Tsunami evacuation shelter, a structure integrated with and used as part of a levee.

Abstract

Construction of tsunami evacuation shelters is not progressing. A massive tsunami from the Nankai Trough is predicted to strike in the middle of winter, at midnight, resulting in 320,000 deaths and 1 million casualties. Ten years have passed since the Cabinet Office's announcement, and it is presumed that construction of crematoriums is progressing. In some areas, a 10-meter tsunami is expected to strike in 5 minutes, leaving no time to evacuate. The challenge lies in how to save as many lives as possible during the uninterrupted 24-hour daily lives of local residents. [Solution] The area has a seawall, making it as if there's a shelter right in front of you, allowing for quick evacuation with your family. 24 hours of peace of mind. Preparedness prevents disaster. What a blessing it is to be able to live each day in safety and security.

Description

Technical Field

[0001] The present invention relates to a tsunami shelter that, in a coastal area where a tsunami strikes suddenly, avoids the direct impact of the tsunami wave force by integrating it with the back of an existing levee, can maintain the amount of survival air inside even when underwater, and allows for early evacuation due to its proximity to houses.

Background Art

[0002] It is predicted that 320,000 people will die in the tsunami associated with the upcoming large earthquake in the Nankai Trough. Ten years have passed since the Cabinet Office announced its prediction in 2011, and people are waiting for the announcement of the results as to how many people have been saved. Building only 10-meter-high flood levees would result in a long coastline extension and bankrupt the national finances. Also, the sea would be out of sight, and there would be strong opposition from the residents. However, it is not the case that nothing needs to be done. Relocating to high ground would require huge costs and labor. Building tsunami towers would also cost a fortune. With a tsunami approaching with a height of 10 meters in 5 minutes, slogans like "Can we escape in time?" and evacuation training on TV to gather residents and evacuate them to high places are completely off the mark. If existing levees are utilized, the evacuation of residents near the coast will be faster, and more people will be saved. When searched on the patent information platform, there was 1 case for "flood levee shelter" and 9 cases for "levee shelter". Among them, 4 cases were relevant. Patent Document 1 is about building a new high levee that does not allow overtopping with embankment, and a shelter is simply provided inside the levee in a cave structure, and the embankment will collapse in case of flooding. Patent Documents 2 and 3 are also new constructions with excessive scale and cost, and the space is large, and there is a possibility of floating by buoyancy. Being fragmented like a three-building structure does not have the original role of the levee. Patent Document 4 is even larger in scale, forming an apartment, school, hotel, etc. inside the levee, and the cost is also enormous and can be said to be out of the question. This application is different in that it utilizes existing low-height levees all over the country and integrates a shelter behind them, which is inexpensive in terms of cost and can save many residents along the levee by making use of the long levee extension.

Prior Art Documents

Patent Documents

[0003] [Patent Document 1] Japanese Patent Publication No. 2006-225996 [Patent Document 2] Japanese Patent Publication No. 2024-040608 [Patent Document 3] Japanese Patent Application No. 2016-164344 [Patent Document 4] Japanese Patent Publication No. 04-309611

[0004] [Non-Patent Document 1] Nakagawa Kogyosho Paper [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The challenge and imperative is to save 320,000 predicted deaths and 1 million victims from the tsunami. 320,000 people live along the coast where the tsunami will strike. Therefore, the most natural and effective approach is to utilize the seawalls that our predecessors built and deployed along the coastlines throughout the country. These seawalls are located along the coast, naturally in coastal areas prone to tsunamis, which means they are in areas affected by tsunamis, and most of the victims live there and are most affected. They are located on the coast, close to the residents, and familiar. They surround coastal areas and have long extensions. They are heavy and robust against wave forces. The only problem is that they are not tall enough. Dismissing them as useless simply because they are not tall enough is too simplistic. They are only lacking in height that exceeds the required height. However, making them 10-meter high seawalls is obviously unrealistic. Therefore, we considered how to compensate for this height deficiency through functionality. In other words, the idea was that by integrating a tsunami evacuation shelter that could retain air and survive even when submerged with a seawall into a single, multi-purpose structure, the weaknesses of the seawall could be compensated for, reviving the seawall, which had been considered an ineffective structure against high tsunamis, and offering a glimmer of hope for saving 320,000 people.

[0006] The Cabinet Office predicts that the tsunami will kill 320,000 people, but we await the announcement of the results of the measures taken over the past decade to determine how many tens of thousands of lives have been saved. I don't think we'll end up with a repeat of the Fukushima Daiichi nuclear disaster, but is this just a matter of praying to God or relying on a magic spell, believing that nothing will be found out, that it won't come, or that it simply won't happen until the tsunami hits? The former president of TEPCO was found guilty in court for failing to take measures despite being able to foresee the tsunami. To avoid being indicted and becoming a defendant, those in charge of the seawalls need to raise the seawalls to more than 10 meters if a 10-meter tsunami is foreseeable. However, it feels like no progress has been made. If measures are not taken despite being foreseeable, it is easy to imagine that the heads of the national and local governments in charge of the seawalls will also be found guilty, given the conviction of the TEPCO president. I'm tired of hearing the same old excuse that it was unforeseen. Residents' lives remain at risk. Doesn't this resemble Israel's disregard for the lives of Gaza Strip residents, and the current situation where lives are left unattended despite the risk of death? Besides raising the seawalls, other proposed tsunami countermeasures include tsunami towers and relocation to higher ground, but especially with tsunami towers, how many of the 320,000 people will actually be able to reach them during the midnight hours of winter when the greatest damage is predicted, while everyone is fast asleep? The cost-effectiveness is extremely low, arguably zero. The greatest damage is predicted to occur in the middle of winter, yet the countermeasures do not take the worst-case scenario into account. These measures also leave behind the elderly, pregnant women, and wheelchair users who will not be able to reach the towers in the middle of winter, and the budget allocation using taxpayers' money is extremely unfair. The entrance to the towers is locked with a fence to prevent intruders. The cost of permanent and overnight caretakers will be high, and even if there is an elevator, emergency power, statutory inspection costs, and maintenance costs will be insufficient. A tsunami tower 35 meters high might be acceptable, but anything lower may not save anyone. To accommodate unexpected increases in elevation, the construction costs of the towers will double. If the height is insufficient after repeated revisions of forecasts, the structure will become dangerous and useless. This is a blatant waste of taxpayers' money. There is absolutely no guarantee of safety at any given height. If someone dies, it's simply because the height was unexpected. Moreover, the townscape will be easily swept away and destroyed. At the very least, residents should not be put at risk of losing their lives. This does not contribute to strengthening the nation's infrastructure. We must learn from past examples, especially the Great East Japan Earthquake. In the case of relocating to higher ground, only the town hall is moved, not the entire town. Can we really abandon the vibrancy of the town and its residents?The image of a father desperately searching for his 15-year-old daughter during the recent Noto flood was heartbreaking. He was relieved when she was found by chance on a fishing boat 10 days later, but it showed just how tragic it is when a family is separated. Even if town hall employees survive, tragedy awaits if their families and many ordinary residents remain missing. They spend the remaining 16 hours of their day outside of working hours on the plains. What are they protecting? Even if there are important documents, digitalization eliminates the need for warehouses. Even if there are resident registers, the residents are no longer alive. The number of people, costs, and duration of the search are limitless. Relocation to higher ground needs to be reconsidered, or if relocation is necessary, taxpayers should be moved first, and measures to save the lives of residents on the plains below must be implemented simultaneously.

