Evaluation of the pile group effect on the bearing capacity of precast reinforced concrete piles in soft soil = Đánh giá hiệu ứng nhóm cọc đến sức chịu tải của cọc BTCT đúc sẵn trên đất yếu

Abstract

When constructing projects with large loads, reinforced concrete piles play an important role in transferring the load to the soil around and under the pile tip. The load bearing capacity of the pile includes the pile tip resistance and the friction resistance between the pile and the soil layers. To increase load bearing capacity, the foundation combines with many piles. This article calculates the coefficient of pile groups considering pile spacing and the number of piles in a foundation (pile foundation) using analytical methods and finite element methods. Research results have shown that the value of the piles group coefficient is calculated according to Plaxis 3D software and some authors such as Converse Labarre (1941), Sayed and Baker, and Das (1998), there is a consistent rule that the coefficient of the pile group increases gradually from few piles to many piles and gradual increases with pile distance from (3 ÷ 6)d. The coefficient of the pile group is calculated according to the formula of Feld (1943) gradually decreases according to the rule from few piles to many piles, and it does not change with the pile arrangement distance from (3 ÷ 6)d. Calculation results using Plaxis 30 software give a group coefficient value that is smaller than when calculated according to analytical methods.