Abstract: The excavation height of left slopes at Jinping I hydropower station is 530 m; faults and deep fracture were developed, unloading range is deep; and its geological conditions is complicated. Slope stability problems are important especially in the construction and operation. The engineering monitoring geological conditions of the slope is analyzed; deformation monitoring layout for the slope is described. The deformation monitoring system of the slope consists of surface deformation observation, shallow deformation observation and deep deformation observation. In three levels, monitorings of the slope deformation are made. For the surface deformation monitoring the geodetical surveying method is used; for the shallow deformation observation the multi-point displacement meters are used; the monitoring depth is 0-90 m; for the deep deformation observation the flat hole ranging, level survey and graphite convergence meters methods, etc, are used installed in exploration flat hole, through the main fault and deep crack, the biggest monitoring depth reach 260 m. By May 2011, monitoring data indicate that the maximum horizontal displacement in surface and shallow is 106.1 mm; the maximum settlement is 58.6 mm; which are controlled by excavation and supporting; the maximum horizontal displacement in deep is 47.48 mm; the maximum settlement is 7.2 mm, controlled by faults and deep fractures. The displacement tends to converge, the maximum deformation rate is 0.1 mm/d; and it meets the designed safety standards, slope has verged to stable.

Key words: deformation monitoring, high slope, Jinping I hydropower station