What was found
(CAN) SHORTLY AFTER TAKEOFF NR 2 ENGINE N1 INDICATION SHOWED 10 PERCENT HIGHER THAN NR 1 AND 3 ENGINES. ALL PARAMETERS WERE THE SAME. WHEN THRUST WAS REDUCED TO LOWER N1 SETTING, NR 2 ENGINE HIGH VIBRATION WAS CONFIRMED ON BOTH CHANNELS AT 2.5 UNITS (VIB. LIGHT ON). ENGINE NR 2 WAS SHUT DOWN PER QRH. AFTER INSPECTION , MAINTENANCE FOUND ICE ACCUMULATION STUCK IN THE DUCT AND MANY LP FAN BLADE TIPS WERE BENT. ALL LP FAN BLADES WERE REPLACED.