抚顺城区采动地裂缝变形特征及其演化过程

Deformation Characteristics and Evolution of Ground Fissures in the Mining Area,Fushun City

抚顺市地裂缝一直是困扰城市发展和安全的重大工程地质问题。本文根据现场调查,结合地面变形监测结果,剖析了抚顺城区地裂缝的分布、变形特征。地裂缝主要发育于抚顺老虎台矿北部城区,整体走向NE 60°~80°,基本沿浑河断裂带分支断裂展布,属拉张型裂缝。地面变形监测结果显示,本文根据现场调查,结合地面变形监测结果,剖析了抚顺城区地裂缝的分布、变形特征。地裂缝区地面不仅发生沉降变形,还发生水平拉裂。地面变形量大小则与距离采空区远近有关,近采空区地裂缝两侧地面沉降、水平变形量大,其最大沉降变形量可达130 mm,最大水平变形量约700 mm,地表一般表现为裂缝沉陷带或裂缝陡坎;而远离采空区地裂缝两侧地面沉降、水平变形量相对较小,裂缝宽度在几毫米至几厘米之间。随着采煤工作面不断向深部及北部城区推进,地面变形日趋强烈,地裂缝扩展迅速,同一条断裂上不同区段地裂缝向两侧扩展、相接,形成几百到几千米不等的地裂缝带。目前,城区地裂缝仍在变形发展中,其形成是由于深部采矿活动诱发,尤其是老虎台矿、西露天矿等矿井开采引起地表下沉或高陡边坡变形。随着地表变形量逐渐加大,先存的浑河断裂带软弱分支断裂面重新活化,沿断裂面向地表扩展、贯通形成地裂缝。因而,有必要进一步研究抚顺地裂缝的成因机制及演化过程,为地裂缝的防治预警提供科学依据。

Ground fissures in Fushun City have always been a major engineering geological problem that retards country development and poses a risk in safety.Based on field investigation and ground deformation monitoring results,the distribution and deformation characteristics of ground fissures in Fushun city are analyzed in this paper.These ground fissures mainly developed in the northern urban area of Fushun Laohutai mine,with a general trend of NE 60°~80°,largely spreading along the branch faults of the Hunhe fault zone,attributed to tensile fractures.The results of ground deformation monitoring show that the ground in the fissure area has not only subsidence,but also horizontal break.The amount of ground deformation is related to the distance from the goaf.Remarkable ground deformation occurs on both sides of the fissures near the goaf,with maximum subsidence 130 mm and horizontal displacement 700 mm,respectively.The surface generally exhibits crack-depression zones or scarps,while the subsidence and horizontal displacement on both sides of the ground fissures far away from the goaf are relatively small,with fissure width ranging several millimeters to several centimeters.As the coal mining face continues to advance to the deep subsurface and towards the northern urban area,the ground deformation is becoming stronger and the fissures spread rapidly.The ground fissures in different sections of the same fault expand and connect to both sides,forming crack zones of hundreds to thousands of meters in length.At present,development of ground fissures in the urban area is still going on,which is caused by deep mining activities,especially the mining of the Laohutai mine and the Xilutian mine which has resulted in surface subsidence or high-steep slope deformation.With the gradual increase of surface deformation,the existing weak branch fractures of the Hunhe fault zone are reactivated,extending and connecting along the fracture surface,forming new ground fissures.Therefore,it is necessary to further study the formation mechanism and evolution process of the ground fissures in Fushun,which would provide a scientific basis for the prevention and early warning of such a geologic hazard.