depends. If you are an experienced hire, it might take longer (up to 6-8 weeks) as they might want to wait until a project in the pipeline is sold. Ask HR to clarify the timeline.
If you are a graduate, you should seek the visibility of SMs and SEs in the office and offer your help on proposals etc. as it's always a very good opportunity to meet other consultants and get known in the firm. I assume you have tried this route, but continue asking, and check also with your counselor and mentor if they see opportunities on their projects to get you involved. In the meantime, you can start working off your required trainings, get involved in your university team, ...and enjoy 9-5.