Stress Analysis of Negative Coal Pillar Gob-Side Entry and Its Principle of Preventing Rock Burst

Table 2

Material parameters and proportion of different constituents in physical model materials.

Rock strata	Density (kg·m^−3)	Proportion number	Materials	Aggregate: materials	Lime: plaster (lime: soil)
Medium sandstone	1.67	6 : 5 : 5	Sand : cement : plaster	6 : 1	5 : 5
Mudstone	1.66	8 : 6 : 4	Sand : lime : plaster	8 : 1	6 : 4
Siltstone	1.70	6 : 5 : 5	Fine sand : lime : plaster	6 : 1	5 : 5
Limestone	1.68	10 : 9 : 1	Fine sand : lime : plaster	10 : 1	9 : 1
Shale	1.69	10 : 6 : 1	Fine sand : lime : plaster	8 : 1	9 : 1
Sandy mudstone	1.60	8 : 6 : 4	Fine sand : lime : plaster	10 : 1	8 : 2
Siltstone	1.70	6 : 5 : 5	Fine sand : lime : plaster	6 : 1	5 : 5
Mudstone	1.66	8 : 6 : 4	Sand : lime : plaster	8 : 1	6 : 4
Coal	1.02	10 : 1 : 0	Fine sand : lime : soil	10 : 1
Mudstone	1.66	8 : 6 : 4	Sand : lime : plaster	8 : 1	6 : 4