Determination of strut loads for excavation in mixed soil deposits

In a densely populated country like Singapore, the need for land space becomes more and more critical problem every day. The civil engineering knowledge and know-hows are becoming more important in land planning. By having a braced excavation, excavation can go deeper as the support system would prevent the weak soil from collapsing. Hence with a deeper excavation, the underground structures can go deeper and the tall buildings can go taller. This would allow more spaces and the buildings can hold more people in the same area of land. Therefore braced excavation has become an important aspect in civil engineering, especially in Singapore. In this project, the Plaxis 2D finite element program would be used to simulate a braced excavation. The main focus of this project would be on the strut forces and maximum lateral wall deflection. The factors that are varied are thickness of sand layer, sand types, wall stiffness, depth of wall embedment and excavation width. The result of this study indicate that the excavation width and wall stiffness are the factors that significantly affect both maximum lateral wall deflection and strut forces. When excavation width is larger, the maximum lateral wall deflection is larger and the strut forces are smaller. When the stiffness of the wall increases, the strut forces are larger, however, the wall deflection is smaller. Comparisons using Peck’s Apparent Pressure Diagram (APD) to estimate the strut forces, indicate that the APD can underestimates the 2nd bottom strut force, and sometimes the middle strut.Bachelor of Engineerin