Utilization of BIM/CIM Models in the Disaster Response on the Noto Peninsula

１.Introduction

 In the construction field, the use of three-dimensional models and related technologies involving BIM/CIM (Building/Construction Information Modeling, Management) is actively promoted, with the aim of improving the productivity of architectural and civil engineering projects and advancing management systems. The Landslide Research Team at PWRI is working on the development and promotion of a BIM/CIM model for landslide disaster response to ensure the rapid application of BIM/CIM even during disasters.

 This model is created by generating 3D color point cloud data (which represents objects and terrain as a collection of points) from UAV-captured imagery of disaster sites and combining it with map data. This allows the virtual reproduction of an affected area on a computer screen, enabling users to freely change viewing angles to assess the situation at the disaster site.

２.Case Study of BIM/CIM Model Utilization in the Landslide Disaster on the Noto Peninsula

 Numerous landslides occurred as a result of the Noto Peninsula Earthquake on Jan. 1, 2024 and the heavy rainfall in Oku-Noto from Sep. 21 to 23, 2024. As part of its technical support for the Noto Reconstruction Office, which performs on-site recovery and reconstruction efforts, the Landslide Research Team created and shared a BIM/CIM model. At the Noto Reconstruction Office, the BIM/CIM model?shown in Figure 1 was utilized for on-site surveys and the planning of countermeasures. During local briefings, the ability to freely change the viewpoint within the BIM/CIM model made it possible to quickly check the disaster site from the desired angles, which was reported to be extremely useful. In addition, since the BIM/CIM model has been in use since the earthquake, it was possible to quickly assess the extent of damage caused by the Oku-Noto heavy rainfall by comparing pre- and post-rainfall models, as shown in Figure 2. In the past, it had been necessary to obtain photos taken from the same angle, a time-consuming process, to confirm changes in the conditions, but utilization of the BIM/CIM model made it possible to conduct faster comparisons and analyses before and after heavy rainfall, significantly reducing the time required.

 The Landslide Research Team will continue to investigate and analyze the practical application of the BIM/CIM model in such a case. By identifying its benefits and challenges, the team aims to further promote the use of BIM/CIM models to accelerate disaster response efforts.

(Contact : Landslide Research Team)

A Study on Predicting Soil Erosion at Agricultural Land

　

 Farmlands are vital for sustainable food production. Although various factors are associated with the degradation of farm productivity, soil erosion (Photo 1) is globally recognized as the most severe. According to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report, global warming is intensifying changes in our climate system. Since the 1950s, most land areas have seen the increased frequency and intensity of heavy rainfall. As heavy rainfall accelerates soil erosion, future increases in intense precipitation due to climate change could significantly worsen soil erosion on sloped farmlands.

 To counter soil erosion, measures include switching to erosion-resistant crops, improving the soil, land development, and implementing better land and field management. To implement soil erosion countermeasures that can also address future increases in precipitation, it is important to predict future soil erosion volumes. Therefore, an analysis of soil erosion was conducted using an erosion prediction model called the Universal Soil Loss Equation (USLE) and projected precipitation data. The analysis compared two timeframes: the present (1990s) and the future (a period when the global average air temperature has risen approximately 2°C from the present temperature), targeting all farmland across Hokkaido.

 The analysis results show that in the “present” scenario without soil erosion countermeasures (Figure 1), many fields in regions such as Southern Hokkaido, Kamikawa, and Okhotsk?where steeply sloped upland fields are widespread?exceed a soil erosion of 10 t・ha-1・year-1. This value of 10 t・ha-1・year-1 is the threshold that must not be exceeded in order to maintain farmland productivity. Looking at the ratio of future to present soil erosion amounts (Figure 2), no regions were found where erosion decreased. The ratios ranged from a minimum of 1.04 to a maximum of 1.54, with an average of 1.26. Regions with high increases (1.3 times or more) included the Sea of Japan side from northern Ishikari to Soya, the Oshima Peninsula, eastern Iburi to western Hidaka, and northeastern Tokachi.

 At farmlands where the amount of soil erosion exceeds the allowable limit, conservation practices such as contour farming must be implemented. If erosion still exceeds the allowable threshold, civil engineering measures such as slope improvement through land development or land readjustment will be necessary. As a future research direction, we plan to examine the impact of soil erosion on the water environment in agricultural watersheds and to explore appropriate countermeasures to such erosion.

(Contact : Irrigation and Drainage Facilities Research Team, CERI)

Landscape Design for the Central Islands of Roundabouts

　

 Arguably the most famous roundabout in the world is the Place Charles de Gaulle in Paris, centered around the Arc de Triomphe (Photo 1). Despite the absence of traffic signals, large volumes of vehicles flow smoothly through this intersection, and more importantly, it has become an iconic location symbolizing Paris itself. In countries where roundabouts are more widely used, it is not uncommon to encounter beautifully designed ones. Focusing on the potential of roundabouts not only to effectively control traffic but also to serve as landmarks for communities, the Scenic Landscape Research Team has been conducting driving experiments to develop landscape design proposals for central islands that offer both aesthetic and safety benefits.

 An experiment was conducted at the Tomakomai Winter Test Track of the Civil Engineering Research Institute for Cold Region in Tomakomai City, Hokkaido. The test involved a roundabout with four branches and a central island diameter of 12 meters. Multiple test drive sessions were conducted, each involving 12 vehicles driving simultaneously through the roundabout for 6 minutes. As shown in Photo 2, even in a simple configuration with no traffic lights and minimal signage, smooth driving was achieved when drivers were aware of the driving rules. This was confirmed through GPS data and driving footage recorded by drones.

 One test participant wore an eye-tracking recorder to monitor gaze behavior when the vehicle entered the circulatory roadway. According to a heatmap of gaze behavior (Figure 1), when there was no mound, attention was dispersed not only to the right but also to the front and left. However, when a mound was installed, the driver’s gaze was more focused on the right?where vehicles are expected to come from.

 In addition to this, an analysis of the distribution of gaze areas and the survey results on driver impressions suggested that installing a mound contributes to improvements in both driver’s perception of the ease of navigating the intersection and driving safety.

 Our team will continue to conduct experiments and analyses with various patterns and will share the research findings in order to support the landscape design of roundabouts that can become iconic scenery of communities.

(Contact : Scenic Landscape Research Team, CERI)