A deep water high pressure penetration and mechanical load coupling test device and method

Abstract

The application discloses a kind of deepwater high-pressure penetration and mechanical load coupling test device and method, belong to offshore wind power structure test technical field, including sealed water injection system, mechanical loading system and monitoring acquisition system.Sealed water injection system adopts UHPC pipe section internal chamber pressurization, by air compressor and precision pressure regulator provide stable water pressure by the way of forming airtight chamber with silk hole steel partition and waterproof structure glue;Mechanical loading system adopts actuator-distribution beam-clamp loading system, and rubber hinge support provides simply supported boundary condition;Monitoring system synchronously acquires multiple physical quantity data.The application uses internal pressurization instead of external pressurization, realizes the synchronous coupling of high-pressure penetration and static force / fatigue load, accurately tests the stress performance and watertight performance of UHPC pipe section and joint, and is suitable for deep-sea floating wind power foundation structure test.

Description

Technical Field

[0001] This invention belongs to the field of offshore wind power structure testing technology, specifically relating to a deep-water high-pressure permeation and mechanical load coupling test device and method. Background Technology

[0002] In deep-sea floating wind power projects, the ultra-high performance concrete (UHPC) pipe sections and joints of floating foundations are subjected to a multi-coupled service environment of deep-water high pressure, combined bending, shear, and torsion static loads, and chloride ion corrosion. In the actual marine environment, the outer wall of the pipe section is subjected to deep-water hydrostatic pressure, and seawater can penetrate into the structure through cracks, causing leakage and steel corrosion. However, under experimental conditions, it is extremely difficult to apply uniform, stable, and controllable deep-water high-pressure water to the outside of large UHPC pipe sections. This presents problems such as complex equipment, difficulty in sealing, and low experimental safety, making it difficult to realistically reproduce the high-pressure environment.

[0003] Existing UHPC stress and seepage resistance testing technologies mostly focus on independent static mechanical tests or single water permeability tests. These methods are limited by test conditions and evaluation methods, and do not consider the coupling effect of load and seepage, resulting in incomplete performance evaluation results. Some coupled test methods use external low-pressure immersion or surface spraying, which suffer from problems such as low water pressure, distorted simulated environment, and inability to maintain stable pressure. They are unable to reflect the real leakage mechanism under deep water and high pressure, and long-term service performance cannot be guaranteed. Although some test devices attempt to carry out load and seepage coupling tests, they still use external pressurization. This not only makes the device complex, difficult to seal, and unsafe, but also fails to recognize that internal pressurization is a more unfavorable and extreme control condition than external water pressure. It cannot reproduce the deterioration process of cracks continuously opening under internal water pressure, and the test results may be biased towards unsafe conditions.

[0004] In summary, existing experimental methods cannot solve the problem of applying external high-pressure water, nor can they utilize internal high pressure or more unfavorable operating conditions for verification, and they cannot achieve synchronous coupling of static load and internal chlorinated seawater high pressure. Therefore, there is an urgent need to develop a new experimental device to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a deep-water high-pressure infiltration and mechanical load coupling test device and method. The device adopts an internal chamber pressurization method to realize the synchronous coupling of high-pressure infiltration and mechanical load, and accurately tests the stress performance and watertight performance of UHPC pipe sections and joints under the most severe working conditions.

[0006] To achieve the above objectives, the present invention provides a deep-water high-pressure seepage and mechanical load coupling test apparatus, comprising: Sealing water injection components, mechanical loading components, and monitoring and acquisition systems; The sealed water injection assembly includes a pipe section, with sealing baffles at both ends to form a sealed chamber inside the pipe section. The sealing baffles are connected to a pressurizing device and a pressure regulating device through pipelines to apply a permeating medium with a set water pressure to the chamber. By pressurizing the inside of the pipe section, the pipe wall is subjected to tension to form a test condition that is more unfavorable than the external water pressure, providing a permeating environment for the coupled test of the mechanical loading assembly. The mechanical loading component includes an actuator and a clamping component. The clamping component clamps the pipe section, and the actuator applies static load or fatigue load to the pipe section through the clamping component, which is coupled with the water pressure in the chamber. The monitoring and acquisition system includes sensors arranged at pipe sections and joints. The sensors simultaneously acquire the permeability parameters of the sealing water injection component and the mechanical response and crack development data of the mechanical loading component.

