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Geotechnical Risks in Yumeshima Development

By | Expo Osaka 2025

The URL for the original Japanese version of the paper:


I am compelled to share profound insights from Emeritus Professor Yoshiaki Tainoshou of Kobe University regarding the geotechnical risks associated with the development of Yumeshima, the proposed site for Expo 2025.

6. Subsidence due to Consolidation of Alluvial and Diluvial Clay Layers

The professor articulates that clay, inherently soft and high in water content, tends to flatten and shrink due to the expulsion of interstitial water under the load of thick landfill layers, resulting in consolidation subsidence. Once subsided, these clay layers do not revert to their original state.

Consequently, only lightweight structures can be erected atop these layers. The City of Osaka (2017) anticipates a subsidence of over 10 cm, proposing elevated landfill as a countermeasure. However, as time progresses, further subsidence is anticipated to become a significant issue.

The Kansai International Airport has faced considerable challenges, not only with the alluvial clay layers but also with older diluvial clay layers that were not initially anticipated, resulting in subsidence exceeding predictions.

The City of Osaka’s “Osaka Port Landfill Project” (2014) acknowledges the issue of landfill layer consolidation subsidence. Still, the underlying alluvial and diluvial clay layers present a more substantial concern due to their extensive consolidation subsidence.

Located immediately below the landfill layers (see Figure 3), alluvial clay exhibits standard penetration test N-values between 2 to 5 (with values below 10 indicating softness), indicating a soft layer similar to paddy fields, prone to consolidation subsidence under the weight of the landfill.

Furthermore, with the alluvial clay layer being over 20 meters thick, there is a grave concern for subsidence beyond initial projections.

While the sand drain method has been considered to expedite consolidation subsidence (City of Osaka, 2017), Kansai International Airport experienced greater-than-expected subsidence despite this method.

Beneath the alluvial clay layer lies an older diluvial clay layer (Ma12) (see Figure 3), exceeding 10 meters in thickness with N-values of about 4 to 5, denoting softness. The lack of anticipation for the consolidation subsidence of this layer was contributory to the predicament.

For the Yumeshima Expo and IR project site, unmitigated consolidation subsidence could result in residual ground subsidence exceeding 50 cm (City of Osaka, 2014), far surpassing the allowable residual subsidence.

Moreover, as the landfill layer also undergoes consolidation subsidence, many areas are expected to exceed the 50 cm threshold, jeopardizing the maintenance of the planned ground level.

This consolidation subsidence could lead to a disconnect between buildings and ground, and coastal areas may see dikes subside, potentially failing to serve their intended purpose, arguably making it the most significant concern for the Expo and IR project development.

Additionally, landfill operations are slated to conclude a year before the Expo (City of Osaka 2017), potentially hindering adequate compaction of landfill materials.

Potential countermeasures such as sand compaction piles, piling, ground improvement (solidification, etc.), and deep mixing methods are under consideration, but no concrete plans have been presented.

Moreover, the assumption that consolidation subsidence occurs uniformly is not guaranteed, and long-term predictions over a decade are extremely challenging to ascertain through laboratory experiments due to parameter limitations.

In essence, the extent of actual subsidence remains uncertain until the landfill is completed, illustrating that the issue of consolidation subsidence remains unresolved to this day.

#GeotechnicalEngineering #YumeshimaDevelopment #Expo2025 #InfrastructureRisk #LandfillSubsidence #SoilConsolidation #CivilEngineering #UrbanDevelopment #EnvironmentalRisk #SustainableConstruction #EngineeringResearch #KobeUniversity

Pioneering Housing Solutions for Expo 2025 Pavilion Builders

By | 未分類

This November we anticipate finalizing a rental agreement for a condominium to accommodate the housing needs of international professionals working on the construction of pavilions for Expo 2025.

Our recent experiences have highlighted the substantial barriers that foreign nationals face when securing rental properties in Japan, from language discrepancies to complex legal understandings and differing real estate practices.

We are navigating these challenges with compassion and dedication, ensuring that contracts meet the rigorous standards required by international governments, including translating documents from Japanese into English and other languages.

We’re committed to not just facilitating a process but ensuring a smooth transition into a new home for those shaping the future of Expo 2025.

#Expo2025 #GlobalHousing #RealEstateJapan #HousingSolutions #InternationalProfessionals #LegalTranslation #CulturalIntegration #PropertyLeasing #InnovativeHousing #ExpatLifeJapan #CrossCulturalCollaboration #RealEstateChallenges

Addressing the Unseen Challenges of Expo 2025 Osaka

By | 未分類

Yesterday, I had the opportunity to engage in a conversation with a diplomat from a consulate in Osaka. As November beckons, they are set to negotiate contracts with Japanese construction firms for Expo 2025. However, they shared a pressing concern: a shortage of construction workers is looming as a potential hurdle.

