Direct Shear Testing Machine, Digital
NL 5052 X / 005

Standard : ASTM D3080, BS 1377-7, AASHTO T236, NF P094 071-1/2

Shear Testing Machines

The Digital Direct Residual Shear Box is a sophisticated geotechnical testing instrument designed to measure the residual shear strength of soils and other granular materials. This advanced devide is essential for evaluating the long-term stability of slopes, embankments and foundations, particularly in landslide-prone areas or critical infrastructure projects. The control panel features an LCD screen and a 16-key membrane keypad for manual settings and operation. The large liquid crystal display ensures clear visibility, while the intuitive keypad allows for easy adjustments.

Features:
1) Digital Control & Display - Features a user-friendly digital interface with an LCD or touchscreen display for real-time monitoring and adjustments.
2) High Precision Sensors - Equipped with high-accuracy load cells and displacement sensors for precise shear force measurement.
3) Automated Testing - Supports programmable test parameters, allowing automated test cycles for consistency and efficiency.
4) Robust Construction - Made from durable materials to ensure long-term stability and minimal maintenance.

Technical Specifications

Unit Consists Of:

*1 Copy of Manual Instruction

Optional Accessories:

Features of Direct Shear Testing Machine

• Automatic Speed Control: Allows for precise control of the shearing rate during the test, ensuring consistent and accurate results.
• Micro Stepper Motor: Used to apply horizontal shear load to the soil specimen at a user-input shearing rate, offering precise control over the testing conditions.
• Proving Ring: Measures shear force readings at specified intervals of horizontal displacement, providing data for analysis.
• Limit Sensors: Incorporated to prevent over-traveling of the shear box during forward or reverse motions, ensuring safe operation of the machine.
• Control Panel: Equipped with an LCD display and keypad for manual setting and control, allowing users to adjust parameters as needed.
• Reciprocating Shear Capability: This enables the machine to perform both the consolidation and shearing phases of direct shear and residual shear tests.
• Data Acquisition and Control: A built-in 16-bit system for acquiring and controlling data, offering precise measurement and analysis capabilities.
• Versatile Applications: Used for determining shear strength properties of soil samples, facilitating the design of foundations, retaining walls, slopes, and other geotechnical structures.

Standards

• ASTM D3080: This is a standard test method issued by the American Society for Testing and Materials (ASTM) titled "Standard Test Method for Direct Shear Test of Soils Under Consolidated Drained Conditions." It provides procedures for conducting direct shear tests on soil specimens to determine their shear strength properties under consolidated drained conditions.
• BS 1377-7: This is a British Standard issued by the British Standards Institution (BSI) titled "Methods of Test for Soils for Civil Engineering Purposes - Part 7: Shear Strength Tests (Effective Stress)." It specifies methods for conducting shear strength tests on soil samples, including direct shear tests, to determine their engineering properties.
• AASHTO T236: This is a test method published by the American Association of State Highway and Transportation Officials (AASHTO) titled "Standard Method of Test for Direct Shear Test of Soils Under Consolidated Drained Conditions." Similar to ASTM D3080, it provides procedures for conducting direct shear tests on soil specimens under consolidated drained conditions.
• NF P094 071-1/2: This is a French standard issued by the Association Française de Normalisation (AFNOR) titled "Soil Investigation and Testing - Laboratory Testing of Soils - Part 071: Direct Shear Tests." It specifies procedures for conducting direct shear tests on soil samples in the laboratory.

Test Procedure of Direct Shear Testing Machine

• Preparation of Soil Sample:
• Obtain a representative soil sample from the site or use a prepared sample.
• Prepare the soil sample to the desired moisture content and density if necessary.
• Trim the sample to fit the dimensions of the shear box, ensuring it fills the box uniformly.
• Assembly of Test Setup:
• Set up the Direct Shear Testing Machine according to the manufacturer's instructions.
• Install the shear box with the prepared soil sample in the upper compartment.
• Ensure proper alignment and seating of the shear box within the machine.
• Application of Normal Stress:
• Apply the desired normal stress (vertical load) to the soil sample using the loading system of the machine.
• The normal stress should be applied gradually to achieve the desired confining pressure.
• Consolidation Phase:
• Apply a constant normal stress and allow the soil sample to consolidate under this stress for a predetermined period.
• Consolidation ensures that the soil sample settles and reaches a stable state before shearing begins.
• Shearing Phase:
• Initiate the shearing phase by activating the horizontal shear load application system.
• Apply horizontal shear force to the soil sample at the desired rate of displacement.
• Monitor and record the shear force and horizontal displacement continuously or at specified intervals during shearing.
• Data Collection:
• Record the shear force readings obtained from the proving ring at specified intervals of horizontal displacement.
• Optionally, monitor other parameters such as pore water pressure, if applicable.
• Continuously monitor and record any changes in sample behavior during shearing, such as deformation and failure.
• Completion of Test:
• Continue sharing until the desired displacement or failure criterion is reached.
• Record the maximum shear force attained during the test.
• If performing residual shear testing, continue shearing until post-failure conditions stabilize.
• Data Analysis:
• Analyze the collected data to determine key parameters such as shear strength, cohesion, and internal friction angle.
• Interpret the results in relation to the engineering properties of the soil and the specific project requirements.