Abstract: Grouting in soft clay for ground improvement generates significant excess pore water pressure and damages structure destruction, resulting in slight improvement of soil strength and appreciable settlement after grouting. This paper proposes a new method named "capsule expansion combined with electro-osmosis" for ground improvement. The capsule expansion is design to control the uncontrollable flow of grout, while synchronous electro-osmosis dissipates the generated excess pore water pressure. Two small-scale model tests are carried out to investigate the behavior of mud with sand improved by capsule expansion combined with electro-osmosis. The difference between the two tests is the content of sand within the mud of the model. Excess pore water pressure, ground vertical displacement, and compression modulus are monitored during the tests. It is found that electro-osmosis can effectively dissipate the excess pore water pressure caused by capsule grouting. The soil structure significantly affects the evolution of the excess pore water pressure. The lower the sand content in the soil, the greater the excess pore water pressure generated by grouting, and the more significant the dissipation effect of electro-osmosis. The ground vertical displacement of the ground surface shows a small and uniform characteristic under the synergistic action of capsule grouting and electro-osmosis. Moreover, the combined action can significantly enhance soil stiffness, with the compression modulus of the soil reaching up to 2.3 times the initial value. The reinforcement effect is more pronounced in areas closer to the grouting zone.