What everybody ought to know to ensure that the embankment being built meets the quality requirements

Throughout my career I have found earthwork supervisors with experience and ability. Most of those successful supervisors were formed with daily work and they learned from good and bad experiences. A remarkable fact is that many of them did not receive any formal training in fundamentals of soil compaction but then instead they have learned by themselves motivated by their inner urge to be better and to improve their job performance. They have also learned by interacting with engineers, inspectors and laboratory technicians. By observing test results taken in the field, they also were able to understand the relations that existed between moisture, compaction equipment and construction procedures through the years. One attribute I noticed about them was that they knew the basic principles of soil properties and fundamental knowledge of compaction. I have also seen supervisors selecting equipment and setting compaction cycle based on soil properties and hauling distances. Those people are able to identify how many passes are needed to achieve the desired compaction based on an understanding of the plasticity index. On the other hand, I have come across equipment operators that were placed as the man in charge just because they could manage people somehow but, not yet possess the necessary competency. On this case, they are unaware of the basics of soil, compacting fundaments and they have no idea what the plasticity index is. They often struggle using soil as construction material and get frustrated with inspectors and technicians when they do not achieve density field test

1. Recording soils’ properties and testing results. I remember one time when I was a contractor’s project manager that one of my supervisors called to inform me that he was unable to pass a density test. He mentioned been working on an area for almost two days and unable to meet the inspector’s requirement. I went to the site to find out what the problem was. The first thing I noticed when I arrived to the site was the evident friction between the supervisor and the inspector. The inspector was able to tell me which Proctor he utilized but, the supervisor wasn’t. By that time, our company did not have a field book to log the testing's results completed on field. So, I offered the inspector to process one more time the area and let the soil dry. Back in my office and looked on the previous testing reports and I found that the Proctor used to determine the field density was not the most adequate for the processing material. I suggested the technician to use a different Proctor because it was a better representation of the material, he understood the reasons and justifications and he modified the procedure. Next morning the density test was done applying the suggested Proctor’s data. As a result, density test passed. That example is a common reality in a job site. Contractors, inspectors and laboratory technicians closely interact during the earthwork construction. They may represent different organizations therefore, they often debate about meeting quality requirements and that is due to the lack of understanding on soil’s properties, constructive procedures and mainly for an erroneous belief that constructors and inspectors are opponents.

   What was the lesson learned from this common problem?

1. Supervisors may not be properly trained on soils’ properties and testing.

2. It is crucial to have a system in place to be able to collect and retrieve information on site in an effective manner

3. It is important to emphasize the importance of the collaboration between contractors and inspectors within the construction process.

What is the solution to this problem?

1. We SHALL have a source of information and training about the minimum knowledge required to master the art of dealing with soils.

2. We MUST records soil’s properties and densities-moisture test results in an effective and systematic way

3. We Must establish a philosophy of cooperation to understand requirements and a commitment to meet quality requirements between our personnel

3. Size matter, as well as how you move it. The type of equipment needed in earthwork operations and its cycles are important too. The cycle of the equipment used for the earthwork operations, refers to the work steps or components that the selected equipment performs over and over again to complete the job. For earthworks operation, the primary cycle is the excavation, hauling, dump and return. The basic steps can be listed as:

1. Loosening the soil to carry it into a state to be manageable

2. Excavating the material to start moving it from their place of origin

3. Hauling the material from their place of origin to a place where it is deposited

4. Spreading and placing the soil in its place of deposit

5. Handling and compacting the soil.

All this can be achieved using selected type of equipment, or using two or more types of equipment working together. It is critical that equipment selected is appropriate to the expected production and the volume of soil to be moved. It is not only about preference but, what it takes to be efficient. The use of inadequate equipment results in production problems, project delays and low quality.

If you already have a reasonable understanding of the nature of soils and if you are able to identify the processes involved to build an embankment with a clear definition of the sizes and the adequate type of equipment required to complete the operation you own the knowledge required to ensure that the embankment that is being built will meet the quality requirements

Is this all we need to know?

These findings are the principles for most earthwork. But, they are just a glimpse to all the steps required to ensure that embankment operations will achieve the quality requirements. Alberto Munguia has developed a unique and specialized Field Book for Quality Control in Earthwork Operations. This book is used precisely, to collect information on site to fully understand the nature of the materials used on the project. Users of this field book are able to demonstrate that the compacted fill meets with soil’s properties, moisture-density relationship and number of testing required. This fieldbook allows the user to monitor closely the information collected and to handle properly the material that is being processed. This book combines construction knowledge and civil engineering that is considered fundamental during the execution of the earthwork. We also invite you to visit and subscribe to our web page at www.cs4highway.com to receive free training on subjects related to highway construction

Where can I get a copy of this Field Book?

Barns and Noble, Amazon, iUniverse