摘要
基于塑性硬化土(HS)模型进行仿真分析,研究了从复合地基施工到路侧真空预压不同阶段素混凝土桩复合地基的应力与变形特征,并建立了对策模型,以近场地处理一侧边桩的水平位移和弯矩作为影响控制效果的评价指标,提出了降低影响的建议。结果表明,HS模型能够区分加卸载时刚度的差异,并较好的反映了淤泥的应力应变关系特性;真空预压处理引起加固区外围土体发生侧向卸荷,最大水平位移发生在密封墙边缘。真空预压场地处理会引起近场地一侧边桩的侧摩阻力和轴向力显著增大,摩阻力零点下移;抽真空时,负孔压先集中在排水板处,然后向土中扩散,渗透性大的土层负压传递较快;增大场地处理边缘距路基距离或者在复合地基边缘设置地下连续墙均能有效减小边桩的侧向变形和弯矩,而水泥土搅拌桩及其格栅墙的支护效果很有限。
Based on the numerical simulation of the plastic hardening soil(HS)model,the stress and deformation characteristics of the plain concrete pile composite foundation at different stages from the construction of the composite foundation to the vacuum preloading of the roadside were studied.The countermeasure model was established,and the horizontal displacement and bending moment of the piles on the side of the near the site treatment were used as the evaluation indexes to control the effect,and the suggestions for reducing the influence were put forward.The results show that the HS model can distinguish the difference of stiffness between loading and unloading,and better reflect the stress-strain relationship characteristics of silt.Vacuum preloading treatment causes lateral unloading of the soil around the soil reinforcement area,and the maximum horizontal displacement occurred at the edge of the sealing wall.The treatment of vacuum preloading site significantly increased the lateral friction resistance and axial force of the pile near the site treatment,and the zero point of friction resistance moved downward.When vacuuming,the negative pore pressure was first concentrated at the drainage board,and then diffused into the soil.The negative pore pressure in the soil with high permeability transmitted faster.Increasing the distance between the site treatment edge and the roadbed or setting up high-pressure jetting piles on the edge of the composite foundation can effectively reduce the lateral deformation and bending moment of the side piles,while the support effect of cement-soil mixing piles and grid-typed cement-soil walls was very limited.
作者
王健
陈仕文
梁东波
WANG Jian;CHEN Shi-wen;LIANG Dong-bo(Zhuhai Aviation City Engineering Construction Co.,Ltd.,Zhuhai 519042,Guangdong,China;Zhuhai Institute ofUrban Planning&Design,Zhuhai 519001,Guangdong,China;Zhuhai Construction Engineering Holding Group Co.,Ltd.,Zhuhai 519090,Guangdong,China)
出处
《地基处理》
2022年第6期530-536,共7页
Journal of Ground Improvement
关键词
地基处理
深厚软土
素混凝土桩
HS模型
复合地基
真空预压
foundation treatment
deep soft soil
plain concrete pile
HS model
composite foundation
vacuum preloading
