摘要
开展了3种不同厚度的HDPE土工膜6种荷载水平下的蠕变与蠕变恢复试验,对土工膜蠕变与蠕变恢复特性及其影响因素进行深入分析。研究表明:荷载施加与卸除的瞬间,土工膜产生瞬时变形,之后变形速率随时间逐渐变小。当荷载水平较低(如小于30%)时,土工膜蠕变随时间持续增加并较快地趋于稳定状态;当荷载水平较高(如大于40%~50%)时,土工膜将进入第二阶段蠕变,变形以恒定速率持续增长,不再稳定。当荷载水平超过20%时,完全卸载后土工膜蠕变恢复时产生残余变形,且残余变形随荷载水平增大近似呈线性增加。土工膜初始模量受荷载水平与蠕变过程的双重影响,当荷载水平上升至40%~50%时,其初始模量将显著下降超100 MPa,其中在加载初期初始模量下降约40%,经过蠕变后卸载初始模量进一步下降约30%。此外,改进建立了考虑材料黏弹性的土工膜蠕变联合元件模型及蠕变恢复模型,与试验数据对比验证了所建模型能较好地反映不同荷载水平下土工膜的蠕变及蠕变恢复过程。
The creep and creep recovery of HDPE geomembrane with three different thicknesses under six different load levels are investigated. The creep and creep recovery characteristics of the geomembrane and their influencing factors are deeply analyzed. The test results show that the geomembrane deforms instantly when the load is applied and removed, and then the deformation rate gradually slows down with time. When the load level is lower than 30%, the deformation of the geomembrane tends to be stable with time. When the load level is higher than 40%~50%, the strain of the geomembrane increases at a constant rate in the second stage creep. When the applied load level exceeds 20%, the geomembrane will produce residual deformation after creep recovery and complete unloading, and the residual deformation will increase approximately linearly with the increase of load level. The initial modulus of the geomembrane is influenced by both the load level and the creep process. When the load level of the geomembrane rises to 40%~50%, its initial modulus will drop significantly by more than 100 MPa. In addition, a composite element model for the creep and creep recovery of geomembrane considering the viscoelastic properties of materials is established. The numerical simulation shows that the proposed model can well reflect the creep and creep recovery process of the geomembrane under different load levels.
作者
岑威钧
文震宇
李邓军
王力波
CEN Wei-jun;WEN Zhen-yu;LI Deng-jun;WANG Li-bo(College of Water Conservancy&Hydropower Engineering,Hohai University,Nanjing 210098,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2022年第11期2143-2150,共8页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51979089,51679073)
水能资源利用关键技术湖南省重点实验室开放基金项目(PKLHD202004)。
