Based on soil sampling, lab experiment and support resistance
monitoring, the disturbance of soil physical quality indices between
different underground mining stages of No 52303 working face was studied
in semi-arid region of western China. Soil sampling was conducted in
same locations before and after mining in 2014. This study proved that
soil water content, soil cohesion and soil porosity were greatly
decreased, while bulk density and dry density were increased by coal
mining. In comparison, coal mining had slight effect on organic matter,
internal fraction angle, and D1 and D2 percent. Underground pressure
monitoring showed that P1 during stage 2 was significantly greater than
that during stage 1, indicating the large difference of pressure
characteristics in tail areas of working face between two stages. Both
soil water content and soil cohesion were decreased during two stages in
two sites. Soil cohesion was strongly correlated to soil water content,
and D1 and D2 percent in 2013 and 2014. Coal mining subsidence increased
the cumulative probability to reach the same value of soil water content
and soil cohesion. The cover depth produced different elastic and
plastic zone widths between sites by theoretical model calculation,
consistent with the support resistances in tail areas of working face.
Higher pressure might cause a more serious destructive rock-soil body
and a larger groundwater level decrease. The dryer and more serious
erosive soil column induced by coal mining is a non negligible matter
for the semi-arid region.