不同成桩工艺条件下冻结粉土中基桩承载性状试验研究  

Experimental research on bearing behavior of piles by using different pile formation technologies in the frozen silt

作　　者：李仁杰 何菲[1] 王旭[1] 张延杰[1] 杜婷 杨进财 LI Renjie;HE Fei;WANG Xu;ZHANG Yanjie;DU Ting;YANG Jincai(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;College of Civil Engineering,Longdong University,Qingyang 745000,Gansu,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]陇东学院土木工程学院,甘肃庆阳745000

出　　处：《冰川冻土》2021年第6期1809-1817,共9页Journal of Glaciology and Geocryology

基　　金：冻土工程国家重点实验室开放基金项目(SKLFSE201607);兰州交通大学青年科技基金(2016016)资助。

摘　　要：桩基础作为冻土工程中最适宜的基础形式,主要采用插入桩、静压桩和灌注桩三种桩型,因其成桩工艺不同对冻土地基及桩基自身造成的差异不一。为研究不同成桩工艺对冻土地基及基桩承载性状的影响,通过开展室内-1.5℃条件下单桩静载模型试验,分析在冻结粉土中不同成桩工艺对地温场、桩基极限承载力、桩身轴力以及桩侧摩阻(冻结力)的影响规律。试验结果表明:灌注桩对桩周地温场扰动剧烈,桩侧温度较高,地温变化幅度大。随着桩周土体的回冻,地温逐步降低,其中灌注桩桩侧降温速率最大;在承载力方面,2根灌注桩的极限承载力约为12.8kN,静压桩为11.6kN,插入桩极限承载力最小,仅为钻孔灌注桩的2/3。并对比4种不同成桩工艺的基桩在不同荷载条件下对应的沉降量,体现出成桩工艺对基桩沉降造成的差异性;随着桩顶荷载的逐级增加,桩侧摩阻(冻结力)和桩端阻力逐渐发挥作用,桩身上部1/3由于温度较低,致使桩侧摩阻(冻结力)较大,在10cm深度附近温度最低,使桩侧摩阻(冻结力)达到最大值;并对比4种不同成桩工艺的基桩在荷载5.6kN下轴力沿桩身的传递情况,发现静压桩更易把荷载传递到冻土区深层地基。As the most suitable form of foundation in frozen soil engineering,pile foundation mainly adopts three types of piles,plugging pile,the static pressure pile and the bored pile.Because of the different pile formation process,the difference between the frozen ground and the pile foundation itself is different.In order to research on the influence of different pile formation technologies on the permafrost foundations and bearing behavior of foundation piles.The introduction dead load model test of the single pile under-1.5℃conditions which is carried out to analyze influence laws of the ground temperature field,the ultimate bearing capacity of single pile,the axial force of pile shaft and the friction resistance on impact of using different pile formation technologies in the frozen silt.It is found that the bored piles has a violent disturbance to the ground temperature field,so the temperature of pile side is higher,and large amplitude of changes in ground temperature.With the refreezing of the soil around piles,the ground temperature is gradually decreased.The cooling rate of the bored piles is the biggest;In terms of bearing capacity,the ultimate bearing capacity of the two types of bored piles is about 12.8 kN,and the static pressure pile is 11.6 kN,the ultimate bearing capacity of plugging pile is the minimum,which is only 2/3 of the bored pile;And compared the corresponding settlement of the piles of four piles by using different formation technologies under different load conditions,and reflecting the difference caused by using different formation technologies on the pile foundation settlement;With the increasement of load on pile top,the friction resistance and the tip resistance gradually play.Due to the temperature of 1/3 of pile is lower which makes the friction resistance larger.The temperature was least near the depth of 10 cm,so the friction resistance reaches the maximum value.Compared the transmission of the axial force along the pile body under the load of 5.6 kN.It is found that the static pressu

关 键 词：冻结粉土 成桩工艺 温度场 承载力 桩侧摩阻(冻结力) 

分 类 号：TU473.11[建筑科学—结构工程] P642.14[建筑科学—土工工程]