ABAQUS. Convergence problem:error-time increment too small- JOINTED ROCK MASS STABILITY

[manos90]

Dear all,

I am trying to examine the stability of a jointed rock mass. I use 3 steps: first step is GEOSTATIC, second step is static and the third is also static where i define gravity loading:
*STEP,UNSYMM=yes, NLGEOM=YES,INC=10000000
*STATIC
.1,1.,,.1
*CONTROLS,ANALYSIS=DISCONTINUOUS
*DLOAD
ALLE,GRAV,0.049,-1,0.
I run this file and the analysis completed successfully.

When i increase the load (0.49), the analysis does not finish. I solved the problem with the follow changes:
*STEP,UNSYMM=yes, NLGEOM=YES,INC=10000000
*STATIC
.01,1.,0.00000001,0.1
*CONTROLS,PARAMETERS=FIELD
1.0,100.0,,200.0
*DLOAD
ALLE,GRAV,0.49,-1,0.

As before, i increase the load to 1 (ALLE,GRAV,1,-1,0.) and the analysis stop again with the error:Time increment required is less than the minimum specified.

I cannot solve this problem. Could anyone please give me some suggestions how can i eliminate this error?

Best regards,
Manos