No,you can't get admission in THAPAR as they require JEE mains marks to get admission,you can try to get admission in other good engineering colleges,there are many other College which give admission via class 12 Marks.

• You can drop an year and then study to give JEE mains next time
• Thapar University is among the top universities in India.Many students havw bagged packages in crores.

Don't get disappointed when you don't get admission instead work hard.
There are many good engineering College in India.
You can use College predictor tool available on this website and can predict your college using your JEE mains rank.
You can give other states entrance exams such as if you want admission in UPTU you can give its exam

• Lpu(Lovely professional University) also give admission based on class 12 marks.
• Chandigarh University is also very good.They have good placement results.

Moreover you can give VITEEE to get admission in vit.
Its also the best engineering college after some IIT.
If you don't get admission in Btech you can also pursue BSC and get job as a teacher in schools and colleges.
Don't get upset if you don't get admission,life is full of ups and down you need to work hard and solve problems.
Upvote if you like my views.