Study on Non-Limit Active Earth Pressure in Finite Soil Behind Cantilever Pile in Sand Excavation

The space around the proposed excavation in complex environments becomes increasingly limited, the semi-infinite space assumed by the classical earth pressure theory is inconsistent with actual engineering, resulting in a lack of reasonable calculation methods for active earth pressure in excavations with limited soil. Taking the flexible retaining piles and sandy soil of limited soil excavations as the research objects, using the single-row pile cantilever retaining mode and the bottom ends of the retaining piles fixed, four excavations model tests under different soil widths were carried out. To explore the distribution characteristics of active earth pressure and horizontal displacement of retaining piles along the retaining piles. The results show that the horizontal displacement of the retaining structure on each soil width side approximates a triangular displacement pattern, and the earth pressure gradually approximates a D-shaped distribution as the excavation depth increases, with the maximum value appearing at approximately 0.8H depth. The force analysis of the soil differential unit was performed through the limit equilibrium method, and the active earth pressure distribution of the finite soil under the limit state was deduced. Combined with the friction angle development model that considers the influence of displacement, the non-limit active earth pressure distribution and resultant force of the finite soil were deduced. and the height of the point of action. The effectiveness of the calculation method in this paper is verified by comparing the earth pressure test values with the theoretical values in this paper. Through parameter analysis, it was found that the earth pressure is positively related to the aspect ratio and negatively related to the internal friction angle. The critical aspect ratio n_cr = 0.5 to distinguish between finite soil and semi-infinite soil.