Soil and structure contact surface testing machine

Abstract

The invention discloses a soil and structure contact surface testing machine. The soil and structure contact surface testing machine comprises a body frame, a structure panel, an X-direction motion system, a Y-direction motion system, a Z-direction motion system, a hydraulic loading and control system, a data acquisition system, a confining pressure chamber system, a temperature control system andthe like. The soil and structure contact surface testing machine is specially designed for researching the problem of the soil and structure contact surfaces, and can complete the research on the problem of the contact surfaces between various soil types, such as clay, fine-grained soil and coarse-grained soil and all kinds of structural panels under various saturation or non-saturation temperature field conditions. The normal stress is directly applied to the contact surfaces during the test. The concept is clear and the stress state is clear, the uniform strain of the soil can be ensured, the strain localization phenomenon is eliminated, the constant areas of the contact surfaces are ensured, and it is ensured that the results are true and reliable.

Description

technical field [0001] The invention relates to a three-dimensional testing machine for the interface between soil and structure, and belongs to the technical field of soil engineering testing instruments. Background technique [0002] The study of the mechanical properties of the contact surface between the soil and the structural panel is one of the important topics in the study of soil mechanics, which has a great impact on the calculation, design and construction technology of the structure. There are mainly two methods for the study of the mechanical properties of the contact surface between the soil and the structural panel, the experimental method and the numerical method. At present, the main test instruments used in the test method are direct shear tester, single shear tester, torsional shearer, dynamic triaxial tester and resonance column tester. Among them, the direct shear tester and the single shear tester are two types of contact surface test instruments that ...

AI Technical Summary

Problems solved by technology

[0003] 1. Most of the instruments used in the research on the contact surface between soil and structure are improved from the existing geotechnical test instruments. The normal stress is applied on the soil instead of the contact surface. The force is not clear and the concept is not clear. clear;

[0004] 2. The current test equipment has uneven soil strain during the test, and there is a phenomenon of strain localization, which leads to distortion of test results and reduced data reliability;

[0005] 3. In the current test instruments, the contact surface between the soil and the structural panel cannot be contacted under saturated conditions, which limits the research field of the instrument, such as the problem of the contact surface between the soil and the structure under water;

[0006] 4. In the current test instruments, it is impossible to study the contact surface between the soil and the structure panel under the condition of confining pressure, which limits the research field of the instrument, such as the problem of non-drainage of the contact surface between the soil and the structure in the deep sea

[0008] 1. The contact surface between the soil and the structural panel cannot be tested under saturated conditions, neither can the test of saturated clay;

[0009] 2. It is impossible to study the contact surface between the soil and the structural panel under the condition of confining pressure;

[0010] 3. The soil-structure contact surface test that cannot realize the coupling between the temperature field and the stress field;

[0011] 4. The tangential friction between the structural panel and the soil container is too large, resulting in distortion of the measurement of the mechanical parameters of the contact surface

During the test, there is non-uniform normal stress between the soil container and the structural panel. When the relative displacement of the soil and the structural panel occurs, there is a large tangential friction force between the structural panel and the soil container, and the friction is not uniform, which is difficult to Calibrated and subtracted from the test results, this friction is still acceptable for coarse-grained soils, large samples, but for fine-grained soils or small samples, the friction between the soil container and the structural panel The friction is unacceptable, and its magnitude may even exceed the friction between the soil sample and the structural panel

This will make it difficult to accurately measure the mechanical properties of the contact surface between the soil and the structure, which in turn will lead to distortion of the test results, and the design is too dangerous, which will cause great harm to the calculation and design.

Even the structural panel and the soil container are stuck due to frictional self-locking phenomenon, and the soil and the structural panel are separated and cannot be contacted;

[0012] 5. During the test, in order to prevent the normal stress generated by the contact between the structural panel and the soil container, resulting in the generation of tangential stress, the upper edge of the soil container will be lower than the top surface of the soil sample, which will cause the gap between the upper edge of the soil container and the structural panel. A large gap is left, causing the soil particles to lose from the gap between the structural panel and the soil container during the test, resulting in a reduction in the contact surface area

[0013] So far, there is no instrument capable of simulating the mechanical behavior of the interface between underwater ocean soil and structures; and with the development of society, the energy burden is becoming increasingly heavy, and the mining of combustible ice in the sea is facing many problems. It is obvious that the mining of combustible ice The phase change problem in the process, combustible ice can only exist stably in a high-pressure and low-temperature environment, and the construction of mining equipment must be based on marine soil. The contact surface between the foundation and marine soil needs to be studied urgently. There is also a need for a set of soil-structure interface test equipment that can simulate underwater high-pressure and low-temperature conditions

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