The purpose of The Dawes Act, authored by Congressman Henry Dawes on February 8, 1887, was to extend citizenship to indigenous people born within the United States and to get them to "[adopt] the habits of civilized life." According to Dawes, there were numerous lifestyle habits, including wearing clothes, "[riding] in Studebaker wagons," and drinking whisky, that made one "civilized." Clearly, Dawes's idea of being "civilized" was based on the supposed lifestyle habits of rural white men who owned small plots of land.
Owning land was (and in some ways, still is) a way to claim citizenship. The land was to be allocated among Native Americans only, as follows:
To each head of a family, one-quarter of a section; To each single person over eighteen years of age, one-eighth of a section; To each orphan child under eighteen years of age, one-eighth of a section; and, To each other single person under eighteen years now living, or who may be born prior to the date of the order of the President directing an allotment of the lands embraced in any reservation, one-sixteenth of a section; . . .
The fractions tell us how much land is to be given to each person designated. For example, each head of the family— presumably a husband and father—would receive a one-quarter parcel of land on a reservation "for agricultural and grazing purposes." What is unique is that children (no mention of sex is given) were also allocated a piece of land on the reservation—one-eighth of a section. Given that land is usually allocated in acres, we can deduce that "a section" indicates an acre.
The Dawes Act did not apply to immigrants because it explicitly makes these allowances to "every Indian born within the territorial limits of the United States." The only way that an immigrant would have benefited is by marrying a Native American. Former slaves did not benefit from the act either. Reconstruction had promised Southern blacks "forty acres and a mule." However, The Compromise of 1877 effectively ended Reconstruction, as well as any further attempts to extend full citizenship, including land ownership, to emancipated black people.
The Dawes Act was successful, insofar as integrating and assimilating natives into the dominant white society. It attempted to coerce the native into understanding that private ownership was fundamental and important. Native American tribes, such as the Mohegan and Seminole, have applied this ethic to their development and ownership of very lucrative casinos. However, they have retained their autonomy from the U.S. government through tax exemptions.
This depends very much on what you think its purpose was.
If the purpose of the Dawes Act was to get Native Americans to assimilate into white ways of life by becoming small farmers, it did not work. Many or most of the Indians were not equipped or trained to farm. Because of this, the Dawes Act did not lead to a situation in which Indian families generally farmed their own private land.
However, if the purpose of the Dawes Act was to destroy the old Indian ways of life and to diminish the power of the tribes, you can certainly argue that it was successful. Through the Dawes Act, huge amounts of land (about 2/3 of the original total) was sold to non-Indians.
So, the Dawes Act didn't do anything to help Indians, but it did help those white people who were able to buy the land and it did help to weaken Indian nations.