Geotechnical Instrumentation Installation Settlement Plate · Piezometer · Inclinometer

Geotechnical Instrumentation Services — SPN Soil Engineering

SPN Soil Engineering installs and reads a full range of instruments that monitor soil and structural behavior, from Settlement Plates, Piezometers and Inclinometers to automatic real-time Datalogger systems, for construction that needs continuous stability monitoring such as deep excavations, embankments and projects with EIA reporting, nationwide across Thailand. See real installation case studies: Inclinometer, deep excavation in Bang Phli · Deep Settlement Point, Bang Na · Piezometer and Monitoring Well, Samut Prakan · Inclinometer, Kraseaw Hydropower slope. For an overview before choosing, read Geotechnical Instrumentation: what it is and 10 types used in practice. Installation follows ASTM D6230 (Inclinometer) and ASTM D7764 (Vibrating Wire Piezometer), and vibration monitoring is compared with the National Environment Board Notification No. 37 (B.E. 2553 (2010)) and DIN 4150-3. The work is carried out by the same engineering team as SPN's soil investigation

1. Settlement Monitoring

Tracks settlement of soil and structures from the surface to deep soil layers, to verify the design and assess the progress of consolidation

• Settlement Plate Measures settlement of the original ground under fill with a 60×60 cm Steel Plate placed at the base of the fill (original ground surface before filling) with a steel rod extended upward; read with an Auto Level every round. Suitable for embankments, roads and projects using Preloading to accelerate consolidation of soft clay
• Multi-level Settlement Point Measures settlement of soil layers at different depths, layer by layer, to identify which layer settles most and to verify theoretical Consolidation Settlement
• Extensometer (Rod / Magnetic) Measures settlement or Heave along a borehole at several depths. The Rod type anchors steel rods at each level and is read at the borehole head; the Magnetic type uses magnetic rings around a pipe with positions read by a probe. Suitable for deep excavation bases, high embankments and tunnels
• Surface Settlement Marker Measures vertical movement of the ground surface around excavations and underground construction, helping detect settlement of adjacent buildings and roads around the project — see also 5 warning signs of foundation problems

2. Pore Pressure and Groundwater Level (Piezometer & Observation Well)

Continuous monitoring of pore water pressure and groundwater level to assess stability and drainage performance

• Standpipe Piezometer Measures the Piezometric Level in a defined depth zone. Simple, low cost, quick to install and read with a Water Level Meter. Suitable for long-term monitoring and EIA projects that need monthly water level data
• Vibrating Wire Piezometer Measures Pore Water Pressure at a specific point in the soil using a vibrating steel wire. High accuracy, fast response and automatic Datalogger support. Suitable for deep excavations, Preloading and projects that need Real-time Monitoring (detailed comparison with the Standpipe type in What is a Piezometer?)
• Observation Well (Monitoring Well) An Open Standpipe groundwater observation well drilled to the soil layer of interest to track seasonal changes in groundwater level and construction impacts. Used for EIA projects and Environmental Monitoring — read installation, reading and precautions in Observation Well for groundwater level

3. Lateral Movement Monitoring

Measures tilt and lateral movement of soil and structures, giving warning before collapse or damage

• Inclinometer Measures the lateral movement profile of soil and retaining walls with depth. An Inclinometer Probe is lowered into an ABS casing installed in the ground, tilt is recorded every 0.5 m and the displacement profile of the whole column is calculated, giving warning before failure — read the principles and how to read results in What is an Inclinometer?
• Tiltmeter Measures tilt of structures, piles, retaining walls and buildings near excavations. Installed directly on the structure, it gives data faster than an Inclinometer and suits work that needs Real-time Alerts — read point layout and alarm criteria for adjacent building monitoring in Settlement Point and Tiltmeter
• Total Station / Prism Monitoring Prism targets are fixed on buildings, retaining walls or key structures and sighted with a Total Station from benchmarks outside the zone of influence, giving 3D (X-Y-Z) movement of many points in one round. Uses the same team and equipment as SPN's surveying

