This is the impression that I got from Full Metal Alchemist Brotherhood and a random Chinese soap opera my mom was watching last night. The whole process seemed to involve a lot of stabbing and it struck me as a rather inefficient way to run a family values government :P
It varied depending on the dynasty, individual emperors' choices, and the dispositions of the wives and concubines. Some emperors (not many- one from the Wei dynasty, one Sui, and one Ming, as far as I know) were in monogamous marriages.
Most emperors had a "first wife," who served as the empress, and concubines, who did not have equal social status; the primary reason for their concubinage was to sire male heirs, in case the first wife did not have sons.
By Confucian social norms, each successive wife or concubine was supposed to be subservient to the ones who had been married to the emperor for a longer time. Ideally, all the wives would share a bond like sisters. However, judging by the prominence of the theme in literature, power struggles among wives/concubines were considered fairly normal. There certainly were cases in history when wives and concubines had violent struggles. One prominent example would be the conflicts that preceded Empress Wu Zetian's reign. It's impossible to know for sure, but one common interpretation of history is that Wu Zetian worked her way up (via manipulation, and likely murder/infanticide) from being a lowly concubine, to being the first wife among nine concubines, to succeeding her husband's reign and starting the self-proclaimed Zhou dynasty.
I rememer a particular part of Record of the Grand Historian says something like this:
(Note: Lu Zhi was the empress then empress dowager of Han. She was.... basically a very cruel and unpleasant person. She was written extensively because she tried to 'take over' the Han dynasty by installing her own family members onto important positions. But this also means some of the records might be exaggerated against her since she essentially tried to undermine the Liu family who were the emperors.... keep this in mind.)
After Lu's husband died she tried to take revenge on one of her late husband's other wives, Qi. Apparently Lu hated Qi so much that she ordered her henchmen to chop off Qi's all 4 limbs, gorged out Qi's eyes, ears, and nose, then threw Qi into a toilet (i.e. a pool of piss and poo).