One strategy for Angry Birds Bad Piggies level 21-11 is to ricochet the White bird into the bottom-left support, causing the main tower to topple. Blast the rightmost stone block, releasing the TNT-toting cart. Blast the remaining pig as needed. The score in the video below is 104,200.
If you have a different strategy feel free to leave a comment below; however, don't just post your score via the comments, as that's what the leaderboards are for.

Same as video, but key is to blow up the post with the 2nd bird as far to the right as possible. This helps to keep the TNT from rocking backwards. It needs to stay forward so when it detonates, it pushes the remaining structure and pigs off the cliff to the left for maximum points.
@dmsral Spectacular tip! I got 112k on my very first attempt after reading this.
Reverse birds from video. As @dmsral mentions, getting the first bird beyond the cement block allows the TNT to keep from blowing until it hits tower, slanting it to the left. Second bird as first in video brings everything down. Consistent 110K+ scores.
Great tips from both @abeggertoo and @dmsral. Waiting for the TNT to stop rocking and getting the tower to slant to the left should produce higher scores. Thank you both!
If the TNT be rockin’ don’t bother knockin’….
I understand wanting to do the left shot 1st because it’s the tougher shot, but it does take away what might be a potential (?) one-shot.
@78RPM – That’s funny…I found the second or right shot to be the much more difficult one. You can use the little purple flowers on the ground as a marker for the (left)first shot but no matter how far to the right my second bird went…the tnt didn’t often get the last two pigs. I finally got a decent score though.
I am not absolutely certain which side is better to do first, but I think my best scores are mostly done going for the left side first, including my current 114k.
Shot 1st bird exactly like the video above but shot second bird in the same manner(tried to knock off the whole structure to the right). It took several tries but got it to fall at last on the bottom right pig. However the TNT survived.
Self destruction is available for this lvl! Top of the house fell to the right! Could not investigate the benefits of it because the chicken was already in the air!
@communistpride — Some info about self-destruction already listed in forum on self-destroying levels, but more info would be useful.
After I read your comment, I did a reset and saw the top of the tower swaying a little. I waited about 10 seconds then little wood block and the helmeted pig rolled off to the left. Nothing else happened after that.
A few resets later, the vertical wood block under the little cement block shifted to the left but did not dislodge the cement block. This happened again after resetting a few more times.