Everything You Need to Know About GPR and Underground Utility Locating

For underground utility locating, GPR (Ground Penetrating Radar) works as a corresponding tool to EM. Whereas the EM method is used to locate active utilities beneath the ground, GPR utility location services help locate and identify different elements that are different from their surroundings. 

Let's take a look at two of the most common yet challenging scenarios and how we can make the most out of the underground utility locating data available:

1.      Multiple Targets

In the presence of multiple buried targets such as rocks, roots, trees, etc., separating buried utilities from them can be quite challenging. Before planning any excavation, one needs to identify target responses from different depths and oriented in different directions.

2.      Weak Targets

Varied composition targets result in highly fluctuated GPR reflection responses depending upon the different soil conditions and depth.  Also, as the composition of conduit utilities and non-metallic pipes contrasts with the properties of the host material, they often create weak responses. In such instances when the response is weak, targets are usually overlooked.

Strategies That Can Help Get the Most from the Available Data

1.      MapView & Interpretation

During underground utility locating, existing records of utility maps offer initial assistance. Further, one needs to create site sketch maps based on observed targets and features. MapView allows us to see the entire surveyed area with all the analysis precisely marked on the screen.

While collecting data, the utility location services provider adds colour-coded interpretations which provides discrimination between the targets and ensures that all the targets are market.

To ensure that the entire area is properly covered, pay special attention to the direction, pattern and spacing of the ground-penetrating radar data path.

2.      Depth Slicing

When there are multiple utilities underneath the ground, depth slicing is the best tool to look for linear subsurface. It collects GPR data at varying depths and generates a 2D map image for the same. The latest GPR (ground penetrating radar) systems direct the locator through set-up, data collection, processing and exhibit depth slice. GPR with accurate GPS allows you to produce a depth slice from the line collection.

As depth slicing helps to visualise the targets and highlight utilities, it can widely help with the first challenge.

3.      Interpretation Overlaid on Depth Slices

For MapViews of user-selected utilities, depth slicing works as a complimentary. For the weak responses that aren't highlighted in a depth slice, MapView allows the utility location services provider to highlight those responses to the best of his experience and knowledge. The combination of depth slicing and MapViews has proven to be highly beneficial in complex areas.

When the target responses in the GPR cross-section are too weak to appear in a depth slice but are visible to the naked eye, it is advised to map the weak hyperbolas. This can be done by adding user selected point interpretation to the weak responses.

There is a range of varied options available to choose the interpretation colour to place on a hyperbola. 

• Choose interpretation colour based on the colour code of utility marking
• Choose the colour code based on the hyperbolic response strength

What's Important is to Choose One Colour Convention and Stick to it Throughout the Project?

Once the point interpretations are added, look in the MapView for the patterns made by interpretations. Some might line up, representing a linear object (mostly a utility) while some might not line up, those are point targets. Adding interpretations and overlaying them on depth slices helps identify and map utilities that do not appear on the depth slices.

Interpretations and depth slicing are the key methods to untangle complex excavation sites and identify missed utilities as a result of their weak responses. Undoubtedly, safety and damage prevention is of paramount importance for safe excavation.

To ensure accurate underground utility locating and mapping, hire professional locators and use all the tools to their best potential.

Author's Bio:

Jon Armstrong possesses immense knowledge related to GPR (Ground Penetrating Radar) and underground utility mapping. For several years, he's been associated with GeoScan Utility &Structural Investigation, renowned underground locators known for providing accurate and timely information related to underground pipe location and much more.

Passive vs. Active Locating Services: Which One to Choose?

When you are planning to commence any excavation project, utility location services should be at the top of your pre-work measure list. Undoubtedly, underground utilities offer an array of advantages, but they also generate a complex maze of cables and lines that run underneath our cities.

To ensure safe excavation without risking the structure of existing utility grid, you need to hire professional underground utility locating services provider who has in-depth industry knowledge & experience to deliver accurate mapping.

There are two types of utility locating method: active locating service and passive locating service. The locator should know which method should be used and when. Let's dig further to gain a better understanding of both the methods and identify which is a better one.

1.  Active Locating Services

Active utility locating services works best when one need to locate a specific utility that runs uninterrupted, which has a continuous metallic connection from end to end. Utility location services provider sends an electromagnetic (EM) frequency on one end and transmitted down its length.

A surface receiver picks up the signal and traces it across the ground surface. Once traced and marked, the locator maps the line for your reference. With the help of this mapping, you can plan your excavation whilst avoiding that line.