[0007] It is understandable that constructing high seawalls to be applicable to every corner of the country would be prohibitively expensive. Therefore, we consider whether we can utilize existing seawalls that have been installed along coastlines throughout the country by our predecessors. These seawalls have long-distance continuity along the coastline, are sturdy and durable due to the hardness of concrete. They are heavy and do not float, and naturally have sufficient resistance to wave forces. However, their biggest weakness is that they are not tall enough to withstand the height of a massive tsunami. Tsunamis overflow far above the seawalls, so if left as is, the entire town would be swallowed up by the overflow or collapse of the seawall. Clearly, low seawalls cannot save the lives of the town's inhabitants. In particular, Rikuzentakata City, which is like a narrow inlet, suffered a tragic fate, with its entire population being swept away. Therefore, we consider that even if submerged by a tsunami, people can at least survive if they can retain air. Compared to the Great East Japan Earthquake and Tsunami, the Nankai Trough mega-tsunami is predicted to have six waves repeating every six hours, and the submersion time is limited, with the tide quickly receding and air being supplied. The levees have sufficient weight and rigidity. Only their height is lacking. On the other hand, shelters containing air are useful for human survival. First, by combining the resistance of the shelter, which is hidden behind and supported by the weight and rigidity of the levees, the effects of large wave forces can be avoided as a whole. We can consider shelters that are integrated with long extensions of levees. There is a great advantage in that people can quickly escape to the nearest shelter in their living area, and low levees, levees that are weak against overflow, and old levees can be reinforced from breach. If even one section of the levees breaches, it is all over, no matter how heavy and rigid they are. It can accommodate as many people as there are who do not want to leave town. The levees in front of them are familiar in daily life, and evacuation is quick. Above all, the cost is low, it can be applied to any region throughout the country, and if a region that wants to participate steps forward, it is relatively easy to secure funding through national resilience measures, saving many people and allowing them to live their days in peace and security without anxiety. What a blessing that would be. In particular, we must not take the lives of young people, especially elementary school students with a bright future. News of the Okawa Elementary School tsunami in the Great East Japan Earthquake spread across the world in an instant. The teachers are also suffering through lawsuits. This suffering must never be repeated. Even if the townscape is destroyed, it is only temporary, and as long as lives are saved, life can be restored. The more people who survive, the greater the expectation of a new town being rebuilt. For example, consolidating land and replacing it with tall, sturdy buildings is also possible in the opposite sense. The town will be reborn as a new town that is resilient to disasters.This will ensure the safety of people's lives and community living. Even levee managers will feel relieved and motivated if they know that even weak and low levees can contribute to saving many lives. The usual excuse of "it was unexpected" will no longer be accepted. How noble it is to be of service to people and to contribute to society. It is no exaggeration to say that this provides the optimal solution for strengthening national resilience.

