COCA CODO SINCLAIR水电站TBM1卡机事故剖析与处理
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摘要
TBM尤其是双护盾TBM对地质条件适应性差,在遇到较大的断层破碎带时掘进将面临较大困难。在对COCA CODO SINCLAIR水电站TBM1卡机事故现场的详细调查基础上,结合岩体物理力学性质、地应力测试结果、超前钻探资料及结构构造发育特征,探明断层影响范围,建立卡机段工程地质模型,发现围岩极破碎,软硬相间,地应力大,空间分布不均,围岩局部大变形是发生盾体被卡的主要原因,而隧洞施工对围岩扰动,加剧相对隔水层破坏,最终导致突泥涌水。据此,决定拆除掌子面后方27m处部分管片,人工开挖清渣洞清除、加固松散岩体,增设排水洞超前探放水,并通过清渣洞绕至刀盘前方对断层破碎带影响区域的主洞顶拱扩挖加固,最终使TBM1成功脱困并顺利穿越断层破碎带。
Because tunnel boring machine(TBM)does not acclimatize to different geological conditions very well,the fault fracture zone great big challenge to TBM's construction,especially double-shield TBM.Based on the detailed investigation in job site of TBM at COCA CODO SINCLAIR hydropower station in Ecuador,considering rock mass physical mechanical property,in-situ stress test,pilot boring,rock mass structure,the faults influence range was determined and engineering geological model of blocked TBM was established.It finds out that the surrounding rock is extremely broken,hard and soft is alternated with each other,ground stress is large and spatial distribution is uneven.Local large deformation of surrounding rock is the main reason for the TBM1's jamming,and the water resisting layer was destroyed by construction resulting in mud and water bursting.Therefore,apart of segments behind the tunnel face 27 mwere removed to excavate the tunnel beside of the headrace tunnel facing to tunnel face.One was used to remove and strengthen loose rock,and the other was for advance water exploration and drainage.When the slag cleaning tunnel across the fault fracture zone,the pilot tunnel was excavated along the axis of the headrace tunnel for reinforcement of surrounding rock of upper part.All the measures were successful for the TBM1 passing the fault fracture zone properly.
Because tunnel boring machine(TBM)does not acclimatize to different geological conditions very well,the fault fracture zone great big challenge to TBM's construction,especially double-shield TBM.Based on the detailed investigation in job site of TBM at COCA CODO SINCLAIR hydropower station in Ecuador,considering rock mass physical mechanical property,in-situ stress test,pilot boring,rock mass structure,the faults influence range was determined and engineering geological model of blocked TBM was established.It finds out that the surrounding rock is extremely broken,hard and soft is alternated with each other,ground stress is large and spatial distribution is uneven.Local large deformation of surrounding rock is the main reason for the TBM1's jamming,and the water resisting layer was destroyed by construction resulting in mud and water bursting.Therefore,apart of segments behind the tunnel face 27 mwere removed to excavate the tunnel beside of the headrace tunnel facing to tunnel face.One was used to remove and strengthen loose rock,and the other was for advance water exploration and drainage.When the slag cleaning tunnel across the fault fracture zone,the pilot tunnel was excavated along the axis of the headrace tunnel for reinforcement of surrounding rock of upper part.All the measures were successful for the TBM1 passing the fault fracture zone properly.
引文
[1] Yellow River Engineering Consulting Co.,Ltd..The Basic Design Report of Coca-Codo Sinclair Hydroelectric Project[R].Zhengzhou:Yellow River Engineering Consulting Co.,Ltd.,2011.
[2] Barton N.TBM Tunnelling in Jointed and Faulted Rock[M].Rotterdam:A.A.Balkema,2000.
[3] Egger P.Design and Construction Aspect of Deep Tunnels(with Particular Emphasis on Strain Softening Rocks)[J].Tunnelling and Underground Space Technology,2000,15(4):403-408.
[2] Barton N.TBM Tunnelling in Jointed and Faulted Rock[M].Rotterdam:A.A.Balkema,2000.
[3] Egger P.Design and Construction Aspect of Deep Tunnels(with Particular Emphasis on Strain Softening Rocks)[J].Tunnelling and Underground Space Technology,2000,15(4):403-408.