深基坑桩锚联合支护体系力学机理与效果评估OA
Mechanical mechanism and effect evaluation of deep foundation pit pile-anchor combined support system
为揭示桩锚联合支护结构在复杂深基坑开挖过程中的变形及力学响应规律,丰富深基坑联合支护的理论体系,以国内某大型改扩建深基坑支护工程为背景,采用有限元软件PLAXIS 3D对锚索分层施工过程中地表变形、灌注桩水平位移及内力进行定量分析,提出了在锚索预拉力分配作用下改进支挡结构稳定性的计算方法,并与强度折减法进行对比;通过回归分析法实现锚索预应力优化设计.结果表明:多层锚索分层施工过程中,地表水平位移变化呈现"陡降缓平"的趋势,灌注桩的位移及内力变化主要集中在灌注桩1/2以上位置;5层锚索施工完成时,锚索预拉力分配作用下的改进公式的最大安全系数为1.88,强度折减法的安全系数为1.94,两者改进公式的计算误差约为3.1％,且保留了更高的安全裕度;不同预应力锚索对应的弯矩变化曲线符合Gauss分布函数,以弯矩最小为控制指标,优化后的多层锚索预应力为423 kN,地表水平位移最大值降低了86.2％.研究成果可为桩锚联合支护深基坑工程的锚索预应力的参数优化提供有效参考.
To reveal the deformation and mechanical response laws of pile-anchor composite support structures during the excavation of complex deep foundation pits and enrich the theoretical system of composite support for deep foundation pits,taking a large-scale reconstruction and expansion deep foundation pit support project in China as the engineering background,PLAXIS 3D finite element software was adopted to quantitatively analyze the internal force and displacement of cast-in-place piles,and the surface deformation during the layered construction of anchor cables.An improved calculation method for the stability of support structures considering the distribution effect of anchor cable pretension was proposed and compared with the strength reduction method.The optimal design of anchor cable prestress was realized by regression analysis.The results show that during the layered construction of multi-layer anchor cables,the horizontal displacement of the ground surface presents a trend of"steep drop followed by gentle leveling",and the displacement and internal force of cast-in-place piles are mainly concentrated in the upper half of the pile body.After the construction of five rows of anchor cables is completed,the maximum safety coefficient calculated by the improved stability formula considering the pretension distribution is 1.88,while the stability formula of the strength reduction method is 1.94.Comparing the two,the calculation error of the improved formular is only about 3.1％,and a higher safety margin is retained.The bending moment variation curves of anchor cables under different prestress values conform to the Gauss distribution function.The optimal prestress of multi-layer anchor cables is 423 kN with the minimum bending moment as the control index,and the maximum horizontal displacement of the ground surface is reduced 86.2％after optimization.The research results can provide effective reference for the optimization of anchor cable prestress parameters in deep foundation pit engineering supported by pile-anchor composite structures.
周建建;宋德威;葛斐;吴健;李进晓;孙阳;薛永利
上海核工程研究设计院有限公司,上海 200233河海大学港口海岸与近海工程学院,江苏南京 210098核工业南京建设集团有限公司,江苏南京 211102上海核工程研究设计院有限公司,上海 200233上海核工程研究设计院有限公司,上海 200233河海大学港口海岸与近海工程学院,江苏南京 210098核工业南京建设集团有限公司,江苏南京 211102
建筑与水利
地基基础工程桩锚联合支护数值模拟强度折减预应力优化
foundation engineeringpile-anchor combined supportnumerical simulationstrength reductionprestress opti-mization
《河北工业科技》 2026 (3)
244-253,10
国家重点研发计划项目(2023YFC3206103)国家电力投资集团公司B类课题(23FW2035)
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