大口径超深孔桩基轴向静荷载试验研究-中南大学学报.PDF

42 5 () Vol.42 No.5 2011 5 Journal of Central South University (Science and Technology) May 2011 1, 2 1 2 2 (1. 410083 2. 410014) 480 m 2.5~2.8 m 3.5 m 12~56 MN 9 c2 25 MN − TU458.3 A 1672−7207(2011)05−1419−06 Diameter axial static loading test about large-diameter ultra-deep-hole pile foundation 1, 2 1 2 2 WANG Jian-jun , PENG Zhen-bin , LIU Mu-feng , LI Fen-qiang (1. School of Geoscience and Info-Physics, Central South University, Changsha 410083, China; 2. Coal Geology Bureau of Hunan Province, Changsha 410014, China) Abstract: Based on the fact that one bridge is a main span cable-stayed beam with 480 m twin towers, its bored pile diameter is 2.5−2.8 m and its geological conditions is complex, the self-balancing method was adopted. The processes were as follows. The load box best location was set 3.5 m away from the pile, and these tests were set 9 grades in 12−56 MN. According to the test data, pile section its tip resistance and relative displacement of soil were analysed. The results show that it almost has no influence on pile top displacement when the load is 25 MN, and the pile body side upper friction is sufficient to resist loads. The soil pile measured displacement-time curves and the fitting curves slow down in the loading stage, which indicates that skin friction basically reaches the limit. Key words: ultra-deep hole; pile foundation; diameter axial static loading