为了更真实地反映锚杆受拉时锚固体与土体界面的特性,较准确地获得包含界面剪切残余段的剪应力–位移(?–s)全过程曲线,自行研发了一种锚–土界面摩阻性能测试仪及相应的锚杆拉拔试样制作装置和方法。该测试仪器和测试方法简便易行,可成批模拟多种环境条件进行室内锚杆拉拔试验。利用该仪器完成了4批次27个不同条件的锚固体拉拔试验,深入研究了锚固体养护龄期、拉拔速率等因素对锚–土界面剪切强度特性的影响,提出了一种锚–土界面?–s全过程本构模型。研究结果表明:界面剪切强度在锚固体养护14 d后增长缓慢;锚杆以0.1~2.5 mm/min拉拔时,速率对剪切强度的影响不大;提出的锚–土界面模型计算曲线与试验曲线吻合良好。
A testing system composed of pull-out testing apparatus simulating frictional behavior of anchoring solid-soil interface and the corresponding devices and techniques of specimen preparation are developed to study the real response of the anchoring solid-soil interface for anchor system under tension, especially to obtain more accurately the whole journey curve of shearing stress and displacement containing the shearing residual portion. This testing apparatus and techniques are simple and operable, which can be adopted to simulate the laboratory pull-out tests on anchoring system in bulk under multiple circumstances. Four groups of pull-out tests under twenty-seven different circumstances are completed on this testing system, and a novel whole-journey constitutive model for the anchoring solid-soil interface is proposed after investigating deeply the influences of curing period of anchor solid, pull-out speed and other factors on the interface shearing strength. The results indicate that the interface shearing strength increases slowly after curing for fourteen days, that the pull-out speed affects slightly the interface shearing strength in the range of 0.1~2.5 mm/min, and that the proposed constitutive model for the anchoring solid-soil interface is able to give calculated curves with good agreement with the test ones.
Chinese Journal of Geotechnical Engineering
anchoring solid-soil interface model
pull-out testing apparatus