You are a professor in the field of building fires in civil engineering please help me polish the following text to make it suitable for SCI journalsWhen a fire occurs inside an immersed tunnel the te

When a fire occurs in an immersed tunnel, the temperature inside the tunnel increases, resulting in significant thermal strain and expansion of the tunnel towards the outside. This expansion causes the external concrete of the immersed tunnel to crack due to tensile forces. As the fire progresses, the cracks on the outside of the tunnel gradually expand, and their depth increases. For hydraulic structures such as immersed tunnels, concrete cracks are highly dangerous. In the design of fire-resistant immersed tunnels, it is crucial to consider not only the reduction of the bearing capacity of the fire structure but also the concrete cracks caused by the high temperature of the fire.

During the cooling stage after the fire, the inner surface of the tunnel may crack due to rapid cooling. The concrete will crack alternately on the inner and outer surfaces of the tunnel due to the alternating action of fire heating and cooling, leading to the formation of through cracks in the tunnel. In this case, tunnel seepage can occur, directly affecting the safety of the immersed tunnel. Even if no through cracks are formed, severe cracks can lead to the exposure of reinforcement to marine chloride environments, accelerate the corrosion of rebars, and reduce the service life of the immersed tunnel. Therefore, it is essential to consider the potential for concrete cracking in the fire resistance design of immersed tunnels