is within the design closure temperature range and shows a stable trend, it is determined that the post-tensioning strip has entered the optimal closure window period, and the optimal time for closure construction is selected within the window period. S5. Post-cast strip interface activation treatment: For post-cast strips deemed suitable for sealing, high-pressure water jet cleaning of interface laitance is used to form a uniformly rough surface with a depth ≥3mm; within 24 hours before pouring, a nano-silane penetrating interface agent is applied with a penetration depth ≥5mm to interact with the old concrete. The reaction produces CSH gel; S6. Intelligent Pouring and Curing of Post-Pouring Strips: Post-pouring strip concrete prepared in S1 is used for pouring. During the pouring process, the flowability of the concrete is monitored by an electrode array, and the amount of admixture added is continuously adjusted according to the flowability loss model. After pouring, the expansion rate and temperature field distribution of the concrete are monitored in real time by pre-embedded sensors. A dynamic optimization model of curing parameters is established, and curing parameters such as spray intensity and heating power are adjusted in real time to ensure that the expansion rate reaches ε2 and the internal and external temperature difference is ≤25℃. The curing time is not less than 28 days, and the temporary support is removed after the concrete reaches the design strength by resistivity monitoring.

[0008] Preferably, the conductive phase material in S1 is graphene or carbon fiber, and its dosage is 0.5% to 1.0% of the cement mass in the post-cast concrete, used to monitor the strength development and density of concrete by correlating resistivity changes.

[0009] Preferably, the distributed strain sensor in S2 is a fiber Bragg grating sensor, which is embedded along the length of the post-cast strip, with the spacing between adjacent sensors ≤10m, and is used to monitor the strain field distribution and crack initiation of concrete in real time.

[0010] Preferably, the silicate low-heat-of-hydration cement in S1 is composed of the following components by mass percentage: 55%–65% low-alkali silicate cement clinker, 15%–20% S95 grade granulated blast furnace slag powder, 10%–15% Grade I fly ash, 3%–5% ultrafine silica fume, 2%–4% 325 mesh limestone powder, and the balance is made up to 100% by quartz fine sand; the specific surface area of ​​the ultrafine silica fume is ≥18000 m² / kg.

[0011] Preferably, the design closure temperature mentioned in S4 is the local annual average air temperature or the target temperature when the structure is closed, which is determined by historical meteorological data and structural temperature field analysis.

[0012] Preferably, the penetration depth of the nano-silane penetrating interface agent in S5 is monitored in real time by the change in resistivity of the interface region. When the resistivity of the interface region recovers to more than 90% of the resistivity of the old concrete, the chemical bonding is determined to be complete.

[0013] Preferably, the dynamic optimization model in S6 includes: Establishing a temperature difference between the inside and outside of concrete With spray intensity The continuous regulatory relationship, when When the temperature exceeds 20°C, follow Proportional-integral adjustment is used to stabilize the temperature difference within the range of 20±2℃; Establish the rate of increase in inflation With maintenance temperature The continuous regulatory relationship, when Below design value At that time, according to Continuously adjust the heating power to make the rate of expansion increase approach the design value; A dynamic compensation model for surface humidity H and evaporation rate E is established. The spray interval and spray volume are automatically adjusted based on real-time temperature and humidity data to maintain the surface humidity above 85%.

[0014] Preferably, the post-cast strip includes a temperature post-cast strip and a settlement post-cast strip; the temperature post-cast strip is closed before the main structure is capped, and the settlement post-cast strip is closed after the main structure is capped and the differential settlement between the main building and the podium is ≤0.01mm / d for 28 consecutive days.

[0015] Preferably, the post-pouring strip area is provided with multiple waterproof structures, including: a water-stop steel plate installed along the entire length of the post-pouring strip, an external rubber water-stop strip installed on the water-facing side of the foundation slab, and an additional polymer self-adhesive waterproof membrane layer added to the construction area; the water-stop steel plate, the rubber water-stop strip and the additional membrane form a multi-layered three-dimensional waterproof system.

