ABSTRACT
The f a i l u r e modes d i s c u s s e d i n p r e v i o u s C h a p t e r s o f t h i s
b ook a r e a l l r e l a t e d t o t h e s l i d i n g o f a r o c k o r s o i l mass
a l o n g an e x i s t i n g o r an i n d u c e d f a i l u r e s u r f a c e . On page
31 b r i e f m e n t i o n was made o f a d i f f e r e n t f a i l u r e mode - t h a t
o f t o p p l i n g . T o p p l i n g f a i l u r e i n v o l v e s r o t a t i o n o f c o l u m n s
o r b l o c k s o f r o c k a b o u t some f i x e d b a se and t h e s i m p l e geo-
m e t r i c a l c o n d i t i o n s g o v e r n i n g t h e t o p p l i n g o f a s i n g l e b l o c k
on an i n c l i n e d s u r f a c e w e r e d e f i n e d i n F i g u r e 11 o n page 3 2 .
T o p p l i n g f a i l u r e s i n h a r d r o c k s l o p e s h a v e o n l y been d e s -
