Types of Piezometers offered by Encardio Rite

• Effective stress (σ') – The load carried by the soil skeleton, responsible for shear strength and structural stability. 

• Pore water pressure (u) – The pressure exerted by water within the voids of soil or rock mass, which counteracts effective stress. 

• Increased pore pressure within soil mass reduces frictional resistance, decreasing the factor of safety against slope failure. 

• Excess pore water pressure reduces cohesion in clays and increases hydraulic gradients in sands, promoting failure along slip surfaces. 

• Loss of Effective Stress: As water accumulates in the slope, pore pressure increases, reducing the shear strength of the soil. 

• Seepage-Induced Instability: In saturated soils, high pore pressure increases hydraulic uplift forces, causing erosion and slope weakening. 

• Liquefaction & Flow Slides: Saturated cohesionless soils under dynamic loading (earthquakes) lose strength rapidly, leading to landslides. 

• Drainage Systems (horizontal drains, relief wells, drainage galleries) reduce excess pore pressure. 

• Soil Reinforcement (geogrids, soil nails, retaining walls) provides additional strength. 

• Slope Reprofiling modifies slope geometry to lower hydraulic gradients. 

• In embankment dams, excessive pore pressure can lead to internal erosion (piping failure) or hydraulic fracturing. 

• High pore pressure in dam foundations weakens abutments and toe structures, increasing the risk of failure during high reservoir loads. 

• Hydraulic Gradient Instability: Water seepage increases pore pressure, reducing the internal stability of earth-fill and rock-fill structures. 

• Uplift Pressure: Excess pore pressure in the dam foundation can cause upward water force, leading to sliding failure. 

• Seepage-Induced Erosion (Piping Failure): Fine soil particles are eroded away, forming internal flow channels, eventually compromising dam integrity. 

• Seepage Control Measures (cutoff walls, grout curtains, drainage blankets) prevent uncontrolled pore pressure rise. 

• Monitoring & Risk Assessment (instrumentation with real-time seepage data) improves dam safety management. 

• High groundwater levels can create hydrostatic uplift forces, leading to bottom heave and instability of excavation walls. 

• Excess pore pressure during excavation reduces soil stiffness, increasing settlement and deformation risks. 

• Basal Heave & Uplift Failure: When groundwater pressure exceeds resisting soil strength, the excavation bottom heaves or fails. 

• Excessive Ground Settlement: Pore pressure dissipation leads to soil consolidation, causing deformation in adjacent structures. 

• Tunnel Face Instability: In soft ground tunneling, high pore pressure weakens tunnel face stability, increasing the risk of collapse. 

• Pre-Excavation Dewatering (wellpoints, deep wells, ejector systems) to lower groundwater tables. 

• Diaphragm Walls & Ground Freezing to stabilize excavation walls under high pore pressure. 

• Tunnel Face Support (slurry shields, compressed air support) to balance groundwater pressures. 

Read more: What Are The Different Types Of Piezometers?

• High pore water pressure in cohesionless soils (sands, silts) causes a reduction in bearing capacity, leading to foundation settlement or failure. 

• Excess pore pressure under dynamic loads (earthquakes, traffic loads) can dissipate rapidly, causing soil liquefaction. 

• Reduced Bearing Capacity: Pore pressure reduces soil strength, increasing the risk of foundation settlement. 

• Liquefaction During Seismic Events: 

• In saturated loose sands, rapid pore pressure buildup causes loss of interparticle friction, leading to sudden strength loss. 

• Structures lose stability as the ground behaves like a fluid. 

• Hydraulic Fracturing: High pore pressure in weak soils induces tensile failure, forming cracks and potential foundation collapse zones. 

• Soil Improvement (vibro-compaction, dynamic compaction, preloading) increases soil density to prevent liquefaction. 

• Drainage Solutions (drainage wells, prefabricated vertical drains) facilitate pore pressure dissipation. 

• Piled Foundations & Raft Foundations distribute loads more efficiently, reducing excess pore pressure influence. 

