Will signing divorce papers constitute a divorce in Shari’ah?

Assalam o Alaikum

I had married my colleague without engaging our families and had husband wife relationship afterwards. we were traveling to Lahore but when she informed her sister back home, her sister insisted requested her to come back and promised that they will amicably send her with me. However subsequently my wife was confined to her house, threatened, beaten and not allowed to resume her very good job. for quite some time we could not even talk but somehow managed to talk. due to her family pressure and threats she asked to divorce her but I kept refusing. meanwhile my family including my first wife her family all kept on emotionally putting pressure on me to sign the divorce paper. under the circumstances whereby my second wife would have lost her job and confined to a room and exposed to beating, I signed the divorce paper in the presence of my sister's husband, my second wife's brother, lawyer and another person. till date I haven't uttered even a single word to divorce her. it is further clarified that my 2nd wife's brother was one of the major threat to my second wife. further while signing the paper my wife wasn't present.