The trench cutting remixing deep wall (TRD) method is a new cement soil cut-off wall construction technique, which has been\nwidely used in cofferdam, embankment dam, and underground waterproof curtain structures. The chain cutter of TRD moves\nhorizontally to cut and stir different soil layers by up and down to form a cement-mixed soil diaphragm wall with continuous and\nuniform thickness, the mechanics and permeability of which are obviously different from those of cement soil with a horizontally\nmixed single soil layer in traditional deep mixing pile (DMP). In this paper, five sets of onsite walling tests with different cement\nratios were carried out to analyse the unconfined compression and permeability of undisturbed cement-mixed soil in TRD. The\ndifference of both unconfined compressive and permeability coefficients in between TRD and DMP was analysed to discuss the\nstirring performance of TRD. Then, the microscopic mechanism of soil properties affecting the performance of cement-mixed soil\nhas been studied by scanning electron microscopy (SEM) in the unconfined compression strength test and permeability coefficient\ntest of cement soil with different mixed soil properties. The test results show that the unconfined compressive strength of cementmixed\nsoil is closely correlated to its gradation. As the mixed soil gradation curve approaches to the Fuller curve, the unconfined\ncompressive strength would gradually increase. In mesoscopic, cement fine sand has a large pore structure, and the average pore\narea is 2.46 times as cement clay. The permeability coefficient of cement-mixed soil is controlled by the proportion of fine sand\ncontent with high permeability.
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