深厚卵石地层桩底注浆灌注桩承载特性分析  

Analysis of Bearing Characteristics of Grouting Cast-in-place Pileat the Bottom of Pile in Deep Pebble Stratum

作　　者：张升进 丁小军[1] 王旭[1,2] 杨强强 ZHANG Shengjin;DING Xiaojun;WANG Xu;YANG Qiangqiang(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;National and Provincial Joint Engineering Laboratory of Road&Bridge Disaster Prevention and Control,Lanzhou 730070,China;Gansu Architectural Design and Research Institute,Lanzhou730070,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]道桥工程灾害防治技术国家地方联合工程试验室,甘肃兰州730070 [3]甘肃省建筑设计研究院,甘肃兰州730070

出　　处：《兰州工业学院学报》2022年第3期30-34,共5页Journal of Lanzhou Institute of Technology

摘　　要：为探讨桩端卵石地层灌注桩注浆后承载力及承载特性,利用理论分析加数值模拟的方法对其承载特性进行分析,根据注浆量并结合球形扩张理论,给出注浆浆球半径的计算公式。结果表明:卵石地层桩端后注浆能有效提高灌注桩的承载力,桩端后注浆桩的承载力是未注浆桩承载力的4倍以上;桩底注浆对桩侧承载力的提高集中体现在桩端附近的3倍桩径范围内,当桩底强度达到桩侧强度40倍之后,其对总承载力的提高不再明显,桩底强度达到5倍桩侧强度时对桩侧承载力的提高不再明显,当桩底强度太弱时反而会限制桩侧摩阻力的发挥;桩侧承载力随着荷载及桩土相对位移的增大先增大后趋于稳定值。In order to discuss the bearing capacity and bearing characteristics of cast-in-place piles in pebble stratum at the pile end after grouting,the method of theoretical analysis and numerical simulation were used to analyze the bearing characteristics of the cast-in-place piles with pebble stratum at the pile end.The expansion theory is given,and the formula for calculating the radius of the grouting ball is given.Numerical simulation results show that post-grouting can effectively improve the bearing capacity of cast-in-place piles in pebble strata,and the bearing capacity of post-grouting piles is more than 4 times that of non-grouting piles.The improvement of the pile side bearing capacity by grouting at the pile bottom is concentrated in the range of 3 times the pile diameter near the pile end.When the pile bottom strength reaches 40 times the pile side strength,the increase in the total bearing capacity is no longer obvious.When it reaches 5 times the pile side strength,the improvement of the pile side bearing capacity is no longer obvious,and when the pile bottom strength is too weak,it will limit the exertion of the pile side friction resistance.The bearing capacity of the pile side first increases and then tends to a stable value with the increase of the load and the relative displacement of the pile and soil.

关 键 词：浆球扩展半径 侧阻力 桩土接触面 数值模拟 承载特性 

分 类 号：TU473.1[建筑科学—结构工程]