一种控制直剪蠕变试验剪应力的简易装置

土的蠕变是指土在保持应力不变的条件下,应变随时间延长而增加的现象。研究土的蠕变性质对于确定土的长期强度有重要意义,土的蠕变研究也是近几年的研究热点。然而,土的蠕变试验周期特别长,因此简便、易行又有一定可信度的蠕变试验仪器,对于土蠕变性质的研究有较大的推动意义。直剪蠕变试验是研究确定土的蠕变性质的一种最简单、最直观的试验方法。但由于该试验只是控制剪切力不变,剪切过程中,试样受剪面积逐渐减小,剪应力持续增大,整个过程并不是蠕变。通过在传统仪器上附加一个简单装置,利用液体的浮力来控制试验剪切力,从而使得试样在剪切过程中的剪应力不变。在对仪器进行相应改进后,做了对比试验,检验该装置对剪应力的控制效果,试验结果表明,该简易装置可在一定程度上控制剪应力。

A kind of simple device controlling shear stress in direct shear creep experiment

Soil’s creep indicates a phenomenon that strain increases with time while keeping soil’s stress stable. Researching soil’s creep properties is very important for confirming soil’s long-term strength; and it is quite popular in recent years. However, a creep experiment costs a lot of time; therefore a simple, feasible and reliable device for soil’s creep properties will boost the research. The soil’s direct shear creep experiment is the simplest and the most intuitive way to research soil’s creep properties. But the experiment just keeps the shearing force stable, in the shearing process, the effective area reduces gradually and the shear stress increases continuously with the shear strain developing, this process is not a proper creep. By adding a simple device on the traditional experiment, the liquid’s buoyancy is used to control the shear stress to keep the shear stress stable in the shearing process. After the corresponding modification of the instrument, we had done a group of contrast tests to check the effect of shear stress controlling. The test results show that it can control the shear stress to a certain level.