首页|基于被动区土弹簧刚度降低过程的基坑围护结构计算增量法及软化p-y曲线

基于被动区土弹簧刚度降低过程的基坑围护结构计算增量法及软化p-y曲线

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  • 国家科技期刊平台
  • NETL
  • NSTL
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基坑围护结构的计算常采用基于杆系有限元的增量法,被动区土弹簧刚度在基坑开挖作用下发生动态降低导致土抗力软化,目前缺少在非线性地基模型基础上对该问题的研究.通过引入两个刚度变化系数来综合量化被动区土弹簧参数随基坑开挖的动态变化过程,建立了基于该过程的基坑围护结构计算增量法.针对非线性地基模型,提出了细化增量法进行数值计算.采用线弹性、理想弹塑性以及双曲线3种基本土弹簧模型计算得到被动区软化p-y曲线,对比显示,基于双曲线基本模型得到的等效水平抗力系数变化曲线更符合实际规律.工程实例计算显示,基于基本土弹簧为双曲线的计算结果与不同开挖阶段墙的位移监测数据对应更好.参数分析显示,与被动区土体极限抗力pu相关的刚度变化系数对计算结果影响较大,采用此方法应着重关注被动区pu的计算方法及开挖卸荷对pu的影响.
Incremental calculation method of foundation pit enclosure structure and softening p-y curves based on stiffness reduction process of the soil springs in the passive zone
The incremental method based on the beam finite element method is commonly used for calculating foundation pit enclosure structures.However,there is a lack of research on the dynamic decrease of soil spring stiffness in the passive zone during excavation,which leads to soil resistance softening.This paper introduces two stiffness variation coefficients to quantify the dynamic change of soil spring parameters in the passive zone and establishes an incremental method for calculating foundation pit enclosure structures based on this process.For nonlinear foundation models,a refined incremental method is proposed for numerical calculations.Three basic soil spring models(linear elastic,ideal elastic-perfectly plastic,and hyperbolic)are used to obtain the softening p-y curves in the passive zone.A comparison of these models shows that the variation curve of the equivalent horizontal resistance coefficient obtained using the hyperbolic soil spring model aligns better with actual observations.An engineering example demonstrates that the calculation results based on the hyperbolic soil spring model correspond better to measured wall displacements at different excavation stages.Parameter analysis highlights the significant influence of the stiffness variation coefficient related to the ultimate resistance pu of the soil in the passive zone.Therefore,when using the proposed method,careful attention should be given to calculating the ultimate resistance pu and the influence of excavation on it in the passive area should be considered.

foundation pit enclosure structureincremental methodfoundation pit passive zonenonlinear soil springsoftening p-y curve

雷国平、苏栋、程马遥、刘慧芬、张维

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佛山科学技术学院交通与土木建筑学院,广东佛山 528225

深圳大学土木与交通工程学院,广东深圳 518061

深圳市城市公共安全技术研究院,广东深圳 518046

基坑围护结构 增量法 基坑被动区 非线性土弹簧 软化p-y曲线

国家自然科学基金面上项目广东省自然科学基金面上项目佛山市教育局高校教师创新项目深圳市自然科学基金

518784162023A15150117722021XJZZ10JCYJ20210324094607020

2024

10.16285/j.rsm.2023.0372

岩土力学
中国科学院武汉岩土力学研究所

岩土力学

CSTPCD北大核心
影响因子：1.614
ISSN：1000-7598
年,卷(期)：2024.45(3)
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