[0008] Therefore, realizing tsunami shelters that save many lives, are readily available and inexpensive, and that ensure the safety of people's lives and communities throughout 24 hours, including the safety of residents, since it is clear that most people will be at home during the night when the greatest damage occurs, can be said to be a way to help solve the problem. It is impossible to know when, where, or at what time a tsunami will strike. In areas where tsunami evacuation is difficult, it is advocated to "get away with it," but it is obvious that people will survive if they get away with it, and most people cannot get away with it. Do not be deceived. In particular, vulnerable people who are unable to escape disasters, such as the elderly, pregnant women, and wheelchair users, cannot get away with it. It is too cruel for the government to say that it is the person's responsibility and that they did not know. On the other hand, looking at daily life, cars are indispensable for work, shopping, and going to the hospital, especially in rural areas. It would be good if one could escape far away by car, but if people concentrate on main roads, they will get caught in traffic jams. Although it is impossible to know when a tsunami will strike, the Cabinet Office has announced that the tsunami accompanying the upcoming Nankai Trough mega-earthquake is predicted to have a maximum tsunami height of 34.4m, 320,000 deaths, and 1 million casualties. Along the coast, a tsunami 10 meters high is projected to strike in 2 to 5 minutes, with the greatest damage occurring in the dead of winter, in the middle of the night. Ten years have passed since the initial warning; how many tens of thousands of people have been saved? Recently, footage of the massive tsunami from the Great Kanto Earthquake has been discovered. The fundamental reason the problem remains unresolved is that while there are many warnings, the faces of those truly responsible for saving countless lives are not visible. There is endless discussion, consideration, and research, and people are self-satisfied, feeling as if they are doing their job. The job is to produce results. This is what is known as the Odawara Council. Nevertheless, evacuation centers serve as temporary mortuaries for 320,000 people. It is now necessary to verify and disclose whether there are enough shelters for the number of people. The announcement of progress in land acquisition and construction of crematoriums is also awaited. Cremation is impossible without identification certificates. Administrative procedures such as DNA testing, dental matching, and fingerprint matching can take 1 to 3 years, and the construction of cold storage facilities to prevent decomposition is urgently needed. In times of emergency and major disasters like this, the government should actively promote the effectiveness of My Number cards with photographs for identifying individuals. I want to believe they don't intend to leave it like this forever. Do they lack wisdom? If they deal with it quickly, people can live each day with more peace of mind. The responsibility for neglecting it for 10 years is not light. But since there is no one in charge, they can't really say anything.The tsunami from the Great East Japan Earthquake struck as early as 15 minutes after the earthquake, and often an hour later, giving people time to evacuate. However, tsunamis from the Nankai Trough mega-earthquake and the Sea of ​​Japan mega-earthquake will have a steeper rise in their waveforms, making this impossible. A sudden strike like the one off Okushiri Island tsunami, which occurred in just one minute, leaves no time to evacuate or even have a buffer. We should have learned this from actual tsunamis. Six waves will repeatedly strike over a period of six hours. Since we don't know when it will strike during the day, we must be prepared 24 hours a day. However, despite the unpredictable and cruel nature of tsunamis, they always follow a natural order and rule: they strike after the shaking of an earthquake, and they have a sense of justice that warns us in advance with receding tides and roaring sounds. We must find a way to cope with this and respond. If the tsunami strikes five minutes later, assuming the shaking subsides two or three minutes after the earthquake, then by subtraction, there may or may not be three or two minutes of time to escape. Spending time and budget on accurate earthquake analysis, becoming complacent with the perceived success of the job, and then having evacuation warning systems issued at the fastest possible time—three minutes after an earthquake—is often too late. Even a primary school student could understand this. It should be understood that it is of no use to residents on the life-or-death boundary in coastal areas. A loud siren or announcement, even if it's just a blaring siren, would suffice for the occurrence of the largest possible earthquake, but like the missile warning sirens issued seconds later in Israel and Palestine, it should be automatically transmitted instantly. The devastation caused by tsunamis is orders of magnitude greater than that of missile strikes. Those responsible for creating systems that are supposed to be accurate are responsible for their accuracy, but they are not responsible for whether they will actually save lives. Even after the tsunami warning following the Tonga volcanic eruption, most people reported not evacuating, even though a ship capsized in Kochi. Unless a loud siren sounds immediately, it won't be enough to put people in a hurry. People must constantly be prepared and trained to make their own judgments and take self-defense measures based on the magnitude of the earthquake's shaking. One might say that you won't have any regrets if you die, but to avoid regrets, you need to decide on at least one thing you would do in that situation. It seems that unless there's a roaring sound, an earthquake, and towering waves right in front of you, the switch to avoid danger doesn't flip and you don't feel like it's happening to you. In the cold winter, resignation comes first and your thinking stops. You don't have time to change your pajamas while bathing or sleeping. Just putting shoes on a fussy child takes five minutes in no time. In any case, there's no time to think.You have to grab your disaster preparedness backpack and run out. I don't know if that's their true feeling, but it's true that many people have given up. Of course, you have to break free from the bias that you'll be fine and everything will be alright. Instant, unconditional reflexes and repetitive action training are necessary. Housing conditions also play a role. In ordinary houses, they will be blown to smithereens and won't stand a chance. In sturdy apartment buildings, it might seem that you'll be safe on a higher floor, but there's no guarantee that the tsunami height will be less than the predicted height. People tend to think that vertical evacuation or evacuation to the roof will save them, but in the end, buildings lower than the tsunami height, and their rooftops, will be swallowed whole by the tsunami. Imagine the terror and merciless cruelty of the approaching tsunami. There was a trial after someone died while evacuating to the roof of a local bank. What is the government thinking? Is an evacuation plan that simply says "get away at all costs" really appropriate? Assuming you're at home for half of the 24 hours, evacuation is not easy in areas without tall, sturdy buildings nearby. Even so, one must anticipate danger 24 hours a day, including at home, at work, and at school, and even in the dead of winter. In any case, setting up evacuation shelters near residents is a way to solve the problem, including providing peace of mind. On the other hand, for those who cannot wait for a tsunami that may strike tomorrow, and for those who prefer self-reliance, setting up their own home or personal shelters would allow for instantaneous evacuation and could also be a contributing factor to the solution. If a budget of 200,000 to 1,000,000 yen per person can save a life, it is worth considering. More importantly, you can't take your money to the grave. It's a once-in-a-lifetime decision to use it wisely while you're alive. Also, shelters located on slightly higher ground in the area, for example, even if the ground is only 1 or 2 meters high, will allow for faster exchange of fresh air, increasing the chances of survival.

[0009] Tsunami evacuation shelters integrated with seawalls are readily accessible and close to residents in coastal areas. If residents pre-assign their own designated shelter entrances, rapid evacuation becomes possible. We must not forget the family members left behind. Even town hall employees returning from higher ground spend eight hours at work, leaving the remaining 16 hours after their return home largely unaffected by the danger. A shelter increases the safe and secure time over a 24-hour period, improving the effectiveness of a fair and positive outcome in saving lives. Thus, families should prepare for rapid evacuation, ready for earthquakes and tsunamis to strike at any time within a 24-hour period. It is crucial that families do not become separated. If they drift and become separated, search and rescue costs will increase several times over. It is important to recognize that this is not merely an individual problem, but also involves enormous national costs. Tsunamis can strike any time and place, and this provides a 24-hour family-centered training exercise to counter the bias of thinking "it won't happen to me." Emergency preparedness is only effective when built upon daily thinking and training. There must be no gaps in our response to tsunamis, which can strike anytime, anywhere. The challenge is to be able to respond 24 hours a day, anytime, anywhere. Saving individuals and families requires foresight and imagination. We have the valuable experience of what happened in eastern Japan. It's easy to foresee the same outcome if we leave it to others. Even with a good education, we must not lose our lives due to inaction. What have we thought, what have we done, and what have we tried to do over the past 10 years? Are our evacuation methods and actions actually putting us in greater danger? How many promising young lives could we have saved? This requires a rigorous self-assessment.

