螺纹桩加固风积沙地基液化特征试验研究  

Experimental Study on Liquefaction Characteristics of Threaded Pile Reinforced Aeolian Sand Foundation

作　　者：赵守全 窦顺 周垣 吴红刚 朱兆荣 ZHAO Shouquan;DOU Shun;ZHOU Yuan;WU Honggang;ZHU Zhaorong(Northwest Research Institute Co.Ltd,of CREC,Lanzhou,Gansu 730070,China;Gansu Tieke Construction Engineering Consulting Co.Ltd,Lanzhou,Gansu 730070,China;Southwest University of Science and Technology,Mianyang,Sichuan 621000,China)

机构地区：[1]中铁西北科学研究院有限公司,兰州730070 [2]甘肃铁科建设工程咨询有限公司,兰州730070 [3]西南科技大学,绵阳621000

出　　处：《铁道工程学报》2024年第3期7-16,共10页Journal of Railway Engineering Society

基　　金：国家重点研发计划(2018YFC1504903);甘肃省自然科学基金(145RJZA068)。

摘　　要：研究目的:随着我国的西部交通建设不断发展,线路工程将难以避免地穿越风积沙河谷地区,路基工程将面临地基液化的问题。螺纹桩作为近年来出现的新型桩基,在地震作用下加固可液化场地的桩土相互作用力学机制和抗液化效果的研究相对较少。本文通过振动台试验,首次从小波包能量变异角度研究了螺纹桩加固风积沙地基的液化特征,并验证了其适用性。进一步分析了螺纹桩复合地基液化易发部位的时频-能量演化规律,并探讨了风积沙的微观液化过程。研究结论:(1)在地震作用下,螺纹桩能提高风积沙地基的刚度和整体抗液化能力,抑制风积沙骨架结构的变化或重组;(2)小波包能量变异特征与孔压响应呈现的液化规律联系紧密,评价地基液化具有适用性;(3)螺纹桩可将风积沙地基的液化易发区从中部转移到浅层,有利于通过地基加固人为干预地基液化;(4)螺纹桩-风积沙复合地基未发生液化时,震动响应能量主要集中在第一频带(0.1~6.26 Hz),而发生液化时,低频(2~5 Hz)积聚的能量逐渐向高频(10~15 Hz)发散,并伴随在时间节点上出现新的能量尖点;(5)在微观层面,风积沙液化过程是剪胀剪缩循环交替的过程,颗粒排布从紧密接触到相互分离,而螺纹桩桩身的螺纹对风积沙的体积应变有抑制作用,降低其液化势;(6)本研究成果可为液化地基螺纹桩加固技术设计提供一定参考。Research purposes:With the continuous development of traffic construction in western China,the line project will inevitably cross the aeolian sand valley area,and the roadbed project will face the problem of foundation liquefaction.As a new type of pile foundation emerging in recent years,there are relatively few studies on the mechanical mechanism of pile-soil interaction and anti-liquefaction effect of reinforced liquefiable site under earthquake action.In this paper,the liquefaction characteristics of aeolian sand foundation reinforced by threaded pile are studied for the first time from the perspective of wavelet packet energy variation through shaking table test,and its applicability is verified.The time-frequency-energy evolution law of liquefaction-prone parts of threaded pile composite foundation is further analyzed,and the micro-liquefaction process of aeolian sand is discussed.Research conclusions:(1)Under the action of earthquake,threaded pile can improve the stiffness and overall liquefaction resistance of aeolian sand foundation,and inhibit the change or reorganization of aeolian sand skeleton structure.(2)The variation characteristics of wavelet packet energy are closely related to the liquefaction law of pore pressure response,and it is applicable to evaluate foundation liquefaction.(3)The threaded pile can transfer the liquefaction-prone area of aeolian sand foundation from the middle to the shallow layer,which is conducive to human intervention in foundation liquefaction through foundation reinforcement.(4)When the threaded pile-aeolian sand composite foundation does not liquefy,the vibration response energy is mainly concentrated in the first frequency band(0.1~6.26 Hz).When liquefaction occurs,the energy accumulated at low frequency(2~5 Hz)gradually diverges to high frequency(10~15 Hz),and new energy cusps appear at the time node.(5)At the micro level,the liquefaction process of aeolian sand is an alternating process of shear expansion and shear contraction.The particle arrangement is from clos

关 键 词：螺纹桩 风积沙 地基液化 小波包变换 能量变异 

分 类 号：O319.56[理学—一般力学与力学基础]