水平加载方向对粘土中群桩响应影响的数值研究

Numerical Study on the Effect of Loading Direction on the Response of Pile Groups in Clay

利用ABAQUS有限元软件,以现场试验为原型,建立数值分析模型,对群桩原位试验进行模拟,对比了单向水平荷载作用下单桩和群桩的水平荷载位移曲线,验证了数值模型和计算参数的有效性,然后利用该土层和桩体信息,研究了在粘土中的1×2群桩、1×3群桩、2×2群桩和3×3群桩在不同方向水平荷载作用下的响应。研究结果表明,群桩中由于桩与桩之间相互影响,导致桩的水平承载力降低,其中前排桩对后排桩的影响最大,后排桩对前排桩的影响次之,而同排桩之间的影响最弱;当沿不同水平方向进行加载时,各单桩所分配到的水平力变化明显,主要取决于其所处的桩位和其他桩对该桩产生的"遮蔽效应"。

Based on the field test,a numerical analysis model was established by using the FEM software ABAQUS. The in-situ test of pile group was simulated and the horizontal load displacement curves of single pile and pile group under horizontal uniaxial loading were compared. Then effects of loading direction on the responses of a 1×2 pile group,a 1×3 pile group,a 2×2 pile group and a 3×3 pile group embedded in clay were studied,using the soil and pile information of the in-situ tests. Based on the results,the horizontal bearing capacity of the pile is reduced due to the interaction between piles in pile group,it was revealed that the impact of the front row piles on the back row piles is the most significant,followed by the influence of back row piles on the front piles,and the impact of the same row piles is the weakest. The horizontal force assigned to each individual pile changes significantly,as the horizontal loading direction vaires,which depends mainly on the pile position and the ' shadowing effect' caused by other piles.