At the time of the decision about building the tunnel, 15.9 million passengers were predicted for Eurostar trains in the opening year. In 1995, the first full year, actual numbers were a little over 2.9 million, growing to 7.1 million in 2000, then dropping to 6.3 million in 2003. Eurostar was initially limited by the lack of a high-speed connection on the British side. After the completion of High Speed 1 in two stages in 2003 and 2007, traffic increased. In 2008, Eurostar carried 9,113,371 passengers, a 10% increase over the previous year, despite traffic limitations due to the 2008 Channel Tunnel fire. Eurostar passenger numbers continued to increase, reaching 10,397,894 in 2014.

does the eurostar go under the english channel?
yes