| Some main achievements of this thesis are included as followings, supported by the development research project of Ministry of Railway named that Labotatory study on dynamic characteristics and design parameters of collapsible loess foundation in Passenger-dedicated traffic(Serial number:2005K001-A(G)):(1)Based on a lot of research resourses investigation including project characteristics of collapsible loess and loess foundation, settlement discipline of loess foundation and subgrade, the treatment methods of loess foundation, at last, the primary plan has been provided for foundation treatment of Zhengzhou-Xi'anpassenger-dedicated traffic.(2)Some static and dynamic triaxial tests have been done, which specimens are collected from typical site of Zhengzhou-Xi'an passenger-dedicated traffic.Some static and dynamic characteristics of undisturbed collapsible loess have been got, that can be used for analysis of subgrade settlement under train load.(3)Numerical analysis for dynamic subgrade settlement under train load has been done using finite difference program, the subgrade model height of which includes 2 metre, 3 metre, 4 metre. The results of calculation indicate: the subgrade settlement for loess foundation without treatment and low subgrade, can not satisfy the post-settlement requirement of Zhengzhou-Xi'an passenger-dedicated traffic that is 15 mm, some suggestions are given that using high subgrade and treating loess foundation.(4) Analysis of subgrade post-settlement has been done with foundation treated by CFG column-net composite foundation, the calculation results of total settlement indicate: 6m height subgrade post-settlement is excess to the 15mm post-settlement requirement, according to experiences, the subgrade post-settlement can satisfy the requirement considering the consolidating settlement of collapsible loess. At last, the rule settlement characteristics need to confirm using in-situ settlement tests.
|
PDF Full Text Request