Automatic Residual Direct Shear Apparatus

Product Specification

Fully Automatic Residual Direct Shear Apparatus BTU-DDS-10 / DDS-5 / DDS-5F / DDS-10F

Description

This series consists offully automatic residual direct shear apparatusesusing a microprocessor‑controlled drive system and keypad command input. Advantages include the ability to pause and reset the test speed, computer control via USB 3.0 interface, programmable speed and functions by the operator, and a self‑check system. The fast return to initial position function provides a convenient way to reset the shear box when starting a new test or continuing a residual shear test.

Models include:

• BTU-DDS-10: British Standard direct shear apparatus (lever loading)
• BTU-DDS-5: American Standard direct shear apparatus (lever loading)
• BTU-DDS-5F: Fully automatic residual direct shear apparatus (5 kN)
• BTU-DDS-10F: Fully automatic residual direct shear apparatus (5 kN? the table shows 5 kN, but the model suggests 10 kN – verify with manufacturer)

Main functions:

• Standard consolidation, standard shear, fast shear, cyclic shear, rheological direct shear
• Optional interface friction test module and temperature control module

Test Standards (International)

• British Standard (BTU-DDS-10): Complies withBS 1377
• American Standard (BTU-DDS-5): Complies withASTM D3080
• Fully automatic residual models (DDS-5F / 10F): Can meet both British and American standards as well as residual strength test standards such asASTM D7608,ASTM D6467(confirm with manufacturer).

Other relevant standards:

• ISO 17892-10(Direct shear test)
• AASHTO T-236
• EN 1997-2(Eurocode 7)

Specification

Note: Although the BTU-DDS-10F model name includes “10F”, the table still lists normal force and horizontal shear force as 5 kN – this may be a typo; check with the manufacturer for actual specifications.

Detail

• Microprocessor control system– Programmable test speed, pause, reset; USB 3.0 communication with computer.
• Fast return to initial position– Automatically returns the shear box to its starting position after a test or during residual shearing, improving convenience.
• Dual standard compatibility– British Standard (DDS-10) uses square specimens (60×60 or 100×100 mm); American Standard (DDS-5) uses round specimens (Φ61.8×20 mm).
• Fully automatic residual models (DDS-5F/10F)– Servo closed‑loop loading, automatic reciprocating shearing for residual strength testing.
• Lever loading (DDS-10/5)– Traditional weight loading, simple and reliable, but requires manual weight changes.
• Wide shear rate range– 0.00001–9.99999 mm/min, covering slow to fast shear.
• Large shear displacement– Up to 25 mm, much larger than conventional direct shear (6‑8 mm), suitable for residual strength testing requiring large displacement.
• Optional modules– Interface friction (soil‑structure, geosynthetics) and temperature control (range to be confirmed).
• Software modules– Standard consolidation, standard shear, fast shear, cyclic shear, rheological direct shear, etc.

Application

• Residual strength testing– Determine residual shear strength (cᵣ, φᵣ) of slip zone soils, fault gouge, etc., under large displacement.
• Conventional direct shear tests– Fast shear, consolidated shear, slow shear to obtain peak strength.
• Cyclic shear– Simulate strength degradation under earthquake or wave loading.
• Rheological direct shear– Study long‑term creep behaviour of soils.
• Interface friction– With optional module, test soil‑concrete, soil‑geomembrane, etc., interface friction angles.
• Temperature‑controlled tests– With optional temperature module, study temperature effects on shear strength.
• Compliance with international standards– Meets BS 1377 and ASTM D3080, suitable for domestic and international projects.

Advantages

• Multiple standard compliance– Dedicated British and American Standard models, plus general fully automatic residual models.
• Large shear displacement (25 mm)– Better suited for residual strength testing than conventional direct shear (6‑8 mm).
• Fully automatic servo closed‑loop (F models)– Automatic reciprocating shearing without manual intervention, precise stress/strain path control.
• Wide shear rate range– 0.00001–9.99999 mm/min stepless, from creep to fast shear.
• USB 3.0 interface– High‑speed data transfer, remote control capability.
• Fast return function– Improves efficiency, especially for multi‑stage residual shearing.
• Modular software– Consolidation, shear, cyclic, rheological modules can be combined as needed.
• Expandability– Optional interface friction and temperature control modules.

What To Choose

Select the model based on testing requirements:

Note: The main difference between DDS-5F and DDS-10F may be specimen size (DDS-5F for round American specimens, DDS-10F for square British specimens), but the table is unclear – confirm with the manufacturer.

Process Flow

Example:Residual strength test on saturated clay (reciprocating shear) using the fully automatic residual direct shear apparatus (BTU-DDS-5F)

• Specimen preparation
  • Cut undisturbed or remoulded clay specimen using a Φ61.8×20 mm cutting ring; saturate.
  • Measure initial water content and density.

• Specimen installation
  • Place the specimen into the lower shear box, install upper box, porous stones, and loading plate.
  • Position the shear box in the direct shear loading frame, connect normal and horizontal loading rods.
  • Install displacement sensors (horizontal and vertical).

• Apply normal stress
  • Apply the target normal stress (e.g., 100 kPa) via the servo closed‑loop system.
  • Record normal displacement until consolidation is stable (drained condition).

• Set shear parameters
  • Select “residual shear module” or “reciprocating shear module”.
  • Set shear rate (e.g., 0.5 mm/min).
  • Set forward shear displacement limit (e.g., 10 mm).
  • Set reverse shear displacement limit (e.g., 10 mm) and number of cycles (e.g., 5).
  • Choose control mode: strain control (typical).

• Start reciprocating shearing
  • The horizontal servo system pushes the shear box forward; after reaching the forward limit, it automatically reverses.
  • Software records shear force, displacement, and time for each half‑cycle in real time.
  • Plot shear stress‑displacement curve (multiple cycles).

• Stop condition
  • Automatically stops when the preset number of cycles is completed or shear stress stabilises (residual strength achieved).

• Disassembly and cleaning
  • Unload normal force, remove specimen, clean shear box.

• Data processing
  • Software automatically identifies peak shear stress (first cycle) and stabilised shear stress (residual) for each half‑cycle.
  • For tests at different normal stresses, plot residual strength envelope to calculate cᵣ and φᵣ.
  • Generate test report.

For lever‑loading models (DDS-10/5): Normal stress is applied manually using weights; during shearing, manual recording or an external data logger is required.

Summary:This series offers British Standard (square specimen), American Standard (round specimen) lever‑loading direct shear apparatuses, as well as fully automatic servo closed‑loop residual direct shear apparatuses (5F/10F). The fully automatic models support large‑displacement reciprocating shear for residual strength testing. All models can be optionally equipped with interface friction and temperature control modules, and feature rich software test modules. Selection should be based on specimen shape, compliance with specific standards, need for fully automatic residual shear testing, and whether higher shear force (10 kN) is required.