Research on the Deformation and Control Technology of Surrounding Rock in Entry Retaining along the Gob Side

Table 9

Questionnaire on deformation and failure of E1316 intake entry.

Mileage (m)	Description of roadway damage
15∼17	Flexible formwork wall is inserted upward
23, 24, 58	The coal body at the bottom of the coal pillar side is extruded 30–50 cm, and the ladder beam is broken.
69	Fracture of the ladder beam in coal pillar side.
78	Flexible formwork wall bulge phenomenon.
82∼84, 100	Fracture of the ladder beam in coal pillar side.
103∼105	Metal net at the lower part of coal pillar side cracking, ladder beam fracture, and flexible formwork wall cracking.
113	The bolt of the coal pillar side failed, and the cables were laid beside it.
118	Fracture of the ladder beam near the second bolt at the bottom of coal pillar side.
132∼138	Cracking of entry floor.
151∼154	Two bolts in the middle of coal pillar side are pulled out by the mining stress.
163	Anchoring cable for pillar reinforcement has been removed in later period.
175∼180	Extrusion and crushing at shoulder corner of the roof and coal pillar side is serious.
188	Unanchoring of the third bolt from the bottom of the coal pillar side.
190–214	Cracking of entry floor.
198∼201	Four rows of ladder beams were broken in the middle and lower parts of coal pillar side.
213	The flexible formwork wall cracks in a 3-square range, the ladder beam at the bottom of the coal pillar side was broken, and the roof protruded seriously.
221	Two failure bolts in the middle of coal pillar side.
229∼232	The upper and lower parts of the flexible formwork wall fall into the bag. The height is 1.2 meters, and the length is 4.5 meters.
239	The second bolt dynamometer reading at the bottom of the coal pillar wall is 24 MPa, which is abnormal; the flexible formwork wall cracks, and the middle part falls into the bag.
247∼253	The damage and deformation of coal pillar side are serious, which are mainly affected by primary mining and adjacent chambers.
259∼267	Roof breakage and subsidence are very serious, especially near the side of the coal pillar.
276	Unanchoring of the third and fourth bolts from the bottom of the coal pillar side.
296	Unanchoring of the third bolt from the bottom of the coal pillar side.
308	Unanchoring of the second bolt from the bottom of the coal pillar side.
311, 312	Unanchoring of the second bolt from the bottom of the coal pillar side.
320∼350	The upper part of flexible formwork wall badly bulge phenomenon.
334∼336	Flexible formwork wall with bulge phenomenon, bulging range is 2 meters.
352∼355	Cracking of the flexible formwork wall is serious.
358	The second repaired cable at the bottom of the coal pillar side has failed.
399∼406	Cracking of entry floor.
413∼422	There are timbers to strengthen support in this area, and there are chambers nearby.
476∼479	Over-excavation of coal pillar side is serious, and the cross section is large and irregular.
537∼541	The roof is broken seriously, the displacement is large, and the flexible formwork wall has bulging problem.
581	Unanchoring of the third bolt from the bottom of the coal pillar side.
583	Unanchoring of the second bolt from the bottom of the coal pillar side.
620	The upper part of the flexible formwork wall bulges and cracks, and the third anchor bolt is removed from the bottom of the coal pillar side.
630∼640	Water accumulation in entry and floor cracking.
652	The upper part of the flexible formwork wall is bulging within 2 meters.