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| Research on the Settlement Characteristics of Subgrade in the Test Section of Tianjin - Baoding Railway |
| CUI Wei – xiao |
| The third Railway Survey and Design Institute Group Corporation，Tianjin 300142，China) |
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Abstract Abstract ： Research purposes ： The thick compressible foundation settlement control is the key technology of subgrade in
the construction of high - speed railway. Based on the in - site test data and analysis of different types of ground
treatment in the test section of Tianjin - Baoding Railway， this paper reveals the relations between the subgrade
settlement and the type of reinforcement pile，pile spacing，length of pile and pile top foundation structure in deep thick
compression layer of ground soil，selects proper method for settlement calculation and analysis.
Research conclusion ：( 1 ) Since the settlement characteristics of prestressed pipe pile reinforced foundation and CFG
pile reinforced foundation， pile top raft foundation and pile cap - net foundation are similar， the same settlement calculation method can be utilized. (2 ) If the diameter of pile and reinforcement depth is same， the pipe pile reinforcement spacing shall be the spacing of CFG pile plus one times of diameter of pile to achieve close settlement
control. (3) If the type of pile，diameter of pile，pile spacing and reinforcement depth is same，the subgrade settlement
of cap - net foundation is 1.4 times of raft foundation. (4) The thickness of compression layer shall be selected based on 0. 1 of the stress ratio when utilizing composite modulus method for subgrade settlement calculation，and 0. 2 of the stress ratio if equivalent application method is adopted. (5 ) When combining the 0. 6 times of calculation results based on
composite modulus method with the 0. 4 times of equivalent application method calculation results，the fitness between the calculation results and field data increases dramatically. (6) The research results can be the guidance of subgrade
settlement control design under condition of thick compressible foundation.
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Received: 27 June 2016
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2016, Vol. 33 
