Ground Control Issues on Photovoltaic Power Generation Facilities Construction in Coal Sinkhole Region

Coal sinkhole region has attracted attention of Chinese government and photovoltaic enterprises to be used for photovoltaic power generation facilities construction land presently. The special requirements of subsidence and deformation were analyzed for photovoltaic power generation facilities construction. The overburden fracture zone height of goafs and load influence depth of construction were calculated. The ground control issues were researched on photovoltaic power generation facilities construction in coal sinkhole region based on stability evaluation. The results showed that, firstly, the allowable subsidence value of collection station is between 150 mm and 200 mm in photovoltaic power generation facilities. Secondly, the allowable subsidence difference or inclination of collection station are 0.002-0.003 times of collation station length while the allowable subsidence difference of photovoltaic support is 0.008 times of support purlins span. Thirdly, when the sum of overburden fracture zone height and load influence depth are less than buried depth of goafs, the foundation of coal sinkhole region is in a stable state and it cannot cause ground subsidence, so the coal sinkhole region can be used as construction site after simple anti-deformation measures have been taken. Last but not the least, when the sum of overburden fracture zone height and load influence depth are larger than buried depth of goafs, the foundation of coal sinkhole region is in an unstable state, and the ground control measures such as grouting for goafs and protective coal pillars reservation should be taken to control ground subsidence. Only after the special anti-deformation design finished, the coal sinkhole region can be used as construction site.