自动撒砂装置的研制与测试

Development and Test of Automatic Sand-pour Device

试样制备是土工模型实验中至关重要的技术环节,装样的质量直接影响着模型实验的成败。为获得高度可重复的指定相对密度的均匀试样,自主研制了基于伺服电机驱动系统的自动撒砂装置。采用福建标准砂进行了多组砂雨法成样的对比试验,分析了砂样落距和流速对成样相对密度的影响。同时通过相对位置测试、CPT强度测试和桩基础承载力离心模型实验,检验了撒砂装置的有效性。试验证明相对密度随砂样落距的增大而增大,随流速增大而减小,且该装置制得的试样均匀性好,可重复度高。

The sample preparation is very important as a vital technique in geotechnical model tests, the quality of which directly determines the success or failure of modelling test. A servomotor-driven automatic sand-pour device has been developed to obtain the homogeneous sandy sample of the designated relative density with high repeatability. Here, several series of comparative pluvial modelling tests with Fujian standard sand are carried out to analyze the influence of drop height and flow rate on the relative density. Simultaneously, the validity of new sand-pour device is checked through relative position test, CFF penetration test and centrifugal modelling test of the bearing capacity of pile foundation. The results show that the relative density of the sample is increased gradually with the increasing of drop height, while decreased with the increasing of sand flow rate, and this newly-developed device is able to prepare the sand specimen with high uniformity and high repeatability.