Abstract
A PVD-DCM method combined with prefabricated vertical drains (PVDs) and deep cement mixing (DCM) piles is presented in this paper based on the field case of Beijing–Shanghai high-speed railway in China. The field performance of soft soil foundation improved by this method is comprehensively analysed, and shows that the PVD-DCM method takes full advantages of PVDs and DCM piles, in which the DCM piles increase the bearing capacity and reduce the total settlement of the soft foundation, while PVDs accelerate the consolidation of the soil by shortening the drainage paths. A plane strain numerical simulation on the field case is then conducted, which is converted by a three-dimensional (3D) problem with equivalent properties and dimensions. The numerical simulation is found to be an effective method to predict the true behaviour of the foundation improved by the PVD-DCM method, such as the load transfer and settlement, with reasonable accuracy. The PVD-DCM method is finally assessed both by PVD method and DCM method in terms of the settlement, implying that the PVD-DCM method can provide an effectiveness of foundation improvement and create a more economical solution.
Acknowledgements
The financial support of the National Natural Science Foundation of China (Grant No. 51478166), the Fundamental Research Funds for the Central Universities (Grant No. 2015B17814, 2015B35414, 2015B06014 and 2015B25914) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry is acknowledged. The authors are also very grateful to the reviewers for their valuable comments and suggestions.