4. Structural Load and Stress Monitoring (Load & Stress)

Measures the actual forces in struts, ground anchors, walls and piles for comparison with design values

• Strain Gauge Measures strain in rebar, beams and highly loaded steel structures to verify actual forces against calculated values. Suitable for Struts, Anchors, Pile Caps and special structural members — read how strain is converted to force and how to choose sensors in Strain Gauges in geotechnical work
• Load Cell Installed between the Strut end and the Waler or under the Ground Anchor head to measure compression or tension directly, without section conversion; can be cross-checked with Strain Gauges
• Earth Pressure Cell (Total Pressure Cell) A fluid-filled cell connected to a pressure transducer, set on the retaining wall face, under a footing or in an embankment to measure the actual total earth pressure on the structure
• Instrumented Pile Strain Gauges at several levels and Telltales are installed in a test pile, which is then static load tested to ASTM D1143 to separate skin friction in each soil layer from end bearing — read more in Instrumented Static Load Test

5. Adjacent Building and Vibration Monitoring

Records existing conditions before work starts and measures impacts during construction to reduce damage and disputes

• Pre-construction Condition Survey (Dilapidation Survey) Survey, photographs and records of the location, length and width of existing cracks in buildings around the project before piling, excavation or demolition, compiled into a report with a survey point plan — read Adjacent building survey before construction
• Building Settlement Point Level markers fixed on columns or walls of adjacent buildings, read with an Auto Level against benchmarks to track settlement and Differential Settlement
• Crack Meter Installed across key cracks, read manually or Vibrating Wire type connected to a Datalogger, to see whether cracks are still widening or have stopped — read Which structural cracks are dangerous?
• Vibration Monitoring 3-axis Geophones installed on adjacent building foundations continuously record peak particle velocity (PPV) and frequency during piling, demolition or soil compaction, compared with the National Environment Board Notification No. 37 (B.E. 2553 (2010)) or DIN 4150-3 as the project specifies — read Vibration monitoring during pile driving

6. Datalogger and Remote Monitoring

Automatic data logging and mobile alerts when readings exceed set limits (compared with readings by field staff: Manual vs Automatic Monitoring)

• Automatic Datalogger Records instrument readings at set intervals, from every 1 minute to daily, stores data on a Memory Card and uploads to a Cloud Server via 4G/WiFi. Supports Vibrating Wire, 4-20mA and RS-485 instruments on multiple channels at once
• Real-time Alert System Thresholds trigger automatic SMS/Line/Email alerts when any reading exceeds safe limits, so engineers can decide immediately without waiting for site readings. Suitable for projects that need 24/7 Monitoring
• Cloud Dashboard & Report Real-time data on an online Dashboard, automatic trend charts and PDF/Excel reports exported on schedule; the engineering team can access it from anywhere at the same time

Summary of instruments and applications

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Projects that should be instrumented

Criteria for deciding whether a project needs a monitoring plan, and when to start baseline readings, are in When is instrumentation required?

• Deep excavations in urban areas Near existing buildings, subways and utility pipes — Settlement, Lateral Movement and Pore Pressure must be monitored to prevent damage to adjacent property, together with earth retaining system design. See monitoring planning for deep excavations in Bangkok soft clay in Deep excavation monitoring in Bangkok soft clay
• Large embankments and dams Settlement and stability monitored throughout the project life; Piezometer data helps check Seepage and embankment safety
• Projects with EIA reporting Impacts on groundwater and the environment monitored under conditions set by the regulator. See also environmental assessment services
• Ground improvement with PVD + Preloading Checks consolidation progress (Degree of Consolidation) and the right time to remove the Surcharge. For an overview of ground improvement, read 8 methods to improve soft soil before construction
• Construction near existing structures Differential Settlement and Lateral Movement monitored to prevent damage to existing foundations, relevant to house settlement and house extensions
• Pile driving, bored piling and demolition near buildings Survey adjacent buildings before work starts, install Crack Meters and monitor vibration during work to keep evidence and control impacts — read Pile driving cracked the house next door?