螺旋锚复合基础对村镇生土建筑抗震性能影响研究

Influence of Screw Anchor Composite Foundation on Seismic Perfor-mance of Rural Raw Earth Buildings

村镇生土结构因其抗震能力不足在遭遇地震时产生破坏严重,而螺旋锚基础能提供抗拔力来防止建筑物的隆起和倾覆。针对砂土中螺旋锚锚盘埋深、间距及数量对上拔承载特性及极限上拔承载力影响因素进行数值模拟研究,通过对比优化确定螺旋锚复合基础参数。并以中国村镇典型单层生土结构为研究对象,对条形基础生土结构和螺旋锚复合基础生土结构进行地震反应分析,以此来研究适合村镇生土结构的抗震构造加固措施。基于非线性动力时程分析方法,提取结构顶层位移,研究螺旋锚复合基础对生土结构地震反应的影响。结果表明:①埋深比为10.5,锚盘间距为4.5D时的双片螺旋锚上拔承载特性最好;②在地震动作用下,螺旋锚复合基础形式在一定程度上影响结构的整体抗震性能,螺旋锚复合基础使生土建筑的抗震性能显著提升;③螺旋锚复合基础在地震动作用下的轴力最大值未达到其极限上拔承载力,基础坚实可靠;④地震动作用下,螺旋锚复合基础降低了生土结构的破坏等级,提高了结构的性能水平。

The soil structure of towns is seriously damaged in earthquakes because of its insufficient seismic capacity,and the screw anchor foundation can provide anti-pullout force to prevent the build-ing from uplifting and overturning.According to the influence factors of the buried depth,spacing and screw anchor plates number on the uplift bearing characteristics and ultimate uplift bearing capacity of the screw anchor in sand,the parameters of the screw anchor composite foundation are determined by comparison and optimization.Taking the typical single-layer raw earth structure in Chinese villages and towns as the research object,the seismic response of the strip foundation raw earth structure and the screw anchor composite foundation raw earth structure are analyzed,so as to study the seismic structural reinforcement measures suitable for rural raw earth structure.Based on the nonlinear dynam-ic time history analysis method,the top displacement of the structure is extracted,and the influence of screw anchor composite foundation on the seismic response of raw earth structure is studied.The re-sults show that:(1)When the buried depth ratio is 10.5 and the distance between anchor plates is 4.5D,the uplift bearing characteristics of double screw anchors are the best;(2)Under the action of ground motion,the form of the screw anchor composite foundation affects the overall seismic perfor-mance of the structure to a certain extent.The screw anchor composite foundation significantly im-proves the seismic performance of raw earth buildings;(3)The maximum axial force of screw anchor composite foundation under the ground motion does not reach its ultimate uplift bearing capacity,and the foundation is solid and reliable;(4)Under earthquake action,the damage grade of raw earth struc-ture is reduced and the performance level of structure is improved.