toughstakes makes a similar design that works great in either loose sand or snow. Its similar to your design except has much larger wings at the bottom of it. You might try and weld some fins on yours for soft sandy soil.
In hard or rocky soil, however, they can dent against a rock or soil if pushed other than by hand.
In rock or hard soil I'd rather have a steak like yours, it is less likely to bend or dent.
Hey, if you want me to take a dump in a box and mark it "guaranteed", I will. I got spare time.