INTERGRATED ANALYSIS OF THE TEMPO-SPATIAL EFFECT OF SURROUNDING ROCK DEFORMATION IN TUNNELING

A characteristic of the surrounding rock deformation in tunneling is its tempo-spatial effect. According to the velocity, the deformation process can be generally divided into three phases, namely rapid deformation phase, steady deformation phase and rheologic phase. Based on the summary of the three phase classification about surrounding rock deformation, this paper focuses on both spatial and time effects of surrounding rock deformation, according to the field data which measured at the D-5H measuring section in Zhongliangshan tunnel. Spatial effect mainly acted in the first phase, resisted mainly by surrounding rock and primary lining. The time effect mainly acted in the third phase. Furthermore, the relationships among tempo-spatial effects and surrounding rock class and cave-in accidents are analyzed. The results show that more than 80% cave-ins happened in the first phase, 13% in the second, only about 7% in the third. Cave-in may happen in all the three phases in class Ⅳ and Ⅴ surrounding rock tunnel. For class Ⅲ, there were a few in rheologic phase. Nearly no cave-in happened in the classⅠandⅡsurrounding rock sections. It is significant for comprehending the law of surrounding rock deformation in detail, and is propitious to prevent and cure the tunnel hazards.