Pitching new batch of Belgian onto Yeast Cake?

I am contemplating utilizing my Yeast Bed of wlp500 (Chimay) that is presently sitting beneath the Dubbel that was started on Nov. 19th. It is in a 9.5-10 gallon batch that is in a 15.5 gallon Sabco Fermenter. OG was 1.076 and as of a week and a half back or so (2 weeks and 2 days in primary) it was down to about 1.016-1.017, when I drained a sample through racking tube. I will be preparing another batch, one of a lighter color but not as strong as a Trippel to pour upon this Cake as opposed to harvesting, cleaning the whole Fermenter which is closed and hasn't been open since pitching the 3 liter starter from stir plate.
Now my question to You Brew Brainiacs, or anyone is.. does this sound like a plausible plan, and if so, any special preperatons like adding a Yeast Nutrient or an additional pitching from another starter from above. I was planning on getting the Ardennes strain of yeast into the Starter on the Stir Plate friday night, and count on a second wind from the Yeast Cake while it's in place. Is there any sense to this? I haven't brewed on a Cake in these Fermenters yet, and haven't done so with a higher gravity wort such as these at any rate. I will be racking the Dubbel off into secondaries either way friday night or saturday. Thanks!

I it definitely plausible. I do not think you need any nutrients or additional yeast pitched. You may consider removing some of the existing cake. I pitched onto a yeast cake recently and had my first krausen mess all over the top and sides of my fermenter. Looking back, I should have dropped some yeast before adding fresh wort. However, the beer fermented quickly and cleared quickly.

I have always read, here and actual brewing books, to avoid reuse of the yeast for high gravity beers. The risk of gimp yeast due to dna damage? I don't know. I was thinking of the same thing. I had a 1.075 beer I made the other day that has a Texas-size yeast pile in the bottom of the carboy. It's probably a good 3/4" thick.

Just seems like a shame to ruthlessly end the lives of a trillion little yeast who have so admirably served The Cause.

I think you will be fine, I know you said it was a double but 1.075 is big but not that big, I've done it with my Wyeast London ale when making back to back porters and they were 1.068-1.070. Thinking now I just did the same with my pale ale and IPA with Wyeast 1056 they were both 1.065-1.068 beers.

Thanks for the feedback folks. It wouldn't be more iffy as for yeast viability with the Beer being in the primary a full month. I pitched at 68 degrees, it reached a max of 75 degrees and settled back down to 62 the last couple of weeks. It was still burping now and then I'd catch it as of 10 days ago or so. So I'll be careful with my wort temp not being too much warmer (5 degrees?) when I pump it in, and just get everything in suspension, oxygenate and wait for some activity ha?