Abstract: The existence of intercalation in sandy soil affect the pore pressure development in saturated sandy soil, thereby impacting the deformation of sandy soil layer. In order to study the pore pressure change during the liquefaction of sandy soil under different intercalation conditions such as location, thickness and type, a liquefaction test of laminated sand under impact load was conducted. This study involved establishing a theoretical model of saturated sandy soil with intercalations and comparing the test results with the theoretical analysis. The findings reveal that the development of pore pressure of saturated sandy soil containing intercalated layers exhibits three stages: rapid rise, rapid dissipation, and slow dissipation. In cases involving high-permeability intercalations, a higher location of the intercalation results in a shorter rapid dissipation time of pore pressure below it, leading to a faster convergence to a stable value. However, the total dissipation time shows no significant change. Conversely, for low-permeability intercalations, an increase in the height or thickness of the intercalation accelerates the rate of rapid dissipation phase of pore pressure above the intercalation, prolongs the stable phase of pore pressure dissipation, and linearly increases the total dissipation time of pore pressure. Additionally, a water film forms below the low-permeability intercalation, and increasing the intercalation height or thickness extends the duration of the water film, with the water film formation primarily affected by the intercalation thickness.. The test results are more consistent with the theoretical analysis, indicating the reliability of the test. The test results align more closely with the theoretical analysis, indicating the reliability of the test.

Key words: stratified sandy soil, impact load, excess pore water pressure, intercalation height, intercalation thickness, water film