1491 Figure 5 - Twin mapping of hydraulic support’s action 3.2 Attitude Evolution and Load Transfer Mechanism of Steeply Dipping Supports During the loading process of the supports in the steeply dipping working face, the average load measured by the support sensors gradually increased to 4.3 kN (2.19 MPa), with the peak total load reaching 38.7 kN (19.74 MPa). Subsequently, the load on the canopy decreased to 35.1 kN (17.90 MPa). The digital twin system indicated that the hydraulic support columns yielded with a height reduction of 3.7 cm. Upon further loading, when the total load reached 38 kN (19.39 MPa), the roof above the support fractured. Highdefinition monitoring showed that the roof mass slid into the down-dip support area, while the twin system displayed that the support tilted in the down-dip direction by approximately 4.25°. As the hydraulic support exhibited a continuous tilting tendency, its real-time tilting posture within the physical space was simultaneously rendered in the system interface. The digital twin system subsequently issued a hydraulic support tilt warning to alert operators for intervention. Attitude change of supports in steeply dipping working face is shown in Fig.6. Figure 6 - Attitude change of supports in steeply dipping working face Following the mitigation of the support instability anomaly, the support condition rapidly returned to normal, with the average sensor load increasing to 1.7 kN (0.87 MPa). Dynamic and static load tests were then conducted on the hydraulic support (Fig.7). When a static load was applied to the support by the platform's loading plate, the maximum, minimum, and average readings from the canopy sensors were 3.86 kN, 3.26 kN, and 3.63 kN, respectively. Under vertical impact loading, the corresponding values were 4.00 kN, 3.50 kN, and 3.75 kN. This indicates that the average load borne by the canopy under impact conditions was significantly greater than under static loading. During side-pushing impact, the readings from the two sensors on the canopy side guard were markedly higher than those from the sensors on the canopy surface, exhibiting a cyclical variation pattern where each cycle’s reading exceeded the previous one. Under rearpushing impact, the sensors on the caving shield showed a characteristic load distribution: highest in the upper inclined region, moderate in the central region, and lowest in the lower inclined region.
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