广州蓄能电站地下厂房喷锚支护施工

Construction of bolt-shotcrete supports at an underground pumped storage power plant

广州蓄能电站地下厂房施工遵循新奥法的基本原则，充分利用围岩自身的承载能力，在围岩发生有害变形之前即进行喷锚支护。通过锚筋、挂网和喷混凝土所形成的喷层紧贴围岩，具一定柔性，共同变形，承载能力高，安全可靠，施工方便、速度快。选用喷层厚１５ｃｍ，分三次喷完。根据实测围岩松动圈厚度、参照法国和瑞典地质专家的建议和鲁布革电站的经验，综合选定系统锚杆长度。随机锚杆则根据地质结构面切割所形成的失稳岩体经计算确定。锚杆造孔采用瑞典ＡＴＬＡＳ公司的三臂液压凿岩台车进行，以挪威ＬＯＢＯＣＯＮ喷浆机喷浆，上海和挪威产注浆机注浆，平台车配合人工插锚杆。原型观测成果表明，顶拱先具下沉、后抬升的规律，证明已形成新的平衡拱；拱脚、侧墙和墙脚等处的应力、应变值均正常；进而表明所选用的喷锚支护参数是合适的，厂区围岩处于稳定状态。西端墙重大断层蚀变带经综合处理后，渐趋稳定。

During construction of Guanszhou underground pumped storage power plant, based on the basic principles of new Austrian tunneling method, before harmful deformations of surrounding rock occur, bolt-shotcrete supporting is carried out fully to use the supporting capacity of surrounding rock mass itself. Shotcrete thickness of 15 centimeters is completed in three times. According to observed thickness of surrounding loosed rock and with reference to proposals of French and Swedem experts as well as experience in Lubuge power plant, the general length of anchor bolts is defined.The length of random anchor bolts is calculated on basis of a specific failure rack block formed by discontinuities. Prototype observation results show that arch crown deformation of settling at first and rising thence-forth indicates the formation of new balanced arch; stresses and strains at arch abutments. sidewalls and wall bases are in normal condition. Thus, selected parameters of bolt-shotcrete supports may be considered reasonable. Rock mass surrounding the power plant is stable. The large faulted erosion zone having been comprehensively treated at the west end of plant trends gradually to-ward stable.