Tsunami evacuation shelter, a dual-purpose structure integrated with the levee

Abstract

【assignment】 Budgetary constraints make it difficult to build levees high enough to accommodate predicted tsunami heights. Construction of tsunami evacuation shelters has also been slow due to the risk of blocking visibility of the ocean. [Solution] By utilizing the existing coastal levee in front of us and stacking a tsunami evacuation shelter that protrudes higher than the levee height on its backside, we can be satisfied with the height and strength. Even if submerged by a tsunami, the box-shaped structure of the tsunami evacuation shelter retains air inside, so people can survive. Just like having an evacuation shelter right in front of you in your daily life, it is easy to gain support for raising the levee. Quick evacuation with the whole family is possible. Peace of mind 24 hours a day. Being prepared is a blessing. Being able to live each day safely and with peace of mind is truly a blessing.

Description

[Technical Field]

[0001] The present invention relates to a tsunami evacuation shelter that protrudes above the height of the top of an existing levee in coastal areas prone to sudden tsunamis, avoiding direct hits from the force of the tsunami by being integrated with the back of the existing levee, maintaining the amount of surviving air inside even when underwater, and allowing for quick evacuation as it is close to houses. [Background technology]

[0002] A tsunami caused by the upcoming Nankai Trough megathrust earthquake is predicted to kill 320,000 people. Ten years have passed since the Cabinet Office announced its prediction in 2011, and we await the results to see how many thousands of people have been saved. Constructing a 10-meter-high seawall alone would extend the coastline and bankrupt the national finances. Furthermore, the ocean would be obscured, and residents would strongly oppose it. However, this does not mean that we can do nothing. Relocation to higher ground would require enormous costs and effort. Tsunami towers would also be extremely expensive. With a 10-meter-high tsunami approaching in five minutes, yells of "run away!" and televised evacuation drills gathering residents to higher ground are completely off the mark. Using existing seawalls would speed up the evacuation of coastal residents, saving many lives. A search on the Patent Information Platform yielded one search result for "seawall shelter" and nine results for "levee shelter." Four of these matched my criteria. Patent Document 1 proposes the construction of a new, high embankment that prevents overflow, and the shelters are simply cave-shaped structures inside the embankment, which would collapse if flooded. Patent Documents 2 and 3 also propose new construction, which is excessively large and expensive, and has large open spaces that could lead to buoyancy. A broken structure like the three-building construction would not fulfill the original function of a levee. Patent Document 4 is even larger, with apartments, schools, hotels, etc. built inside the embankment, which would be prohibitively expensive. This application differs in that it utilizes existing, low-height embankments found throughout the country as shields, integrating tall shelters behind them, which would be inexpensive and take advantage of the long length of the embankment to save many residents living along the embankments. [Prior art documents] [Patent documents]

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

[0004] [Non-Patent Document 1] Nakagawa Kogyosho Paper Summary of the Invention [Problem to be solved by the invention]

[0005] High seawalls would be effective against the massive tsunamis that would accompany a major earthquake along the Nankai Trough. However, building them at a maximum height of 34 meters is unrealistic. High seawalls, in the first place, require a large budget, and residents strongly oppose them because they would obstruct the ocean view and block sea breezes. A 10-meter-high seawall would also be met with strong opposition. However, based on footage of the tsunami overflowing the levee during the Great East Japan Earthquake, even if the existing levee is 2 meters high, it would be too low, as it would easily overflow. In reality, the overflow height would be 1 to 3 meters, and the levee is therefore insufficient in height. However, raising the existing levee to make up the difference would be difficult due to potential risks, such as toppling. Furthermore, aging levees are weak and prone to collapse. Therefore, integrating tsunami evacuation shelters that extend beyond the levee and extend beyond it would serve as a countermeasure against collapses, strengthen the levee, and help save the lives of coastal residents. Environmental damage to the ocean would also be minimized. Every meter that the elevation is raised increases the chances of preventing the destruction, annihilation, and total annihilation of an area or cityscape caused by overflow. If it means saving lives, it is easier to gain the consent of residents. However, even if the elevation is raised from 1 to 3 meters, it is necessary to explain why it is not raised any higher. If lives can be saved in tsunami evacuation shelters even if they are submerged, it is easier to gain understanding. The challenge and mission is to save the lives of 320,000 people and 1 million casualties from a projected tsunami. These 320,000 people live along the coastline where the tsunami will strike. Therefore, we believe that utilizing the levees built by our ancestors along coastlines throughout the country as a shield is the most natural and effective approach. The levees are located along the coast, naturally in the coastal areas that are likely to be hit by the tsunami. This means that they are in the tsunami-affected areas, where most of the victims live and are most affected. They are located on the seashore, close to the residents and familiar to them. They surround the coastal areas and are long. They are heavy and strong against wave force. However, they simply lack height. It would be simplistic to dismiss them as useless simply because they are not high enough. They are only lacking in height beyond the height of the levees themselves. However, it would be unrealistic to build a 10-meter-high seawall. Therefore, we considered compensating for this lack of height with functionality. In other words, if a tsunami evacuation shelter that protrudes higher than the height of the levee, which would allow people to retain air even if submerged, could be combined with the levee into a single structure, the weaknesses of the levee could be compensated for, and the levee, which had been seen as an ineffective tool against high tsunamis, could be brought back to life, and there could be hope of saving 320,000 people.