[0016] Preferably, the standard for determining whether concrete has reached its design strength by resistivity monitoring as described in S6 is: the measured resistivity value reaches more than 95% of the resistivity threshold corresponding to the design strength of the specimen cured under the same conditions, and remains stable for no less than 3 days.

[0017] The present invention provides a method for treating ultra-long, non-expansion jointed structures in special environments. Compared with existing technologies, its advantages are as follows: By preparing double-expansion gradient concrete, the expansion rate of the foundation concrete is restricted. The restricted expansion rate of the post-cast strip concrete is 0.015% to 0.020%. With an expansion gradient of 0.025% to 0.030%, this design solves the problem in existing technologies where a single expansion rate cannot simultaneously meet the requirements for foundation shrinkage compensation and post-cast strip interface compaction. Tests have shown that this gradient design can effectively offset cement hydration shrinkage stress in the foundation concrete, while simultaneously generating 0.2–0.4 MPa of compressive stress in the post-cast strip concrete under constrained conditions. This proactively compacts the interface at the material level, significantly reducing the risk of cracking.

[0018] By deploying an intelligent post-cast strip system, distributed strain sensors and temperature and humidity sensors are pre-installed on both sides of the post-cast strip interface, and an electrode array is embedded in the post-cast strip concrete to form an intelligent sensing network. This solves the shortcomings of existing technologies, such as the inability to monitor the post-cast strip status in real time and the reliance on experience-based judgment for closing timing. Fiber Bragg grating sensors can collect strain field distribution and temperature data in real time, and the electrode array monitors resistivity changes through conductive phase materials, linking them to concrete strength development. This transforms post-cast strip construction from a "black box" to "transparent and controllable," providing a data foundation for scientific decision-making.

[0019] By employing data-driven dynamic decision-making for post-cast strip closure, a shrinkage strain development prediction model is established based on real-time collected data. The optimal closure window is determined when the predicted cumulative future shrinkage increment is less than a set threshold, the relative displacement rate is below a limit, and the ambient temperature is within the design closure temperature range. This addresses the fundamental flaw of existing technologies where fixed-time closure cannot adapt to actual shrinkage development and environmental changes. The application of algorithms such as Kalman filtering continuously improves prediction accuracy. Verified in multiple projects, this decision-making method can shorten the settlement post-cast strip closure time by 8–10 months compared to traditional methods, significantly reducing the construction period. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 This is a flowchart illustrating the present invention. Detailed Implementation

[0021] 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 should fall within the scope of protection of the present application.

[0022] It should be noted that the terms "first," "second," etc., used in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0024] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0025] In addition, the term "multiple" should mean two or more.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0027]

Example 1

[0028] S1. Preparation of double expansion gradient concrete After extensive orthogonal experiment optimization, the silicate low heat of hydration cement in this embodiment is composed of the following components by mass percentage: 60% low-alkali silicate cement clinker, 18% S95 grade granulated blast furnace slag powder, 12% Grade I fly ash, 4% ultrafine silica fume, 3% 325 mesh limestone powder, and the remainder is quartz sand to make up to 100%. The measured specific surface area of ​​the ultrafine silica fume is 18500 m² / kg, which can effectively fill the nanoscale pores between cement particles. The mineral composition of the cement clinker includes 48% dicalcium silicate, 27% tricalcium silicate, 4.2% tricalcium aluminate, 13.5% tetracalcium aluminoferrite, 0.3% free CaO, and 2.1% MgO. The measured heat of hydration after 3 days is 228 kJ / kg, and after 7 days it is 261 kJ / kg, meeting the requirements for low heat of hydration.

[0029] The mix proportions per cubic meter of foundation concrete are as follows: 335 kg of the aforementioned silicate low-heat cement, 700 kg of medium sand from Zone II, 1020 kg of 5-25 mm continuously graded crushed stone, and 155 kg of drinking water. Simultaneously, 10% of the cement mass is added as a sulfoaluminate-type expansive agent, 1.5% as an environmentally friendly liquid densifier, and 1% as a polycarboxylate high-performance water-reducing agent. The water-cement ratio is 0.43, and the design impermeability grade is P8. By adjusting the expansive agent dosage, the restricted expansion rate of the foundation concrete was tested. It is 0.018%.