[0010] The Nankai Trough tsunami is projected to occur in coastal areas with six waves repeating over a six-hour period. Assuming one wave per hour, the waves recede for half the time, and when the water level at low tide falls below the shelter entrance, fresh air is automatically replenished and replaced. Therefore, the idea is that it's sufficient to withstand 30 minutes of flooding. This provides a hint for crisis avoidance. In other words, a regional characteristic value of 0.5 m³ / person·hour can be used. Since children and the elderly have lower lung capacity, it's also possible to arbitrarily interpret this as half of that, 0.25 m³ / person·hour. Humans cannot survive underwater without air. It's almost instant death. Considering this, it can be argued that having a shelter is better than having none, and realistic values ​​of smaller volumes, such as 0.5 m³, 0.3 m³, and 0.25 m³, could be adopted for any excess capacity. Since tsunamis can occur at any time, seasonal equipment and measures against winter cold are necessary. In this way, the challenges of adapting responses to each region, personnel, and season can be solved. Since the entrance is located at the bottom, drainage from the interior is quick, reducing humidity and condensation, and solving the maintenance and corrosion prevention problems that are common in structures. If there is enough space inside, preparing rubber boats or air mats inside will solve the problem of vulnerable people such as the elderly not getting wet even if the building is flooded. In particular, during the winter months, hypothermia is a concern, so air mats or blankets would be appreciated to prevent direct contact with cold water. It is important to consider the optimal response for each season. By enabling evacuation according to the living situation and the number of people, it is possible to solve problems in an even wider area. At the fish market, where the workplace is very close to the sea, it is a matter of concern. It is an immediate evacuation, and safety and security can be ensured almost in the course of daily life. It is close, fast, and above all, simple. It is important to speak out in order to save the lives of 320,000 people. [Means for solving the problem]

[0011] To solve these problems, the present invention provides a tsunami evacuation shelter that is integrated with and can be used as a dual-purpose structure for embankments. This shelter is integrally installed on the back of an existing embankment, using the heavy embankment as a shield. By being located on the back, it can avoid the direct wave force of a tsunami and also avoid tipping over due to the tipping moment acting on the shelter. The shelter can be extended in the direction of extension by utilizing the long length of the embankment. When a tsunami enters, the water surface is filled at the height of the entrance, and even if submerged by a tsunami, it has an airtight, hollow structure with a closed top that has the necessary volume of air for survival underwater. The entrance is on the land side, making it an unsealed structure. As a result, the wall surface of the structure does not receive a large bending moment, so the wall thickness can be made relatively thin. Even so, the weight of the concrete structure is greater than the buoyancy acting on the structure when submerged, so it does not float. End walls are provided at both ends in the length direction to form a hollow box shape, and the overlap of the embankment and the shelter with the tsunami wave force also reinforces the embankment and prevents breach.

[0012] Furthermore, the tsunami evacuation shelter for the embankment and its integrated / combined structure of the present invention is characterized in that the area near the entrance of the open structure inside the shelter is enclosed in a U-shape in plan view with a pool wall slightly higher than the height of the entrance, or the enclosure is extended to the end walls at both ends, thereby mitigating the intrusion of floating debris and temporarily forming a reservoir for tsunami water, thereby contributing as a damper that can mitigate the direct impact of tsunami waves. Moreover, in the event of a large tsunami, the water surface is filled to the height of the pool wall of the reservoir, preventing air from escaping from the floor height of the shelter as internal air, i.e., compressing it into air, thereby increasing the internal volume of survivable air compared to the open structure without enclosure.

[0013] Furthermore, the tsunami evacuation shelter, which is an integral and multi-purpose structure with the embankment according to the present invention, is characterized in that the top of the embankment is used as a road for embankment management or for the passage of general vehicles and bicycles.

[0014] Furthermore, the tsunami evacuation shelter, which is an integrated and dual-purpose structure with a levee according to the present invention, is designed to accommodate tsunami heights even slightly higher than the height limits of existing levee crests. It is characterized by the ability to increase the overturning resistance by installing a small levee on top of the levee crest, incorporating and raising the existing levee crest, or by extending the shelter to the area behind it, thereby allowing for the installation of an even taller small levee.

[0015] Furthermore, the tsunami evacuation shelter of the present invention, which is integrated with and can be used as a structure with a levee, is characterized in that it extends towards houses in order to facilitate more rapid evacuation, and expands or extends in a direction perpendicular to the levee. While there are various names for embankments, such as quays, breakwaters, storm surge embankments, seawalls, and revetments, here we will refer to them collectively as embankments. Tsunami evacuation shelters serve as shelters not only for tsunamis but also for floods, storm surges, typhoons, strong winds, tornadoes, and missile blasts. [Effects of the Invention]