[0006] The Cabinet Office predicts that a tsunami will kill 320,000 people, but we await the results of the measures taken over the past decade to determine how many tens of thousands of lives have been saved. I doubt we'll see a repeat of the Fukushima Daiichi nuclear disaster, but perhaps we're relying on divine intervention or a spell to ensure that the tsunami won't be discovered until it arrives, or that it won't arrive, or that it can't possibly arrive. The then-president of TEPCO was found guilty in court for failing to take countermeasures despite being able to foresee the tsunami. To avoid prosecution and becoming a defendant, the levee managers should have raised the levees to more than 10 meters if a 10-meter tsunami was predicted. However, progress seems to be slow. If measures were foreseen but not implemented, it's easy to imagine that the heads of the national and local governments responsible for managing the levees will also be found guilty, given the TEPCO president's guilty verdict. I'm tired of hearing the usual excuse that it was unexpected. Residents' lives remain at risk. Isn't this similar to the current situation in which Israel treats the lives of Gaza residents with little regard for their safety and neglect? In addition to raising the levees, other proposed tsunami countermeasures include building tsunami towers and relocating people to higher ground. However, how many of the 320,000 people would be able to reach the tsunami towers during the predicted peak hours of midnight in winter, when people are fast asleep? The cost-effectiveness is extremely low, or even zero. Even though the greatest damage is predicted to occur in the middle of the night, the countermeasures do not anticipate the worst-case scenario. This measure also leaves behind elderly people, pregnant women, and wheelchair users who cannot reach the premises in the middle of the night, and is a significant lack of fairness in the budgeting process, using taxpayers' money. The entrance to the tower is locked behind a fence to prevent unbelievers. The cost of a permanent, night-time caretaker is high, and even if there is an elevator, emergency power, legal inspection fees, and upgrade costs are difficult to cover. A 35-meter-tall tsunami tower would be a different story, but anything smaller would likely be unavoidable. To accommodate unexpected elevation increases, the additional construction costs of the tower will double. If the forecast is revised each time and it is found to be insufficient, it will become a dangerous and even useless structure. It is a veritable waste of tax money. There is no guarantee that a certain height will save lives. If people die, it will simply be because the height was unexpected. What's more, the townscape will easily be washed away and destroyed. At the very least, residents' lives must not be put at risk. This will not strengthen the nation's resilience. We must learn from past examples, particularly the Great East Japan Earthquake. When it comes to relocating to higher ground, only the town hall is being relocated, not the entire town. Is it really okay to abandon the bustle of the town and its residents?The sight of a father desperately searching for his third-year junior high school daughter during the recent Noto flood was heartbreaking. Ten days later, the family was discovered by chance by a fishing boat at sea, a relief, but it also made me realize how devastating it is for a family to be torn apart. Even if the town hall employees survive, tragedy awaits if their families and many other residents remain missing. They spend the remaining 16 hours of their day outside of work on flat ground. What are they protecting? Even if there are important documents, they can be digitized and no longer needed in a warehouse. Even if they are storing resident registers, the residents are no longer alive. The number of people searching, the cost, and the duration are limitless. Relocation to higher ground needs to be reconsidered, or, if relocation is necessary, tax-paying residents should be relocated first, while measures to save the lives of residents living on the flat ground below should also be implemented.

