CN-122016630-A - Laboratory corrosion simulation method for wharf pile foundation

CN122016630ACN 122016630 ACN122016630 ACN 122016630ACN-122016630-A

Abstract

A laboratory corrosion simulation method for a wharf pile foundation belongs to the technical field of port engineering and comprises the following steps of 1, designing and preparing a test piece, 2, designing and manufacturing a water tank according to a wharf marine environment report, S22, immersing the test piece in the water tank for 60 days before corrosion, guaranteeing that chloride ions in a seawater solution permeate into concrete, S24, calculating the electrifying time and the corrosion efficiency, S25, measuring the corrosion rate of a steel bar, S26, collecting and sorting data, analyzing, S27, detecting the corrosion degree and external characteristics of the concrete, and S28, performing mechanical property experiments. The laboratory corrosion simulation method of the wharf pile foundation can provide theoretical basis and data foundation for durability design and full life cycle management of the high-pile wharf.

Inventors

SU LEI
ZENG GUIYU
LIANG HAIZHI
CHENG QIANQIAN
Zhou Linlu
LING XIANCHANG

Assignees

青岛理工大学

Dates

Publication Date: 20260512
Application Date: 20260227

Claims (8)

1. A laboratory corrosion simulation method of a wharf pile foundation is characterized by comprising the following steps: Step 1, designing and preparing a test piece; step 2, an accelerated corrosion experiment, which comprises the following specific steps: s21, designing and manufacturing a water tank, namely designing the water tank according to a reduced scale model, and reserving a water outlet and a water pumping port of the water tank; s22, designing an acceleration system according to a wharf marine environment report; S23, before corrosion, placing the test piece in a water tank for soaking for 60 days, and ensuring chloride ions in the seawater solution to permeate into the concrete; S24, calculating the power-on time and the rust efficiency; s25, measuring the corrosion rate of the steel bars; s26, data acquisition and arrangement analysis; S27, detecting the corrosion degree and external characteristics of the concrete; s28, mechanical property experiment.
2. The laboratory corrosion simulation method of a pier foundation according to claim 1, wherein the step 1 comprises the following steps: s11, designing a test piece type: the test piece types include: A type is a material grade test piece, wherein a cylinder with the diameter of phi 100 multiplied by 200mm is used for testing chloride ion permeation, electrochemical parameters and microscopic analysis; The B-type component-level test piece is used for making a reduced scale model according to an actual high pile wharf and reinforcing bars according to a reinforcing bar rate so as to simulate the bending resistance and crack resistance degradation of a pile body; Drawing a section diagram of a high pile wharf, calculating the embedding depth of an elastic long pile according to specifications to obtain the calculated length of the pile, carrying out scale reduction according to a ratio of 1:5 or 1:6, reinforcing steel bars according to a scale reduction ratio and meeting the reinforcing steel bar ratio, and additionally installing a pile pier at the pile bottom to obtain a scale reduction model; S12, experimental grouping: dividing the test pieces into 8 groups of A1-A4 and B1-B4 according to service environment differences and load working conditions, wherein each group comprises parallel test pieces, the group A researches a chloride corrosion path and a time effect, the group B researches a mechanical-environment coupling effect, and each group is provided with a control group and an accelerated corrosion group; And S13, when the test piece is prepared, concrete raw materials, the mixing ratio and the maintenance system are actually consistent with the engineering, connecting the inductor, the strain gauge and the lead in advance when the test piece is prepared, checking whether the inductor, the strain gauge and the lead can work normally or not after pouring is finished, and carrying out corrosion experiments after all the test pieces are required to be subjected to standard maintenance for 28 days.
3. The laboratory corrosion simulation method of a pier foundation according to claim 2, wherein in S22, the acceleration system comprises: the corrosion mode is dry-wet circulation based on electrifying acceleration and seawater solution corrosion; a simulation area for the splash zone and the tidal range zone; the solution is sea water; and (3) dry-wet circulation, namely filling seawater to a splash zone, and pumping and draining water by a periodic water pump to realize water level variation so as to simulate the tidal range and splash of the ocean.
4. A laboratory corrosion simulation method for a pier foundation according to claim 3, wherein S24 comprises the following steps: calculating the electrifying time by using the A-type test piece, so as to correct the electrifying time of the B-type test piece, wherein the steel bar corrosion rate is 5%,10%,15% and 20% respectively according to experimental design; The electrified density of the steel bar in the experiment is calculated as follows: ; wherein I is the rust current density, I is the power-on current intensity, l is the length of the steel bar, and d is the diameter of the steel bar; And then reversely calculating the power-on time by using the following formula: ; Wherein, the = Wherein, k is the electrochemical equivalent of metal, g/(A.s), I is the current magnitude, A is the unit; t-time, unit s; And after the electrifying time of the test piece reaches the preset time, taking out the concrete test piece, destroying the test piece, taking out the rusted steel bar, cleaning up residual concrete on the surface of the steel bar, placing the steel bar into hydrochloric acid for pickling and rust removal, neutralizing residual hydrochloric acid on the surface of the steel bar by saturated lime water, and finally washing the steel bar with clear water. The steel bar is dried and then placed in a drying box, and the steel bar is weighed after the quality is stable to obtain the quality after the steel bar is rusted The actual rust amount of the steel bar is obtained by comparing the initial mass of the steel bar The calculated steel bar rust efficiency is shown in the following formula: 。
5. the laboratory corrosion simulation method of a pier foundation of claim 4, wherein S25 comprises the following steps: After the A-type test piece reaches the predicted power-on time, breaking the concrete to obtain a rusted steel bar test piece; removing concrete residues attached to the surface of the steel bar, derusting the steel bar by using dilute hydrochloric acid, neutralizing the acid-washed steel bar by using alkaline lime water solution, placing the washed steel bar into a drying box, measuring the weight of the steel bar after the quality of the steel bar is stable after the drying is finished, and calculating the actual corrosion degree of the steel bar according to a mass corrosion rate formula by using an electronic scale.
6. The laboratory corrosion simulation method of a pier foundation of claim 5, wherein S26 comprises the following: The method comprises the steps of connecting a steel bar with a positive electrode of a power supply through a lead, connecting a copper sheet to a negative electrode, configuring the steel bar in an electrolytic cell as the positive electrode, and using the copper sheet as the negative electrode; And connecting the embedded sensor and the strain gauge into the acquisition instrument by using four core wires, checking whether each instrument can work normally, and repeatedly debugging the acquisition instrument. And (3) pushing experiment acquisition data according to an experiment scheme, and carrying out statistics, arrangement and analysis on the obtained experiment data.
7. The laboratory corrosion simulation method of the pier foundation of claim 6, wherein the step S27 comprises the following steps of observing and recording rust matters on the surface of the test piece, cracks and development of the rust cracks and the like after the energizing time of the test piece reaches an expected calculated value, and analyzing the relation between the external characteristics and the distribution of chloride ions.
8. The laboratory corrosion simulation method of a pier foundation of claim 7, wherein the step S28 comprises the steps of performing a mechanical property test on the test piece after the corrosion test is completed, and comparing the obtained test data with the test piece which is not corroded.