Furthermore, There are Two Kinds of Active Service Locating Methods:

• Conductive Locating – In this method, a transmitter is directly attached to the utility line which produces an EM field on the outer field.
• Inductive Locating – It is used when there is no possibility of a direct connection. In this method, EMF is introduced to the line by placing the transmitted directly above it over the ground. 

Applications:

• Locate a conductive or metallic utility line with an uninterrupted content from end to end.
• Suitable for locating utilities with the presence of cathodic protection or tracing wire.
• Rail services

 

2.  Passive Locating Services

While active utility location is a great method to acquire specific and accurate information about specific utility lines that run under a property, there are certain scenarios where it isn't effective.

For instance, when there are broken pipes, interrupted lines or non-metallic pipes (plastic/concrete), the frequency won't be transmitted across the entire length, making it difficult to fully trace it. This is where passive utility location method can help. It allows us to identify and map unknown lines as well.

One of the most popular passive utility location methods is ground penetrating radar (GPR). It allows us to map the complete surface beneath the ground which includes not only utilities but also other features which you might not be aware of, such as old wells, obstacles or voids.

Applications:

• To locate broken utilities or where frequency can't be transmitted fully
• For locating non-conductive lines or pipes
• Used when access points are unknown
• Performed at the end to ensure no utility is missed

Final Thoughts

All in all, settling on which is a better underground utility locating services method depends upon the project needs. Every method has its own advantages and disadvantages. Depending on the location of the utilities, there's also a possibility of conducting both methods in a single project itself. You might not always be aware of what type of situation is underneath – it's better to leave it in the expert's hands to find out.

Author's Bio:

Jon Armstrong is an expert of underground pipe & cable location in Geelong offering extensive experience of underground utility mapping and locating methods. Jon Armstrong is closely associated with GeoScan Utility & Structural Investigation which is a renowned underground utility locating services company in Geelong. To get a quote, you can call on 0417 309 710.

Things to Consider before Choosing Best Underground Services Provider

Any industry dealing with digging up the ground can take for granted importance of best underground services provider at its own peril!

Such industries may include engineering plants, telecommunications, electricity, archaeology, among many others. One common thing that all these industries share is their need to have clear ground to execute their ambitions projects. It is here that they need to be careful in choosing their underground services provider.

There are so many underground services providers in Melbourne and Geelong area that it is a daunting task to find the one that is right for you. Let us have a look at some of the things that you need to consider before finalizing your underground services provider.

Types of services

It is very important to check what kind of services they are providing to their customers. If they are providing many types of services, it means they have the knack of the industry and they know what it is to provide underground services to their clients. Major underground services available in Melbourne and Geelong area include:

• Cable fault detection
• Metal detection
• Ground penetrating radar imaging
• GIS Utility & Ground Mapping
• Underground pipe and cable location

Knowledge of technology, equipments

It is obvious that you want to avail the services from those who use latest technology and advanced equipments. When you are considering your underground services provider, you need to find out what technology they are using and with what equipments they execute their knowledge. Some of the technologies to look for include:

• High frequency antennas for concrete scanning
• Simple-to-use acoustic pipe locator
• Flexible tracer rods to carry out underground pipe detection
• Latest ground penetrating radar equipment to locate and calculate the size, length and width of the project

Customer Care

Check what their customer care service is all about. When it comes to underground services, at times, there may be an emergency. It would be very important to know whether they are equipped to handle any such emergencies.

Accreditations

These are very crucial benchmarks to find out authenticity of underground services provider. Do check for such accreditations as these accreditations mean that the service provider knows the importance of rules, regulations and permits. Following are some of the important accreditations to look for:

• Australian plant locators license (Telstra) for Telstra copper and optic fiber cables
• Australian petroleum industries accreditation
• Rail accredited Level 1 track awareness
• Dial Before You Dig registered
• Construction industry accredited (red card)
• OH&S company representative accredited
• First aid level two

Testimonials

Do not forget to check the experiences of other customers. It always helps in decision making process. True and authentic testimonies reflect services providers' ability to execute the projects efficiently and skillfully.

These are some of the things you need to consider before choosing best underground services provider in Melbourne and Geelong areas.

Types of Underground Services Provided by GeoScan in Geelong

If you are looking for any type of underground services in Geelong, do check out Victoria-based GeoScan Utility Location Service. It is a company that provides a range of underground services with the help of advanced technology to locate underground assets and execute site survey investigations.

