砂土中螺旋锚上拔承载力与安装扭矩之间的关系研究

Relationship between uplift capacity and installation torque of screw anchor in sand

基于螺旋锚锚盘承载模型,根据竖向上拔承载力与安装过程中抵抗扭矩间的关系,提出了一种安装扭矩理论模型。在此基础上,利用该模型研究了螺旋锚结构参数和土体密实程度对安装扭矩的影响。研究结果表明:当达到或超过临界旋入深度时,安装扭矩增幅相对减弱;螺旋锚的直径比、锚杆尺寸以及土体密实程度对安装扭矩影响较大;螺旋锚尺寸越大或者砂土越密实,安装扭矩变化越明显,锚盘所产生的抵抗扭矩占总安装扭矩的比重也越大,锚盘抵抗扭矩占比在66%~88%之间;安装扭矩亦敏感于锚盘数量,当锚盘数量大于3时,安装扭矩增幅逐渐减弱;锚盘倾角对安装扭矩的影响呈线性关系。

Based on the individual bearing model of screw anchor and according to the relationship between the uplift capacity and the resisting torque during the installation, a kind of installation torque model is proposed in this paper. Then the influences of structure parameters for screw anchor and soil parameters on installation torque are investigated by utilizing this theoretical model. Research results show that when the embedment depth of screw anchor reaches or exceeds the critical depth, the increase of installation torque will be weakened. The diameter ratio(D/d) of screw anchor, the size of anchor shaft and the compactness of the sand have a significant effects on the installation torque. If the size of anchor plate is larger or the sand is denser, the change of installation torque becomes relatively obvious. And the proportion of resistance torque caused by the anchor plate to the total resistance torque will increase. Anchor plate resistance torque is between 66% and 88%. The installation torque is also sensitive to the number of anchor plates. The increment of installation torque is gradually weakened when the number of anchor plates is greater than 3. The inclination angle of anchor plate has linear effect on the installation torque.