The lag distance of abutment pressure behind working face increases, but the convergence coefficient of vertical stress doesn't change obviously with the increase of mining height.
The convergence of air at the lower levels and divergence aloft imply a vertical circulation which is schematically shown in the following cross-sectional diagram.
下面是热带气旋的垂直环流示意图，图中可看到低层的空气辐合及高层的空气辐散。
3
The Newton iterative method is used in the calculation of entropy density function, by which the non-convergence issue in the calculation for the vertical bearing capacity of piles is solved.