Electrical Resistivity Imaging Equipment

The WDJD-4A Electrical Resistivity Imaging Equipment is a high-density geophysical data acquisition system developed for subsurface electrical imaging and engineering geophysical investigation.

The instrument uses a 32-bit microcontroller and high-precision 24-bit A/D conversion technology to collect detailed electrical resistivity and induced polarization data. Rather than relying on measurements from a single point, the system uses multi-electrode arrangements to acquire a large amount of field information along a survey profile, providing the data foundation for two-dimensional and three-dimensional subsurface imaging.

The WDJD-4A supports both centralized multi-electrode switching and distributed electrode survey configurations. More than 18 electrode array methods are available, allowing survey teams to select an appropriate configuration according to the target structure, survey-line length and site conditions.

Field operation is handled directly through the instrument's LCD interface. Measurement parameters can be configured before acquisition, while collected readings and survey records can be checked and stored during the investigation.

A complete system can include the main instrument, multi-core survey cables, cable reels, electrode accessories and compatible resistivity inversion software, creating a practical workflow from field acquisition to data processing and resistivity imaging.

1. Receiver Section

□ Voltage channel: ±50V, ±0.2% ±1 LSB, 24-bit A/D

□ Maximum voltage sampling resolution: 0.01μV

□ Input impedance: ≥100MΩ

□ Apparent polarizability measurement accuracy: ±1% ±1 LSB

□ SP compensation range: ±10V

□ Current channel: 6A, ±0.2% ±1 LSB, 24-bit A/D

□ Maximum current sampling resolution: 0.02μA

□ 50Hz power frequency interference suppression: >80dB

2. Transmitter Section

□ Maximum transmission power: 7200W

□ Maximum output voltage: ±1200V (i.e., 2400Vp-p)

□ Maximum output current: ±6A (i.e., 12Ap-p)

□ Output waveform: Pulse width 1–60 seconds, 1:1 duty cycle, bipolar

3. Others

□ Display: LCD

□ Storage capacity: ≥1GB

□ Power supply: Built-in 12V/9Ah lithium battery (or external 12V power supply); continuous operation for over 30 hours

□ Main unit interfaces: A, B, M, N; DC high voltage; external battery/charging; 2 interfaces for distributed high-density cables; RS-232 and USB, etc.

□ Dimensions: 270mm × 246mm × 175mm

□ Weight: ≤4.4kg

□ Operating temperature: -10°C to +50°C, 95% RH

□ Storage temperature: -20°C to +60°C

• High-Density ERT Data Acquisition

Collects large volumes of resistivity data along a survey line for efficient subsurface imaging.

• 2D & 3D Resistivity Imaging

Works with inversion software to generate clear 2D sections and 3D models of subsurface resistivity distribution.

• 18+ Electrode Array Configurations

Supports more than 18 survey arrays for different geological and engineering investigation requirements.

• Centralized & Distributed Survey Modes

Provides two multi-electrode survey modes for flexible field layouts and different survey-line lengths.

• Fast Field Measurement

Hundreds of measurement points can be acquired in approximately 15 minutes under suitable conditions, reducing field survey time.

• 100 Preset Parameter Groups

Stores up to 100 electrode-spacing settings, allowing operators to quickly recall commonly used configurations.

• Built-In Fault Diagnosis

Helps identify connection problems and abnormal components during field measurements for faster troubleshooting.

• Multi-Level Interference Suppression

Reduces the influence of electromagnetic noise from power lines, construction sites and other electrically noisy environments.

Application

 

Engineering Geological Investigation

Use resistivity imaging to investigate subsurface structures before construction and identify changes in underground geological conditions that may affect engineering work.

Urban Underground Investigation

The compact field system can be used for geological mapping and underground structure investigation in urban areas, including sites affected by existing buildings, roads and utility infrastructure.

Road, Railway and Bridge Surveys

ERT profiles can help investigate bedrock depth, geological interfaces and subsurface anomalies along planned transportation infrastructure corridors.

Landslide Investigation

Electrical resistivity sections can provide supporting information for investigating geological boundaries, fractured zones and possible subsurface structures associated with unstable slopes.

Dam and Levee Inspection

Resistivity imaging can be applied to investigate abnormal subsurface zones around dam foundations, embankments and levees as part of geological and infrastructure condition assessments.

Geological and Mineral Reconnaissance

The WDJD-4A can also be used for preliminary investigation of subsurface electrical anomalies and geological structures in mineral and geological research projects.