[0030] The concrete mix proportions per cubic meter for the post-cast strip are as follows: 345 kg of the aforementioned silicate low-heat cement, 690 kg of medium sand from Zone II, 1010 kg of 5-25 mm continuously graded crushed stone, and 152 kg of drinking water. Simultaneously, 11% of a sulfoaluminate-type expansive agent, 1.8% of a silicate crack-resistant agent, and 1.1% of a polycarboxylate high-performance water-reducing agent are added by weight of the cement, along with 0.8% of graphene by weight of the cement as a conductive phase material. Testing revealed that the restricted expansion rate of the post-cast strip concrete... The value was 0.028%. Experiments showed that when the graphene content was 0.8%, the correlation coefficient between the change in concrete resistivity and strength development reached 0.96, which meets the requirements for real-time monitoring.

[0031] S2. Deployment of intelligent post-pouring strip system Within the construction area of ​​an ultra-long foundation, a post-cast strip with a width of 800mm is set every 30m. The longitudinal and transverse reinforcing bars within the post-cast strip are continuous and uninterrupted. Based on the structural stress characteristics, post-cast strips are divided into temperature post-cast strips and settlement post-cast strips.

[0032] Fiber Bragg grating strain sensors and temperature and humidity sensors are pre-installed on both sides of the post-cast strip interface, with an 8m spacing between adjacent sensors. To prevent damage to the sensors during concrete vibration, they are protected with φ8mm stainless steel flexible hoses, and the vibrator is kept at least 300mm away from the sensors. A stainless steel electrode array is pre-embedded in the post-cast strip concrete, with an electrode spacing of 0.5m. The lead wires are centrally led out and waterproofed, forming an intelligent sensing network.

[0033] S3. Segmented pouring and curing of the foundation The foundation was poured in sections using S1-grade concrete. When the ambient temperature was above 30°C during construction, the concrete was mixed with 6°C cold water. The concrete transport trucks were shaded and wrapped, and the pump pipes were wrapped with wet burlap sacks for continuous water spraying to cool them down. The pouring was carried out between 5:00 AM and 9:00 AM to ensure that the temperature of the concrete entering the formwork was controlled below 28°C.

[0034] Immediately after the concrete has initially set, a curing agent is sprayed on it, and it is then covered with double-layer plastic film for heat preservation and moisture retention. The curing period is no less than 14 days. During this period, strain development data and temperature data of the foundation concrete are collected in real time using fiber Bragg grating sensors, with the collection frequency set to once every 30 minutes.

[0035] S4. Data-driven dynamic decision-making for post-gating strip closure Based on the strain data collected in real time by S3, a prediction model for the shrinkage strain development of the foundation concrete was established. The model parameters are dynamically updated using the Kalman filter algorithm. Calculations show that when the predicted cumulative contraction increment over the next 28 days is ≤50... At that time, it was determined that the concrete shrinkage tended to stabilize.

[0036] Simultaneously monitor the relative displacement of the interfaces on both sides of the post-cast strip. Calculations based on data from pre-embedded sensors indicate that when the relative displacement rate is ≤0.02mm / d for 10 consecutive days, it indicates that the deformation of the foundations on both sides is coordinated. The ambient temperature must be within the design closure temperature range of 18℃±3℃ and show a stable trend. The design closure temperature is determined based on the local annual average temperature of 18℃.

[0037] When all of the above conditions are met, the post-tensioning strip is considered to have entered the optimal closure window. During this window, the closure construction should be carried out during the period with the smallest temperature difference and the highest humidity.

[0038] For post-settlement concrete strips, the differential settlement between the main building and the podium must also meet the condition of ≤0.01mm / d for 28 consecutive days. Actual measurement data shows that 45 days after the main building was topped out, the differential settlement rate dropped to 0.008mm / d, meeting the requirement.