[0007] It is understandable that building high seawalls would be prohibitively expensive to adapt to every corner of the nation. Therefore, we considered whether we could utilize existing levees, already installed by our predecessors along coastlines throughout the nation. Levees are continuous along long stretches of coastline, and their hard concrete makes them sturdy and durable. They are heavy and do not float, and naturally have sufficient resistance to wave force. However, their greatest weakness is that they are not high enough to withstand the height of a large tsunami. Tsunamis would overflow far above the levees, and if left unchecked, they would overflow or breach, engulfing the entire town. As expected, low levees cannot save the lives of townspeople. Rikuzentakata, a narrow inlet, was particularly devastated, with everyone wiped out in one fell swoop. Therefore, we believe that as long as air can be retained even if the tsunami submerges, people can at least survive. Compared to the Great East Japan tsunami, a massive Nankai Trough tsunami is predicted to have six waves every six hours. The submergence time is finite, and the tide quickly recedes, providing air. Levees are heavy and sturdy enough. They lack height. Meanwhile, air-filled shelters are beneficial for human survival. First, the weight and stiffness of the levee, combined with the supportive shelters that hide behind it, allow the entire structure to avoid the impact of large wave forces. It's possible to envision shelters integrated with long levees. This offers significant benefits, including the ability to quickly escape to shelters closest to residential areas and the ability to reinforce low levees, levees weakened by overflows, and old levees in case of breach. Even a single breach can mean the end of the story, even if the levee is heavy and sturdy. Those who don't want to leave town can accommodate as many people as they want. The existing levees are a part of everyday life and allow for quick evacuation. Best of all, they're inexpensive and can be applied anywhere in the country. If regions that want them step up, funding for national resilience is relatively easy, saving many lives and allowing people to live their lives without worry. What a blessing! We must never take the lives of young people, especially elementary school students who represent a bright future. News of the destruction of Okawa Elementary School in the Great East Japan tsunami instantly spread around the world. Teachers are also suffering through the trials. This suffering must not be repeated. Even if the townscape is sacrificed, it is only temporary, and as long as people survive, life can be restored. The more people who survive, the more we can expect to rebuild the town. 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 local communities. Levee managers will feel relieved and proactive if they can contribute to saving many lives even with weak and low levees. The usual excuse that it was unexpected will not be tolerated forever. How precious it is to be able to help and contribute to others. It is no exaggeration to say that this will provide the optimal solution for strengthening the nation's resilience.