The diplomat’s revelation was telling—it seems the intricacies and challenges discussed among Japan’s construction experts are not fully communicated to foreign pavilion stakeholders. There’s an unsettling silence on the cost estimates for liquefaction and ground improvement measures for Yumeshima’s terrain, with no clear insights offered to date.

Before the arrival of international visitors, it is likely that prolonged negotiations have occurred between Osaka’s dominant political force, the Osaka Ishin no Kai, and Japanese construction firms. While politics push for the realization of the Expo and a casino on Yumeshima, technical difficulties suggest a stalemate, with the two sides on parallel tracks.

In response, it appears that the Osaka Ishin no Kai sought the intervention of the central government, leading to political deals between just the two parties.

In striving to maintain political dominance, we witness a divergence: the insistence on political agendas overshadows the realities of technically challenging construction projects. It’s crucial for all involved stakeholders to be apprised of these underlying issues to ensure the success and safety of the upcoming world event.

Let’s bring these discussions to the forefront to facilitate a successful and sustainable Expo 2025.

#Expo2025 #OsakaExpo #ConstructionChallenges #GlobalDiplomacy #Infrastructure #JapanesePolitics #TechnicalFeasibility #InternationalCooperation #SustainableDevelopment #YumeshimaProject

Innovative Thinking for Expo 2025 Osaka Amid Rising Costs and Geotechnical Challenges

By | 未分類

Recent reports have indicated that the construction costs for Expo 2025 Osaka have surged by 1.8 times, yet this figure reportedly excludes the substantial costs for liquefaction and ground improvement measures for the Yumeshima site. Remarkably, there seems to be no available estimates for these significant geotechnical interventions.

As we prepare to welcome visitors from around the world, our hope is to offer them a delightful experience in Japan.

For example The grounds of Osaka Castle are likely among the best in Osaka, chosen by Toyotomi Hideyoshi 400 years ago after meticulous evaluation. It’s not just the optimal transportation access or the safety of the land that makes it special, but also its appeal to both locals and tourists.

With construction already underway in Yumeshima, perhaps we could entertain the idea of a hybrid approach to the Expo. Utilizing Osaka Castle Park or other suitable sites could alleviate land shortages and might even reduce ticket prices, making the event more accessible and enticing to a broader audience.

#Expo2025 #Osaka #ConstructionCosts #GeotechnicalEngineering #Liquefaction #GroundImprovement #SustainableDevelopment #CommunityEngagement #TourismJapan #CulturalEvents #OsakaCastlePark #Accessibility #Affordability #GlobalExpo #InfrastructureInnovation #EventPlanning #PublicInterest

Understanding the Ground Reality: Insights from Expo 2025 Pavilion Construction Guidelines

By | 未分類

Recently, I came across an excerpt from the “Pavilion Type A (Site Handover Method) Design Guidelines,” distributed to foreign pavilion construction teams by the organizers of Expo 2025. The document includes detailed cross-sectional diagrams addressing the geotechnical issues of Yumeshima.

The guidelines openly acknowledge that the ground in Yumeshima is prone to subsidence. Two mitigation strategies are mentioned, but their feasibility appears questionable. This level of detail suggests that the ground conditions of Yumeshima have been well understood among experts for some time.

On the other hand, In the last few days, the Governor of Osaka Prefecture and the Minister for the Expo held press conferences broadcasted on Japanese TV. They addressed the nation about the Expo’s construction costs, which have soared to 1.8 times the initial budget. The explanations provided were confined to two factors:

1. The surging prices of building materials.
2. The escalating wages of construction workers.

Interestingly, there was a notable absence of questions from reporters and subsequent answers during the lengthy press conferences. Moreover, there was no mention of the challenges pertaining to Yumeshima’s ground conditions and logistics.

#Expo2025 #PavilionConstruction #GeotechnicalEngineering #Yumeshima #GroundSubsidence #ConstructionChallenges #EngineeringSolutions #SustainableDesign #InfrastructureDevelopment #UrbanPlanning #ExpoOsaka2025 #InternationalEventPlanning #GlobalExhibitionStandards #ConstructionGuidelines #EngineeringInsights

Navigating Unique Challenges at Osaka Expo 2025: The Floating Bridge to Yumeshima

By | 未分類

As we eagerly anticipate the upcoming Osaka Expo 2025, there’s a unique logistical challenge that has caught my attention—the single bridge that connects us to the Yumeshima Expo site. 🌉

To add another layer of complexity, this bridge is retractable to allow for large ships to pass through. Essentially, it’s floating on the water, meaning it can only handle so much weight before it becomes unstable. 🚢

#Expo2025 #OsakaExpo #EngineeringMarvels #FloatingBridge #LogisticalChallenges #TrafficPlanning #CulturalExchange #InnovativeSolutions #GlobalGathering #Yumeshima

Debunking the Myths of Floating Foundations: A Deep Dive into Expo 2025 Pavilion Construction

By | 未分類

I decided to explore the ‘floating foundations’ in greater detail. The photo attached below provides an excerpt from the official Expo Pavilion Construction Guidelines, which state:

1. Excavate the part of the ground that will serve as the foundation for the building. Let’s call the weight of the excavated soil ‘W.’
2. Install the Pavilion in the excavated cavity. The weight of the Pavilion is denoted as ‘P.’
3. Make sure that ‘P’ weighs less than ‘W,’ implying that if you construct a building lighter than the soil you’ve removed, it won’t sink.

