Encardio Rite: A Guide on Geotechnical Instruments: Types, & Application
Credits: Encardio Rite
As the world is developing rapidly and transforming into a concrete jungle, the need for geotechnical instrumentation and monitoring has increased.
Geotechnical instruments are the sensors that are used in the geotechnical field or large civil engineering projects to monitor the health of the structures.
The range of geotechnical instruments and their application field is limitless. We are living in an era of magnificent structures.
Be it the impressive Gotthard Base Tunnel or the skyscraper Burj Khalifa. Their existence is next to impossible without geotechnical monitoring and instrumentation.
Geotechnical monitoring is necessary to keep a regular check on structures like dams, bridges, tunnels, railway tracks, buildings, etc. Starting from the surveying of land before constructing a structure on it till its completion, geotechnical monitoring plays a vital role.
Let’s dig deeper into the fascinating world of geotechnical sensors, their types, working, as well as, the applications.
What is geotechnical monitoring?
Geotechnical monitoring is a branch of geotechnical engineering that deals with constant health check-up of the structures. The civil engineering projects require an extensive amount of monitoring pre and post-construction to ensure everyone’s safety.
Monitoring begins right from the surveying of the construction land and nearby areas and continues until the structure is built.
For buildings, structures and bridges etc., it is recommended that Structural Health should be continuously monitored to ensure proper maintenance and safety of man as well as the material.
Encardio-Rite is a 52-year-old geotechnical monitoring company that provides indigenous online monitoring services for civil engineering structural projects and water resources with remote access to collected data in real-time.
Encardio-rite is one of the few geotechnical instrumentation and monitoring companies in the world which manufactures geotechnical instruments and has developed advanced integrated software in-house, for processing and displaying monitored data along with web-based monitoring solutions.
|Read More: Geotechnical Instrumentation & Monitoring: Services &Types |
Why geotechnical monitoring is essential?
A structure can fail because of numerous reasons like design error, geological instability, poor maintenance, deterioration of construction material, etc.
However, a good geotechnical monitoring programme can prevent such failures by providing the following information:
Geotechnical Monitoring during construction:
- To verify the hypothesis and the assumptions of design
- To monitor safety during construction
- To measure the change in parameters during construction
- To ensure that the interface of construction with adjacent structures and foundation is sound
- To certify the performance of the new construction
Geotechnical Monitoring after construction is completed:
- Performance monitoring for safety during the life of the structure
- Evaluation of the effect of the structural operation on parameters like stress, strain, water, pressure, inclination, deflection etc.
- Comparison of observed data with design assumptions
Geotechnical Monitoring for research
- Determination and evaluation of design parameters
- Testing of new construction materials and techniques
- Study of the laws of behaviour of soil, rock and man-made materials used in the construction of such structures.
Advantages of Geotechnical Monitoring
Design Verification
- Instruments are used to verify design assumptions and to check that performance is as predicted.
- Instrument data from the initial phase of a project may reveal the need (or the opportunity) to modify the design in later phases.
Construction Control
Instruments are used to monitor the effects of construction. Instrument data can help the engineer determine how fast construction can proceed without the risk of failure.
Safety
- Instruments can provide early warning of impending failures, allowing time for safe evacuation of the area and time to implement remedial action.
- Safety of adjacent structures
- Safety monitoring requires quick retrieval, processing and presentation of data so that decisions can be made promptly.
Legal Protection
Instrument data can provide evidence for a legal defence of designers and contractors against owners of adjacent properties if they claim that construction has caused damage.
Performance
- Instruments are used to monitor the in-service performance of a structure. For example,
- Monitoring parameters such as leakage, pore-water pressure, and deformation can provide an indication of the performance of a dam.
- Monitoring loads on tiebacks or rock bolts and movements within a slope can provide an indication of the performance of a drainage system installed in a stabilized slope.
What is geotechnical instrumentation?
Figure 1: BHE Installation at DTS T02 Project, Abu Dhabi
Instrumentation plays a key role in safety monitoring of structures and people, providing necessary information on its performance and detect problems at an early stage.
The extent and nature of instrumentation not only depends on the complexity of the structure but also on the potential for loss of life and property nearby.
This information is critical for the structure’s owner who is directly responsible for any consequences of its failure.
Geotechnical instrumentation includes different types of sensors used for measuring pore pressure, groundwater level, water flow, lateral movement, deformation, stress, strain and temperature. It also includes geodetic targets measured using surveying techniques.
Advances in geotechnical instrumentation, surveying technologies and data transmission systems make it possible to monitor the dams, bridges, railways, metros, buildings, tunnels, etc. from any remote location, conveniently and economically.
The data logger and total station automatically collect reading from the installed sensors and targets, at selected intervals. An alarm is triggered or SMS is automatically sent if any of the pre-determined trigger values are exceeded.
Data is transmitted to a remote data management system, at a central server or cloud, where large quantities of collected data are processed, evaluated and presented as meaningful information.
The same becomes accessible to the concerned authorities, at their desk or mobile devices through the World Wide Web.
