摘要
采用数值模拟方法预测加筋土桥台的性能是一种常见的手段,目前的数值模拟研究中常将土工合成材料筋材假设为线弹性材料,赋予筋材常应变快速拉伸试验获得的恒定拉伸刚度,然而一些常见的土工合成材料在工程实际拉伸条件下表现出明显的蠕变行为,对加筋土结构的力学行为有重要影响.为此,本文采用有限差分法模拟加筋土桥台,分别赋予筋材忽略蠕变特性的恒定刚度值以及考虑蠕变的恒定刚度值和非线性刚度值,研究筋材蠕变特性对桥台服役性能的影响.模拟结果表明,采用考虑蠕变的非线性筋材刚度与恒定筋材刚度的加筋土桥台具有相近的力学行为,后者得到的桥台变形以及筋材应变稍微偏大;采用常应变快速拉伸试验获得的恒定筋材刚度计算得到的桥台变形以及筋材应变远小于考虑筋材蠕变特性的两组工况,且差值随着荷载的增大而增大,但其筋材拉力较另外两组偏大.对于在加筋土桥台中应用广泛的高密度聚乙烯(HDPE)土工格栅,其蠕变特性对筋材所需抗拉强度造成的折减系数约为1.2,该值在不同服役荷载条件下基本不变.
Numerical simulation is a widely adopted method for predicting the performance of geosynthetic-reinforced soil (GRS) abutments. Incurrent studies, geosynthetic reinforcement materials are typically modeled as linear elastic with constant tensile stiffness derivedfrom constant rate-of-strain (CRS) tensile tests. However, many common geosynthetic materials exhibit significant creep behaviorunder practical engineering tensile conditions, which can substantially affect the mechanical behavior of reinforced soil structures.This paper employs the finite difference method to simulate GRS abutments, incorporating reinforcement modeled with constantstiffness that neglects creep, as well as both constant and nonlinear stiffness that account for creep behavior. The influence of creepcharacteristics on the service performance of the abutments is examined. The simulation results reveal that GRS abutments modeledwith nonlinear stiffness considering creep demonstrate mechanical behavior comparable to those with constant stiffness that alsoaccounts for creep, though the latter exhibits slightly greater deformations and reinforcement strains. In contrast, the deformations andstrains calculated using constant stiffness from CRS tests are significantly lower than those in the scenarios that incorporate creep,with the discrepancy increasing as the load intensifies. Notably, the tensile force in the reinforcement modeled with CRS-derivedstiffness is higher than in the other two scenarios. For the HDPE geogrid widely used for GRS abutments in the field, the reductionfactor for the required tensile strength due to creep is approximately 1.2, this value remains relatively stable under varying serviceload conditions.
作者
邓嘉隆
郑俊杰
郑烨炜
DENG JiaLong;ZHENG JunJie;ZHENG YeWei(School of Civil Engineering,Wuhan University,Wuhan 430072,China)
出处
《中国科学:技术科学》
北大核心
2025年第6期1055-1066,共12页
Scientia Sinica(Technologica)
基金
国家自然科学基金项目(批准号:52078392,52478358,52338007)
国家重点研发计划项目(编号:2022YFC3080400)资助。
关键词
土工合成材料
蠕变
加筋土桥台
服役性能
geosynthetic
reinforced soil bridge abutment
creep
service performance
