Abstract:As one of the waterproof curtains, trench cutting re-mixing deep wall (TRD) possesses unique advantages of fitting most layers and getting good qualities, however, the high cost hinders its popularization. Thus, if cement can be partly substituted by cheaper fly ash, slag and other industrial waste, the application scope of TRD will be greatly enlarged. In order to verify the performance of the cement replaced by industrial waste, the authors conduct a lot of strength and permeability tests. And results show that fly ash and slag can substitute partially for cement and there is an optimal mixture ratio for the composite cement soil. The best mixing ratio and water-solid ratio is 30% and 0.6 respectively for clay, and 40% and 0.6 for sand. Generally, the physical and mechanical properties will be superb when fly ash mixing with sand, while slag is more suitable for clay. The long-term strength of clay is close when adding fly ash or slag, while the average strength of sand after adding fly ash is more stable and 2.4 times larger than that of sand adding slag. In addition, the average permeability coefficient of clay and sand after adding fly ash is about 35% than that of clay and sand adding slag.