Study On Optimization And Improvement Of Pressure Plate

The soil-water characteristic curve plays a very important role in estimating the strength,infiltration and deformation of the soil.Accurate measurement of it is the basis for solving other problems.Therefore,it is of great significance for the improvement and research of the accuracy of existing experimental instruments.In this paper,3D printing technology is introduced into the improvement of the anti-evaporation of the pressure chamber and the improvement of the saturation method of the micro tensiometer,and the evaporation and balance problems of the pressure plate instrument water bottle are explored,and the following main results are obtained:(1)Aiming at the deficiencies of the pressure plate meter and the micro tensiometer,3D printing technology is used to print the water storage ring for the improvement of the pressure chamber and the vacuum drum cover,the saturation ring,and the saturation ring fixing plate for the improvement of the saturation method of the micro tensiometer.It was found that except for the vacuum lid with higher requirements for strength and tightness,the rest of the printed objects can meet the needs of the experiment.(2)In view of the evaporation problem of the pressure plate instrument water collection bottle,the principle was analyzed,and it was found that the evaporation mass would accumulate in the test.In the step-by-step pressure test that uses the quality of drainage to backcalculate the water content of the soil sample,the evaporation quality of the water collection bottle can be corrected by recording the evaporation quality at intervals to improve the accuracy of the experiment.(3)The evaporation of soil sample moisture in the pressure chamber is mainly related to the humidity and temperature of the air within the pressure.The greater the air humidity,the more stable the temperature,the smaller the evaporation of the soil sample.On the contrary,the greater the evaporation of the soil sample is when the humidity is lower and the temperature fluctuation is greater.The improvement of increasing humidity by placing a water storage ring and filter paper in the pressure chamber can effectively reduce the evaporation of water in the soil sample.(4)In the case of a water storage ring and filter paper,a large temperature fluctuation will cause water vapor to condense into the soil sample,while without a water storage ring and filter paper,a large temperature fluctuation will make the soil sample evaporate larger.Therefore,large fluctuations in temperature should be avoided during the experiment.(5)The balance time judged by the judgment condition that the 24 hr displacement is less than 0.1g is longer than the time judged by the slope method,but the difference in SWCC obtained by the two methods is smaller.(6)Before the evaporation of the pressure chamber was improved,the inverse calculation result of the continuous pressurization experiment was quite different from the inverse calculation result of the single pressurization method.