Have a Look at Our Major Services

Acoustic water main detection service in Geelong

The purpose of acoustic water main detection technique is to address the challenges earlier faced by using electromagnetic locators to identify underground pipes, cables and conduits. With the advent of this advanced technique with its simple-to-use acoustic pipe locator, it has become easier to provide underground investigations in Geelong area with state-of-the-art equipments.

GeoScan Utility employs fully trained human resources who are constantly updated with the changes in technology. Also, we give equal importance to each of our customers along with providing 24/7 emergency response service throughout Victoria, NSW, Tasmania and South Australia including Melbourne and Geelong.

Underground Pipe and Cable Location

This service can be used in different areas such as domestic water services, fire services, gas networks, electrical networks - both high and low voltage, telecommunications, storm water, sewer or drainage conduits among others. When it comes to metal detection, GeoScan induces an electromagnetic signal to identify the targeted object. The purpose of using this powerful latest technology is not only to identify the location of the object but also its depth and size. This information can go a long way in any type of excavation demanding less time and energy.

Ground Penetrating Radar Imaging

With the introduction of this geophysical technique, it has become easier to image objects, changes, voids or cracks or any other activity happening under the surface. The objects may include rock, soil, ice, fresh water, pavements and structures. Some of the best clients of GeoScan Utility include engineering companies, organizations/people interested in environmental studies and even archaeology.

GeoScan is committed to take full advantage of this technology. As a result, we use latest equipment to execute ground penetrating radar imaging process. The equipment is not radioactive and is operated by electromagnetic signals. Our equipment does not require you to connect GPR to any services like underground pipe or cable locators.


Other benefits include:

• Accurate information of size and depths of underground objects
• Can be used even on rough terrain
• Information can be stored in USB stick

Other underground services provided by GeoScan Utility Location Service include:

• Cable fault detection
• Metal detection
• Site survey and drafting

Having obtained range of technical capacities and accreditations, GeoScan Utility has become a trusted name in Geelong area when it comes to providing various types of underground services. One of the major accreditations that we have is Australian plant locators license (Telstra) for Telstra copper and optic fiber cables and Dial Before You Dig.

Give us a call and see we can do for you and explore possibilities together. 

How to Select the Right Underground Utility Location Company?

Many utilities like electric, telephone, internet cables, water and SWR pipes are laid underground to save space and for greater safety. The cables are laid in trenches or conduit pipes and often do not need any maintenance for many years. The water or SWR pipes are made of concrete, Frp or metal and are also expected to be maintenance free.

However, in case there is a cable fault or a crack in the pipe, it may be necessary to find where exactly the fault is located, so that suitable repairs can be carried out. Digging large stretches of land may not be economical, and may also be very inconvenient for a large number of people using the area. In such cases it is advisable to use the services of a underground utility location company like GeoScan. This article discusses how to select the right Underground Utility Location Company based on various factors.

The main consideration while selecting an Underground Utility Location Company is the kind of utility to be located. It is relatively easier to locate a fault in a pipe carrying a fluid like water, as the leaking fluid will seep to the surface, if the pipe is not laid very deep underground. On the other hand, if there is a cable fault like short circuit or a loose contact, it may be very difficult to find the exact location where the fault has occurred. In such cases, specialized equipment is needed to find the exact fault location and the Underground Utility Location Company should have suitable equipment.

Equipment and tools owned by the Underground Utility Location Company is another consideration while selecting the right Underground Utility Location Company. A company owning the latest high-tech equipment like GeoScan, may be able to locate the fault more quickly compared to other firms, which use less sophisticated techniques.

Pricing and terms and conditions are always a major consideration while finalizing an order with any contractor for engineering products and services. Pricing depends on a number of factors such as scope of work to be done, equipment to be used, after sales support needed, so selecting a company that offers the lowest price may not always be the best option in the long run.

Experience of the staff of the underground fault location company can affect both the quality of the work as well as the time taken for the project to be completed. An experienced person is likely to have handled similar requests for utility location, and may be able complete the work efficiently.

The location of the Underground Utility Location Company is also important. A local Underground Utility Location Company will reach the area where the utility is located quickly compared to another company offering similar services located in another state. They will also be aware of the terrain in the area, local rules and regulations, which they have to comply with.

Another consideration is whether the Underground Utility Location Company has relevant certifications which complies with organizational health and safety laws. Working underground can be dangerous and the company should provide adequate insurance coverage to all workers involved in this hazardous activity.