Table of Contents

• What is on-site earthwork quantity management?

• Why earthwork quantity management determines construction efficiency

• Cost reduction effects from earthwork quantity management

• Traditional earthwork quantity management methods and their challenges

• Improving efficiency with new technologies

• What is simple surveying with LRTK?

• Benefits of using LRTK

• Conclusion

• Frequently Asked Questions (FAQ)

Accurately managing the volume of soil and fill on construction sites is directly linked to improving construction efficiency and reducing costs. In excavation and land development works, it is important to grasp daily progress—whether excavation and filling are proceeding according to plan. However, on-site earthwork quantity management has traditionally relied heavily on manual methods and heuristics, making accurate assessment difficult. This article explains key points and how to leverage the latest technologies to dramatically improve construction efficiency and reduce costs under the keyword “on-site earthwork quantity management.” At the end, we also introduce simple on-site surveying using LRTK.

In today’s construction industry, labor shortages and tight schedules demand higher productivity, and digital transformation (DX) on sites is accelerating. Improving the accuracy and efficiency of earthwork quantity management is an unavoidable challenge within this trend. Technologies that enable “visualization” and “automatic measurement” are already changing how site work is performed.

What is on-site earthwork quantity management?

“As the name implies, on-site earthwork quantity management” means directly managing and understanding the amount of soil generated or used at the construction site. Specifically, it refers to accurately measuring the volume of excavated spoil and the amount of soil used for backfill or embankment and controlling those quantities appropriately. In civil engineering and land development, plans are made at the design stage to balance cut (excavation) and fill (backfilling), but during actual construction differences can arise due to ground hardness, terrain changes, and other factors. Therefore, it is required to measure earthwork quantities on-site in real time and proceed with construction while comparing plans with actual results.

Proper on-site earthwork quantity management allows accurate execution of progress management and as-built verification (checking whether the completed terrain matches the design). For example, if too much is excavated, extra disposal costs will occur; conversely, if excavation is insufficient, it will be necessary to procure fill soil externally, incurring additional costs. On-site earthwork quantity management is the fundamental task to prevent such waste and losses and to keep the project on schedule.

Why earthwork quantity management determines construction efficiency

The skillfulness of earthwork quantity management greatly affects construction efficiency. First, accurately grasping excavation and fill volumes enables optimization of the operation plan for heavy machinery and dump trucks. For example, if the amount of spoil is known in advance, you can estimate the required number of dump trucks and number of trips. This reduces heavy-equipment idle time and enables smooth soil transport. Also, strict control to avoid unnecessary excavation and to perform fill without deficit reduces extra work and streamlines work processes.

Furthermore, conducting earthwork quantity management on-site in real time makes it easy to fine-tune daily construction plans. If excavation has progressed more than planned, you can reduce the next day’s workload; if progress is behind, you can take corrective action early. This enables timely optimal allocation of resources (such as personnel and equipment reallocation) and waste-free process management. On sites with solid earthwork management, construction status is always understood through data, allowing rapid response when problems occur and resulting in a significant improvement in construction efficiency.

In addition, appropriate earthwork quantity management helps prevent schedule delays. If the timing and required quantities for soil transport are unknown, soil piles can block work and stop operations, or machines may stand idle due to lack of soil. By predicting soil volume increases and decreases in advance and reflecting them in transport schedules and layout plans, such unnecessary interruptions can be avoided. As a result, the overall schedule proceeds as planned and construction can be carried out with margin.

Cost reduction effects from earthwork quantity management

Proper earthwork quantity management also greatly contributes to reducing overall project costs. First is the reduction in costs for spoil disposal and soil procurement. If surplus soil generated by the work is accurately known, disposal or reuse options can be considered early. If large amounts of spoil are produced without a plan, expensive disposal fees may have to be paid later. Conversely, if the volume of soil needed for filling is accurately predicted, you can prepare the correct amount in advance and avoid costly emergency purchases or expedited arrangements.

Improved accuracy in earthwork quantity management also reduces rework. For example, if fill is built significantly different from the plan, corrective work such as trimming or additional filling will be required. This double handling leads to wasted labor and heavy equipment operating costs. If work is done with the correct soil volumes from the start, such unnecessary costs can be avoided.

Furthermore, being able to grasp soil volumes on-site in real time reduces the frequency of outsourcing surveying or additional investigations. Historically, every measurement of as-built quantities required commissioning a professional surveying team, incurring costs each time; if site staff can measure and manage earth volumes themselves, those costs are saved. This leads to improved project profitability. Reducing unnecessary soil transport not only saves fuel costs but also yields environmental benefits such as lower CO2 emissions.

