城市近郊深部条带老空区综合探测及关键技术

Comprehensive Detection and Key Technology of Deep Strip Old Goaf in Urban Suburbs

城市近郊老空区地基不稳定的问题是阻碍城市空间扩张发展的关键因素之一,查明老空区的赋存状态,量化各项参数,才能作出合理老空区处治方案。首先分析了城市近郊条带老空区地质采矿背景及地球物理特征,讨论了适宜的地面物探、孔间物探和钻探的探测方案;综合运用地面物探(高密度三维地震、瞬变电磁法)、孔间物探(孔间电法CT)及钻孔探测(垂直钻孔、定向钻孔)技术,获得条带老空区的平面分布范围、垮落断裂带高度和充水状态等参数。结果表明:(1)城市近郊深埋、厚松散层条带老空区适宜选择综合物探普查+钻探验证的综合探测方案;(2)对于不具备垂直钻孔布置条件但对拟建场区稳定性可能产生较大影响的关键区域,可采用多分支双靶点受控定向钻探进行钻孔验证,同时可作为施工阶段注浆孔;(3)城市近郊条带老空区为非充分采动形成,整体处于不充分垮落全充水状态,顶板部分发生垮落,采空区内部存在较大空间与裂隙,仍可能产生较大的残余变形量。

The foundation instability of strip miningin in urban suburbs was key factor to prevent the expansion and development.Only identified occurrence state and quantifying various parameters could made reasonable treatment plan.Analyzed the geological and mining background and geophysical characteristics in urban suburbs.Discussed the suitable exploration.Used high-density 3D seismic exploration,transient electromagnetic exploration,electrical CT detection,vertical drilling and directional drilling technology.Obtained the plane distribution of strip mining,the height of the collapse fault zone and the water filling state.The results show that:(1)The comprehensive geophysical survey and drilling verification scheme were suitable for the strip mining of deep buried and thick loose layer in urban suburbs.(2)It was an effective method used multi branch and double target controlled directional drilling to verify the key areas where drilling may had a great impact on the stability of the proposed site.In addition,the directional drilling could be used as grouting hole in construction stage.(3) The strip mining goaf was insufficient collapse and full water filling,the roof part collapses,distribution large spaces and cracks inside,which may still produce large residual deformation in future.