Development of a simple system to measure shear modulus of soft ground surface

本文研制了一种简单的软土地基剪切模量原位测量系统。它利用了一个事实，即当系统位于软土表面时，单自由度系统的基本周期被拉长。该系统由扭振自由振动器、压电测量装置、a /D转换器和手持式计算机组成，总重量小于2kgf。振动器为不锈钢材质，基本旋转周期约为1/10秒。系统只需5分钟左右即可显示单个测试结果。将该系统应用于不同压实程度的砂岩模型。试验结果与射板法获得的剪切模量值进行了比较，证明了该方法对剪切模量约为50 ~ 150kgf /sq.cm的软土具有实际应用价值。

A simple system has newly been developed for in-situ measurement of shear modulus of soft ground surface. It utilizes a fact that a fundamental period of a single degree of freedom system is elongated when the system is situated at a soft soil surface. The system is made up of a torsional free-vibrator, piezo-electric measurement devices, a A/D converter and a hand-held computer, having total weight less than 2 kgf. The vibrator is mode of stainless steel, having the fundamental rotating period about 1/10 sec. The system takes only 5 minutes or so to indicate a single test result.The system was applied to a sand deposit model with different compaction levels. Test results were compared with shear modulus values obtained by the plate-shooting method, demonstating its usufulness in practical use for soft soil having shear modulus about 50 - 150 kgf/sq.cm.