Mechanism of weakening pressure arch of hydraulic fracturing to regulate mining-induced stresses
MA Ying
WU Qunying
LI Jianzhong
GAO Fuqiang
LOU Jinfu
YUAN Guiyang
YANG Jinhong
Abstract：Hydraulic fracturing(HF)is a key technology for stress relief in surrounding rock of coal mine roadways.Optimizing its parameters is crucial for achieving effective pressure relief and stress transfer in surrounding rock.Taking a fully-mechanized mining face in a specific mine as the engineering background,the stress evolution laws of the floor and coal pillar under HF was investigated using integrated physical similarity model tests and UDEC discrete element numerical simulation.The pressure relief mechanism of HF by weakening the pressure arch to regulate mining-induced stresses was revealed.Furthermore,the influences of the HF horizon height and the rock mass damage degree in the HF-affected zone on the pressure relief effect were analyzed.The results show that when the HF fracture propagation zone is located above the high-stress zone of the coal mass,the peak vertical stress in the high-stress area of floor and shallow coal mass decreases by 10.8%-12.1%,while that in the deep low-stress zone increases by only 1.1%.When HF fractures distribute along the high-stress transfer path of the pressure arch,the load-bearing capacity of the roof in this area is significantly weakened,promoting the transfer of high stress to deeper regions.This results in a characteristic distribution featuring significant pressure relief within a shallow limited zone and slight pressure increase across a large deep zone.This elucidates the pressure relief mechanism whereby HF regulates the stress transfer path by weakening the pressure arch structure.The pressure relief effect is closely related to the HF horizon height and the rock mass damage degree in the HF-affected zone.Increasing the vertical horizon extends the pressure relief range deeper and elevates the stress in the shallow coal mass.An increase in damage degree of rock mass within the HF-affected zone significantly enhances the pressure relief magnitude in the high-stress area,further inhibiting the ability of the damaged zone to transmit the high stress of the pressure arch,thereby promoting the transfer of high stress to deeper rock mass.Field implementation demonstrates that HF significantly reduces coal pillar stress and enhances surrounding rock stability.The research findings provide theoretical bases for optimizing HF parameters to weaken hard roofs,prevent rock bursts,and de-stress in roadways subjected to intense mining-induced stresses.
Keywords：hydraulic fracturingintense mining induced stressstress regulationpressure archpressure relief mechanism
Publication Date：2025-08-31
Online Publishing Date：2025-09-05(First online date of this platform, not the publication date of the document)
Pages：14( 215-228 )