土工格室不同结点连接方式失效机制试验研究

Experimental investigations on failure mechanism of different junction connections of geocells

结点连接方式对土工格室的性能至关重要。结点在加筋结构中往往会受到不同方向的作用力,然而对结点在不同受力状态下的失效机制缺乏系统的研究。通过对焊接、插接、铆接3种结点连接方式的土工格室进行单轴拉伸试验,研究了结点连接方式对土工格室条带性能的影响,比较了在不同受力状态下结点的失效模式及抗拉强度。此外,通过引入“条带强度保持率”、“条带变形保持率”、“结点强度发挥率”评价了不同结点连接方式的性能。结果表明:焊接结点对HDPE土工格室条带拉伸性能的协调发挥影响较低,为4.82%;而铆接结点对PET土工格室条带影响较高,为22.2%。焊接、铆接、插接结点主要受剥离强度的控制,但焊接结点的剥离结点强度发挥率可达28.3%,分别是插接、铆接结点强度发挥率的11.32倍、6.58倍,体现了焊接结点的性能优势。插接结点在3种受力状态下结点强度相差很大,需采取注塑等措施来改善结点在剪切、剥离作用下的强度,从而均衡发挥插接结点的性能。试验结果可为土工格室的合理选用以及加筋机理的研究提供参考。

The connection mode of junctions is crucial to the performance of geocells.The junction will be generally subjected to different directions of loading in the reinforced structure.However,there is a lack of detailed researches on the failure mechanism of the junctions under different loading models.Through the uniaxial tensile tests on the geocells with three junctions of welding,latching and riveting,the effects of connection modes on the performance of geocell strips are studied,and the failure modes and tensile strength of the junctions under different loading models are compared.The performance of different junction connections is evaluated by the indexes like"strip strength retention rate","strip deformation retention rate",and"junction strength utilization rate".The results show that the welding junctions have the lower impact on coordination of tensile properties of HDPE geocell strips,which is 4.82%,while the riveting junctions have the higher impact on the coordination of PET geocell strips,which is 22.2%.The welding,riveting and latching junctions are mainly controlled by the peeling strength.However,the strength utilization rate of the welding junctions under peeling can reach 28.3%,which is 11.32 times and 6.58 times that of the latching and riveting ones,respectively,reflecting the performance advantages of the welding junctions.The strength of the latching junctions varies greatly under three loading models,and the measures like injection connection need to be taken to improve the strength of the junctions under shearing and peeling to balance the performance of the latching junctions.The test results can provide references for the reasonable selection of geocells and the study on reinforcement mechanism.