承张高速某段穿越铁矿采空区稳定性评估

Stability assessment of a goaf in iron deposit crossedby Chengzhang Expressway

地面高速在经过矿区采空区时,路基及车辆荷载会引起地表沉降,从而影响采空区的稳定性。本文以承张高速某段穿越滦平县国铁矿业有限公司郎营铁矿二采区为研究区,通过高密度电阻率法测试深部采空区、钻探工程验证,并采用稳定性有限元计算分析,认为采空区顶板局部不稳定或稳定性差,但由于采空区埋深相对较大、顶板岩性完整、岩体抗压强度高,在路基和公路荷载作用下围岩受的影响不大;而地表沉降增幅较大、采空区跨度较大时,在流变及风化、上部车辆荷载的扰动作用下,顶板上覆围岩将会发生垮落,顶板厚度逐渐减小,可能影响到上方地表路基的正常运行。

When the high-speed ground transportation passes through the goaf,the subgrade and vehicle load may cause the surface settlement,thus affecting the stability of the goaf.In this paper,No.2 mining area of Langying Iron of Guotie Mining Corporation in Luanping County,which crossed by Chengzhang Expressway,was taken as the research area.The deep goaf was tested by high density resistivity method,and verified by drilling engineering.The stability finite element calculation analysis was adopted.It is believed that the goaf roof is locally unstable or poor in stability.However,due to the relatively large buried depth of goaf,the goaf roof has intact lithology and high compressive strength of rock mass.The surrounding rock has little influence under the load of roadbed and highway.However,when the surface settlement increases greatly and the goaf span is large,the surrounding rock on the roof may collapse under the disturbance of rheology,weathering and upper vehicle load,and the roof thickness may gradually decrease,which could affect the normal operation of the surface subgrade above.