Abstract: The Earth pressure box can be checked and calibrated before using，and the earth pressure box can be selected to ensure the earth pressure measurement in engineering test.According to the condition and mechanism of water pressure，this paper puts forward a method of water pressure calibration which does not need high precision professional equipment such as testing instrument，and can be carried out in a simple scientific research environment.Then，a vertical closed pipe with adjustable water level is designed to provide controllable water pressure，and the relationship between water pressure and strain is obtained by detecting the output of the electric signal of the pressure box.Comparing the results of calibration coefficient with the results of oil pressure calibration provided by the supplier，it is found that the two results are basically consistent，and the maximum deviation of calibration coefficient K is only 4.3%.This method can be widely used in the self-calibration of earth pressure cell under simple conditions.

Key words: earth pressure box, water pressure, strain, oil standard, daily calibration, calibration factor

摘要： 为便于用户在使用土压力盒之前进行自检和日常标定,筛选出能够正常工作的土压力盒,为工程测试中的土压力测量提供保障,文中根据水压力产生的条件和机理,提出了一种不需要测试仪表等高精度专业设备的水压标定方法,设计了一个可调节水位高低的竖向封闭管道以提供可控水压力,通过检测压力盒电信号的输出,得到了水压力与应变的关系,从而实现了土压力盒的现场标定;将该方法的标定系数结果与供货方提供的油压标定结果对比后发现,两者结果基本一致,二者标定系数K的最大偏差仅为4.3%。实验结果表明,该方法原理简单、操作方便、精度高,可以广泛应用于科研环境简单条件下用户对土压力盒的自检和日常标定。

关键词: 土压力盒, 水压力, 应变, 油标, 日常标定, 标定系数