Measurement of surrounding-rock deformation and support-resistance demand in roof-cut automatically formed roadways of inclined thick coal seams

Abstract

The deformation control of roof-cut automatically formed roadways in inclined thick coal seams is strongly dependent on the reliable measurement of roof subsidence, rib convergence, stress redistribution and support-resistance demand. Taking the 1703 fully mechanized top-coal caving face of Hongling Coal Mine as an engineering case, this study develops an integrated measurement and interpretation framework combining theoretical supportresistance analysis, DIC-based physical model testing and field convergence monitoring. The measured results show that the dynamic-pressure roadway-formation zone is the most critical stage: rotational subsidence of the roof cantilever on the goaf side induces support failure and rapid surrounding-rock deformation. The theoretical support resistance required in this zone is 2097.4 kN/m, which is higher than the 1352 kN/m provided by the original support system. Physical model measurements indicate that the displacement concentration first occurs near the cutting slot and then transfers towards the roadway middle and solid-coal side, with the peak relative displacement reaching 3.68 mm. Field measurements further show that the highresistance hydraulic support reduces the roof-floor convergence at the slotting side from 1200 mm to 220 mm and reduces rib-to-rib convergence from approximately 700 mm to 190 mm. The results demonstrate that the coupled measurement of displacement field, stress response and support resistance can provide a quantitative basis for identifying insufficient support and optimizing temporary support design in roof-cut gob-side entry retaining.