As described above, rigorous earthwork quantity management suppresses unnecessary spending and ultimately improves project profitability.

Traditional earthwork quantity management methods and their challenges

Traditionally, on-site earthwork quantity management has relied mainly on human judgment and experience. Site supervisors often made empirical judgments by visually inspecting soil piles or estimated approximate volumes from the number of dump truck trips. However, such methods lack accuracy and can produce large errors. Also, when accurate volumes were required, surveying by professional surveyors was necessary, which took time and effort. For example, methods such as using a total station or level to measure ground heights on a grid and calculating volumes from pre- and post-construction terrain data using the average cross-section method provide a certain accuracy but are impractical for frequent daily measurements.

A key issue with traditional methods is the lack of real-time capability. Manual surveying takes time from measurement to calculation and result reflection, during which site conditions may change. Additionally, specialized staff are required, and it is difficult in the current environment of labor shortages to always have surveying experts on-site. Thus, traditional earthwork quantity management methods are time-consuming, infrequently executable, and prone to large errors—factors that hinder efficient on-site earthwork management.

Improving efficiency with new technologies

In recent years, advances in ICT and digital tools have dramatically improved the efficiency of earthwork quantity management. A representative technology is photogrammetry using drones (unmanned aerial vehicles). By photographing the entire site from above and creating a 3D model with dedicated software, large areas of earthwork can be measured in a short time. Surveys that used to take a full day can be completed in several tens of minutes to several hours with a drone, and accurate volumes can be calculated from the obtained point-cloud data.

Using terrain models captured by drone makes it possible to visualize soil volumes—for example, by color-coding cut and fill distribution. This allows all site staff to intuitively understand the situation and improves communication.

Similarly, ground-based 3D laser scanners and measurement devices mounted on moving platforms have emerged, enabling efficient measurement of complex terrain and large sites.

Moreover, GPS surveying instruments and wearable devices that utilize high-precision satellite positioning technology called RTK-GNSS are becoming more common. With these tools, workers can obtain terrain data simply by walking the site, enabling immediate volume calculations.

The greatest advantage of these new technologies is that they dramatically increase surveying frequency. Whereas as-built checks used to be done about once a week due to effort, they can now be conducted daily.

Frequent measurements let you track daily earthwork changes and quickly address discrepancies with the plan. Data can be managed and shared in the cloud, enabling real-time information sharing between the site and the office and facilitating rapid decision-making. The introduction of new technologies has evolved on-site earthwork quantity management into a process that is truly “fast, accurate, and easy.”

What is simple surveying with LRTK?

Among the many new technologies, one that is attracting attention for on-site ease of use is simple surveying using LRTK. LRTK (pronounced “L-R-T-K”) is the name of a compact high-precision positioning device that can be attached to a smartphone or tablet. Using this device makes centimeter-level positioning (cm level accuracy (half-inch accuracy)) achievable by anyone via RTK-GNSS (real-time kinematic), which previously required professional equipment. In other words, a smartphone becomes a high-precision civil engineering surveying instrument.

The features of simple surveying with LRTK are its ease and immediacy. Site staff attach the LRTK device to a smartphone and, with a dedicated app, can accurately record the coordinates and elevation of the point where they stand by simply pressing a button. It is also possible to continuously record positions while walking the site or to capture terrain with the smartphone camera and convert it into 3D data. For example, a single person can walk a large land development site, collect ground elevation data at various points, and quickly create a model of the current terrain to calculate its volume (excavation/fill amounts). Thus, LRTK is expected as a means to instantly measure earthwork volumes on-site without specialized surveying equipment or drones.

Benefits of using LRTK

So, what concrete benefits can be obtained by using LRTK on-site? The main points are summarized below.

• High-precision positioning: Because positions and elevations can be measured to the centimeter level, the accuracy of earthwork calculations improves. Small differences in excavation and fill volumes can be captured due to the low error.

• Ease and speed: Operable with a smartphone and capable of one-touch surveying, measurements can be taken on-site whenever needed. Results can be checked immediately, eliminating lengthy post-processing.

• Labor saving and cost reduction: Since one person can complete measurements, labor costs for multiple personnel and outsourcing fees can be reduced. The initial investment is also smaller than dedicated equipment or drones.

• Improved safety: Because it can measure remotely on dangerous slopes or unstable footing, it reduces the risk of workers adopting unsafe postures during surveying. Short measurement times also minimize interference with on-site work.

