摘要
为了给孔内深层强夯法(SDDC工法)处理Q_(2)湿陷性黄土地基设计方案提供优化参数,以西安灞桥某地基处理项目为背景,基于离散元数值方法和原位测试技术,研究不同黄土地层参数、不同SDDC工法设计参数对湿陷性黄土地基的挤密效果的影响,并提出优化建议,最后基于试验段实测结果进行了对比验证。研究表明,SDDC工法对细粒径、粒径比小和刚度低的地基挤密效果更显著,土体的初始孔隙率、剪切模量和泊松比变化对地基挤密效果的影响较小。适当增大夯击能和成孔直径,可有效提高地基挤密效果,橄榄型锤对地基的挤密宽度影响更显著,矩形锤对挤密影响深度更有优势。本场地建议SDDC工法的设计参数是:采取橄榄型锤施工,单次夯击能不宜低于800 kJ、成孔直径D=1.2~1.4 m;受施工扰动影响,地表以下及桩底以上2 m范围内挤密效果较差,建议采取其他辅助压实手段消除端部效应。
In order to provide an optimal design scheme for the treatment of Q_(2)collapsible loess foundation by super down-hole dynamic compaction(SDDC)method,based on a foundation treatment project in Ba Bridge,Xi’an,the compaction effect of different parameters of loess and different SDDC design parameters on collapsible loess foundation was studied using discrete element numerical method and in-situ tests,and the optimization suggestions were put forward.Finally,it is verified based on the measured results of the test section.The results show that the SDDC method is more effective for the foundation with fine particle size,and low particle size ratio and low stiffness,and the changes of initial porosity,shear modulus and Poisson’s ratio of soil have little influence on the foundation compaction effect.Appropriately increasing the tamping energy and hole diameter can effectively improve the compaction effect of the foundation.The conical hammer has a more significant effect on the compaction width of the foundation,and the rectangular hammer has more advantages on the compaction depth.The design parameters of SDDC method construction,recommended for this site are:adopt conical hammer for construction,the single tamping energy should not be less than 800 kJ,and the hole diameter D=1.2~1.4 m.Due to the influence of the construction disturbance,the compaction effect is poor within the range of 2 m below the surface and above the pile bottom,and other auxiliary compaction methods are recommended to eliminate the end effect.
作者
朱才辉
周小松
乔建伟
李鑫磊
ZHU Caihui;ZHOU Xiaosong;QIAO Jianwei;LI Xinlei(Institute of Geotechnical Engineering,Xi’an University of Technology,Xi’an 710048,China;China Jikan Research Institute of Engineering Investigations and Design,Co.,Ltd.,Xi’an 710043,China)
出处
《自然灾害学报》
北大核心
2025年第1期217-229,共13页
Journal of Natural Disasters
基金
国家自然科学基金项目(52279110)。
关键词
孔内深层强夯法(SDDC工法)
湿陷性黄土
加固效果
离散元
super down-hole dynamic compaction method(SDDC)
collapsible loess
compaction effect(CE)
discrete element
