综放工作面过运煤公路下开采技术

为了解决公路下安全高效开采技术问题,将工程实践、岩移观测、数值计算、理论分析相结合,对黄土沟壑区开采沉陷特征及公路下开采技术进行了研究。结果表明:由于煤层埋藏浅,第四系冲积层厚度大强度低,覆岩破坏剧烈,导水裂缝带直达地表,综放回采初期在上下顺槽内侧和切眼外侧出现台阶裂缝,裂缝走向与回采边界平行,落差较小;煤层开采达到或超过充分采动后在回采边界岩体沿煤壁整体切落,地表出现大的台阶裂缝;地表台阶裂缝的出现受地形影响比较明显,边坡土体在重力作用和开采沉陷影响下,地表裂缝更加发育;路基下部的厚黄土层可吸收部分开采沉陷变形,对减轻公路破坏发挥了一定作用;可按台阶裂缝角划定公路保护煤柱,煤柱内不放煤,地表及时采取措施可实现公路的安全运行。研究成果为相似地质条件公路下煤矿开采提供了技术参考。

Mining Technology under Highway of Coal Transportation in Fully Mechanized Top-coal Caving Working Face

In order to realize safe and high efficient mining under highway,the ground subsidence law and mining technology under highway in loess hilly-gully region were studied deeply through the comprehensive application of the engineering practice,field observation,numerical simulation and theoretical studies.The results showed that：because of the coal seam buried shallowly,the heavy thickness and the low strength of the Quaternary alluvium,the overlying rock strata in stope damaged severely and water conducted zone reaching to surface directly.At the initial of the fully-mechanized top-coal caving，step cracks appear inside of gate roads and outside of the cutting hole.Fracture trend parallel to the stope boundary,with small step throw.When coal mining reach or exceed the full mining,rock mass is cut down as a whole along the coal wall at the mining boundary,and big step cracks appear at the surface.The surface cracks are greatly affected by terrain.The surface cracks are well developed under the action of gravity and coal mining subsidence.The thick soil lager under subgrade can absorb part of the mining subsidence deformation,and this played a certain role in reducing highway damage.The coal pillar for highway safety can be designed by the steps cracks angle,and these pillars are not mined.The highway can run safely with some measures taken.This research provides a reliable reference for coal mining under highway with similar geological conditions.