Scope of Geotechnical Instruments in Various Monitoring Fields
Dam Monitoring Solutions
Parameters MonitoredWater level, Water pressure and seepage Lateral ground movement, Deformation, Displacement Stress, Strain, Load Temperature Tilt, Surface SettlementServices OfferedCloud-based web data presentations for online as well as manual data Sub-surface and surface monitoring of various parameters Pre and post construction building condition survey Laser ScanningGeotechnical Instrumentation RangePiezometers Earth Pressure Cells Strain Gauges Inclinometers Plumb Lines Extensometers Crack Meters, Joint Meters Temperature Meters Load Cells Data Loggers Geodetic Targets Database Management System
Typical Instrumentation Scheme — Earth Dam
Typical Instrumentation Scheme — Concrete Dam
Tunnel Monitoring Solutions
Parameters Monitored
Lateral ground movement, Deformation, Displacement
Stress, Strain, Load
Temperature
Tilt, Surface Settlement
Areas Monitored
Underground tunnels and excavations
Struts in cut and cover constructions
Diaphragm Walls
Pile foundations and sheet piles
Adjoining buildings, structures, pavements etc.
Services offeredCloud-based web data presentations for online as well as manual data
Sub-surface and surface monitoring of various parameters
Pre and post construction building condition survey
Laser Scanning
Geotechnical Instrumentation Range
Piezometers
Earth Pressure Cells
Strain Gauges
Inclinometers
Plumb Lines
Extensometers
Crack Meters, Joint Meters
Temperature Meters
Load Cells
Data Loggers
Geodetic Targets
Database Management System
Parameters Monitored
Lateral ground movement, Deformation, Displacement
Stress, Strain, Load
Temperature
Tilt, Surface Settlement
Areas Monitored
Underground tunnels and excavations
Struts in cut and cover constructions
Diaphragm Walls
Pile foundations and sheet piles.
Adjoining buildings, structures, pavements etc.
Services offered
Cloud-based web data presentations for online as well as manual data
Sub-surface and surface monitoring of various parameters
Pre and post construction building condition survey
Laser Scanning
Geotechnical Instrumentation Range
Piezometers
Earth Pressure Cells
Strain Gauges
Inclinometers
Plumb Lines
Extensometers
Crack Meters, Joint Meters
Temperature Meters
Load Cells
Data Loggers
Geodetic Targets
Database Management System
Typical instrumentation scheme — NATM Tunnel
Typical Instrumentation Scheme — TBM Tunnel
Typical instrumentation scheme — Deep Excavation
Structural Monitoring Solutions
Parameters MonitoredTilt Monitoring Crack Monitoring Settlement Monitoring Lateral Ground Movement Temperature Monitoring Pore Pressure MonitoringMonitoring AreasSafety of high-rise buildings during construction Safety of buildings and infrastructures during construction activity in vicinity Safety of old and depleted buildings Safety of structures subjected to long-term movement or degradation of materials Safety of monuments and structures of historical importance Safety of structures in landslide prone areasGeotechnical Instrumentation RangePiezometers Earth Pressure Cells Strain Gauges Inclinometers Plumb Lines Extensometers Crack Meters, Joint Meters Temperature Meters Load Cells Data Loggers Geodetic Targets Database Management System
Typical Instrumentation Scheme — Structures
Typical Instrumentation Scheme — Pile Testing (Foundation)
Types of geotechnical instruments
Multiple sensors are used in the field of geotechnical monitoring. Encardio-Rite deals with a wide range of geotechnical instruments which include piezometers, extensometers, data loggers, strain gauges, load cells, pressure cells etc.
Let’s have a look at each one of them.
Piezometers or Pore Pressure Meters
Pore pressure measurement is crucial for large civil engineering projects like high rise buildings, tunnels, dams, etc. The pressure experienced by the water accumulated in the pores of earth materials, concrete structures or rocks is called pore water pressure.
The pore water pressure is measured by a piezometer sensor which is also popularly known as ‘pore pressure meter’.
Encardio-Rite deals with different types of piezometers to according to the application field.
Casagrande is the simplest type of piezometer consisting of a Casagrande tip connected to the lengths of the extension pipes. The water level inside the pipe is measured through a dip-meter.
The electric piezometer, generally vibrating wire type, is most commonly used, as it provides hassle-free, accurate and real-time data.
| Read More: Piezometers: Types, Functions, & How it works? |
Types of Piezometers
Encardio-Rite deals with the following models of piezometers to monitor pore pressure in standpipes, boreholes, embankments, fully and partially saturated natural soils, rolled-earth fills and the interface of retaining structures.
Model EPP-10/10SP Casagrande Piezometer/Standpipe
Groundwater table monitoring is significant because of depleting groundwater reserves. The measurement of groundwater level can be done by open standpipes or constructing observation wells.
The Model EPP-10/10SPopen standpipe is used to monitor groundwater level in boreholes near dams, rivers, high-rise buildings, farmhouses, factories, institutes etc.
Model EPP-10/6 Water Level Indicator
The Model EPP-10/6water level indicator is used to measure water level in boreholes, wells, Casagrande piezometers and standpipes. It is accurate, robust, lightweight as well as convenient to use.
Model EPP-30V Vibrating Wire Piezometer
The Model EPP-30V vibrating wire piezometer is made with the latest vibrating wire technology to provide a remote digital readout of fluid and/or water pressure in standpipes, boreholes, embankments, fully and partially..[Read More]