[0039] S5, Post-pouring strip interface activation treatment For post-cast strips deemed suitable for closure, high-pressure water jet cleaning of interface laitance was employed. The water jet pressure was 55 MPa, forming a uniform rough surface with a depth ≥ 3.5 mm. The measured density of the rough surface was 22 points / dm², exposing fresh concrete aggregate.

[0040] Apply a nano-silane penetrating interface agent within 24 hours before pouring, at a rate of 0.3 kg / m². Testing showed that the interface agent penetrated to a depth of 5.8 mm, effectively interacting with the existing concrete. The reaction produces CSH gel. The resistivity change at the interface is monitored in real time; chemical bonding is considered complete when the resistivity of the interface recovers to 92% of the resistivity of the old concrete. After application, a protective shed is erected to prevent rainwater and debris from falling in.

[0041] S6, Intelligent Pouring and Curing of Post-Pouring Strips S1-prepared post-cast strip concrete was used for pouring. During the pouring process, the flowability of the concrete was monitored in real time using an electrode array, and a flowability loss model was established. When the slump is below 180mm, a retarding water-reducing agent is automatically added to the mixer truck. The amount added is continuously adjusted by a peristaltic pump using a PID algorithm to maintain the slump within the range of 180-220mm.

[0042] The concrete pouring was carried out in layers using pumping, with each layer being 250mm thick. The time interval between two adjacent layers did not exceed the initial setting time. A 50mm diameter immersion vibrator was used for compaction, with vibration points arranged in a quincunx pattern at 350mm intervals. The vibrator was quickly inserted and slowly withdrawn, penetrating 70mm into the lower layer of concrete, and compacted until the surface was smooth and free of air bubbles. After the concrete was poured to be flush with the top surface of the foundation slab, it was leveled with a screed and smoothed with a wooden trowel. A second troweling was performed before initial setting.

[0043] After pouring, the expansion rate and temperature field distribution of the concrete are monitored in real time using pre-embedded sensors, and a dynamic optimization model for curing parameters is established. Temperature difference control: When the temperature difference ΔT between the inside and outside of the concrete exceeds 20℃, follow the instructions. The spray intensity was continuously adjusted to stabilize the temperature difference within a range of 20±2℃. Actual measurement data showed that when the temperature dropped sharply on the night of the third day, the system automatically activated the spray, bringing the temperature difference back down from 28℃ to 22℃ within 20 minutes.

[0044] Expansion rate control: Set the target expansion rate Real-time monitoring of the rate of increase in inflation. when Below design value At that time, according to The curing temperature was continuously adjusted. On the 7th day, the measured expansion rate was 0.021%. The system automatically adjusted the curing temperature from 20℃ to 28℃. On the 14th day, the expansion rate reached 0.026%, and finally stabilized at 0.0285% after 28 days.

[0045] Humidity control: Based on real-time monitored temperature and humidity data, the evaporation rate of water on the concrete surface is calculated, and the spraying interval and spraying volume are automatically adjusted to maintain the surface humidity above 85%.

[0046] The curing period shall not be less than 28 days. After curing, the concrete shall be judged to have reached the design strength by resistivity monitoring: the temporary support can be removed only if the measured resistivity reaches 97% of the resistivity threshold (2.8kΩ·m) corresponding to the design strength of the specimen cured under the same conditions, and remains stable for 4 days.

[0047] The post-pouring strip area is equipped with multiple waterproofing structures: a 330mm×3mm waterstop steel plate is installed along the entire length of the post-pouring strip at the center of the foundation slab thickness, with an overlap length of 200mm and full welding on both sides; a 200mm wide external rubber waterstop is installed on the water-facing side of the foundation slab, extending 300mm to the outside of the post-pouring strip on each side; an additional polymer self-adhesive waterproof membrane layer is added to the construction area of ​​the post-pouring strip, with a width equal to the full width of the post-pouring strip and extending 500mm to each side, and is fully bonded to the main waterproof layer of the foundation slab.

[0048] Six months after the implementation of this embodiment, ultrasonic testing showed no cracks in the post-pouring strip area, and core sampling revealed that the interface was intact, with the impermeability grade reaching P10, meeting the design requirements.

