Fig 1.
Mining subsidence damages and ground fissures in Wanli Town, Dongsheng District, Erdos City, Inner Mongolia, China.
Fig 2.
Directions of layer movements caused by subsidence in a flat coal seam.
Fig 3.
Results of conventional physical similar simulation tests.
Table 1.
Geological conditions in model (ratio of similitude 100:1).
Fig 4.
The accomplished two-dimensional plane model.
Table 2.
Similar material properties.
Fig 5.
The hydraulic loading devices.
(A) “RSC–1050” jacks and “CP–180” hydraulic pump. (B) Spring-steel plate mechanisms.
Table 3.
“RSC–1050” jacks’ parameters.
Fig 6.
The final model of Test 1.
Fig 7.
Quasi-three-dimensional high-pressure hydraulic loading simulation experiment platform.
Fig 8.
The simulation hydraulic support with working resistance monitoring sensor.
Table 4.
Geological conditions in model (ratio of similitude 100:1).
Table 5.
Similar material properties.
Fig 9.
(A) Mixture of materials. (B) Compaction of materials. (C) Mica powder for layer separation. (D) The accomplished model.
Fig 10.
Two cases with and without three-hinged arch structure.
Fig 11.
Slots set on the right side of the models.
Fig 12.
Overlying strata movement and breakage during the excavation.
Fig 13.
Overlying strata movement and breakage during the excavation.
Table 6.
The distance of fracture ahead, initiation angle and fracture angle at different position.
Fig 14.
Overlying strata movement and breakage before excavated to 70cm.
Note: “60b”means the coal wall is at 60cm but the support is at 50cm and doesn’t lower, “60a”means the coal wall is at 60cm and the support lowers at 50cm.
Fig 15.
Overlying strata movement and breakage when excavated to 70–100cm.
Fig 16.
Overlying strata movement and breakage when excavated to 130cm and 180cm.
Fig 17.
Overlying strata movement and breakage when excavated to 180cm.
Fig 18.
Overlying strata movement and breakage after finished excavation.
Table 7.
The distance of fracture ahead, initiation angle and fracture angle at different position.
Fig 19.
The stress of the hydraulic support during the caving process.
Fig 20.
Mechanical model of roof’s fracture.
Fig 21.
The three-hinged arch structure.
Fig 22.
Stress distribution in beam.
Fig 23.
Stress distribution in beam under different l.
Fig 24.
Crack initiation angle under different shift step distance.
Fig 25.
The breakage when excavated to 100cm.
Fig 26.
Stress distribution in beam under different l.