[0007] Preferably, the pipe section of the sealed water injection assembly has a joint inside, a sealing layer is provided between the sealing partition and the inner wall of the pipe section, a valve is installed on the sealing partition, and the valve is connected in sequence to a pressure regulating device, a storage tank and a pressurizing device through a pipeline, and the storage tank contains a simulated seawater solution.

[0008] Preferably, the pipe section is a UHPC pipe section, the joint is a UHPC wet joint, the sealing partition is a steel partition with threaded holes, the sealing adhesive layer is a waterproof structural adhesive, the pressure regulating device is a precision pressure regulator, the pressurizing device is an air compressor, the pipeline is a pressure-resistant metal flexible hose, and the valve is a two-way valve.

[0009] Preferably, the simulated seawater solution is a 3.5% sodium chloride solution, and the set water pressure of the sealed chamber is 0.2 MPa.

[0010] Preferably, the sealant layer is a modified epoxy resin adhesive.

[0011] Preferably, the clamping assembly of the mechanical loading component includes a distribution beam and a clamp, the actuator is connected to the distribution beam, the clamp clamps the pipe section of the sealing water injection component, an elastic pad is provided between the clamp and the pipe section, and hinge supports are provided between the clamp and the distribution beam and between the clamp and the support base.

[0012] Preferably, the elastic pad is a rubber pad, the hinge support is a rubber hinge support, the support platform is a concrete platform, and it also includes a ground anchor. The rubber hinge support provides a simply supported boundary condition that provides only vertical support and allows free rotation.

[0013] Preferably, the sensors of the monitoring and acquisition system include strain gauges, strain rosettes, displacement gauges, and inclinometers arranged on the surface of the pipe section, anchor gauges arranged on the internal reinforcement, crack observation points arranged at the joints, and pressure gauges and seepage measurement points arranged in the cavity. All sensors are connected to the data acquisition equipment.

[0014] This invention also provides a method for coupled testing of deep-water high-pressure seepage and mechanical load, comprising the following steps: S1. Prepare pipe section specimens including joints; S2. Install a sealing water injection assembly to form a closed chamber inside the pipe section and apply a permeating medium with a set water pressure to the chamber. By pressurizing the inside of the pipe section, the pipe wall is stretched to form an extreme test condition that is more unfavorable than the external water pressure. S3. Install the mechanical loading components to clamp the pipe section and form the set boundary conditions; S4. Deploy a monitoring and acquisition system, and install sensors at pipe sections and joints and connect them to the acquisition equipment; S5. Perform pre-loading debugging and check the sealing performance and the working status of the loading system; S6. Conduct a coupled loading test, keep the water pressure in the chamber constant, and apply external loads in stages to achieve synchronous coupling of water pressure and load; S7. Perform data processing and performance evaluation, calculate permeability parameters, and evaluate the stress performance and watertightness of pipe sections and joints.

