Model tests on consolidation of soft foundation by deep cement mixing method

In order to determine various construction parameters of underwater deep cement mixing, the field tests needs more time and cost. Based on the (deep cement mixing) DCM method of China Communications Group, the DCM model test devices are developed, and a series of tests are carried out including the blade upgrading, soil layer identification and unconfined compressive strength (UCS) tests. The tests results indicate that adding free blades can effectively prevents blade wrapping issues in clay soils using the DCM method. The torque at the interface of different soil layers changes abruptly, and different soil layers can be identified by the change of torque at different depths. Under the same cement content conditions, the UCS of the cement mixing piles with different soil samples cured 14, 28, 60 d and 90 d is that silt soil < clay < sandy soil. In sandy soil, the compressive strength of the cement soil is larger and the growth rate is faster than that of clay, and the amount of cement grouting in sand layer can be reduced. The results of model tests may provide reference for deep cement mixing piles.