地下厂房锚梁围岩加固技术研究

Study on Reinforcement Technology of Anchor Beam Surrounding Rock of Underground Powerhouse

某电站右岸地下厂房布置在河床右岸的山体内,主厂房围岩支护系统包含上下游边墙系统锚杆和预应力锚索。根据安全监测资料分析主厂房两根锚索拉力值长期缓慢增长,但无突变,总体拉应力超过设计值。经研究,认为5′-5′监测断面附近软弱夹层出露,造成围岩长期缓慢变形所致。采用“上倾式大孔径深孔预应力树脂锚杆+脉冲挤压法灌浆”进行围岩加固,增设20根长度12 m、上倾角15°、P=100 kN的预应力树脂锚杆,同时安装4套锚索测力计自动化监测,以保障设备和人员安全,加固效果良好。

The underground powerhouse on the right bank of a power station is arranged in the mountain body on the right bank of the river bed.The surrounding rock supporting system of the main powerhouse includes the anchor rod and the prestressed anchor cable of the upper and lower side wall system.According to the safety monitoring data,the tension values of the two anchor cables in the main building increase slowly for a long time,but there is no sudden change.The overall tensile stress exceeded the design value.After study and discussion,it is considered that the weak intercalation near the 5’-5’monitoring section is exposed,which results in the long-term slow deformation of the surrounding rock.In this paper,the surrounding rock reinforcement is carried out by up-inclined large-diameter and deep-hole prestressed resin anchors combined with pulse extrusion grouting.20 prestressed resin anchors with length of 12 m,up-inclined angle of 15°,P=100 kN are added.At the same time,4 sets of anchor cable dynamometers are installed for automatic monitoring to ensure the safety of equipment and personnel,and the reinforcement effect is good.