[0015] Preferably, S1 specifically involves: fabricating UHPC pipe section specimens according to the design scale ratio. The specimens include precast pipe sections and UHPC wet joints. The precast pipe sections are equipped with longitudinal reinforcing bars, stirrups, and prestressed steel strands. The UHPC wet joints are reserved with lap length of reinforcing bars and shear key structure. After casting, the specimens are cured to the design strength according to standard. S2 specifically involves: pre-embedding and casting a perforated steel partition and a two-way valve at the end of the pipe section; uniformly applying waterproof structural adhesive at the joint between the perforated steel partition and the inner wall of the UHPC pipe section to form an independent, sealed water pressure chamber; connecting the storage tank, air compressor, precision pressure regulator, and two-way valve to the chamber via a pressure-resistant metal hose; and preparing a 3.5% sodium chloride solution in the storage tank to simulate seawater. S3 specifically involves: bolting the actuator to the distribution beam, clamping the upper and lower sides of the UHPC pipe section with a clamp and padding with rubber pads, padding with rubber hinge supports between the distribution beam and the intermediate clamp, and between the end clamp and the concrete platform to form a simply supported boundary, and anchoring the clamps at both ends with ground anchors. S4 specifically involves: installing strain gauges, strain rosettes, displacement gauges, and inclinometers on key sections of the specimen; installing anchor gauges on the reinforcement; installing crack observation points at the wet joints of the UHPC; installing pressure gauges and seepage measurement points in the chamber; and connecting all sensors to the data acquisition system. S5 specifically involves: injecting sodium chloride solution into the chamber and purging the air, slowly pressurizing to 0.1 MPa and holding the pressure for 15 minutes to check the sealing performance, applying 0.2 times the design load to check the loading and acquisition system, and unloading and zeroing after confirming that there are no errors. S6 specifically involves: first, stabilizing the water pressure in the chamber to 0.2 MPa and keeping it constant, corresponding to a water depth of 21 m; then, applying static loads in stages to achieve synchronous coupling of seepage and mechanical loads; pausing loading when the UHPC wet joints open and leak; draining the sodium chloride solution and then continuing loading until the specimen reaches its ultimate bearing capacity. S7 specifically involves: calculating the permeability coefficient based on Darcy's law, measuring the chloride ion penetration depth using the silver nitrate colorimetric method, establishing the load-deflection-strain-crack width-permeability coupling relationship, and evaluating the stress performance and watertightness of UHPC pipe sections and UHPC wet joints under coupled conditions.

[0016] Therefore, the present invention employs the aforementioned deep-water high-pressure seepage and mechanical load coupling test device and method. Compared with the prior art, the technical solution of the present invention has the following beneficial effects: (1) By using the internal chamber pressurization technology of UHPC pipe section, the technical problems of difficult external high pressure water loading, complex sealing and poor safety of large components are overcome. In this way, the technical effect of simple and reliable device, stable and controllable pressure is achieved. The test results are more conservative and safe. (2) By using the technique of filling the cavity with 3.5% sodium chloride solution and applying it simultaneously with static / fatigue load, the technical problem that existing tests cannot reproduce the multi-field coupling effect of load-permeability-erosion in deep water environment is overcome, and thus the technical effect of truly simulating the deep-sea service environment and accurately reproducing the actual stress state of the floating body tube section is achieved. (3) By adopting the technical means of simultaneous monitoring of multiple physical quantities and universal design of multiple components, the technical problems of incomplete evaluation of single index and narrow application range of test device are overcome. Thus, the technical effects of synchronously collecting a full set of data to accurately reveal the coupling degradation mechanism, being applicable to a variety of pipe sections and joint types, and having strong versatility and good economy are achieved.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the sealing water injection component structure of a deep-water high-pressure permeation and mechanical load coupling test device according to Embodiment 1 of the present invention; Figure 2 This is a cross-sectional view of a UHPC pipe section in Embodiment 1 of the deep-water high-pressure permeation and mechanical load coupling test device of the present invention; Figure 3 This is a longitudinal cross-sectional view of a UHPC pipe section in Embodiment 1 of the deep-water high-pressure permeation and mechanical load coupling test device of the present invention; Figure 4 This is an overall structural diagram of an embodiment of the deep-water high-pressure permeation and mechanical load coupling test device of the present invention.

[0019] Figure Labels 1. Air compressor; 2. Pressure-resistant metal hose; 3. Storage tank; 4. Sodium chloride solution; 5. Precision pressure regulator; 6. Two-way valve; 7. Perforated steel partition; 8. Waterproof structural adhesive; 9. UHPC pipe section; 10. UHPC wet joint. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used in the present invention should have the ordinary meaning understood by those skilled in the art.

[0021] Example 1 like Figures 1-4 As shown, this embodiment provides a deep-water high-pressure permeation and mechanical load coupling test device and method. It should be understood that the specific parameters and models mentioned in this embodiment are examples used to help those skilled in the art understand the present invention, and are not intended to limit the present invention.

[0022] The present invention provides a deep-water high-pressure permeation and mechanical load coupling test device, comprising three main parts: a sealing water injection component, a mechanical loading component, and a monitoring and acquisition system.

