饱和黏土中钢管螺旋桩抗压静载试验研究OA

Screw pile foundations are typically composed of steel pipes and helical blades.Due to their advantages such as convenient construction and recyclability,they have shown application potential in various engineering fields.Currently,research mainly focuses on the uplift bearing capacity of screw piles,while studies on the compressive bearing capacity of single and group piles in saturated clay are limited.To address this issue,based on field tests,the compressive bearing capacity of single and group piles with different geometric parameters was investigated.The results show that in saturated clay,single screw piles have relatively large settlement and low ultimate compressive bearing capacity during the compressive bearing process.Increasing the pile length can significantly enhance its bearing capacity.The bearing capacity decreases with the reduction of pile spacing,but the compressive bearing capacity of double-blade piles is not lower than that of single-blade piles.Increasing the number of blades effectively improves the bearing capacity at the pile tip.From single-blade piles to three-blade piles,the improvement in compressive bearing capacity is significant.An increase in blade diameter enlarges the bearing area of the soil at the pile tip,reducing settlement.However,due to the constraint of the blade spacing ratio,the increase in bearing capacity is limited.Increasing the pile diameter enhances the bearing capacity but also increases settlement.Additionally,the bearing performance of group piles is significantly affected by pile spacing:as the pile spacing decreases,the area of the soil under load beneath the pile tip blades reduces,leading to a decrease in ultimate compressive bearing capacity and an increase in settlement of the group pile foundation.When the group pile spacing is 3D(D being the blade diameter),the effect coefficient of pile groups is approximately 0.993;when the pile spacing is reduced by one blade diameter,this coefficient drops to 0.854,indicating a significant enhancement in the group pile effect.