深埋隧道侧穿采空区施工安全距离及能量演化机制

Safety distance and energy evolution mechanism of deep tunnel construction when side-crossing a goaf

为确保近接采空区隧道工程的施工与运营安全,基于动力数值分析,并通过FISH语言编程对FLAC 3D数值模拟软件进行二次开发,以实际工程为依托,分析讨论了深埋隧道侧穿采空区施工安全距离及能量演化机制。研究结果表明:依据隧道侧穿采空区的不同安全距离,隧道结构安全区域分为危险区、影响区和安全区;累积应力水平能量和应力比之间的曲线可分为加速、均速和减速3个阶段,3个阶段的能量演化亦能较好地反映围岩内部损伤破坏机制;现场振速实测曲线表明,安全距离为1 D时采空区对隧道的稳定性影响有限,隧道侧穿采空区地段施工整体上稳定且符合安全需求;隧道与采空区间的最佳安全距离约为隧道跨度的1倍。

In order to ensure the safe construction and operation of the tunnel excavation near a goaf,based on the dynamic numerical analysis,we redeveloped the FLAC 3D numerical simulation software using FISH programming to investigate the safety distance and energy evolution mechanism of the deep tunnel construction of an actual project.The results show that according to the different safety distances between the tunnel and the side goaf,the tunnel structure is divided into dangerous zone,influenced zone and safe zone.The relationship between the cumulative horizontal energy and stress ratio can be divided into three stages,which are acceleration,average stability and deceleration,and the energy evolution of the three stages can also reflect the damage and failure mechanism inside the surrounding rock.Moreover,the measured field vibration velocity curve shows that when the safety distance is 1 D,the goaf has limited influence on the stability of the tunnel,and the construction of the side-crossing section of the tunnel is safe on the whole and meets the safety requirements.Therefore,the optimal safety distance between the tunnel and the goaf is about the same as the tunnel span.