# Study on the Deterioration of Chloride Erosion in Tunnel Construction Joints Under a Multifactorial Environment

## TL;DR

This study examines how water pressure and erosion time significantly affect chloride ion concentration in concrete cracks under various environmental factors.

## Contribution

The paper introduces a novel test system to analyze chloride erosion in concrete under multifactorial conditions.

## Key findings

- Water pressure and erosion time are the most significant factors affecting chloride ion concentration.
- Nonlinear surface fitting with R-squared over 0.95 models the relationship between chloride concentration, water pressure, and erosion time.

## Abstract

Structural crack seepage in concrete is a common condition in engineering applications. Under the combined effects of multiple factors such as water pressure and load, cracks are more likely to occur inside the concrete structure, thus aggravating the water seepage problem. To simulate the chloride ion erosion of structural cracks, an independent test system that can simultaneously consider the coupling effect of multiple factors was developed. Three typical factors—water pressure, vertical load, and erosion time—were selected and designed using the orthogonal test method to analyze the effect of factors on the chloride ion concentration. The results revealed that the vertical load is the least influential factor, water pressure and erosion time are the most noticeable factors, and the factors influencing the diffusion of chloride ion in concrete are, in order of magnitude, water pressure (0.86), erosion time (0.66), and vertical load (0.36). Nonlinear surface fitting, with an R-squared value exceeding 0.95, was used to characterize the relationship between chloride ion concentration, water pressure, and erosion time.