• High-precision vibrating wire technology for accurate pore pressure measurement. 

• Hermetically sealed under vacuum (0.001 Torr) for enhanced durability. 

• Stainless steel construction ensures resistance to corrosion and mechanical stress. 

• Integrated thermistor for temperature compensation. 

• Compatible with data loggers for real-time monitoring. 

• Dams and Embankments: Measuring pore pressure variations in earth/rockfill dams to monitor seepage and structural stability. 

• Deep Foundations: Installed in foundation piles to assess water pressure effects. 

• Tunneling & Underground Works: Used in tunnels and underground excavations for pore pressure monitoring. 

• Slim 19 mm diameter design, ideal for small-diameter boreholes and open standpipes. 

• Fast response time with minimal lag in pressure measurements. 

• Robust stainless steel construction for durability. 

• Temperature-compensated for improved accuracy. 

• Confined space installations: Used where borehole diameter is limited. 

• Slope Stability Assessments: Used in embankments, retaining structures, and excavations. 

• Groundwater Monitoring: Installed in reservoirs and hydraulic structures to track groundwater fluctuations. 

• Direct push-in installation, eliminating the need for boreholes. 

• Stainless steel construction with hermetically sealed vacuum housing for longevity. 

• Low air entry filter (40-micron standard) to allow accurate pore pressure readings. 

• Protected against lightning spikes. 

• Soft Soils & Landfills: Suitable for soft clay and loose deposits, where conventional boreholes are impractical. 

• Earth-Fill Dams: Used in dam foundations for pore pressure measurement. 

• Slope Stability and Dewatering Monitoring: Deployed in landfill drainage and embankments. 

• Designed for low hydrostatic pressures and shallow groundwater monitoring. 

• Provides precise groundwater level measurements where hydrostatic heads are below 7 meters. 

• Suitable for post-construction behavior monitoring of groundwater conditions. 

• Groundwater Investigations: Installed in boreholes for shallow aquifer monitoring. 

• Construction Monitoring: Used in basements and underground structures to track water seepage. 

• Hydraulic Structures: Installed in reservoir embankments and seepage control studies. 

• Uses vibrating wire technology for uplift pressure monitoring. 

• Hermetically sealed under vacuum (0.001 Torr) to prevent moisture ingress. 

• Compatible with data loggers for remote data collection. 

• Designed for installation in standpipes, pressure vessels, and foundations. 

• Dams & Reservoirs: Installed in dam galleries to monitor uplift pressure variations. 

• Deep Foundations: Tracks hydraulic pressure in tunnel linings and concrete foundations. 

• Seepage Control Studies: Helps assess grouting effectiveness and drainage efficiency. 

• Mechanical pressure gauge providing direct readings. 

• Cost-effective & simple to use, requiring manual data collection. 

• Installed in standpipes for uplift pressure measurement. 

• Dams & Hydraulic Structures: Suitable for uplift pressure monitoring in dam foundations. 

• Underground Works: Used in tunnels and deep excavations. 

• Reliable and cost-effective for long-term groundwater level monitoring. 

• Durable PVC construction with a slotted intake pipe for water flow measurement. 

• Easy to install in boreholes near dams, rivers, and high-rise structures. 

• Groundwater Table Monitoring: Installed near dams, rivers, and urban developments to track groundwater levels. 

• Post-Construction Monitoring: Used in infrastructure and environmental impact assessments. 

• Porous tube design allows precise groundwater level measurements. 

• Carborundum/alundum porous filter for water intake. 

• Resistant to silting compared to conventional observation wells. 

• Hydrological Investigations: Used in dams, tunnels, and shallow excavations for monitoring seepage. 

• Stability Analysis: Helps assess pore pressure variations in embankments. 

• Delineation of Phreatic Line: Helps track subsurface water movement in earth/rockfill structures. 

• Project type (dam, tunnel, foundation, landfill, embankment). 

