Geodetic Monitoring is the study of the earth's geometry, and at the same time, developing methods and techniques using space technology to monitor them. If used judiciously with geotechnical instrumentation, geodetic monitoring provides co-related data that is relevant and extensively used in civil construction and structural monitoring. Encardio Group uses an in-house developed control box with advanced software to control robotic total stations.
The geodetic system ensures valuable and timely monitoring of the displacements, providing high measurement density, simultaneous wireless transmission, and automatic entry of the results in the monitoring database.
Geodetic Surveying definition includes using geotechnical instruments at pre-construction, during-construction, and post-construction stages to monitor the fundamental parameters affecting the construction. Due to its relatively low cost, it is widely spread and used in all civil engineering projects.
Let’s discuss more on geodetic surveying, its importance, and application areas.
What is the geodetic survey?
When there’s a large area, usually beyond 100 square kilometers, the surveying requires the consideration of the curvature of the earth. Such type of surveying serves as the definition of a geodetic survey. In geodetic surveying, two stations (points) far from each other are chosen. The latitude and longitude of these two points are determined astronomically. The line joining these two points is known as the baseline, which is measured precisely.
The position of a third station is defined by the angle made with each end of the baseline. The complete process is known as triangulation. It is continued until the entire survey land is mapped and a geodetic survey marker is employed.
Now that we are done with our introduction to geodetic surveying, let’s take a look at what is geodetic level.
What is the geodetic level?
Geodetic leveling is the process of determining the relative height of the stations or points on the earth’s surface.
Level surface: It is defined as the surface, which is parallel to the earth’s mean spheroidal surface.
Level Line: It is the line lying on the level surface and, hence, it is normal to the plumb line at all points.
Horizontal Line: It is a straight line tangential to the level line.
Vertical Line: It is the line normal to the level surface.
What is the objective of geodetic surveying?
The following are the objectives of geodetic surveying:
| Also Read: A Guide on Geotechnical Instruments: Types, & Application |
Geodetic Surveying Application
The application of Geodetic Surveying includes Geodetic monitoring along with geotechnical instrumentation that provides data widely used for structural monitoring.
1. Settlement detection: Leveling measurement of preinstalled targets on buildings, structures, pavements, deep points, and embankments using high-accuracy digital levels and invar staff.
2. 3D optical targets
The geodetic survey instrument includes the three-dimensional displacement measurements with bi-reflex targets or monitoring prisms that are installed in tunnels, structures buildings, etc., using high-end total stations to provide for manual as well as automatic data.
An in-house software by Encardio Rite named Terramon is available that can be installed on a tablet, laptop, or PC to achieve semi-automatic measurements, maximize their accuracy, and minimize field time.
For automatic monitoring, Drishti or Terramove is available depending on the requirement from project to project. Terramove can also be used for co-relating data from TBM sensors with data available from geotechnical and geodetic instrumentation, whether manual or automatic.
3. Automatic monitoring system
Project safety requires 24/7, high frequency, & accurate measuring monitoring systems.
The Encardio group uses an in-house developed system that consists of a series of network robotic total stations, each one controlled by the Terramon software, installed in the dedicated total station control box.
The system ensures valuable and timely monitoring of the displacements, providing high measurement density, simultaneous wireless transmission, and automatic entry of the results in the Terramove monitoring database.
4. Laser scanning
It is a method based on exceptionally dense mapping of three-dimensional coordinates of the points on the surface to be monitored. It is one of the most widely used geodetic surveying techniques.
Laser scanning is a rapid and reliable surveying method, collecting data in static, stop-and-go, or kinematic mode.
From the point cloud produced, the exported section profiles can be used to monitor deformations or displacements mainly in tunnels, but also on other structures or landslide and rockfall areas.
5. Monitoring using drones/UAV
A rapid and safe way of collecting data for large-scale areas like deserts, and mountains where mm accuracy is not necessary but the motion of the mass is vital to be determined.
Unmanned and remotely piloted aircraft follow a preprogrammed flight path. Equipped with HD/IR/Thermal cameras, they capture aerial images over a defined area.
The point clouds, meshes, and 3D models produced are the data to be compared between sequel flights during monitoring time.
6. Tunnel Boring Machines
Tunnel excavation is associated inevitably with ground loss and high-pressure conditions which, in turn, results in associated ground movement.
Hence, it is important to closely monitor the TBM parameters when tunneling, especially through urban areas.
Through advanced software, we can integrate the essential parameters from the TBM with the monitoring and geophysical data to provide essential information.
| Also Read: All About Tunnel Boring Machine – Components, Types & Advantages |
Geodetic Survey Solutions
Dilapidation Survey using advanced technologies
A dilapidation survey is carried out using both advanced as well as manual methods. The advanced methodology involves Aerial mapping, laser scanning, and mobile mapping.
Drones are used to provide information to clients on the progress of the project.
The drones and fixed wings (aeroplanes) UAVs that are equipped with HD/IR/Thermal cameras or Lidars capture aerial images, videos, or point clouds over a defined area and a specified height with a needed overlap between the image exposures.
Following the progress of a project, quantity or quality is very important for all involved parties. This is a low-cost and precise method to monitor the progress of any large-scale project.
Encardio Rite also provides Geometry control services for construction projects, laying railway tracks, and design.
Geometry control for construction
Geometry Control for Design
Here we come to this exclusive guide on Geodetic Survey and Monitoring. Being cost-efficient as well as accurate, it is the most preferred option to complete the geotechnical monitoring.
Bi Reflex Target
Mini Prism Target
Soil Settlement Point
Pavement Settlement Point
Control box for Total station
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