Pore/Earth Pressure Sensor Multiplex Calibrator DPCM-I

Equipped with static/dynamic response testing function

Pore water pressure and earth pressure are key mechanical indices for the development of soil mechanics and geotechnical engineering, and also fundamental components of K. Terzaghi’s effective stress principle. They can directly reflect the mechanical properties and failure process of saturated/unsaturated soil skeletons. Therefore, the measurement and analysis of pore water pressure and earth pressure have always been important topics in the field of soil mechanics and geotechnical engineering. Compared with other pressure sensors, pore water pressure sensors take the intergranular pore fluid stress as the measurement object, and their structural design is relatively more complex. Although earth pressure sensors are less structurally complex than pore water pressure sensors, their measurement accuracy is disturbed by more factors due to the influence of the soil arching effect and stress distribution.

In view of the small model size in geotechnical centrifuge tests, the scale effect between the model and the prototype must be fully considered. Moreover, the seismic loading duration in geotechnical centrifuge tests is usually less than 1 second, and the buildup of pore water pressure/earth pressure exhibits an approximately “transient” characteristic. In addition, the frequency bandwidth of compressive seismic waves can reach hundreds of hertz. If the response rate of the sensor does not match the rapid cyclic shear process of the soil, it will hinder the in-depth understanding of the liquefaction mechanism and its threshold conditions. Therefore, the development of a dynamic response calibration device for miniature pore water pressure sensors is of great significance for improving the key measurement technologies in geotechnical centrifuge tests. The DPCM-I dual-purpose calibration device for pore water pressure and earth pressure is specially designed to meet the requirements of such complex working conditions.

Typical features

• Uniform pressure transmission: The multi-channel pressure chamber adopts a circular air channel, 6 uniformly distributed air ports and a specific drainage line air channel inside, which can ensure the rapid and uniform inflow/outflow of high-pressure gas.

• Long-term pressure-bearing sealing: The pressure-bearing range is ≥1.0MPa, the pressure-bearing time is ≥72h, and it can be adapted to sensor cables with a diameter of 1.0~4.0mm.

• Arbitrary load input, It can input static waves such as linear waves and step waves, as well as ultimate liquefaction pressure loads with a range of ≤500kPa and sine waves with a frequency of ≤20Hz.

• Capable of calibrating 11 sensors simultaneously.

Typical applications

• Static performance calibration test

• Dynamic response performance calibration test

• Long-term stability calibration test

• Pore fluid viscosity influence test

• Sensor performance comparison test

                                              1.High pressure nitrogen cylinder; 

                                                     2.Regulating valve; 

                                                     3.Electromagnetic valve; 

                                                     4.Multi channel pressure chamber; 

                                                     5. Control and acquisition interface