Cyclic dynamic test of water-rich loess tunnel subgrade for high-speed railway
（1.School of Civil Engineering, Southwest Jiaotong University, Chengdu, Sichuan，610031，PRC；2.LA Department of Water & Power, 111 N. Hope Street, Los Angeles, CA 90012, USA）
Abstract： It is an indispensable important parameter for tunnel design that the rules of transmission and attenuation for vertical vibration velocity and earth pressure with depth in arc of tunnel and soil bellow the arc under cyclic dynamic load of high-speed train. Effects of water pressure should be taken into consideration as for tunnels with most part below water table. There is no any report concerning these issues at home and abroad. Relying on important issues of scientific research and development plan of the Ministry of Railways of P.R.C, cyclic dynamic test that simulates high-speed train vibration effect has been put into practice in water-rich loess tunnel for the first time. Attenuation laws for vertical vibration velocity and earth pressure in and below tunnel invert arc under different frequencies are obtained. Changes rule for earth pressure at different depth under constant frequency are obtained. Relationships between excess pore pressure versus loading frequency and loading number are obtained and analyzed comparing with monitoring results. Research fruits provide possibility for optimizing design the invert thickness and filling materials of tunnel, provide experimental basis and technical support for design and construction of tunnel under analogous conditions.
2010, Vol. 29 
