【go to ground】 —

1. fall down:

• Larsson claimed a penalty when he went to ground after a tussle with Amoruso.

2. (also: go to earth) go into hiding; put oneself out of sight:

• Some key gang leaders had been arrested and the assumption was that the others had “gone to ground.”

【go to the ground】 —

1. = 【go to ground】 1:

• Several of us were hit including me who went to the ground in a pool of blood.

2. be overcome; perish:

• Each vagabond that arrived bent his neck to the yoke of gain…. The strong survived, the weaker went to the ground.

Note: The expression does not fully correlate in meaning with the phrase go on the ground— = 【go to the ground】 1:

• She went on the ground and I picked her up and a couple of fellows came along, saying, “Do you want any help, officer?”