Stability analysis and deformation control method of swelling soft rock roadway adjacent to chambers

Abstract

The surrounding rock of swelling soft rock roadway has high clay mineral content, strong expansibility after encountering water, low strength and poor cementation. The roadway is prone to large deformation under the influence of complex geostress. Combined with the support change of the development roadway of 2# coal in Hongqingliang mine, through geological survey, field observation and indoor test, the failure mechanism of the traditional support method of “anchor bolt + anchor cable + anchor mesh + shotcrete” was revealed by the adjustment of the surrounding rock stress after the excavation and support of the adjacent chambers. The research results show that the surrounding rock stress will cross the adjacent chambers and form a concentrated area near the weakly cemented roadway, and the maximum stress increase ratio of surrounding rock within the stress concentration range will reach 50%. The farther the chambers are from the weakly cemented roadway, the smaller the range of the surrounding rock stress concentration area. When the distance exceeds about 12 times the average height of the chambers, the surrounding rock stress concentration tends to disappear. Based on the fully enclosed combined support method of the "U-shaped steel sheds closure roof and sides + filling flexible material behind the sheds + laying reinforcement mesh and concrete in floor + strengthening key parts", the construction process flow applicable to the working condition of swelling soft rock roadway is formulated.

Surrounding Rock Deformation Mechanism and Control Technology for the Roadway in the Fault-Disturbed Zone under Special-Shaped Coal Pillars

“…On the one hand, reinforced support of anchor cables can connect the deep surrounding rock with the pretightening force bearing structure formed by rock bolt support. This will fully mobilize the bearing capacity of deep surrounding rock and realize the common bearing capacity of rock mass in a wider range [46]. On the other hand, the high pretightening force provides surrounding rock with compressive stress, which played a part in forming a skeletal network structure with the compression stress area formed with rock bolts, keeping the overall stability of surrounding rock [47,48].…”

Burst Failure Characteristics and Energy Evolution Law of Coal with Prefabricated Cracks at Different Angles

“…Te whole process from loading deformation to destruction of coal body is accompanied by the accumulation and transformation of energy. Energy is the essential factor leading to the destruction of the coal bodies [19][20][21][22][23][24][25][26]. Many scholars have carried out a lot of research on energy and rock failure, but there are few studies on the energy of cracked coal, which still needs further research.…”

Step by step and combined supporting technique with allowable deformation + limiting shape for soft rock roadway

“…At present, U-shaped steel shed is widely used in mining engineering, but there are obvious differences in economy, stiffness, bearing capacity and other aspects of U-shaped steel shed based on different support time [ 21 , 22 ]. Zhang et al [ 23 ] found that the U-shaped steel shed is difficult to be removed and repaired after the roadway is damaged and deformed. The construction and support time of the U-shaped steel shed would have a significant impact on the support effect.…”