Abstract: Taking a foundationpit ina highway project as anexample, a numerical model was established using finite element software. Based on the verification of the model’s correctness through on-site monitoring results and improved formulas, the deformation of the foundation pit under two working conditions of double row pile closure and single row pile closure was compared and analyzed. The influence of pile diameter, row spacing, and pile spacing on the stability of double row pile support structure through variable analysis method were studied and range values were provided. The results show that the stiffness and stability of the double row pile support structure are higher than the single row pile support structure, and the closing effect is also better. The calculated values obtained by improving the formulas have a similar growth trend to the finite element simulation values, which verifies the correctness of the formula and model. The pile diameter, row spacing, and pile spacing can affect the deformation of the double row pile support structure. When the pile diameter is 0.8~1.1 m, the row spacing is 2~3.5 times the pile diameter, and the pile spacing is 2~4 times the pile diameter, the best effect of the double row pile support structure can be achieved.

Key words: double row piles, open foundation pit, closing effect, numerical analysis, deformation