基于界面本构模型的砂土中单桩荷载−沉降响应预测方法  

Prediction method for load-settlement response of a single pile in sand based on an interface constitutive model

作　　者：周攀 李镜培[1,2] 李盼盼 刘耕云 张超哲 ZHOU Pan;LI Jing-pei;LI Pan-pan;LIU Geng-yun;ZHANG Chao-zhe(Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Institute of Geotechnical Engineering,Southeast University,Nanjing,Jiangsu 211189,China)

机构地区：[1]同济大学岩土及地下工程教育部重点实验室,上海200092 [2]同济大学地下建筑与工程系,上海200092 [3]东南大学岩土工程研究所,江苏南京211189

出　　处：《岩土力学》2024年第6期1686-1698,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.42272310)。

摘　　要：基于界面本构模型提出了一种新的砂土中单桩荷载沉降响应的预测方法。首先,从土−结构界面本构模型出发推导了严格的桩−土界面非线性荷载传递模型,该模型承继了界面本构模型特征,能够模拟桩−土界面上发生的应变硬化/软化、剪胀与应力路径依赖性等行为。此外,采用双曲线荷载传递模型模拟桩端−土相互作用的非线性应力−位移关系。上述荷载传递模型所需参数可以通过室内界面剪切试验和土工试验进行校准。继而,基于荷载传递法,提出了单桩荷载沉降响应分析的一维计算模型,并采用迭代算法进行数值求解。最后,将理论解答与已报道的模型试验、自主开展的模型桩试验以及数值模拟结果进行比较,以验证所提出的理论方法的正确性。试验结果表明,预测值与实测值吻合较好,且该方法能够很好地预测非位移桩与位移桩的荷载沉降响应。提出了一个基于界面本构模型的单桩荷载沉降响应分析框架,为竖向荷载下砂土中单桩优化设计提供了理论参考。A novel method for predicting the load-settlement response of a single pile in sands is developed based on an interface constitutive model.Firstly,a rigorous nonlinear load-transfer model for the pile-soil interface is derived from the soil-structure interface constitutive model.This model incorporates the beneficial features of the adopted interface constitutive model and effectively simulates fundamental interface characteristics,such as strain hardening(or softening),normal shear dilation,and stress path dependency occurring at the pile-soil interface.Additionally,a hyperbolic load-transfer model is employed to simulate the nonlinear stress-displacement relationship between the pile end and soil.The parameters for the aforementioned load-transfer model can be calibrated through experimental interface shear tests and geotechnical experiments.Subsequently,a one-dimensional computational model for analyzing the load-settlement response of a single pile is proposed based on the load transfer method,with numerical solutions obtained using an iterative algorithm.Finally,the theoretical results are compared with reported and independently conducted model pile tests to validate the accuracy of the proposed theoretical approach.The experimental results show a good agreement between the predicted and measured values,demonstrating the method’s excellent capability in predicting the load-settlement response of both displacement and non-displacement piles.This paper presents an analytical framework based on the interface constitutive model for analyzing the load-settlement response of single piles,providing a theoretical reference for optimizing the design of pile foundations in sandy soils under vertical loads.

关 键 词：单桩 砂土 荷载-沉降响应 桩-土相互作用 界面本构模型 模型试验 

分 类 号：TU473.1[建筑科学—结构工程]