[0016] By utilizing existing seawalls, the enormous costs associated with conventional tsunami countermeasures such as relocating to higher ground, constructing high seawalls, and building tsunami towers can be avoided, and the savings can be used to save the lives of many coastal residents who are anxious about the direct and sudden impact of tsunamis. Moreover, they will be saved from tsunamis that could strike at any time within 24 hours. It is a miracle from the brink of despair. Families will not be separated, and how fortunate they are. Existing low and old seawalls can be reinforced all at once by integrating them with tsunami evacuation shelters. We will make effective use of them while being grateful for the hard work of our predecessors who built seawalls along the long coastline. We will give them a new lease on life. Seawall managers can also breathe a sigh of relief by promoting this. Furthermore, if seawall managers designate tsunami evacuation shelters as structures that also function as seawalls, they can promote the project as part of national resilience. It will be a rewarding and encouraging experience to contribute to saving the lives of many residents. Managers will not be held liable, become defendants, and suffer an unfortunate and undesirable end. Tsunami evacuation shelters behind seawalls are particularly effective in coastal areas of narrow inlets where tsunamis strike like demons in an instant, and are even more effective in densely populated areas and areas with limited garden space. They can also be applied to seawall sections and sheet pile revetments in river areas where the height is insufficient and tsunamis surge in simultaneously, provided that the ground conditions can be resolved. The entrances and exits of the seawall evacuation shelters are designated seats for each resident, a gift from heaven, allowing them to jump in immediately. If there are countermeasures in place that can save lives, cooperation will be united, enabling proactive disaster prevention. The total estimated damage is 170 trillion yen, and it is unclear how much of that is lost to human lives, but in any case, lives are precious. Proactive disaster prevention should be considered with human lives as the top priority. A glimmer of hope will appear for the lives of 320,000 people and 1 million victims that had been given up on, or rather, neglected. The person themselves has no idea that they are one of them. They vaguely understand, but they don't think they will die. When a glimmer of hope appears, people become more positive. All sorts of ideas will emerge. If continuous 24-hour evacuation throughout the year becomes possible, people can practice self-help training. They will be able to respond to evacuations instantly. Through that effort, they can live their daily lives in peace. What a blessing that would be. Community solidarity can be expected. If the enormous budget for Tohoku's reconstruction is further burdened by tsunami countermeasures that are progressing at a snail's pace, it is clear that Japan will sink. Therefore, building a crematorium for 320,000 people and securing land for it would have a great economic effect. Not being able to respond despite damage being predicted 10 years ago is truly a disgrace to the world. It is clear that we will be the target of criticism. Who is responsible? The fact that no one other than the levee managers has been identified, and that there is a lack of self-awareness, is why progress is so slow. It is our own fault, and self-help, mutual aid, and public assistance will never progress no matter how long we wait, but first and foremost, we need the resolve to protect our own lives. The daily movements of family members going to school and work are anticipated, allowing them to act together as a family, strengthening their sense of unity and bonds, and preventing them from falling apart. Tsunami evacuation shelters on nearby seawalls are safe zones they can quickly reach, designated spots that provide emotional support. This is where the national budget should be used. It is clear to everyone that if we prepare today for a tsunami that may strike tomorrow, we will be safe from tomorrow onward. It will become a valuable asset to society. We can be grateful for the precious time we have now. No one would call this a waste of money.If it can save lives, the life insurance company will not go bankrupt either. The tsunami that could strike at any time, perhaps tomorrow, but if the state funds the construction of shelters, it might save 320,000 lives. The predicted number of deaths during the winter, at night when people are at home, is 320,000. Considering that they would be instantly killed or drowned as their houses are washed away, in the present invention, even if the house is washed away, the lives that have fled to the dike will not be washed away. Compared to the dignity of life, it is extremely cheap. Japan, which has spent 10 years just doing training exercises for TV appearances, being complacent, good at making excuses and doing nothing, is only laughed at by the whole world. Let a flower bloom here. If the shelter is made of precast concrete products, it can be manufactured in the factory, has good quality and is suitable for direct transportation. The construction period is also short. Hurry up.

Brief Description of the Drawings

[0017] [Figure 1] Image cross-sectional view of an existing dike receiving the high tide wave force [Figure 2] Image cross-sectional view of an existing dike receiving the tsunami wave force [Figure 3] Image cross-sectional view of a trapezoidal box-shaped tsunami shelter behind the dike taking on the wave force [Figure 4] Cross-sectional view of a parallelogram and box-shaped tsunami shelter along the slope of the dike [Figure 5] Cross-sectional view of a rectangular precast product and culvert box tsunami shelter behind the dike [Figure 6] Schematic cross-sectional view for calculating the required wall thickness based on the relationship between the weight and buoyancy of the shelter [Figure 7] Cross-sectional view of a shelter of type A for the vulnerable [Figure 8] Cross-sectional view of a shelter of type B for the healthy [Figure 9] Plan view of a continuous shelter arrangement of A, A, B, B [Figure 10] Plan view of an alternating shelter arrangement of A, B, A, B [Figure 11] Explanatory plan view with the pool wall as the boundary wall with a protruding bottom and through-passage holes provided at the lower part of the boundary wall [Figure 12]Diagram showing the upper surface of the shelter open to the access road, general roadway, and bicycle path. [Figure 13] Cross-sectional view showing a small embankment on the upper surface of the shelter. [Figure 14] Cross-sectional view showing the existing levee with its top raised, making the entire structure even taller. [Figure 15] Cross-sectional view showing the embankment extended to the area behind it to increase its resistance to tipping and raise its height. [Figure 16] This is an explanatory plan showing the extension of the connecting shelters perpendicular to the embankment, extending towards the local community and the elementary school. [Modes for carrying out the invention]

[0018] Common reference numerals are used throughout the drawings and detailed descriptions to indicate the same elements.

[0019] Many residents live in coastal areas along the seawalls. Furthermore, in narrow cove areas, many houses are densely packed close to the coastline. In coves, tsunamis become amplified in height and force, sweeping away houses in one fell swoop. It is easy to imagine people being swallowed and tossed about by the waves. Measures must be taken urgently. Since the shelters are supported behind the seawalls, the rigidity, weight, and length of the existing seawalls can be utilized. By integrating with the existing seawalls, the load-bearing capacity is improved, and the tsunami evacuation shelters can be considered a mutually beneficial structure that works in conjunction with the seawalls, as it also saves many lives in coastal areas. There will be two types of shelters: Type A, which has no walls at the entrance, is for vulnerable people such as wheelchair users, the elderly, and pregnant women; and Type B, which has a vertical wall and pool wall approximately 80 cm high, higher than the entrance height, at the back of the entrance to prevent floating debris from entering, and to increase the evacuation space and the amount of air that can be held in the water, but is for able-bodied people as it requires climbing over. It would be good to add handles if possible.