• Ease of data utilization: Measurement data are saved in digital form, making cloud sharing and importing into CAD software for volume calculation easy. Transferring data into daily reports or records is also smooth.

These benefits make simple surveying with LRTK a powerful tool for on-site earthwork quantity management. Its ease of use has encouraged adoption especially in small- to medium-scale jobs and sites where frequent as-built checks are required. By wisely leveraging the latest technologies, earthwork quantity management, which once required significant time and effort, can be dramatically streamlined.

Conclusion

We hope it is clear that properly implementing “on-site earthwork quantity management” is key to significantly improving construction efficiency and reducing costs. Accurately grasping and controlling earthwork volumes eliminates unnecessary tasks and expenditures and keeps projects running smoothly. By replacing traditional experience-based management with technologies such as drones and LRTK devices, site staff themselves can easily achieve high-precision earthwork management.

Digital technologies will continue to be indispensable for improving productivity on construction sites. Please consider the points introduced in this article and adopt efficient earthwork management methods at your sites. By leveraging new solutions such as simple surveying with LRTK, on-site earthwork quantity management becomes easier than ever, and the quality and outcomes of construction management can be significantly enhanced.

Frequently Asked Questions (FAQ)

Q: What exactly does on-site earthwork quantity management involve? A: It refers to measuring the volume of soil (excavated soil and fill) generated at a construction site and managing construction based on that data. The goal is to grasp daily excavation and backfill volumes, adjust differences from the plan, and appropriately arrange for soil procurement or disposal.

Q: What are the benefits of streamlining earthwork quantity management? A: The biggest benefit is reducing unnecessary work and costs. Efficient earthwork management reduces waiting times for heavy equipment and trucks and allows smooth progress. Preventing surplus soil generation or soil shortages that cause work stoppages also shortens schedules and lowers costs.

Q: What is the difference between drone surveying and LRTK surveying? A: Drone surveying photographs the entire site from above and creates a 3D model, enabling rapid surveying of large areas, but it is affected by weather and flight restrictions. LRTK surveying is performed on the ground by a person walking and is better suited to smaller areas; it is highly mobile and can be conducted at any time. The two methods are chosen according to site scale and purpose, and using both can balance accuracy and efficiency.

Q: Can beginners use LRTK? A: Yes. LRTK pairs with an intuitive smartphone app and is designed to be usable without specialized surveying knowledge. The basic procedure is to start the app and press a button at the point you want to measure, so site staff can master it with short training.

Q: How accurate is surveying with LRTK? A: LRTK uses RTK-GNSS technology and achieves errors on the order of several centimeters (cm level accuracy (half-inch accuracy)), which is very high precision. However, some error may occur depending on satellite signal conditions and the surrounding environment. Even so, it satisfies the accuracy required for earthwork quantity management in civil engineering.

Q: Is the cost of introducing LRTK high? A: Compared to traditional large surveying equipment or commercial drones, the introduction cost of LRTK is lower. Since it combines a smartphone with a small device, the initial investment is small and operating costs are mainly labor. Specific prices vary by model and plan, but the cost-effectiveness is high and payback often occurs in a relatively short period.

Q: Is it worthwhile to introduce LRTK on small sites? A: Yes, it is worthwhile. Smaller projects, where it is difficult to assign a dedicated surveyor, particularly benefit from the ease of surveying with LRTK. Even on small crews, accurately knowing earthwork volumes prevents over-ordering equipment or wasting materials. Because it can be introduced at low cost, small-scale projects can expect returns that justify the investment.

Q: How are measured earthwork data utilized? A: Measured earthwork data are used in various aspects of construction management. For example, data can be included in daily progress reports shared with clients, used for as-built quantity management to settle partial payments, or serve as a basis for design changes or plan revisions if discrepancies are large. Accumulated data can be analyzed to improve efficiency and accuracy in future projects.

Q: What methods exist for calculating earthwork volumes? A: Broadly, there are traditional manual methods and methods using digital technology. Manual methods typically involve measuring terrain cross-sections with surveying instruments and calculating volumes using average cross-section methods; simple estimates from dump truck trips have also been used on sites. Digital methods include photogrammetry from drone aerial photography to compute volumes from 3D models and direct volume calculation from point-cloud data obtained by LRTK devices or laser scanners. The latter offers high accuracy and efficiency and is becoming mainstream. It is important to choose the optimal method according to site scale and purpose.