| Summary: | Tunnel fire is a part of applied thermal problems. With increase of transient
temperature of the tunnel fire on the structure surface (i.e. tunnel
lining), the heat transfer from the surface is possibly varying transient
temperature distribution within the structure. The transient temperature
distribution is also possibly damaging the composition of structure
(micro-crack) because of critical damage temperature. Therefore, the
transient temperature distribution has a significantly important role on
defining mechanical and physical properties of structure and determining
thermal-induced damaged region. The damage at pre-period stage of tunnel
fire is perhaps more significant than that at the other period stages
because of thermal gradient. Consequently, a theoretical model was developed
for simplifying complicated thermal engineering during pre-period stage of
tunnel fire. A hollow solid model (HSM) in a combination of dimensional
analysis and heat transfer theory with Bessel’s Function and Duhamel’s
Theorem were employed to verify a theoretical equation for dimensionless
transient temperature distribution (DTTD) under linear transient thermal
loading (LTTL). Experimental and numerical methods were also adopted to
approve the results from this theoretical equation. The heating rate (M) is
a primary variable for discussing DTTD on three means. The heating rate of
10.191, 10 and 240°C/min were applied to experimental and numerical studies.
The experimental and numerical results are consistent with the theoretical
solution, successfully verifying that the theoretical solution can predict
the DTTD well in field. This equation can be used for thermal/tunnel
engineers to evaluate the damaged region and to obtain the parameters
related to DTTD.
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