Innovative Control Technique for the Floor Heave in Goaf-Side Entry Retaining Based on Pressure Relief by Roof Cutting

Abstract

To solve the difficulty in controlling floor heave of a retained goaf-side roadway, a new control technique was investigated from the perspective of the pressure relief by roof cutting by combining mechanical analysis, numerical simulation, and engineering tests. The mechanical principle of controlling the floor heave based on pressure relief by roof cutting was attained by analyzing the movement of overlying strata and mechanical characteristics of key blocks before and after the roof cutting. A new technique for controlling the floor heave based on pressure relief by roof cutting was proposed. Research results have shown that after performing pressure relief by roof cutting, the caved gangues in the goaf can support the overlying strata and, thereby, change the movement law thereof and weaken the abutment pressure on the coal wall. Furthermore, the pressure exerted on the roadway floor by the coal wall is lowered to prevent plastic deformation of the floor, thus controlling floor heave in the roadway; a new integrated technique for controlling the floor heave based on pressure relief by roof cutting, flexible yielding, controlling with double-direction-control anchor bolts, and controlling with reinforcing anchor cables is developed, and the technological processes of support, cutting, and protection are summarised. The results of field testing showed that, after applying the new technique, the average floor heave amount of the roadway declines by 64% and the average speed of the floor heave up to 231 m behind the working face decreases by 61%.

Floor Heave Control in Gob-Side Entry Retaining by Pillarless Coal Mining with Anti-Shear Pile Technology

“…(a) An analysis of the floor heave dynamic monitoring showed that this phenomenon evolved with different intensities at different stages of the gateroad's life. This is generally consistent with previous studies [15,17,27,41]. The gateroad that was an object of study had no water inflows.…”

“…Many scholars have studied the floor heave mechanism in gob-side entry retaining [15][16][17]. It can be concluded that failure or plastic flow of the immediate floor, caused by stresses exceeding the strength limit of the rock, is a prerequisite for floor heave [18].…”

Dynamic Pressure Manifestation Mechanism and Control Techniques for Roadways with Large Mining Heights and Intense Mining: A Case Study

“…Since roadways are a key component of the production and transportation system in coal mines, improving their safety, reliability, and stability is of great importance for coal mine production. With the recent increase in coal mining depths and intensity; however, dynamic pressure phenomena such as rib spalling, floor heave, and roof fall have appeared frequently in roadway surrounding rock, posing serious threats to safety and efficient production [1][2][3][4]. In response, many scholars have intensively studied the dynamic pressure manifestation in coal mine roadways.…”