However, adhering to these guidelines may result in ground subsidence. The reason is straightforward: there is no ‘buoyancy’ at play. Reports indicate that the Yumeshima area features a 3-meter mound of soil atop a soft clay layer. For buoyancy to function effectively—much like how a ship stays afloat—the object must reach a depth where buoyancy comes into effect.

Interestingly, the Expo guidelines explicitly mention: ‘Do not dig deeper than 2.5 meters.’ This means the Pavilion won’t extend into the clay layer that would allow for buoyancy.

In conclusion, the Pavilion is destined to sink if built according to these guidelines. The assumption that ‘if P is less than W, the ground won’t sink’ is fundamentally flawed.

#Expo2025 #ConstructionChallenges #FloatingFoundations #PavilionConstruction #GroundSubsidence #EngineeringDilemmas

Expo 2025: A Look Back at Transformative Experiences and Forward to New Possibilities

By | 未分類

Expo 2025 is around the corner, and it promises to be a tremendous occasion for international cultural exchange, with people from over 150 countries descending on Osaka for a span of six months. 🌏

One of my company’s wonderful female staff members has a nostalgic connection to the 1970 Osaka Expo. As a young woman, she took a part-time job at the Canadian Pavilion. She was so well-regarded by the Pavilion Director that he invited her to visit Canada, a trip she fondly remembers to this day. 🇨🇦🇯🇵

She’s now over 70, a grandmother, and still speaks with excitement about her youth and the indelible memories formed during that 1970 Expo. The experience influenced her profoundly, encouraging her to learn English, meet her future husband, who worked for Singapore Airlines, and even live abroad. ✈️

Fast forward to 2023, and she’s bringing that international flair to her work as a housekeeper for diplomats at the Osaka Consulate in my company. At 70+, she still comes alive when providing services to international clients.

As we look forward to Expo 2025, I wish for nothing less than a similarly transformative and enriching experience for all those who will participate.

#Expo2025 #OsakaExpo #CulturalExchange #LifeChangingMoments #InspirationalStories #CanadaPavilion #JapanCanadaFriendship #InternationalCareerPaths #DiplomaticRelations #EnrichingExperiences #CommunityBuilding

Registration for the Supplier List (Service Apartment) for Official Participants

By | 未分類

In the spirit of warmth and respect, we would like to address an important aspect of Expo 2025. The construction and operation of pavilions from various countries will involve the hard work of many international staff members, who will require suitable living accommodations. As such, there is a considerable demand for furnished service apartments.

We aim to provide you with a comprehensive understanding of the real estate market in Osaka, with a specific focus on furnished housing. We will also delve into how the market is responding to the unique needs of international residents. It’s a fascinating intersection of culture, comfort, and practicality, and we are excited to explore this topic with you.

Please join us as we navigate this dynamic landscape, in anticipation of the truly international gathering that is Expo 2025. We are committed to fostering a sense of community and ensuring that all those who join us from abroad feel welcomed and well-accommodated.

Our Vision Statement

By | Vision

Dear valued customers, partners, and team members,

We are delighted to share a pivotal milestone in the journey of Dios Co., Ltd. – the creation of our Vision Statement.

Our Vision Statement reads:

“Dios aims to provide a warm, compassionate heart to all our customers and stakeholders through meticulous services, powered by our rich experience and expertise.”

In business, while it’s essential to provide products and services, we aim to be a company that offers something even more valuable – a ‘Heart.’ The term ‘Heart’ might seem abstract, and therefore, it must be embodied through specific products, services, and actions. However, we believe our focus should primarily be on the ‘Heart,’ rather than merely on goods or services. It is imperative that all our customers can feel our warm, caring heart through our products and services.

As Dios Co., Ltd. approaches its 30th term, I find myself reflecting on the three decades since I founded the company. In doing so, I have come to realize that some aspects of my past management philosophy were misguided.

In the past, we have provided excellent service to those who had a contract with our company while ignoring those who had chosen to work with other companies. I had believed that this approach was a natural part of business. But now, I have realized that this way of thinking must be eliminated from our future management policies.

Moving forward, Dios Co., Ltd. must offer a warm, compassionate heart to all our customers, all our employees, and all stakeholders, regardless of their contractual relationship with us. This is our Core Value.

As we take this new direction, we deeply appreciate your continued support and look forward to growing together in warmth and compassion.

With warmth,

Masahiro Fukai
Dios Co.,Ltd