[0020] Figure 1 shows a general cross-sectional image of the wave force on existing seawalls throughout Japan under conditions of high waves. Figure 2 is an image illustrating the wave force situation when a tsunami of about 10m strikes. The wave force is said to be three times that of hydrostatic pressure. It is affected by severe overflow. Figure 3 is a general diagram illustrating how a tsunami evacuation shelter is installed in accordance with the slope of the seawall's back, and how it resists the wave force of a large tsunami as a single unit with the seaward side wall and trapezoidal box-shaped structure. Figure 4 is a diagram of a parallelogram with a slope that matches the slope of the seawall, and Figure 5 is an example of a box culvert made of a rectangular precast product. Concrete is filled in the space with the back of the seawall to make it a single unit. In all tsunami evacuation shelters, in order to reduce the effects of overflow, the height of the top of the shelter is basically the same as or less than the height of the top of the existing seawall, and partitions are installed at regular intervals along the length of the seawall, taking into account the joints and gaps of the existing seawall, to divide it into hollow rooms. The shelter should be constructed in blocks of approximately 10m in length, and intermediate walls may be added for reinforcement if necessary. A hollow shelter that holds air will float if it is too light. First, to prevent the tsunami evacuation shelter from floating, the weight of the hollow concrete structure must be greater than the buoyancy acting on the structure. Figure 6 is a schematic diagram that simplifies calculations by using a rectangle to determine the required wall thickness for reinforced concrete with a specific gravity of 2.5. Entrances should be provided at the bottom of the landward side wall or end wall. The structure is an open structure, not a sealed structure, and according to Pascal's principle, the air pressure and water pressure inside and outside the shelter are equal, so there is no bending moment on the wall, and therefore the structural wall thickness does not need to be very large. In extreme cases, the wall could be as thin as a single sheet of paper. However, the wall thickness is necessary to support and assist the strong wave forces acting on the embankment from behind, creating a box-like structure. The necessary cover and wall thickness are required to protect against salt damage. The structure also needs adequate rigidity and resistance to twisting and deformation. A box-shaped shelter with an extended rear section naturally possesses resistance moments against overflow and tipping due to its box-like characteristics. For simplicity, a rectangular wall thickness calculation example is shown below. The weight of the structure must be greater than the buoyancy. As a rough estimate, assuming a levee height of 2m, a pool with the same height of 2m, width of 3m, length of 1m, entrance height of 0.7m, pool wall height of 0.8m, wall thickness of 0.3m, and a specific gravity of 2.5 for reinforced concrete, the weight = (2*3 - 0.7*2.7 - 0.7*2.4)*2.5 = 6.075 tons > buoyancy = 2*3 - 0.7*2.7 = 4.11 tons. If the wall thickness is a thin 0.2m and it is a plastic cast product, the weight = (2*3 - 0.7*2.8 - 0.8*2.6)*2.5 = 4.9 tons > buoyancy = 2*3 - 0.7*2.8 = 4.04 tons. It will not float, but it can be said that there is less weight margin when it is thin. In type B with a pool wall, the weight of the pool wall is added. With a wall thickness of 0.3m, it increases by 0.3*0.8*2.5 = 0.6 tons. A wall thickness of 0.2m increases the weight by 4 tons. Assuming a distance of 1m to the entrance, the buoyancy = 2*3 - 0.8*1 = 5.2 tons. With a wall thickness of 0.3m, the weight is 6.075 + 0.6 = 6.675 > 5.2, and with a precast product wall thickness of 0.2m, the weight is 4.9 + 0.4 = 5.3 > 5.2. Therefore, if using a precast product, the wall thickness should be 0.25m or more. However, if calculated per 10m of length, the remaining land-side wall section of the entrance is 7m, the end wall is 2*3*0.2m to 0.3m, and there are also intermediate walls and corner reinforcing haunches, so the calculation should be fine, but it would be desirable to have some margin.

[0021] The application of natural theorems is also useful. According to Archimedes' theorem, air, which is lighter than water, rises in water. The rising air is concentrated in the convex space. According to Archimedes' theorem, the buoyancy force on the shelter is equivalent to the volume of water displaced by the object. Although it is a hollow shelter containing air and therefore light, the weight of the structure must exceed the buoyancy force. Furthermore, if a 10m tsunami comes, Boyle's law compresses the internal volume to half, and at the same time the buoyancy is halved. According to Pascal's principle, the pressure inside and outside the shelter is equal. Because of this, there is no pressure difference between the inside and outside as in a sealed structure on the walls all around the perimeter of a shelter with an entrance at the bottom of the side wall. Even a wall the thickness of a single sheet of paper would suffice. According to Boyle's Law, the horizontal water surface that forms near the bottom of the shelter's entrance creates a sealed space. With a tsunami height of 10m and a water pressure of 2 atmospheres, the air inside the shelter will be compressed to half its volume at the top, to one-third at 20m, and to one-quarter at 30m. Consequently, the water level and surface will rise, so do not panic. Since the interior is a closed space, the water level will rise slowly at 1 / 20th the rate of the internal water level (0.5m) because the external water level (10m) is linked to the internal water level (0.5m), and air will always remain at the top ceiling. The air intake should naturally be at the top, and you should draw in the compressed air that rises and accumulates around the ceiling of the top plate. The buoyancy is equivalent to the volume of air inside the shelter underwater, so as the water level inside the shelter rises, the buoyancy will also gradually increase. However, if the water level rises above the height of the shelter's entrance, the internal air will be compressed and its volume will decrease, so the buoyancy will decrease. When setting the capacity of a shelter, it's important to consider that the elderly and children with low lung capacity consume half the amount of oxygen, so any excess capacity can be covered or considered as a buffer. Regarding the water pressure burden from a maximum tsunami of 34m in height, there was news in 2013 of people being rescued from the bottom of a shipwreck off the coast of Nigeria at a depth of 30m after 62 hours. Once the first wave is over, the water level will recede, allowing fresh air to replace the water. With a design of 1m³ / hour, there's not much to worry about. First and foremost, the priority is to build shelters without any further hesitation. If we continue to hesitate and do not act, we will be submerged when the tsunami hits, and if there is no air, even for a moment, we will die. This is like the Odawara Council, a waste of time, endless deliberation and research, without achieving the goal of saving human lives. The time lost in the last 10 years will never come back. Nothing can be expected in the next 10 years either.There's no one in charge who needs to produce results. However, I want to believe that if we have the courage to move forward, we can reclaim productive time in the next 10 years.

