摘要
通过基于数字图像相关技术的模型试验和离散元数值模拟方法(PFC),研究了叶片设置、砂土相对密实度、受荷工况等因素对螺杆桩抗拔承载力和变形特性的影响,利用试验结果校准离散元程序的细观参数,模拟结果用于分析螺杆桩的荷载分担特性、螺纹叶片间距对承载力的影响以及桩周土体滑动面特征。结果表明:抗拔工况下桩基荷载位移曲线呈现软化特征,0.05 D破坏准则适用于抗拔桩的极限承载力判定,叶片的设置使得桩承载力提高37%,螺纹段荷载分担比接近70%,直杆段荷载分担比是抗压工况的2倍;上拔承载力随叶片间距增加呈降低趋势,H/D=1.00是此工况下合理参数;砂土相对密实度的提高使得螺杆桩和直杆桩抗拔承载力分别增长19.4%、26%,而对抗拔桩周围土体位移模式影响有限,螺杆桩桩周土体最大影响范围约为4 D,而直杆桩约为2 D。
Through model tests based on digital image correlation technology and discrete element numerical simulation method(PFC),the influence of thread setting,the relative density of sand,loading conditions on the uplift bearing capacity,and deformation characteristics of the screw-shaft pile are studied.The test results are used to calibrate the micro parameters of the discrete element program.The simulation results are used to analyze the load sharing characteristics,the influence of pile type parameters on the bearing capacity and the sliding surface of the soil around the pile.The results show that:The uplift force-displacement curves of pile foundation present softening characteristics,and the 0.05 D failure criterion is applicable to the determination of the ultimate bearing capacity of the uplift pile.The setting of the screw threads increases the bearing capacity of the pile by 37%,the load sharing ratio of the threaded section is close to 70%,and the shaft section is twice that of the compression condition.The uplift bearing capacity decreases with the increase of thread pitch.H/D=1.00 is a reasonable parameter under this condition.The improvement of the relative density of sand makes the uplift bearing capacity of screw-shaft pile and straight rod pile increase by 19.4%and 26%respectively,while the influence of displacement mode of soil around the uplift pile is limited.The maximum influence range of soil around the screw-shaft pile is about 4D,while that of straight rod pile is about 2 D.
作者
陈亚东
于艳
孙华圣
龚成中
蔡江东
Chen Yadong;Yu Yan;Sun Huasheng;Gong Chengzhong;Cai Jiangdong(Faculty of Architecture and Civil Engineering,Huaiyin Institute of Technology,Huaian,Jiangsu 223001,P.R.China;Jiangsu Huaiyin Water Conservancy Construction Co.,Ltd,Huaian,Jiangsu P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2024年第5期1581-1588,1664,共9页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金(51408254,51708245)
江苏省六大人才高峰资助项目(JZ-051)。
关键词
抗拔螺杆桩
模型试验
离散单元法
承载力
位移模式
uplift screw-shaft pile
model test
discrete element method
bearing capacity
displacement mode