[0049]

Example 2

[0050] S1. Preparation of double expansion gradient concrete In this embodiment, the silicate low-heat-of-hydration cement is composed of the following components by mass percentage: 58% low-alkali silicate cement clinker, 20% S95 grade granulated blast furnace slag powder, 13% Grade I fly ash, 3% ultrafine silica fume, 3% 325 mesh limestone powder, and the balance is made up to 100% by quartz sand. The specific surface area of ​​the ultrafine silica fume is 19200 m² / kg.

[0051] The mix proportions per cubic meter of foundation concrete are: 330 kg cement, 710 kg medium sand (zone II), 1040 kg 5-25 mm continuously graded crushed stone, and 158 kg drinking water. Additions include 10% sulfoaluminate-type expansive agent, 1.5% silica-based crack-resistant agent, and 1% polycarboxylate superplasticizer by weight of cement. Testing showed that the foundation concrete's limited expansion rate... It is 0.016%.

[0052] The concrete mix proportions per cubic meter for the post-cast strip are: 340 kg cement, 700 kg medium sand from Zone II, 1030 kg 5-25 mm continuously graded crushed stone, and 155 kg drinking water. It also includes 12% sulfoaluminate-type expansive agent, 2.0% environmentally friendly liquid densifier, 1.2% polycarboxylate superplasticizer, and 0.6% carbon fiber as a conductive phase material. Testing showed that the post-cast strip concrete has a limited expansion rate... The value was 0.029%. Experiments showed that when the carbon fiber content was 0.6%, the correlation between concrete resistivity and strength was good, with a correlation coefficient of 0.94.

[0053] S2. Deployment of intelligent post-pouring strip system The post-cast strips are spaced 25m apart, with a width of 800mm, and the reinforcing steel runs continuously throughout. Distributed resistance strain gauge sensors and temperature and humidity sensors are pre-installed on both sides of the post-cast strip interface, with adjacent sensors spaced 5m apart. A copper electrode array is pre-embedded in the post-cast strip concrete, with an electrode spacing of 0.3m, forming a high-density intelligent sensing network.

[0054] S3. Segmented pouring and curing of the foundation The foundation concrete was poured in sections, with the pouring temperature controlled between 8℃ and 28℃. During the curing period, data was collected in real time using sensors every 15 minutes, and the curing time was 16 days.

[0055] S4. Data-driven dynamic decision-making for post-gating strip closure A shrinkage strain development prediction model was established, and parameters were dynamically updated using an extended Kalman filter. When the predicted cumulative shrinkage increment over the next 21 days is ≤45με, the relative displacement rate between the two interfaces of the post-cast strip is ≤0.015mm / d for 10 consecutive days, and the ambient temperature is within the design closure temperature range of 20℃±2℃, the post-cast strip is determined to have entered the optimal closure window period.

[0056] A settlement prediction model for the main building was established for the post-settlement pouring strip. The parameters were dynamically updated using particle filtering. When the main building reached the 60th floor, the model predicted a final settlement of 82mm, 16mm for the podium, and a differential settlement of 66mm. The measured differential settlement rate was determined to meet the closure conditions when it remained ≤0.008mm / d for 30 consecutive days.

[0057] S5, Post-pouring strip interface activation treatment The interface is cleaned using high-pressure water jet at a pressure of 60 MPa, creating a rough surface with a depth ≥4 mm and a density of 25 points / dm². A nano-silane penetrating interface agent is then applied at a rate of 0.35 kg / m². The penetration depth is monitored in real-time by changes in resistivity. Chemical bonding is considered complete when the resistivity of the interface area reaches 93% or more of the resistivity of the old concrete.

[0058] S6, Intelligent Pouring and Curing of Post-Pouring Strips During the pouring process, the concrete fluidity was monitored using a carbon fiber conductive phase, and a PID algorithm was used to control the amount of water-reducing agent added, ensuring a stable slump of 550±30mm (corresponding to a slump of 180~220mm). The pouring layer thickness was 200mm, and the vibrator was inserted 80mm into the lower layer of concrete.

