How long can my employer keep me employed with no work?

My job has slowed down a lot over the past couple months. The past 3 weeks I haven't had any work at all and was told to stay home. I call in the mornings and they say stay home today, theres no work. A lot of my co-workers are facing the same trouble too. How long before I can collect unemployment? I am afraid if I apply for partial unemployment, while still employed, my company will retaliate by making me work out of town (happend before). I filed for unemployment a couple years because we were slow, and my employer fought it and said there was work. When my employer spoke with me, they were pissed off because I filed and forced me to work out of town for several weeks. I've heard that you can collect unemployment if you quit, under certain cirstances. Any suggestions?