分级加卸载作用下冻结界面黏弹塑性剪切蠕变解耦分析研究  

Study on viscoelastic-plastic shear creep decoupling analysis of frozen interface under graded loading and unloading

作　　者：王博通 张明礼[1] 王运华 高樯[3] 温智[3] 周志伟[3] 马巍[3] 王大雁[3] WANG Botong;ZHANG Mingli;WANG Yunhua;GAO Qiang;WEN Zhi;ZHOU Zhiwei;MA Wei;WANG Dayan(Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province,Lanzhou University of Technology,Lanzhou 730050,China;Xinjiang Chiyu Electric Power Engineering Consulting Co.,Ltd,Urumqi 830002,China;State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]兰州理工大学、甘肃省土木工程防灾减灾重点实验室,甘肃兰州730050 [2]新疆驰誉电力工程咨询有限公司,新疆乌鲁木齐830002 [3]中国科学院、西北生态环境资源研究院冻土工程国家重点实验室,甘肃兰州730000

出　　处：《冰川冻土》2023年第6期1849-1858,共10页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(42301163,42371140);冻土工程国家重点实验室自主课题(SKLFSE-ZQ-202102);甘肃省科技计划项目(23JRRA670);中国科学院西部之光“西部青年学者”项目;甘肃省基础研究创新群体项目(20JR5RA478)资助。

摘　　要：桩-土界面间冻结力及荷载作用下界面的剪切力学行为是决定冻土区桩基础承载性能和荷载传递的关键。由于冰的显著流变性及高含冰量冻土区上限附近厚层地下冰的广泛分布特征,桩基础中上位具有的冰冻结界面剪切蠕变特性对桩基础的承载性能有显著影响。为研究桩冰冻结界面剪切变形特征及其内在机制,开展了-3℃、-5℃下冰-钢管结构分级加卸载剪切蠕变试验。通过对变形曲线的分段独立解耦,分析了冻结界面的黏弹塑性剪切变形行为。结果表明,界面剪切变形可分解为瞬弹性(Sie)、瞬塑性(S_(ip))、黏塑性(S_(vp))以及黏弹性变形(S_(ve))。广义弹性剪切模量随分级荷载的增加逐渐变大,表明加卸载过程中结构未加速破坏前界面存在明显的强化效应。界面剪切蠕变特征随剪应力水平的增加由衰减向非衰减过渡。其中,黏弹性变形和低剪应力水平下黏塑性变形均表现为衰减性,且荷载越大,黏弹性变形越大。高应力水平下黏塑性表现为非衰减性,且变形速率随剪应力水平增加显著提升。整体而言,冻结界面塑性变形值占总累计变形的比例先减小,后增大,其中瞬塑性变形主要存在于应力水平较小的加载阶段。蠕变过程中冻结界面的强化效应可能与剪应力作用下界面接触带压密、负温环境下界面重冻结有关。The ad-freezing force and shear mechanical behavior at the interface between piles and soil under load is pivotal in determining the bearing performance of pile foundations and the transfer of loads in frozen soil re⁃gions.Due to the significant rheological properties of ice and the widespread distribution of thick underground ice near the upper limit in ice rich permafrost areas,the shear creep characteristics of the ice-pile interface pres⁃ent in the upper part of pile foundations significantly affect their bearing capacity.To investigate the shear defor⁃mation characteristics of the pile-ice interface and its underlying mechanisms,a series of multi-level loads load⁃ing-unloading shear creep tests were conducted on ice-steel pipe structures at temperatures of-3℃and-5℃.By independently decoupling the deformation curves into segments,the viscoelastic-plastic shear deformation be⁃havior of the frozen interface was analyzed.The results reveal that the interface shear deformation can be decom⁃posed into instantaneous elasticity(Sie),instantaneous plasticity(S_(ip)),viscous plasticity(S_(vp)),and viscoelastic deformation(S_(ve)).The generalized elastic shear modulus gradually increases with increasing load level,suggest⁃ing a notable strengthening effect at the interface before accelerated structural failure during loading and unload⁃ing cycles.The shear creep characteristics of the interface transition from attenuation to non-attenuation with in⁃creasing in shear stress levels.Specifically,viscoelastic deformation and viscoplastic deformation at low shear stress levels both exhibit attenuation behavior,with greater loads leading to increased viscoelastic deformation.At high stress levels,viscoplastic deformation shows non-attenuation behavior,and the deformation rate signifi⁃cantly increases with higher shear stress levels.Overall,the proportion of plastic deformation at the frozen inter⁃face to the total cumulative deformation initially decreases and then increases,in view of instantaneous

关 键 词：冻结界面 加卸载剪切蠕变 黏弹塑性变形 变形解耦分析 

分 类 号：P642.14[天文地球—工程地质学]