[0059] A multi-parameter coupled optimization model was used during the maintenance period: Temperature difference control adopts adaptive fuzzy PID, with ΔT-20 as the error input and output spray intensity expansion rate control to establish a neural network model. Real-time optimization of heating power and humidity control adopts a feedforward-feedback composite control strategy. The curing time is 32 days. The strength is determined by monitoring the resistivity of the carbon fiber conductive phase. The standard is that the resistivity reaches a threshold of 96% or more and remains stable for 4 days.

[0060] The waterproof construction is the same as in Example 1.

[0061] After implementation of this embodiment, the sealing time of the post-settlement gating strip is 2 months earlier than that of the traditional method, and the impermeability grade of the post-gating strip area reaches P10 or above.

[0062]

Example 3

[0063] S1. Preparation of double expansion gradient concrete In this embodiment, the silicate low-heat-of-hydration cement is composed of the following components by mass percentage: 62% low-alkali silicate cement clinker, 16% S95 grade granulated blast furnace slag powder, 11% Grade I fly ash, 5% ultrafine silica fume, 2% 325 mesh limestone powder, and the balance is made up to 100% by quartz sand. The specific surface area of ​​the ultrafine silica fume is 18800 m² / kg.

[0064] The mix proportions per cubic meter of foundation concrete are: 345 kg cement, 690 kg medium sand (zone II), 1010 kg 5-25 mm continuously graded crushed stone, and 152 kg drinking water. Additions include 10% sulfoaluminate-type expansive agent, 1.6% environmentally friendly liquid densifier, and 1.1% polycarboxylate superplasticizer by weight of cement. The foundation concrete's limited expansion rate... It is 0.019%.

[0065] The concrete mix proportions per cubic meter for the post-cast strip are: 350 kg cement, 680 kg medium sand from Zone II, 1000 kg 5-25 mm continuously graded crushed stone, and 150 kg drinking water. It also includes 12% sulfoaluminate-type expansive agent, 2.0% silica-based crack-resistant agent, 1.2% polycarboxylate superplasticizer, and 0.7% graphene conductive phase material (by weight of cement). The post-cast strip concrete has a limited expansion rate. It is 0.030%.

[0066] S2. Deployment of intelligent post-pouring strip system The post-cast strips are spaced 35m apart, with a width of 800mm, and the reinforcing steel runs continuously throughout. Fiber Bragg grating sensors and temperature and humidity sensors are pre-installed on both sides of the post-cast strip interface, with adjacent sensors spaced 10m apart. A stainless steel electrode array is pre-embedded in the post-cast strip concrete, with an electrode spacing of 0.6m.

[0067] S3. Segmented pouring and curing of the foundation The foundation concrete is poured in sections, with the pouring temperature controlled between 5℃ and 30℃. During winter construction, 40℃ warm water is used for mixing, and transport equipment is insulated and wrapped. 50mm extruded polystyrene boards are laid on the outside of the formwork for insulation. The curing period is 14 days, during which data is collected in real time using sensors.

[0068] S4. Data-driven dynamic decision-making for post-gating strip closure A shrinkage strain development prediction model was established, and the model parameters were dynamically updated using a particle filter algorithm. The optimal closure window for the post-cast strip was determined when the predicted cumulative shrinkage increment over the next 30 days was ≤55με, the relative displacement rate between the interfaces on both sides of the strip was ≤0.01mm / d for 14 consecutive days, and the ambient temperature was within the design closure temperature range of 15℃±3℃. The design closure temperature was determined based on the average annual temperature of 16℃ in the Chengdu area.

[0069] S5, Post-pouring strip interface activation treatment The interface is cleaned using high-pressure water jet at a pressure of 55 MPa, creating a rough surface with a depth ≥3.5 mm. A nano-silane penetrating interface agent is then applied at a rate of 0.3 kg / m². The penetration depth is monitored in real-time by changes in resistivity. Chemical bonding is considered complete when the resistivity of the interface area reaches 90% or more of the resistivity of the old concrete.