[0023] The sealed water injection assembly includes a UHPC pipe section 9, with a UHPC wet joint 10 inside. Both ends of the UHPC pipe section 9 are fitted with perforated steel baffles 7. A waterproof structural adhesive 8 is applied between the perforated steel baffles 7 and the inner wall of the UHPC pipe section 9. The waterproof structural adhesive 8 is evenly applied to the joint, forming a continuous sealing layer to effectively block leakage paths and ensure the stability of the chamber water pressure. A two-way valve 6 is installed on the perforated steel baffle 7. The two-way valve 6 is connected in sequence to a precision pressure regulator 5, a storage tank 3, and an air compressor 1 via a pressure-resistant metal hose 2. The storage tank 3 contains a sodium chloride solution 4. The air compressor 1 provides pressurization power, and the precision pressure regulator 5 achieves precise water pressure control. The pressure-resistant metal hose 2 has high pressure resistance and corrosion resistance, ensuring safe and reliable high-pressure medium transportation.

[0024] The mechanical loading assembly includes an actuator, with a distribution beam connected to its lower end. A clamp is bolted to the bottom of the distribution beam, clamping the upper and lower sides of the UHPC pipe section 9. Rubber pads are placed between the clamps and the UHPC pipe section 9. These rubber pads achieve uniform load distribution through elastic deformation, avoiding localized stress concentration that could cause pressure damage to the UHPC matrix, while also increasing the friction of the contact surface to prevent specimen slippage during loading. Concrete platforms are installed below both ends of the UHPC pipe section 9. Rubber hinge supports are placed between the clamps and the distribution beam, and between the clamps and the concrete platforms. These rubber hinge supports provide simply supported boundary conditions with only vertical constraints and allow free rotation, eliminating the interference of additional bending moments on the test results and ensuring consistency between the stress state and the theoretical calculation model. The clamps are anchored via ground anchors to achieve stable application of cyclic fatigue loads.

[0025] The monitoring and acquisition system includes strain gauges, strain rosettes, displacement gauges, and inclinometers. Strain gauges and strain rosettes are arranged on key sections of the UHPC pipe section 9 surface. Displacement gauges are positioned along the vertical deformation direction of the specimen, and inclinometers are installed at the ends of the pipe section. The system also includes anchor gauges, crack observation points, pressure gauges, and seepage height measuring points. Anchor gauges are located on the reinforcing bars and prestressed steel strands. Crack observation points are located at the UHPC wet joint 10. Pressure gauges and seepage height measuring points are located within the chamber. All sensors are connected to the static strain acquisition system and data acquisition instrument, enabling simultaneous and continuous acquisition of multiple physical quantities.

[0026] Example 2 The present invention provides a deep-water high-pressure seepage and mechanical load coupling test method, comprising the following steps: S1. Fabricate UHPC pipe section 9 specimens according to the design scale. UHPC pipe section 9 specimens include precast pipe sections and UHPC wet joints 10. The precast pipe sections are equipped with longitudinal reinforcing bars, stirrups and prestressed steel strands. The UHPC wet joints 10 are reserved with the lap length of the reinforcing bars and are equipped with shear key structures. After pouring, standard curing is performed to the design strength. S2. The perforated steel partition 7 and the two-way valve 6 are pre-embedded and cast at the end of the pipe section. Waterproof structural adhesive 8 is evenly applied at the joint between the perforated steel partition 7 and the inner wall of the UHPC pipe section 9 to form an independent closed water pressure chamber. The storage tank 3, air compressor 1, precision pressure regulator 5, and two-way valve 6 are connected to the chamber through the pressure-resistant metal hose 2. A 3.5% sodium chloride solution 4 is prepared in the storage tank 3 to simulate seawater. S3. Connect the actuator to the distribution beam with bolts, clamp the upper and lower sides of the UHPC pipe section 9 with clamps and pad with rubber pads, and pad with rubber hinge supports to form simply supported boundaries between the distribution beam and the intermediate clamps and between the end clamps and the concrete platform, and anchor the clamps at both ends with ground anchors. S4. Install strain gauges, strain rosettes, displacement gauges, and inclinometers on the key sections of the specimen, install anchor gauges on the reinforcement, install crack observation points on the UHPC wet joint 10, install pressure gauges and seepage measurement points in the cavity, and connect all sensors to the data acquisition system. S5. Inject sodium chloride solution 4 into the chamber and purge the air. Slowly pressurize to 0.1MPa and hold for 15 minutes to check the sealing performance. Apply 0.2 times the design load to check the loading and acquisition system. After confirming that there are no errors, unload and reset to zero. S6. First, stabilize the water pressure in the chamber to 0.2MPa and keep it constant. Then, apply static load in stages to achieve synchronous coupling of high pressure infiltration and mechanical load. When the UHPC wet joint 10 opens and leaks, stop loading. After draining the sodium chloride solution 4, continue loading until the specimen reaches the ultimate bearing capacity. S7. Calculate the permeability coefficient according to Darcy's law, measure the chloride ion penetration depth using the silver nitrate colorimetric method, establish the coupling relationship of multiple physical quantities, and evaluate the stress performance and watertightness performance of UHPC pipe section 9 and UHPC wet joint 10 under the most unfavorable working conditions.

