HKUST体变测量方法在动三轴中的应用

The Application of HKUST Volumetric Change Measuring Method in Dynamic Triaxial Test

摘要:

动三轴试验是一种获得土体的动剪切强度、模量和阻力比的重要方法，三轴试验中试样的体变难以直接精确测量。本文总结当前动三轴试验中主要的体变测量方法，并分析这些方法在动三轴测试中的优缺点。结合GDS动三轴试验仪的特点，提出了基于HKUST双压力室体变测量装置的动三轴体变测量方法，通过改进试样底座，采用内压力室测量试样在动态试验过程中的体积变化。最后采用三轴试样进行测试，结果表明HKUST方法在动三轴体变测量中是可行的。该方法目前还不能够进行拉伸试验，同时振动对体变测量精度的影响也有待进一步研究。

Abstract:

Dynamic triaxial testing is an important method used to obtain the dynamic shear strength，modulus，and damping ratio of soil.However，it is often difficult to accurately measure volume change of a soil specimen in a triaxial test.This paper summarizes several commonly used methods of volumetric change measurement and analysis in dynamic tests in addition to their advantages and disadvantages.Combined with unique features of Geotechnical Digital Systems （GDS）dynamic triaxial test equipment，a novel method of using the total volume measuring wall device of Hong Kong University of Science and Technology （HKUST）is presented.In this novel method，inner cells are used to measure the volumetric change in a soil specimen during a dynamic test by improving the sample base.The accuracy and applicability of this new method are verified and illustrated by conducting tests on clay samples.The test results reveal that this novel method is feasible in dynamic triaxial testing.This method is not applicable for the pull test，and the influence of vibration on total volume measurement requires further research.