Influence of the boundary effect on the mechanical response test of pavement cushion under the wetting effect of silt  

粉土湿化作用下边界效应对垫层力学响应试验的影响

作　　者：Luo Qiqi Yu Qian Zhang Sheng Ma Xinyan Ye Xinyu Du Yinfei 罗其奇;余虔;张升;马新岩;叶新宇;杜银飞(中南大学土木工程学院,长沙410075;民航机场规划设计研究总院有限公司岩土工程所,北京100020;湖南铁院土木工程检测有限公司,长沙410075)

机构地区：[1]School of Civil Engineering,Central South University,Changsha 410075,China [2]Department of Geotechnical Engineering,China Airport Planning and Design Institute Co.,Ltd.,Beijing 100020,China [3]Hunan Tieyuan Civil Engineering Testing Co.,Ltd.,Changsha 410075,China

出　　处：《Journal of Southeast University(English Edition)》2024年第3期266-274,共9页东南大学学报（英文版）

基　　金：The National Natural Science Foundation of China(No.52008401);the Natural Science Foundation of Hunan Province(No.2021JJ40770);the Open Fund of Hunan Tieyuan Civil Engineering Testing Co.,Ltd.(No.HNTY2022K04).

摘　　要：Through a self-developed model test system,the mechanical properties of silt and the deformation characteristics of airport runways were investigated during the period of subgrade wetting.Based on the test results,the reliability of the numerical simulation results was verified.Numerical models with different sizes were established.Under the same cushion parameter and loading width ranges,the effects of the cushion parameters and loading conditions on the mechanical responses of the cushion before and after subgrade wetting were analyzed.The results show that the internal friction angles of silt with different wetting degrees are approximately 34°.The cohesion is from 8 to 44 kPa,and the elastic modulus is from 15 to 34 MPa.Before and after subgrade wetting,the variation rates of the cushion horizontal tensile stresses with the same cushion parameters and loading width ranges are different under the influence of boundary effects.After subgrade wetting,the difference in the variation rates of the cushion horizontal tensile stresses under the same cushion parameter range decreases compared with that before subgrade wetting;however,this difference increases under the same loading width range.Before and after subgrade wetting,the influence of the boundary effect on the mechanical response evaluation of the cushion is not beneficial for optimizing the pavement design parameters.When the cushion thickness is more than 0.25 m,the influence of the boundary effect can be disregarded.采用自研的模型试验系统,研究了道基湿化过程中粉土力学特性和机场跑道变形特征.依据试验结果验证了数值模拟结果的可靠性,并建立了不同尺寸的数值模型.在相同垫层参数和荷载宽度区间条件下,研究了道基湿化前后边界效应对垫层力学响应的影响.结果表明,不同湿化程度粉土内摩擦角接近34°,黏聚力为8~44 kPa,弹性模量为15~34 MPa.道基湿化前后,受边界效应影响,相同垫层参数和荷载宽度区间下垫层水平拉应力的变化率并不相同.道基湿化后,相同垫层参数区间下垫层水平拉应力变化率差异较湿化前减小,相同荷载宽度区间下变化率差异却有所增加.道基湿化前后边界效应对垫层应力响应评估的影响不利于道面设计参数优化.垫层厚度大于0.25 m时,可忽略边界效应的影响.

关 键 词：pavement cushion silt subgrade WETTING boundary effect mechanical response 

分 类 号：U416.2[交通运输工程—道路与铁道工程]