[0008] Therefore, the realization of tsunami shelters—which save many lives, are readily available, affordable, and ensure the safety of residents and their communities 24 hours a day, even during the nighttime when damage is greatest—can help solve this problem. Tsunamis can strike at any time, anywhere, or at any time. In areas where tsunami evacuation is difficult, the advice to "escape" is often given. While escaping is a given, most people do not. Don't be fooled. The elderly, pregnant women, and wheelchair users are particularly vulnerable to disaster evacuation. It is extremely cruel for the government to assume that ignorance is a personal responsibility. Meanwhile, in everyday life, cars are essential for work, shopping, and medical appointments, especially in rural areas. While it would be ideal to be able to escape by car far away, concentrating on major roads leads to traffic jams. While tsunamis are unpredictable, the Cabinet Office predicts that a tsunami resulting from a major Nankai Trough earthquake could reach a maximum height of 34.4 meters, resulting in 320,000 deaths and 1 million casualties. A 10-meter-high tsunami is expected to strike coastal areas in two to five minutes, with the greatest damage occurring in the middle of the night in midwinter. Ten years after the announcement, how many thousands of people have been saved? Recently, video footage of the massive tsunami from the Great Kanto Earthquake was discovered. The fundamental reason the problem remains unresolved is that we are constantly bombarded with warnings and no one to identify who is truly responsible for saving countless lives. We are consumed with discussions, deliberations, and research, and feel complacent, thinking this is our job. Our job is to find results. This is commonly known as the Odawara Council. Even so, evacuation centers will serve as a mortuary for 320,000 people. It's now time to verify and publicize whether they are adequate for the number of people. We also need to wait for announcements on the progress of land acquisition and construction for crematoriums. Cremation is impossible without identification documents. There are one- to three-year waits for administrative procedures such as DNA testing, dental records, and fingerprint matching, and the construction of refrigerated warehouses to prevent decay is also urgently needed. With an eye on emergencies and major disasters like these, the government should actively promote the effectiveness of My Number cards with photographs for identifying people. I would like to believe that they don't intend to leave it alone forever. Do they have no wisdom? The sooner they deal with it, the more secure people will be able to live their daily lives. The responsibility for leaving it alone for 10 years is not light. But with no one in charge, they don't seem to care.The tsunami that hit the Great East Japan Earthquake struck as early as 15 minutes after the earthquake, and in many cases after an hour, giving people ample time to evacuate. However, this is not the case with tsunamis caused by massive Nankai Trough earthquakes or massive earthquakes in the Sea of ​​Japan, as the waveform rises sharply. A sudden one-minute attack, like the tsunami off the coast of Okushiri Island, leaves no time to evacuate or even any grace period. We should have learned from actual tsunamis. Six waves strike repeatedly over a six-hour period. Since we don't know when during the day they will strike, we must be prepared 24 hours a day. However, despite the unpredictability and cruelty of tsunamis, they adhere to the natural order and rules that always follow the shaking of an earthquake, and a sense of justice is felt when advance warnings are given through receding tides and roaring noises. We must find a way to respond to this. The phrase "5 minutes after the tsunami hits" implies that, assuming the shaking subsides 2-3 minutes after the earthquake, there is a 3-2 minute window to escape, but not necessarily a 3-3 minute window. If we spend time and money on accurate earthquake analysis, and become complacent about it as our job, and our evacuation warning system issues its warning 3 minutes after the earthquake, it is often already too late. Even an elementary school student can understand this. It is of no use to coastal residents who are on the brink of death. A loud siren or announcement announcing the arrival of a major earthquake would be fine. Instead, we should follow the example of Israeli and Palestinian missile warning sirens that sound just a few seconds after an earthquake, and issue an automatic, instantaneous warning. The devastation caused by a tsunami would be far greater than that of a missile airstrike. The creators of supposedly accurate systems take responsibility for their accuracy, but not for their effectiveness in saving lives. Most people reported not evacuating when a tsunami warning was issued following the recent Tonga volcanic eruption. Even a ship capsized in Kochi. If the shrill siren didn't sound immediately, it would be a real disaster. People must be constantly trained and able to make self-judgments, prepare for self-defense, and practice self-defense immediately, based on the magnitude of the earthquake's shaking. While it's true that you won't regret your life if you die, to avoid regrets, you need to decide at least one thing you would do if you were in a situation like that. It seems that unless a roaring roar, rumbling earth, or high waves are imminent, it's difficult to take responsibility for the crisis and think about it. In the cold winter, resignation takes over and our thinking stops. While bathing or sleeping, there's no time to change pajamas. Even getting a fussy child to put on their shoes can easily take five minutes. There's no time to think. Grab your disaster preparedness backpack and head out. It's unclear whether this is what people really think, but many people are resigned to their situation. Of course, you must break away from the bias that you will be able to manage and be okay. You need instant unconditioned reflexes and repetitive behavior training. Housing conditions also have an impact. Average homes will be reduced to smithereens and will not survive. In a sturdy apartment building, those on higher floors may be able to survive, but there is no guarantee that the tsunami height will be below the predicted height.While it's tempting to think that vertical evacuation or rooftop evacuation will save lives, the reality is that buildings lower than the tsunami's height are swallowed whole by the tsunami. Just imagine the terror and merciless cruelty of the surging tsunami. Recently, a lawsuit was filed over the deaths of people evacuating from the roof of a local bank. What is the government thinking? Is an evacuation plan that simply requires people to "get away no matter what" awaits? Given that people spend half their time at home, evacuating in areas without tall, sturdy buildings nearby is not easy. Even so, we must anticipate danger 24 hours a day, including at home, at work, and at school, throughout our daily lives, even in the middle of the night in the middle of winter. In any case, establishing evacuation shelters near residents will help resolve this issue, including providing peace of mind. Meanwhile, for those who cannot wait for a tsunami that could strike any day and who wish to help themselves, simply building their own home or personal shelters will allow for instant evacuation and help resolve the issue. If a life can be saved with a budget of 200,000 to 1 million yen per person, it is definitely worth considering. In fact, you can't take money to the grave with you. It's a once-in-a-lifetime decision, and it's important to use it wisely while you're still alive. Also, shelters in areas with slightly higher ground, say just 1 or 2 meters, allow fresh air to circulate more quickly, increasing the chances of survival.

[0009] Tsunami evacuation shelters integrated with levees will be close and immediate for coastal residents. If residents take the initiative in allocating the entrance to the designated shelter they will jump into in advance, it will be possible to evacuate quickly. Don't forget about the family members who will be looking after the house while you are away. The town hall staff who return from high ground work for eight hours a day and are not at home, so the remaining 16 hours after they get home make up a large part of the dangerous time. The shelter increases the number of hours of safety and security throughout the 24 hours, and it can be said that this increases the fair outcome and effective value of the possibility of saving lives. In this way, families should prepare for quick evacuation so that earthquakes and tsunamis can strike at any time within the 24 hours. It is important that families do not become separated If the body is adrift and broken up, the search costs will be several times higher. It is not just a personal problem of being lost, but it is important to recognize that being lost will cost the nation a huge amount of money. Tsunamis can strike at any time and in any place, so 24-hour family-centered training can be used to counter the bias of thinking that only you will be safe. Emergency preparedness is only effective if it is based on daily thinking and training. There must be no gaps in preparation for a tsunami that can strike at any time and in any place. The challenge of being able to respond 24 hours a day, anytime, anywhere, can be solved. Saving individuals and families requires foresight and imagination. We have the valuable experience of the Great East Japan Earthquake. It's easy to imagine that leaving it up to others would lead to the same outcome. Even if people have received a good education, they must not lose their lives through inaction. What have they been thinking, doing, or trying to do over the past 10 years? Are their evacuation methods and actions actually putting them at risk? A critical self-evaluation is needed to determine how many promising young lives they have been able to save.