• Soil & groundwater conditions (soft clay, confined aquifers, shallow vs. deep groundwater). 

• Measurement accuracy and monitoring duration. 

• Automation needs (manual vs. remote monitoring) 

• EPP-30V (Heavy-Duty Piezometer – deep boreholes, high-pressure monitoring). 

• EPP-40V (Slim Piezometer – confined boreholes). 

• EPP-60V (Low-Pressure Piezometer – groundwater level monitoring). 

• Drill the borehole using a mud rotary, auger, or diamond core drill to minimize soil disturbance. 

• Borehole diameter: 50 mm to 100 mm (depending on sensor size). 

• Ensure the borehole reaches the target monitoring depth as per project specifications. 

• Saturate the piezometer filter element with de-aired water to remove trapped air bubbles and ensure proper water pressure readings. 

• Perform a zero-reading calibration before installation to establish a baseline measurement. 

• Lower the piezometer gradually into the borehole to prevent tilting or dislocation. 

• Position the filter element precisely at the target measurement zone. 

• Surround the piezometer with a sand filter (coarse sand or No. 8 filter sand) to allow free water movement. 

• Place a bentonite seal (300–500 mm thick) above the sand filter to prevent vertical flow and cross-contamination. 

• Fill the remaining borehole space with cement-bentonite grout to seal it off from external water sources. 

• Extend signal cables to a junction box or data logger, ensuring proper mechanical protection. 

• Secure the cables with non-abrasive clips at regular intervals to prevent excessive strain and damage. 

• Allow the installation to stabilize for 24–48 hours before recording the first set of measurements. 

• Compare baseline readings with initial calibration values to ensure accurate sensor response. 

• Soft clay, silt, and landfills where drilling is difficult. 

• Shallow earth-fill dam foundations. 

• Thread the EPP-50V piezometer into a drill rod for push-in installation. 

• Ensure the cable is passed through the drill rod for easy retrieval. 

• Use hydraulic jacking, static push, or hand-driving (for shallow depths). 

• Avoid excessive force, as it may damage the diaphragm or alter pressure readings. 

• Follow the same cable protection and routing guidelines as borehole-installed piezometers. 

• Connect the sensor to a data logger or manual readout unit for continuous monitoring. 

Read more: Vibrating Wire Piezometer Installation Procedure in a Borehole

• Long-term groundwater monitoring in soil and rock formations. 

• Hydrological studies and seepage control. 

• Drill a 50 mm to 100 mm borehole to the required depth. 

• Place the Casagrande filter tip (porous element) at the monitoring zone. 

• Pack the filter tip with coarse sand (300–500 mm thick) to allow free water movement. 

• Add a bentonite seal above the sand filter to prevent vertical seepage contamination. 

• Extend the standpipe to ground level and cover it with a lockable protective cap to prevent contamination. 

• Use manual water level indicators (diameter/electric tape) or an automated data logger. 

• Install the vibrating wire (EPU-20V) or Bourdon gauge (EPU-20G) inside a pre-drilled borehole in the foundation. 

• Use cement-bentonite grout to prevent leakage pathways. 

• Route cables securely to protect against mechanical damage. 

• Use a shut-off valve in uplift monitoring to allow controlled pressure readings. 

• Verify sensor response using manual reference measurements. 

• Cross-check readings from adjacent instruments to detect anomalies. 

• Ensure signal cables are free from mechanical damage. 

• Protect cables from rodents, chemical exposure, and weather conditions. 

• Check for data drift, power fluctuations, and calibration errors in automated systems. 

• Use temperature compensation for vibrating wire sensors. 

• In subzero environments, install heated enclosures or use antifreeze solutions in standpipe piezometers to prevent freezing. 

• Piezometer Implementation: Encardio Rite installed vibrating wire piezometers to monitor pore water pressure within the dam's structure and its foundation.  
• Outcome: The data collected facilitated the assessment of the dam's stability, enabling timely interventions and maintenance to prevent potential failures.