Research on semi-assembled shallow foundation using sewer pipes on weak geology with sand leveling

Abstract

The article studies the solution of using sewer pipes as a semiassembled foundation for low-rise houses in the condition of soft soil with sand leveling. Static compression tests are carried out on bottomsealed sewer pipes (closed-end hollow pipe) and unsealed sewer pipes tightly filled with sandy soil (open-ended pipe), located in the leveling sand layer. The results of static compression tests on pipes are compared with the ones on natural ground, showing a good settlement reduction effect, especially with closed-end pipes. Compared with the open-ended pipe with sand filled into it, the bearing capacity of the closed-end pipe is three times greater, and the settlement is five times less. The semi-assembled foundation using bottom-sealed and nonbottom-sealed pipes can be put into practical application. Depending on the workload, we can choose the appropriate foundation type. With a closed-end hollow pipe foundation, it can be considered a floating foundation. However, with the open-ended pipe foundation, there are no documents guiding the load capacity calculation. The author has given the solution to use the formulas applied to the piles. The results show that the formulas of AIP or FinnRA are quite simple and give consistent results with static compression experiments when adjusting some coefficients accordingly.

Keywords: Sewer pipe; floating foundation; filling sand; weak soil; static load test.