The phrase "average spalling ratio" is correct and usable in written English.
It can be used in contexts related to materials science, engineering, or construction, particularly when discussing the extent of spalling in a material or surface.
Example: "The average spalling ratio of the concrete samples was measured to assess their durability under extreme weather conditions."
Alternatives: "mean spalling rate" or "typical spalling ratio".
Figures 33 and 34 show spalling depth and spalling ratio at different ground pressure periods respectively (average 4.9 m/d).
In the middle part of the face, the spalling depth was 0.6 m, maximum spalling ratio was 49.15 % and maximum spalling length was 50.75 %. (3) Coal wall spalling at the lower part of the face.
a Relationship between average rib spalling depth and face advance rate, b relationship between rib spalling ratio and face advance rate, c relationship between rib spalling length and face advance rate.
a Relationship between average rib spalling depth and face advance rate, b relationship between rib spalling length and face advance rate, c relationship between rib spalling ratio and face advance rate During the period of periodical ground pressure, the average coal wall spalling depth at the lower part of the face decreased with the increase of the face advance speed.
Open image in new window Fig. 33 Comparison of average spalling depth at different ground pressure periods under different face advance speeds Open image in new window Fig. 34 Comparison of spalling ratio at different ground pressure periods under different face advance speeds.
a Relationship between average rib spalling depth and face advance rate, b relationship between rib spalling length and face advance rate, c relationship between rib spalling ratio and face advance rate During the non-periodical pressure period, at the lower part of the face, the relationship between coal wall spalling and face advance speed showed a certain degree of randomness.
a Relationship between average rib spalling depth and face advance rate, b relationship between rib spalling length and face advance rate, c relationship between rib spalling ratio and face advance rate During the period of periodical ground pressure, the spalling depth presented a trend of decrease early on, and increasing later with the increase of face advance speed.
The statistical analysis of the spalling ratio showed: the spalling ratio in the middle part of the face > the spalling ratio at the upper part of the face > the spalling ratio at the lower part of the face.
