Effect of stress ratio K due to varying overburden topography on crack intensity of tunnel liner. by Islam, Amber, Abdullah, Rini Asnida, Ibrahim, Izni Syahrizal, Lai, Goh Thian, Chaudry, Muhammad Hamid, Junaid, Muhammad, Iqbal, Zafar, Jamal, Norhadziana, Abd. Aziz, Azizul Faiz, Salim, Adam