[0070] S6, Intelligent Pouring and Curing of Post-Pouring Strips During the pouring process, the flowability of the concrete was monitored using a graphene conductive phase, and the amount of water-reducing agent added was optimized using a model predictive control algorithm to stabilize the slump at 550±40mm. The pouring layer thickness was 300mm, and the vibration was inserted 60mm into the lower layer of concrete.

[0071] During the curing period, a multi-parameter coupled optimization curing model was established, using the temperature difference between the inside and outside of the concrete ΔT, surface humidity H, and expansion rate ε as input variables to establish a curing effect evaluation function. Using spray intensity Q and heating power P as control variables, the gradient descent method is employed to optimize the value of J in real time, causing J to converge towards its minimum. When abnormal fluctuations occur in the monitoring data, the system automatically switches to emergency maintenance mode, increasing the spray intensity and activating the backup heating device.

[0072] The curing period is 28 days. The strength is determined by resistivity monitoring, with the standard being that the resistivity reaches more than 95% of the threshold and remains stable for 3 days.

[0073] The waterproof construction is the same as in Example 1.

[0074] After implementation of this embodiment, there were no visible cracks in the post-pouring strip area, and ultrasonic testing showed that the internal density was uniform and the impermeability grade reached P10.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for treating ultra-long, expansion-free sections suitable for special environments, characterized in that, Includes the following steps: S1. Preparation of double-expansion gradient concrete: Using silicate low-heat hydration cement, adding an expansion agent, and preparing foundation concrete and post-cast strip concrete, the restricted expansion rate of the foundation concrete is... The restricted expansion rate of the post-cast strip concrete is 0.015% to 0.020%. The resistivity ranges from 0.025% to 0.030%, forming an expansion gradient; the post-cast concrete contains conductive phase material to enable real-time monitoring of resistivity changes. S2. Deployment of intelligent post-pouring strip system: Set up a post-pouring strip every 25m to 35m within the construction range of the ultra-long foundation. The longitudinal and transverse steel bars in the post-pouring strip are continuous throughout. Distributed strain sensors and temperature and humidity sensors are preset on both sides of the post-pouring strip interface. Electrode arrays are pre-embedded in the concrete of the post-pouring strip to form an intelligent sensing network. S3. Segmented pouring and curing of foundation: The foundation concrete prepared by S1 is poured in segments. The temperature of the concrete mixture when it is poured into the formwork is controlled at 5℃~30℃. After pouring, it is kept warm and moist for no less than 14 days. During this period, the strain development data and temperature data of the foundation concrete are collected in real time through the aforementioned sensor. S4. Data-driven dynamic decision-making for post-tensioning strip closure: Based on the real-time data collected in S3, a prediction model for the shrinkage strain development of the foundation concrete is established, and the model parameters are dynamically updated through a filtering algorithm. When the predicted future cumulative shrinkage increment is less than the set threshold, and the relative displacement rate of the interfaces on both sides of the post-tensioning strip is continuously lower than the limit, and the ambient temperature is within the design closure temperature range and shows a stable trend, it is determined that the post-tensioning strip has entered the optimal closure window period, and the optimal time for closure construction is selected within the window period. S5. Activation treatment of post-cast strip interface: For post-cast strips that are determined to meet the sealing conditions, use high-pressure water jet to clean the interface laitance and form a uniform rough surface with a depth of ≥3mm; apply nano silane penetrating interface agent within 24 hours before pouring, with a penetration depth of ≥5mm, and react with Ca(OH)2 in the old concrete to generate CSH gel. S6. Intelligent Pouring and Curing of Post-Pouring Strips: Post-pouring strip concrete prepared in S1 is used. During pouring, changes in concrete fluidity are monitored via an electrode array, and the amount of admixture added is continuously adjusted based on a fluidity loss model. After pouring, pre-embedded sensors monitor the development of concrete expansion rate and temperature field distribution in real time, establishing a dynamic optimization model for curing parameters. Spray intensity, heating power, and other curing parameters are adjusted in real time to ensure the expansion rate stabilizes. The internal and external temperature difference should be ≤25℃; the curing time should be no less than 28 days, and the temporary support should be removed after the concrete reaches the design strength by resistivity monitoring.