[0027] Therefore, the present invention adopts the above-mentioned deep-water high-pressure infiltration and mechanical load coupling test device and method. The device adopts an internal chamber pressurization method to realize the synchronous coupling of high-pressure infiltration and mechanical load, and accurately tests the stress performance and watertight performance of UHPC pipe sections and joints under the most severe working conditions.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A deep-water high-pressure seepage and mechanical load coupling test device, characterized in that, include: Sealing water injection components, mechanical loading components, and monitoring and acquisition systems; The sealed water injection assembly includes a pipe section, with sealing baffles at both ends to form a sealed chamber inside the pipe section. The sealing baffles are connected to a pressurizing device and a pressure regulating device through pipelines to apply a permeating medium with a set water pressure to the chamber. By pressurizing the inside of the pipe section, the pipe wall is subjected to tension to form a test condition that is more unfavorable than the external water pressure, providing a permeating environment for the coupled test of the mechanical loading assembly. The mechanical loading component includes an actuator and a clamping component. The clamping component clamps the pipe section, and the actuator applies static load or fatigue load to the pipe section through the clamping component, which is coupled with the water pressure in the chamber. The monitoring and acquisition system includes sensors arranged at pipe sections and joints. The sensors simultaneously acquire the permeability parameters of the sealing water injection component and the mechanical response and crack development data of the mechanical loading component.

2. The deep-water high-pressure seepage and mechanical load coupling test device according to claim 1, characterized in that, The sealed water injection assembly has a joint inside the pipe section, and a sealing layer is provided between the sealing partition and the inner wall of the pipe section. A valve is installed on the sealing partition, and the valve is connected in sequence to a pressure regulating device, a storage tank and a pressurizing device through pipelines. The storage tank contains simulated seawater solution.

3. The deep-water high-pressure seepage and mechanical load coupling test device according to claim 2, characterized in that, The pipe section is a UHPC pipe section, the joint is a UHPC wet joint, the sealing partition is a wire-perforated steel partition, the sealing adhesive layer is a waterproof structural adhesive, the pressure regulating device is a precision pressure regulator, the pressurizing device is an air compressor, the pipeline is a pressure-resistant metal flexible hose, and the valve is a two-way valve.

4. The deep-water high-pressure seepage and mechanical load coupling test device according to claim 2, characterized in that, The simulated seawater solution is a 3.5% sodium chloride solution, and the set water pressure of the sealed chamber is 0.2 MPa.

5. The deep-water high-pressure seepage and mechanical load coupling test device according to claim 2, characterized in that, The sealant layer is a modified epoxy resin adhesive.

6. The deep-water high-pressure seepage and mechanical load coupling test device according to claim 1, characterized in that, The clamping assembly of the mechanical loading component includes a distribution beam and a clamp. The actuator is connected to the distribution beam. The clamp clamps the pipe section of the sealing water injection component. An elastic pad is provided between the clamp and the pipe section. Hinge supports are provided between the clamp and the distribution beam and between the clamp and the support base.

7. The deep-water high-pressure seepage and mechanical load coupling test device according to claim 6, characterized in that, The elastic pad is a rubber pad, the hinge support is a rubber hinge support, the support platform is a concrete platform, and it also includes a ground anchor. The rubber hinge support provides a simply supported boundary condition that provides only vertical support and allows free rotation.