Description

Laboratory corrosion simulation method for wharf pile foundation Technical Field The invention belongs to the technical field of port engineering, and particularly relates to a laboratory corrosion simulation method of a wharf pile foundation. Background The main body structure of the high pile wharf consists of a large number of prestressed concrete pipe piles and steel pipe piles which are driven into water, and the working environment is extremely severe marine corrosion environment. The seawater contains high-concentration Cl -, can penetrate through the concrete protective layer, damage the passivation film on the surface of the steel bar, and initiate and accelerate electrochemical corrosion. The difference of dry and wet alternation and oxygen supply causes the local corrosion to be aggravated, the corrosion is most serious in a splash zone and a tidal range zone, and the concrete is in periodic soaking (hypoxia) -exposing (oxygen enrichment) circulation, so that a perfect oxygen concentration battery is formed. The structural characteristics result in extremely difficult and expensive repairs, concealment, irreplaceability, and costly repairs. Thus, pile foundation corrosion directly threatens the safety and durability of the dock, and once the pile foundation fails, the entire structure may collapse, causing catastrophic results and significant economic loss. Although field exposure experiments truly reflect the reality of the environment, certain limitations remain. Such as extremely long corrosion time, taking years and even decades as units, complete structural size, real protective layer thickness, macro crack system and the like, no boundary effect, corrosion is the result of long-time cooperative competition of multiple mechanisms, difficult, expensive and lagged data acquisition and control, extremely high cost and huge risk. In order to decompose, purify and accelerate complex natural processes, and to know how key variables (such as chloride ion concentration and water cement ratio) affect results in an acceptable time, it is necessary to study a laboratory corrosion simulation method of a pier foundation. Disclosure of Invention The invention discloses a laboratory corrosion simulation method of a wharf pile foundation, which aims to reproduce and explore a corrosion damage process which can only occur in a natural environment for decades in a scientific, controllable and accelerated mode. The corrosion environment monitoring method comprises the steps of comparing and verifying with a field exposure experiment, ensuring reliability and engineering applicability of an experiment result, simulating corrosion environments in different service stages by accurately regulating and controlling key parameters such as chloride ion concentration, humidity, temperature and dry-wet cycle period, introducing an electrochemical monitoring technology to track corrosion progress of the steel bar in real time, combining microscopic morphology analysis and macroscopic mechanical property test to establish a corrosion damage evolution model, and finally providing theoretical support and data foundation for durability design, life prediction and protection strategy optimization of a high-pile wharf structure. In order to achieve the above purpose, the technical scheme of the invention is as follows: A laboratory corrosion simulation method of a wharf pile foundation comprises the following steps: Step 1, designing and preparing a test piece; step 2, an accelerated corrosion experiment, which comprises the following specific steps: s21, designing and manufacturing a water tank, namely designing the water tank according to a reduced scale model, and reserving a water outlet and a water pumping port of the water tank; s22, designing an acceleration system according to a wharf marine environment report; S23, before corrosion, placing the test piece in a water tank for soaking for 60 days, and ensuring chloride ions in the seawater solution to permeate into the concrete; S24, calculating the power-on time and the rust efficiency; s25, measuring the corrosion rate of the steel bars; s26, data acquisition and arrangement analysis; S27, detecting the corrosion degree and external characteristics of the concrete; s28, mechanical property experiment. Preferably, the step 1 includes the following: s11, designing a test piece type: the test piece types include: A type is a material grade test piece, wherein a cylinder with the diameter of phi 100 multiplied by 200mm is used for testing chloride ion permeation, electrochemical parameters and microscopic analysis; The B-type component-level test piece is used for making a reduced scale model according to an actual high pile wharf and reinforcing bars according to a reinforcing bar rate so as to simulate the bending resistance and crack resistance degradation of a pile body; Drawing a section diagram of a high pile wharf, calculating the embedding depth of an elastic long