[0022] Even if the tsunami height is very high, six waves will repeat in a maximum of six hours, creating troughs in the waves and allowing for natural air exchange. This means that the amount of air to be designed can be measured in terms of the tsunami period, or in one-hour increments. If there is an elementary school nearby, consider extending the tsunami evacuation shelter closer to it. In extreme cases, to prevent sudden death from hypothermia in extremely cold conditions, consider installing a wind tunnel-like connecting passage, similar to an airplane's boarding ramp. Such ingenuity can bring a glimmer of hope to the projected figure of one million casualties, a stark reminder of the impersonal mass of individual lives presented. Using precast concrete manufactured in a factory, although subject to transport size limitations, can be expected to result in higher quality and shorter construction times. Consider applying rectangular box culverts. Pouring concrete between the embankment slope and the culvert will create a unified structure. In addition, if air becomes insufficient and breathing becomes difficult, it would be good to place a lifebuoy with a 10-meter rope attached. This will allow people to surface, breathe, and return after the tide recedes. The rope anchor should be placed inside the shelter wall, and the lifebuoy outside the shelter. Ensure that the total amount of air equivalent to the volume of the inflatable ring is not lost. However, you will need to take measures such as coiling the rope so that only the inflatable ring floats. [Examples]

[0023] The seawall is built to withstand the wave forces and lateral forces of high waves. Therefore, the seaward side wall of the box-shaped shelter is fundamentally designed to be a single, integrated structure closely attached to the back of the seawall. This has a reciprocal effect, both by absorbing some of the reaction force of the waves and by providing cover to avoid direct impact from the waves. On the other hand, the seawall is vulnerable to overflow that exceeds its crest. Therefore, the top of the shelter is basically below the height of the seawall's crest to avoid the effects of overflow. The shelter's structure is made of concrete, with a non-sealed, hollow structure that provides enough air for survival at a rate of 1 m³ per person. The entrance is approximately 0.7 m high and can be 2 m to 5 m wide. It is installed at the bottom of the landward side wall and end wall. Both ends of the shelter are enclosed by vertical walls and end walls. The concrete structure has enough weight to overcome buoyancy so that it does not float even when submerged in water. That is, the wall thickness of the concrete structure needs to be 30 cm or more for general reinforced concrete. For precast products, a height of 25 cm or more is desirable. Assuming end walls are installed at 10 m intervals, the internal air volume for type A in Figure 7 would allow for 0.7 * 2.4 * 10 = 16.8 people. It is advisable to add a slope or ramp towards the back of the entrance. For type A, which is for vulnerable evacuees such as the elderly, pregnant women, and wheelchair users who may not be able to evacuate quickly, handrails are necessary. For this reason, lowering the base slab by about 0.3 m will ensure an entrance height of 0.7 m from the ground. The gap between the back of the embankment and the newly constructed tsunami shelter can be filled with concrete mortar or integrated, or a method of mitigating the impact of the old and new concrete can be considered using jointing materials or thin materials such as waterproof sheets, fiber sheets, plywood, or elastite. However, since there are differences in the amount of expansion and contraction due to temperature changes and differences in drying shrinkage over time between the new and old embankments, it is necessary to interpose jointing materials appropriately to prevent cracking and avoid mutual interference. Since the existing embankment has joints at regular intervals, the spacing of the end walls of the new concrete shelter needs to be adjusted to match these joints to avoid being affected. The shelter's height should be around 0.7m to prevent people from congregating at the same time, but the width should be 2m to 5m to accommodate two people or a motorcycle jumping in at the same time. [Examples]

[0024] Figure 8, Type B, is for able-bodied individuals and requires climbing over a wall. Providing a gathering area and pool at the shelter entrance acts as a damper to mitigate tsunami wave forces and maintains a large amount of air necessary for survival. Type B accommodates 0.6*2.4 + 0.8*1.4 = 25.2 people. Figures 9 and 10 show plan views where the pool wall and vertical walls are U-shaped, or where the vertical walls at both ends and the walls extend to the end walls as shown in Figure 11. The latter has less air volume than the former, so caution is needed. The height should be about 10 cm higher than the entrance height. It is advisable to provide handles on the top of the entrance wall and the pool wall. Providing benches inside will allow for comfortable living. [Examples]

[0025] By creating passageways between adjacent rooms and through-holes in the lower part of the intermediate walls and retaining walls of the shelters, many shelters can be installed in a continuous row, like a row house, along the longer direction of the shelter. As an example of arrangement shown in Figure 9, if the continuous arrangement is A, A, B, B, then if a passageway is provided at the bottom of B, even if one shelter is damaged and flooded up to the ceiling, people can escape to the adjacent room. As an example of arrangement shown in Figure 10, if the alternating arrangement is A, B, A, B, it is advisable for evacuees to decide in advance which shelter they will take refuge in. However, care must be taken as creating a hole between adjacent A and B may cause a loss of air in B. If residents decide which shelter to take refuge in during prior training, evacuation will be quicker and more direct. However, as shown in Figure 11, if the pool wall of type B is extended to the boundary wall, and a through-hole at the height of the pool wall or entrance is provided at the bottom of the boundary wall, continuous passage between A and B, and passage along the entire length of the continuous shelter, will be possible. [Examples]

[0026] The top of the shelter will be used as a service road, a lane for general vehicle traffic, or a bicycle path. See Figure 12. [Examples]

[0027] If, for example, raising the crest height of the existing levee slightly relative to the L1 level would save more homes and residents in relation to the tsunami height, then we should consider constructing a small levee on top of the shelter, within the limits of the shelter's resistance and strength against tipping. Furthermore, if it is possible to raise the crest of the existing levee in conjunction with the main levee, the overall height of the small levee can be further increased. In addition, if the tsunami evacuation shelter can be extended to the area behind it, it will become stronger against tipping and the small levee can also be made higher. See Figures 13, 14, and 15. [Examples]

