雪峰山地应力英文报告.doc

3-D INITIAL GEOSTRESS REGRESSIVE ANALYSIS OF XUE FENG SHAN TUNNEL China Communication 2nd Highway Surveying , Design and Research Institute April, 2002 Written by: Qiu Xiangbo Li Shuchen Participants: Li Shucai Chen Congxin Qiu Xiangbo Li Shuchen Xu Bangshu Checked by: Prof. Li Shucai Prof. Chen Congxin 1. PREFACE Xue Feng Shan tunnel， a very long tunnel located at Shangrui Highway from Shaoyang to Huaihua, Hunan, which length about 2*7500 meters, is the most long highway tunnel which already in construction designing step in our country. Although the surrounding rockmass is mostly “integral”, but there are also located several penetrative faults. Parts of rockmass is a little fragmented, whose depth reach about 850 meters. The geostress’ magnitude and distribution will play an very important role on stability of tunnel when carrying out tunnel excavation under such a situation. Geostress in situ measurement using hydraulic fracturing method have been carried out in three bore, altogether 28 measuring points, the result shows that, compared with other area’s geostress in China, it belong to middle geostress horizontal. Although the in situ measurement is the most directly way to get the geostress field information, but for the reason of location and expense, it’s impossible to carry out in situ measurement in large scale. On the other hand, since the complexity of geostress’ cause of formation and the excessive impact working on, the measuring point’s result is in fact just the reflection of a local stress field. Furthermore, since it affected by the errors, the measuring result is, to some extent, discrete. So, to satisfy the need of engineering design and construction in a more reasonable way, it quite necessary to carry out the geostress regressive analysis which jointing the in situ geological conditions , through effective computation analysis method, and on the basis in situ measurements. Then we can get the more precise geostress field which can be u