临涣矿区地表沉降对井壁破裂的影响

Influence of Surface Subsidence on Fract ure of Shaft wall in Linhuan Coalfield

调查5个立井井壁破裂情况,监测第四含水层水位下降、地表沉降和井壁压缩下沉情况,地表下沉对井壁产生附加力,使井壁破裂。

There are 11 vertical shafts at 3 coal mines in Linhuan Coalfield.Fractures of shaft walls have been discovered since July 1987.After monitoring and measuring water level of water-bearing beds, surface subsidence and compressive deformation of shaft wall,water level descends max. 150 m and descendant speed of water level is 11 m/ year. Surface Subsidence value is more than 200 mm; Area of surface subsidence is 34 km^2; Max. surface subsidence value topped 500 mm; Average annual surface subsidence value is 40-50 mm. Surface subsidence influences shaft wall with minus frictional force.The minus frictional force changes along with the seasons change.The minus frictional force in summer is relatively large and causes comparative serious damage;The minus frictional force in winter is relatively small and causes light damage or does not cause any damage.Period of minus frictional force change is one year.In brief, underground water level decreases; surface subsides; surface slips along shaft wall, which causes additional force and fractures of shaft wall. Grout is grouted into outside of shaft wall to strengthen shaft wall,block against water and decrease deformation of shaft wall.