摘要
为研究自平衡试桩法中负摩阻力转换系数的影响因素及其规律,确保自平衡试桩法在膨胀土地区的适用性,对自平衡试桩和传统静压桩的模型试验进行了数值模拟研究。采用控制单一变量法,分析了膨胀土的性质、桩体几何参数、桩土接触面性质等因素对自平衡法转换系数的影响规律,并通过拟合得到各因素与转换系数间的二次项分布关系式及相关系数。研究表明:负摩阻力转换系数随膨胀土含水率增大而减小,膨胀土含水率由初始值18%增加到30%时,转换系数减小约0.2,且膨胀土自由膨胀率、抗剪强度对试桩极限承载力影响较大;此外,负摩阻力转换系数随着桩长、桩径的增大而增大,可推测负摩阻力对大直径超长自平衡试桩影响较小。
In order to study the influencing factors and regularity of the conversion coefficient of self-balanced pile tested in expansive soil area,and to ensure the applicability of the self-balanced test method in expansive soils area,a numerical simulation on model test of self-balanced pile and traditional static pressure pile was carried out.The influence rule of the properties of expansive soil,geometric parameters of pile body and properties of pile-soil contact surface on the conversion coefficient of self-equilibrium method were analyzed by the method of controlling single variable.By the method of fitting,the quadratic term distribution formula and correlation coefficient between each factors and conversion coefficient were obtained.The results show that the conversion coefficient of negative friction resistance decreases with the increase of water content in expansive soil.The conversion coefficient decreases by about 0.2 when the water content of the expansive soil increases from the initial value of 18%to 30%,and the free expansion ratio and shear strength of expansive soil have large influence on the ultimate bearing capacity of piles.In addition,the conversion coefficient of negative friction resistance increases with the increase of pile length and pile diameter.Thus,it can be inferred that the negative friction resistance has less effect on large diameter and extra-long self-balanced piles.
作者
欧孝夺
白露
江杰
李胜
秦金喜
OU Xiaoduo;BAI Lu;JIANG Jie;LI Sheng;QIN Jinxi(College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Nanning 530004,China;Guangxi Engineering Research Center for Metallic Tailings Security Prevention and Control,Nanning 530004,China;College of Civil Engineering,Tongji University,Shanghai 200092,China)
出处
《人民长江》
北大核心
2022年第5期189-196,212,共9页
Yangtze River
基金
国家自然科学基金资助项目(51978179,51768006)
广西重点研发计划项目(AB19245018)。
关键词
自平衡试桩
膨胀土
桩基承载力
转换系数
self-balanced pile
expansive soil
bearing capacity of pile foundation
conversion coefficient
