Not that I'm aware of. I know ours gauged 8 weeks from dig date, but could change due to weather, permitting and other issues that could arise during construction. It was in summer and the days were long with not many days lost to weather. Plus our city is really good about inspecting at each phase quickly and they got done right at the 6-week mark.
That said, if construction is supposed to start on or around X date, and maybe a month or more goes by with nothing, I bet you would be within your right to terminate the contract. Might ask someone familiar with construction litigation to get the specifics.