Fig. 2

The overall situation and profile of five typical cases (1 Limestone; 2 Siltstone; 3 Argillaceous siltstone; 4 Gravelly soil; 5 Coal seam; 6 Goaf; 7 Fractures; 8 Stratigraphic boundary; 9 Fault; 10 Upper member of the Lower Triassic Yelang Formation; 11 Lower Triassic Yelang Formation lower member; 12 Lower Triassic Jialingjiang Formation; 13 Lower Triassic Yongningzhen Formation; 14 Lower Triassic Feixianguan Formation; 15 Upper Permian Changxing-Dalong Formation; 16 Upper Permian Longtan Formation; 17 Section direction; 18 Rock occurrence).