Finally Richards got up and strode aimlessly about the room, ploughing his hands through his hair, much as a somnambulist might do who was having a bad dream.

1. ploughing his hands through - 词典上没找到这样类似的用法。

2. 上面much as是否省略了一个as？应该是as much as,  比较的是前后2个动作的程度much吗？

3. 另外一点，是否有much as 单独作为连词的用法，含意是“虽然，尽管”， 可理解为习惯用语吗？