2. The treatment method for ultra-long, non-expansion joint applications in special environments according to claim 1, characterized in that, The conductive phase material mentioned in S1 is graphene or carbon fiber, and its dosage is 0.5% to 1.0% of the cement mass in the post-cast concrete. It is used to monitor the strength development and density of concrete by correlating resistivity changes.

3. The treatment method for ultra-long, non-expansion joint applications in special environments according to claim 1, characterized in that, The distributed strain sensor described in S2 is a fiber Bragg grating sensor, which is embedded along the length of the post-cast strip with a spacing of ≤10m between adjacent sensors. It is used to monitor the strain field distribution and crack initiation of concrete in real time.

4. The treatment method for ultra-long, non-expansion joint applications in special environments according to claim 1, characterized in that, The silicate low-heat-of-hydration cement described in S1 is composed of the following components by mass percentage: 55%–65% low-alkali silicate cement clinker, 15%–20% S95 grade granulated blast furnace slag powder, 10%–15% Grade I fly ash, 3%–5% ultrafine silica fume, 2%–4% 325 mesh limestone powder, and the balance being quartz fine sand to make up to 100%; the specific surface area of ​​the ultrafine silica fume is ≥18000 m² / kg.

5. The treatment method for ultra-long, non-expansion joint applications in special environments according to claim 1, characterized in that, The design closure temperature mentioned in S4 is the local annual average temperature or the target temperature when the structure is closed, which is determined through historical meteorological data and structural temperature field analysis.

6. The treatment method for ultra-long, non-expansion joint structures suitable for special environments according to claim 1, characterized in that, The penetration depth of the nano-silane penetrating interface agent described in S5 is monitored in real time by the change in resistivity of the interface region. When the resistivity of the interface region recovers to more than 90% of the resistivity of the old concrete, the chemical bonding is determined to be complete.

7. The treatment method for ultra-long, non-expansion joint structures suitable for special environments according to claim 1, characterized in that, The dynamic optimization model described in S6 includes: Establishing a temperature difference between the inside and outside of concrete With spray intensity The continuous regulatory relationship, when When the temperature exceeds 20°C, follow Proportional-integral adjustment is used to stabilize the temperature difference within the range of 20±2℃; Establish the rate of increase in inflation With maintenance temperature The continuous regulatory relationship, when Below design value At that time, according to Continuously adjust the heating power to make the rate of expansion increase approach the design value; A dynamic compensation model for surface humidity H and evaporation rate E is established. The spray interval and spray volume are automatically adjusted based on real-time temperature and humidity data to maintain the surface humidity above 85%.

8. The treatment method for ultra-long, jointless structures in special environments according to claim 1, characterized in that, The post-cast strip includes a temperature post-cast strip and a settlement post-cast strip; the temperature post-cast strip is closed before the main structure is capped, and the settlement post-cast strip is closed after the main structure is capped and the differential settlement between the main building and the podium is ≤0.01mm / d for 28 consecutive days.

9. The treatment method for ultra-long, non-expansion joint structures suitable for special environments according to claim 1, characterized in that, The post-pouring strip area is equipped with multiple waterproof structures, including: a water-stop steel plate installed along the entire length of the post-pouring strip, an external rubber water-stop strip installed on the water-facing side of the foundation slab, and an additional polymer self-adhesive waterproof membrane layer added to the construction area; the water-stop steel plate, rubber water-stop strip and additional membrane form a multi-layered three-dimensional waterproof system.

10. The treatment method for ultra-long, non-expansion joint applications in special environments according to claim 1, characterized in that, The standard for determining whether concrete has reached its design strength through resistivity monitoring, as described in S6, is that the measured resistivity value reaches more than 95% of the resistivity threshold corresponding to the design strength of the specimen cured under the same conditions, and remains stable for no less than 3 days.

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