Properties Analysis On Interaction Of Soil Pressure Sensor And Soil Medium

Soil pressure sensors have been applied since about one hundred years ago in science research and practice on Geotechnical Engineering. Although theories and applied technology are constant developing, the research on interaction of sensor and soil medium is lagging behind the application of sensors, needs to be enhanced.To analysis the mechanism of interaction of sensors and geotechnical medium, through the study of pressure sensor matching—error with finite element method and laboratory experiment, conclude briefly as follows:1)According to finite-element-method (FEM) calculation, under same conditions, if the ratio of soil pressure sensor's modulus for deform to medium's increases, the matching-error increases, and the other parameters have a little effect. Under same conditions, the ratio of soil pressure sensor's thickness to radius increase, the matching-error increases, nonlinear if the ratio of sensor's modulus to medium's is 0.1 and linear if the ratio is 10.it's in accordance with classic theories and demonstrates it important to enhance sensor's stiffness and low the ratio of thickness to radius.2)As FEM calculation, the stress disturbance along the borders of sensors is greater than it in the central area.3)For translating sensor, the matching-error in experiment with sand medium is higher than values according to the three methods:Д.C.bapaHOb's equation, FEM and Enhanced-rigid-block method.4)The experiment results read that the matching-error for sensor with Single flexing diaphragm is almost equal to twice-indentation-method if the ratio of modulus is great, but greatly different if the ratio is little.5)The experiment results read matching-errors for translating-sensor and Single-flexing-diaphragm-sensor are over 40% and negligent. The matching-errors for sensors varies greatly with conditions of soil medium include diameter, content of cement, and so on, not only the ratio of modulus and thickness to radius. So the sensors should be calibrated in the same states with practical application if possible。6) According to the experiment results, if the diameters of soils changes gradually, the dispersion of value that sensor outputs is steady firstly, then increases.the critical soil diameter is about 1/4～1/3 of the diameter of sensor.