Pneumatic static lateral pressure instrument and test method thereof

Abstract

The invention discloses a pneumatic static lateral pressure instrument, which comprises a static lateral pressure instrument container, a vacuum pressure regulating cylinder and a pressurizing base, wherein the pressurizing base is internally provided with a pressure chamber, the bottom of the pressure chamber is connected with an air compressor, the pressure chamber is internally provided with apressure film depressing downward, there is a piston guide rod above the pressure film, and the piston guide rod is located at the bottom of the static lateral pressure instrument container. The pneumatic static lateral pressure instrument adopts pneumatic pressurizing equipment, can automatically load in a grading manner and can set the pressurizing time according to requirements. The pneumatic static lateral pressure instrument is more stable compared with manual weight loading, the soil sample is also uniformly stressed, and the test accuracy is improved. The pneumatic static lateral pressure instrument regulates the water body in the container by adopting a vacuum pressure regulating cylinder via a manual pressure regulating valve, thereby effectively preventing a gas from entering thepressure chamber of the container, ensuring the volume of water in the sealed pressure chamber to be constant in the testing process, guaranteeing the accuracy of pressure conduction, and improving the test accuracy.

Description

technical field [0001] The invention relates to the field of geotechnical engineering testing, and is a pneumatic static side pressure instrument used for indoor geotechnical testing. Background technique [0002] The static lateral pressure coefficient of the soil is the ratio of the lateral effective stress to the axial effective stress of the soil under the condition of no lateral deformation. The static lateral pressure coefficient is one of the important parameters for calculating the stability of foundation pits and slopes. The indoor geotechnical test determines the static lateral pressure coefficient of the soil by measuring the relationship between the axial stress and the lateral stress of the soil sample under lateral and axial drainage conditions. [0003] The instruments used in indoor geotechnical tests to test the static side pressure coefficient of soil mainly include stress-type and strain-type static side pressure instruments. At present, stress-type stati...

AI Technical Summary

Problems solved by technology

The traditional stress-type static side pressure gauge has the following disadvantages: 1. When using a lever-type consolidation instrument to apply a graded load, it is necessary to manually control the time and move the weight, which is inefficient; 2. When applying axial pressure, due to the compression deformation of the soil It will cause the lever to be out of balance. In order to keep the lever in balance, it is necessary to manually adjust the lever, otherwise the force on the soil sample will be inaccurate; 3. The lever-type consolidation instrument has been used for a long time, and it is difficult to adjust the balance of the lever due to mechanical wear and tear; 4. When using a syringe to pump out the water in the pressurized chamber, it is difficult to prevent the gas from entering the pressurized chamber of the pressure vessel on the static side due to the poor sealing of the junction between the syringe and the water inlet hole, thus affecting the water volume in the pressurized chamber to remain unchanged Requirements that affect pressure conduction test results

5. The instrument is bulky and has many counterweights, which is not conducive to handling and carrying

In short, when the traditional lever-type consolidation instrument is used for static side pressure coefficient test, it not only consumes manpower and occupies space, but also has low work efficiency and low test accuracy.

In view of the above reasons, in order to meet the technical requirements of the test, improve work efficiency, overcome the lack of accuracy of the lever-type artificial weight pressurization test, and the inability to guarantee the volume of water in the pressurized chamber of the static side pressure vessel during the test process when using a syringe to adjust the pressure Invariant disadvantages, this device is designed to

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