[0028] It is expected that a combination of seawalls and shelters will provide better resistance to the force of a tsunami. However, people who are a little far from the shelters may still hesitate in deciding whether to flee to an evacuation building, a mountain, or higher ground. Therefore, the shelters should be extended and expanded in the direction of the town, that is, perpendicular to the seawall. This can be described as extending a helping hand. In particular, extending and expanding towards the elementary school would bring the entrance closer, allowing for a quicker evacuation. We must not take the lives of elementary school children who have a future ahead of them. Protecting them is the greatest responsibility of adults. In areas with declining populations, cooperation from residents, such as providing vacant land, can also be expected. See Figure 15. [Examples]

[0029] Although it is a hollow shelter, if cracks occur, air will escape underwater. Air leaks can be fatal. Possible causes include the drying shrinkage of concrete over time, strain and cracking of the structure due to the massive earthquake before the tsunami, and cracks caused by the age difference with existing seawalls, joint locations, and mutual interference due to surface contact. Countermeasures are necessary. Therefore, placing plastic bags such as upward-convex poly bags or airtight sheet bags upside down along the interior walls provides double safety in case of emergency and prevents air leaks. Personally, I think even garbage bags are useful. The required amount of air is basically 1.0 m³ / person·hour, but for children and the elderly, their lung capacity is lower, so considering half the characteristic value will be helpful if the capacity is exceeded. A disaster preparedness backpack containing a lifebuoy, a water-permeable frame to prevent debris from entering, a small air cylinder, a small oxygen cylinder, a protective board from debris, a flashlight, a smartphone, a radio, hand warmers, bread, water, a portable toilet, blankets, warm clothing, garbage bags, etc., a waterproof sheet, a shovel for removing mud accumulated outside, and a lifebuoy with a rope about 10m long attached would be helpful in case of difficulty breathing. You can float up and return to your original location when the tide goes out. Placing water-permeable gabions near the entrance will prevent debris from entering and can be used as seating when pulled inside. Long benches can be used as benches. You can easily endure an evacuation of about 6 hours. In addition, a wooden raft is also useful. Lifebuoys should be placed outside the shelter, and their anchors should be secured inside the shelter. It is unavoidable to have only enough for about 10 people. It would be good to equip the landward side walls with protective devices or cushioning devices such as tires to mitigate the impact force of debris. To prevent getting wet from tsunami flooding, it's a good idea to place things like battens, rubber boats, vinyl floating floors, air mats, and boards inside. You should also consider having a hole through the adjacent room as a precaution. In any case, regular awareness campaigns, education, and training are necessary for tsunami countermeasures. [Explanation of symbols]

[0030] 1. Embankment 2. Tsunami evacuation shelters 3 Shelter Walls 4. Shelter Interior Air Space 5 entrances / exits 6. Embankment crest 7. The back of the existing levee, the sloping slope 8 high wave wave power 9 ground 10 sea level 11 Tsunami wave force 12 Overflow tsunami wave force 13 Inverted trapezoidal box-shaped shelter 14 parallelogram box-shaped shelters 15 rectangular shelters, culvert box-shaped shelters 16-span concrete 17 Pool Walls 18 wheelchairs 19 handrails 20 Water-permeable floating debris intrusion prevention fence set 21 benches 22 inflatable rings 23 handles, anchors 24 ropes 25. Horizontal water surface created at the entrance height when a tsunami enters. 26. Horizontal water surface created at the height of the pool wall when a tsunami enters. 27 Shelter floor that retains air until flooded to the height of the pool wall. 28 vehicles 29 bicycles 30 guardrails 31 small embankment 32 Hunch 33. Partition walls, partition walls, boundary walls, or retaining walls, end walls that separate adjacent areas. 34. Connection to adjacent rooms at the bottom of the bulkhead, passageway 35 Retaining Wall 36 front wall 37. Concrete section for raising the crest of existing levees 38 Intermediate walls, reinforcing walls 39. Resistance to tsunami wave forces 40 houses 41 Land side wall

Claims

1. This tsunami evacuation shelter is integrated with an existing seawall, using the heavy seawall as a shield. By being located on the back, it can avoid the direct force of tsunami waves and prevent tipping due to the overturning moment acting on the shelter. The shelter can be extended in the direction of extension by utilizing the long length of the seawall. When a tsunami enters, the water surface is filled at the height of the entrance, and even if submerged by a tsunami, it has an airtight, hollow structure with a closed top that has the necessary volume of air for survival underwater. The entrance is on the land side, making it an unsealed structure. As a result, the wall surface of the structure does not receive a large bending moment, so the wall thickness can be made relatively thin. Even so, the weight of the concrete structure is greater than the buoyancy acting on the structure when submerged, so it does not float. End walls are provided at any two ends in the length direction to form a hollow box shape, and the overlap of the seawall and the shelter against tsunami wave forces reinforces the seawall and prevents it from breaking.

2. A tsunami evacuation shelter integrated with a dike, which is a multi-purpose structure, characterized in that the area near the entrance of the open structure inside the shelter is enclosed in a U-shape in plan view with a pool wall slightly higher than the height of the entrance, or the enclosure is extended to the end walls at both ends, thereby mitigating the intrusion of floating debris and temporarily forming a reservoir for tsunami water, thereby contributing as a damper that can mitigate the direct impact of tsunami waves, and in the event of a large tsunami, the water surface is filled to the height of the pool wall of the reservoir, preventing air from escaping from the floor height of the shelter as internal air, i.e., compressing it into internal air, thereby increasing the internal volume of survivable air compared to the open structure without the enclosure.

3. A tsunami evacuation shelter that is integrated with or serves as a dual-purpose structure of a levee, characterized by having its top surface open to the road used for levee management or to the passage of general vehicles and bicycles.

4. This tsunami evacuation shelter, which is an integrated and dual-purpose structure with a levee, is designed to cope with even slightly higher tsunami heights than the existing levee crest height which has a limit. It can be constructed within the range of the overturning resistance moment of the tsunami evacuation shelter behind it. This is achieved by installing a small levee on top of the levee crest, or by incorporating and raising the existing levee crest, or by extending the shelter to the area behind it. This increases the overturning resistance and allows for the installation of even higher small levee structures.

5. A tsunami evacuation shelter integrated with a levee, or a multi-purpose structure, characterized by extending the shelter toward houses to facilitate faster evacuation, and extending or expanding perpendicular to the levee.

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