Excavation monitoring systems are used to ensure safety during construction excavations. The goals of monitoring systems and the various types of monitoring systems are described. Excavations in the past were done utilising conservative design approaches and lesser excavation depths. Construction disasters have resulted as a result of this, however they are limited in number.However, many parts of the building industry have seen significant growth in recent years. The widespread use of deeper excavations has had an impact on excavation activities. The majority of deep excavations take place in densely populated areas. Such activities have resulted in significant property destruction and loss.Construction procedures relating to analysis, design, and construction techniques have advanced significantly in the civil engineering area.
However, no effective method for dealing with the dynamic behaviour of excavation-related works has been developed. As a result, it is necessary to have a well-organized monitoring system for the excavation process in order to minimise worries about safety, loss of life, and property during excavation.
Table of Contents
Objectives of Excavation Monitoring Program
The following are the primary goals of an excavation monitoring programme:Excavation Monitoring System for Construction Safety During Excavation is the first goal. The most significant and primary goal of an excavation monitoring programme is to guarantee that there are safety considerations in place from the beginning to the finish of excavation activities. Any disaster or trouble that arises as a result of the excavation process will almost certainly be preceded by certain signs or warnings. The monitoring system members must monitor and assess these situations so that the engineers can take appropriate measures to prevent the disaster from occurring. The monitoring team must not ignore any signs of danger.
The majority of the excavations are carried out in densely populated areas, busy areas, or commercial areas. Many subsurface structures already exist in this crowded area, and they must not be harmed in any way by future excavation work. Any newly planned excavation procedure must not have negative consequences for nearby structures, subterranean pipes and foundations, soil distress or deformation, public services, or pedestrians.The designer in charge must take into account all of the following variables when designing. The monitoring system was created in response to these concerns, with the primary goal of ensuring the safety of people and property.
Objective : Confirming to the Design Conditions
In most circumstances, the design conditions will not match the site’s actual conditions. The fundamental reason for this is that existing analysis theories are not yet mature enough, and geological conditions and considerations cannot accurately describe in-situ settings. They lack the ability to adequately adjust to the challenges of the building environment. However, if we perform a back analysis with the help of monitoring findings and use this as the foundation for modifying the original design, we can achieve significant cost savings and similarity in the construction. This strategy results in a more realistic design that is based on the construction environment. A design is created by assessing all of the difficulties that will occur on the site in a specific order.
This strategy lowers construction costs, shortens the excavation period, and changes the design basis. These developed design methodologies can be applied again for comparable concepts. This aids in the improvement of excavation methods. Objective : Develop and maintain a long-term behaviour After an essential project’s excavation and building work is completed, a monitoring system can be set up and maintained to help with long-term follow-up. This aids in the analysis of the case’s long-term behaviour.This is a type of case study that is carried out in order to confirm the initial premise. This can serve as a foundation for confidently repeating the same process for similar tasks.
Supply of Factual Materials and Information for Legal Judgment
If the work is interrupted due to a disaster or property damage, the monitoring system’s information can give all of the necessary evidence. This is also where you’ll find the construction records. These resources aid in the analysis of the true causes of these disasters, thereby eliminating any future conflicts. This makes it even easier to do the restoration and compensation tasks.Instruments commonly utilised for geotechnical needs and investigation can also be used to monitor excavation activities. Special devices have been developed for the monitoring of excavations, and they have the following characteristics.
Field performance is primarily measured using characteristics such as deflection, stress, strain, and a variety of other physical qualities. The following are the most regularly used monitoring elements in the excavation process:The soil movement or the structure The stress or strain on structures or water pressure and level of the Watershed following are some of the objects that are monitored in the movement of soil and structure:The soil’s lateral Deformations soil’s lateral deformation The structure is swaying.The ground surface’s settlement Buildings that have settled The central post’s elevation The excavation’s bottom heave The following items are included in the stress and strain measurement:The loads on the strut The retaining structure’s Stress The pressure exerted by the earth on.
Electronic Type
The electronic instruments are extremely sensitive and easy to read. These instruments can be combined to create a monitoring system that is either fully automated or semi-automated. The precision of measurement and the reading value obtained are heavily influenced by the installation technique and the surrounding environment. The device used must be inspected on a regular basis in order to precisely measure and monitor the excavation over time. As a result, when we decide to put an electronic instrument at a measuring site, durability is a fundamental consideration, and it necessitates careful attention. Instruments used in plane surveying, such as tapes and theodolites, can be used to measure the movement of the soil or building.
Electronic devices or plane surveying can be used to determine the tilt angle. Strain gauges or electronic transducers that use the strain gauge as the measuring unit can be used to measure stress or strain. Regardless matter whether it is an electronic or mechanical system, the manual system requires a human to read the values. Electronic sensors are used in the automatic system, which is linked to a computer system.The computer is used to obtain the appropriate measurement for each monitoring instrument. This aids in the acquisition of continuous measurement values. The automated systems are costly, but they are effective. This technology avoids the difficulties that come with human reading. This is frequently used in excavation projects where environmental sensitivity is high.
Deep excavation is necessary at various levels during the construction of structures such as high-rise buildings, underground garages, underground mass transportation networks, and underground water sewer systems. Ground movement is induced by excavation in soft ground, posing a threat to neighbouring sensitive structures in the zone of influence. As a result, at all levels, deep excavation risk assessment and foundation crack monitoring are critical. In a deep excavation, deformation must be kept to acceptable limits. For safety during and after the deep excavation, appropriate apparatus is required to monitor deformations at various levels. Deep excavation sites require instrumentation to assure the safety of the excavation and the effect zone, to verify that design factors are being followed, to record long-term behaviour, and to provide legal documentation.
All of the devices provided and installed at the site are monitored online by Encardio Rite. The Web Data Monitoring Service, which Encardio-Rite provides to users all over the world, is at the heart of the online structural monitoring instrumentation systems. It’s a web-based data management and presentation application for data gathered by data loggers of the ESDL-30 series. Any data or report from the same site can be seen by several authorised users at different locations at the same time. For access to the logged data, each user is given a unique password. Popular online browsers such as Microsoft Internet Explorer and Mozilla Firefox, among others, can be used to view graphs and reports. The server for the above WDMS services is housed at Encardio-rite and is kept up to date 24 hours a day, seven days a week.
In-place inclinometers (IPI) are used for continuous monitoring.
Instrumentation and monitoring technology are increasingly used to monitor structures.
During the construction of structures like high rise buildings.
Also Check
Architectural Cast-in-Place Concrete and its Mix, Features and Uses