斜桩竖向抗压承载变形性状模型试验

Model Test for Vertical Compressive Bearing Deformation Behavior of Battered Pile

斜桩广泛应用于岩土工程中,但如何确定其竖向抗压承载力目前还没有合理的方法。因此,通过模型试验研究了竖向荷载作用下斜桩的承载变形性状,分析了斜桩桩身倾角和长径比对其竖向抗压极限承载力与桩顶沉降的影响,通过拟合方法建立了斜桩竖向抗压极限承载力和沉降的计算公式并与文献结果进行了对比。试验结果表明:(1)在竖向荷载作用下,当桩身倾角较小时,斜桩荷载-沉降曲线(Q-S)与荷载-水平位移曲线(Q-H)均为缓变型;当桩身倾角与长径比较大时,其Q-S曲线与Q-H曲线均为陡变型;斜桩的沉降大于相应直桩的沉降,桩身倾角越大,斜桩桩顶沉降和水平位移就越大。(2)斜桩的竖向抗压极限承载力小于直桩,桩身倾角越大,斜桩竖向抗压极限承载力就越小。(3)建立的斜桩竖向抗压极限承载力与桩顶沉降公式的计算结果与文献结果吻合较好。

Battered piles have been widely applied in various geotechnical engineering.There is no reasonable ap-proach to determine the vertical bearing capacity at present.In this paper,the bearing deformation behaviors of bat-tered piles under vertical loads is researched by model tests.The effects of the pile shaft inclination angle and length-diameter ratio on the ultimate bearing capacity and settlement at the pile top are analyzed.The formulas for vertical ultimate bearing capacity and settlement of battered piles are established by fitting methods and compared with literature results.The test results show that:both the Q-S curve and the Q-H curve of vertically loaded battered pile with a small shaft inclination angle show slow variant characteristics;They show steep variant characteristics for piles with a large inclination angle and a large length-diameter ratio;The settlement of battered pile is greater than that of vertical pile.And the larger the pile inclination angle,the greater the settlement as well as the horizontal dis-placement of the battered pile.The ultimate bearing capacity of vertically loaded battered piles is smaller than that of the vertical piles.The greater the pile shaft inclination,the smaller the bearing capacity.The calculating results of ultimate bearing capacity and the top settlement formulas of battered piles show good agreement with the literature results.