Test Study on the Fatigue Lives of Tunnel Bed Structures When Bedrocks Full of Groundwater
Fatigue testes with scale of 1:2 are carried out on PMS-500 fatigue machine to study the fatigue behaviors of tunnel bed structures under the condition that their foundations are full of groundwater. The occurrence and development of cracks appearing in structures are observed and analyzed, as welt as the failure modes of structures. Both static stresses and dynamic stresses distributed at the top and bottom of structures are also discussed. According to the final cycles of loading, the fatigue lives of tunnel bed structores are obtained. It is found that the most dangerous position where the critical fatigue damage of tunnel bed structures will take place is just below tow mils. And the cracks of structures extend almost along longitudinal direction. Furthermore, compared to the diffusion of groundwater, mechanical effects can be assumed to occur instantaneously when trains run at high speed and then high pore water pressure produce. Such alternating pressure together with impact and shock loading due to running trains consequently accelerates the occurrence of cracks and the failure of structures. So the groundwater, which can decrease the fatigue lives of tunnel bed structures greatly, is one main cause of the obvious reduction of their fatigue lives. Therefore, in order to decrease the diseases of tunnel bed structures, it is an efficient way to keep their foundation dry, by reasonable waterproofing and draining.
tunnel bed structure fatigue life groundwater mode test
HUANG Juan PENG Limin YANG Weicao
School of Civil Engineering and Architecture,Central South University,Changsha 410075,Hunan,China
国际会议
The 2008 International Symposium on Safety Science and Technology(2008年安全科学技术国际会议)
北京
英文
2232-2237
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）