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Rammed concrete pile is the development of columnar-hammer rammed and expanded technique. Due to the twice compaction effect during installation process and high compression strength of pile shaft, rammed concrete pile has the advantages of high bearing capacity and relatively low cost. The main purpose of this paper is to study the installation procedure, the bearing behavior of rammed concrete pile and compaction effect on the surrounding soil. The indoor tests results indicate that the rammed concrete specimens take only 14 days, only half of the common concrete, to achieve the design strength, which is favorable to shorten the construction period of foundation. Additionally, the compression strength of rammed concrete is about 10 to 50 percent higher than the regular concrete with the same cement content ratio. Field tests results show that rammed concrete pile offers greater capacity than driven and cast-in-place pile. Finally a case history is introduced that further verified the compaction effect of the rammed concrete pile to the surrounding soil.

Stiffened Deep Cement Mixed (SDCM) pile technique has provided a new approach for treating soft. soil. The main focus of this paper is the bearing behavior and capacity prediction of single SDCM pile. Static load tests data of 67 piles collected from six different districts in China are analyzed in this paper. The bearing capacity, load-settlement curve and failure modes of SDCM piles are studied. According to the bearing mechanism of SDCM pile, a new approach to predict the capacity, Sectioning and Summarizing method, is proposed. To calculate the capacity, one SDCM pile should be divided into two segments: the upper segment with core pile and the lower segment without the core pile. The total shaft resistance of SDCM pile is the summation of the two segments. Finally the dominate factors influencing the pile resistance are analyzed. The study results show that the capacity of SDCM pile is mainly affected by the parameters of the core pile. The resistance provided by the pile shaft including core pile was 1.0∼2.9 times that of bored and cast-in-place concrete pile. The proposed Sectioning and Summarizing method can be used to estimate the capacity of the SDCM pile and get more logical result than the currently used methods.