Research And Design Of Plane Strain Apparatus In Soil Test

In order to guarantee the safety of structure and engineering facilities, and proper civil engineering design, it is necessary to study the soil property and the interactional process between soil and structures. Soil test is to measure the property parameters, which could be better used in engineering design and numerical calculation, and then engineering problems could be accurately analyzed and anticipated. Plane strain test is one of the soil testes, which simulates the soil that is settled in the plane strain condition in engineering practice. Plus, plane strain test can better measure local deformation and shear band, which can be useful for soil property research.The research illustrates that soil strain is caused by pore strain, soil granula slippage, and fragmentation. If the soil granula slippage and fragmentation rules can be obtained from the test, then soil stress strain relationship can be studied with the method of pore medium mechanics, which is different with the current method of continuum theory.The main purpose of plane strain apparatus is to create a platform, which based on image measurement technique, to study the surface layer sand soil granula slippage and fragmentation under external force in the plane strain test. At the same time, it can be used for shear strength test under the condition of plane strain, to obtain shear band location and study the soil local deformation. Compared with traditional plane apparatus, the main difference is that the test specimen is sand soil without rubber membrane during the test, so that the soil granula can be observed by image measurement.Based on the research about plane strain apparatus characteristics home and abroad, according to the micro image measurement requirement, the apparatus structure and data collecting system are designed. Pro/E software is employed in mechanical structure design, including side standing board, side-force board, pressure part component structure, displacement sensor component structure, etc. And the apparatus is conducted with kinematic emulation. In data collecting system, LabVIEW software is used to collect pressure sensor and displacement sensor data.Compared with traditional plane strain apparatus, the plane strain apparatus in this paper has a different way of loading and measurement. And the specimen is sand without rubber membrane. The test result illustrates that this apparatus can be used properly in plane strain test, and the micro image of soil granula on the surface layer can be measured clearly, which can be used in the theory research about soil granula slippage, and damage deformation mechanism. And the apparatus can satisfy the test requirement.