now i am in final year civil engineering. can i do my integrated phd? without doing m.tech?

If integrated course is available than yes you can join it without MTech as integrated course includes two courses of different levels those in your case are MTech and Phd.

Yes its very much possible by enrolling urself for any research masters in Civil in abroad. Especially in UK and in US, universities do allow to enroll international students to Join the Research Masters which leads to Phd...