<s>
Discontinuous	B-Algorithm
deformation	I-Algorithm
analysis	I-Algorithm
(	O
DDA	O
)	O
is	O
a	O
type	O
of	O
discrete	B-Algorithm
element	I-Algorithm
method	I-Algorithm
(	O
DEM	O
)	O
originally	O
proposed	O
by	O
Shi	O
in	O
1988	O
.	O
</s>
<s>
DDA	O
is	O
somewhat	O
similar	O
to	O
the	O
finite	B-Application
element	I-Application
method	I-Application
for	O
solving	O
stress-displacement	O
problems	O
,	O
but	O
accounts	O
for	O
the	O
interaction	O
of	O
independent	O
particles	O
(	O
blocks	O
)	O
along	O
discontinuities	O
in	O
fractured	O
and	O
jointed	O
rock	O
masses	O
.	O
</s>
<s>
and	O
Jing	O
who	O
resolved	O
this	O
problem	O
by	O
adding	O
finite	B-Application
element	I-Application
meshes	O
in	O
the	O
two-dimensional	O
domain	O
of	O
the	O
blocks	O
so	O
that	O
stress	O
variations	O
within	O
the	O
blocks	O
can	O
be	O
allowed	O
.	O
</s>
