Surrounding Rock Stability Study Of ZhongNanShan Large Section And Deep Shaft

This paper studies the second Ventilated Shaft of Qinling Zhongnanshan tunnel in Xi'an-Ankang freeway, and makes a research of the stability of the shaft surrounding rock through the construction process in different depth. Then discuss the weak intercalation in the surrounding rock, gain it's effect on the stability of the shaft surrounding rock. Finally discuss the effort of the air shaft on the vertical shaft.Firstly the abutment pressure distribution laws and the fractured zone of surrounding rock after the excavation are discussed, and then analyze the design of support, then make a research of the stability of the shaft surrounding rock in different depth structure. Through the analysis of the actual measurement data in work site, gain the stability of the actual stability of the surrounding rock during the excavate process. Secondly discuss the Weak intercalation which was found through the excavate process. The effort of four factors of the weak intercalation on shaft was discussed. These are the length, distribution, thickness and the depth of the weak intercalation. Because of the complexity of the joint of the vertical shaft and other three air shaft on the bottom of the shaft, finally the effort of the air shaft excavation on vertical shaft was discussed.