Research methods : Based on the construction practice of reinforcing weak soil composite subgrade in the experiment section of Wuchang-Guangzhou Railway Passenger Dedicated Line, the systematic researches are done on application of strong tamping and its replacement technology in reinforcing subgrade of passenger dedicated line from the fields of selection of construction method, design of technique procedure and quality control according the engineering geological conditions.
Research results: Taking the performances of construction machinery and geological conditions into account, the tests of strong tamping and its replacement technology are done in the different typical areas in Wuhan Experiment Section and the comparison and analysis are made for the tested results before and after strong tamping to determine the its applicability for Wuchang-Guangzhou Passenger Dedicated Line under similar geological conditions, improve the construction technique，sum up its experience and lay down the technical parameters and test methods. The practice shows strong tamping and its replacement technology are feasible for reinforcing subgrade with satisfying the requirements of bearing capacity and design deformation and better control post-construction settlement.
Research conclusions: Tamping capacity is an important index of reinforcement depth for using tamping and its replacement technology. It needs rational interval time to use strong tamping and its replacement technology for reinforcing clay soil, especially for saturated clay soil. Strong tamping and its replacement technology are suitable for reinforcing the composite subgrade of passenger dedicated line.
2007, Vol. 24 