8. The deep-water high-pressure seepage and mechanical load coupling test device according to claim 1, characterized in that, The sensors in the monitoring and acquisition system include strain gauges, strain rosettes, displacement gauges, and inclinometers arranged on the surface of the pipe sections; anchor gauges arranged on the internal reinforcement; crack observation points arranged at the joints; and pressure gauges and seepage measurement points arranged in the chambers. All sensors are connected to the data acquisition equipment.

9. A method for coupling deep-water high-pressure permeation with mechanical load, applied to the deep-water high-pressure permeation with mechanical load coupling test apparatus as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Prepare pipe section specimens including joints; S2. Install a sealing water injection assembly to form a closed chamber inside the pipe section and apply a permeating medium with a set water pressure to the chamber. By pressurizing the inside of the pipe section, the pipe wall is stretched to form an extreme test condition that is more unfavorable than the external water pressure. S3. Install the mechanical loading components to clamp the pipe section and form the set boundary conditions; S4. Deploy a monitoring and acquisition system, and install sensors at pipe sections and joints and connect them to the acquisition equipment; S5. Perform pre-loading debugging and check the sealing performance and the working status of the loading system; S6. Conduct a coupled loading test, keep the water pressure in the chamber constant, and apply external loads in stages to achieve synchronous coupling of water pressure and load; S7. Perform data processing and performance evaluation, calculate permeability parameters, and evaluate the stress performance and watertightness of pipe sections and joints.

10. The deep-water high-pressure seepage and mechanical load coupling test method according to claim 9, characterized in that, S1 specifically refers to: fabricating UHPC pipe section specimens according to the design scale ratio. The specimens include precast pipe sections and UHPC wet joints. The precast pipe sections are equipped with longitudinal reinforcing bars, stirrups and prestressed steel strands. The UHPC wet joints are reserved with the lap length of the reinforcing bars and are equipped with shear key structures. After pouring, the specimens are cured to the design strength according to standard. S2 specifically involves: pre-embedding and casting a perforated steel partition and a two-way valve at the end of the pipe section; uniformly applying waterproof structural adhesive at the joint between the perforated steel partition and the inner wall of the UHPC pipe section to form an independent, sealed water pressure chamber; connecting the storage tank, air compressor, precision pressure regulator, and two-way valve to the chamber via a pressure-resistant metal hose; and preparing a 3.5% sodium chloride solution in the storage tank to simulate seawater. S3 specifically involves: bolting the actuator to the distribution beam, clamping the upper and lower sides of the UHPC pipe section with a clamp and padding with rubber pads, padding with rubber hinge supports between the distribution beam and the intermediate clamp, and between the end clamp and the concrete platform to form a simply supported boundary, and anchoring the clamps at both ends with ground anchors. S4 specifically involves: installing strain gauges, strain rosettes, displacement gauges, and inclinometers on key sections of the specimen; installing anchor gauges on the reinforcement; installing crack observation points at the wet joints of the UHPC; installing pressure gauges and seepage measurement points in the chamber; and connecting all sensors to the data acquisition system. S5 specifically involves: injecting sodium chloride solution into the chamber and purging the air, slowly pressurizing to 0.1 MPa and holding the pressure for 15 minutes to check the sealing performance, applying 0.2 times the design load to check the loading and acquisition system, and unloading and zeroing after confirming that there are no errors. S6 specifically involves: first, stabilizing the water pressure in the chamber to 0.2 MPa and keeping it constant, corresponding to a water depth of 21 m; then, applying static loads in stages to achieve synchronous coupling of seepage and mechanical loads; pausing loading when the UHPC wet joints open and leak; draining the sodium chloride solution and then continuing loading until the specimen reaches its ultimate bearing capacity. S7 specifically involves: calculating the permeability coefficient based on Darcy's law, measuring the chloride ion penetration depth using the silver nitrate colorimetric method, establishing the load-deflection-strain-crack width-permeability coupling relationship, and evaluating the stress performance and watertightness of UHPC pipe sections and UHPC wet joints under coupled conditions.

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