there have greate possibility to crack top IIT in civil with 700 score in GATE .. you can check all IIT cutoff through the following link :

Hello Ritu,

Congratulations! 

You scored so well. 700 is enough score to get into IITs.

As per your score, You can get any of top IIT like IIT Bombay, IIT Madras, IIT Delhi etc. If you need Structural Engineering or Construction Technology and Management then it is possible that you may not get Top IIT. But if you opt for Water Resources Engineering or Environmental Engineering then you can get any of top IIT.

Choose branch Wisely.

Check Best possible option for you by following Link

Https://engineering.careers360.com/gate-college-predictor?icn=gate-clgpd&ici=QnA_Answer

Hope for best