[0010] In coastal areas, a Nankai Trough tsunami will cause six waves to repeat over a six-hour period. If we assume that these six waves occur once per hour, and the waves recede for half the time, fresh air will automatically be replenished and replaced when the water level at low tide drops below the height of the shelter's entrance / exit, then it is sufficient to endure the half-hour of flooding (30 minutes). This provides a hint for crisis prevention. Specifically, the regional characteristic value of 0.5 m3 / person-hour can be used. Because children and the elderly have lower lung capacity, it is possible to halve this value to 0.25 m3 / person-hour, with some discretionary interpretation. Humans cannot survive underwater without air. Death is virtually instantaneous. Considering this, it can be argued that having a shelter is better than not having one at all. Smaller volumes, such as 0.5 m3, 0.3 m3, or 0.25 m3, could be adopted for shelters exceeding capacity. Since tsunamis can occur at any time, seasonal equipment and measures to protect against the cold winter are necessary. This approach allows for tailored responses for each region, number of people, and season, resolving issues. The lower entrances allow for quick drainage, reducing humidity and condensation, and addressing the maintenance and corrosion prevention challenges common to structures. If there is sufficient space inside, providing items like rubber rafts and air mattresses can help keep vulnerable evacuees, such as the elderly, dry even in flooded areas. Hypothermia is a particular concern in winter, and air mattresses and blankets are helpful to prevent direct contact with cold water. Consider optimal responses for each season. Evacuations tailored to specific life situations and numbers can address even larger regional issues. At the fish market where I work, close to the ocean, I held my breath. This immediate evacuation ensured safety and security in everyday life. It was familiar, fast, and simple. Speaking up is crucial to saving the lives of 320,000 people. [Means for solving the problem]

[0011] In order to solve such problems, the tsunami evacuation shelter of the present invention, which is a dual-purpose structure integrated with a levee, is designed to be able to achieve a tsunami height equivalent to that of a levee by integrating a tsunami evacuation shelter that protrudes higher than the height of the levee onto the back of the levee, in case of a tsunami height that exceeds the height of the levee.The tsunami evacuation shelter is a highly stable rectangular box structure with a base dimension that is larger than the height dimension, a pile foundation box structure with the base dimension reduced, or a heavy box structure with a thick base that resists tipping over due to the force of tsunami waves, and the tsunami evacuation shelter is a structure that protrudes higher than the top of the levee, Although the area of ​​the protruding height will be directly hit by the wave force, by using the embankment body below the top of the embankment as a shield, the area directly hit by the tsunami can be reduced, which will increase the resistance of the tsunami evacuation shelter to collapse. This overlapping will prevent the existing embankment in front from collapsing, being damaged, or breaking, which will eliminate the difficulty of raising the embankment alone. The tsunami evacuation shelter will be elevated above the top of the embankment, which will expand the internal space, and this will bring hope to the coastal residents who were in a desperate situation due to the increased number of evacuees, and will also contribute to the long extension of the embankment. It is said that it can be extended in the extension direction using this, and even if it is overflowed and submerged by a larger tsunami, when the inside is flooded, the water surface will be at the height of the entrance and exit, and it will be an airtight, upper-closed hollow structure with the necessary air volume to survive underwater, and the entrance and exit will be located on the land side, making it an unsealed structure, and because it does not receive a large bending moment on the body wall, the wall thickness can be made relatively thin, and even then, the weight of the concrete body and the resistance of the piles will exceed the buoyancy acting on the body when submerged, so it will not float up, and end walls will be provided at any end of the length to form a hollow box shape, and the levee required for the tsunami height will be By ensuring the height is the same as that of the tsunami evacuation shelter, the same effect as raising the embankment can be achieved, and a larger evacuation capacity can be secured in the event of flooding.Furthermore, if a pool wall is installed inside, the amount of air that can be held can be increased, or by installing a small embankment on the top of the tsunami evacuation shelter or on the components on the top of the embankment, it is possible to contribute to even higher tsunami heights.The synergistic effect of the embankment and the tsunami evacuation shelter overlapping at the front and back against the tsunami wave force will reinforce the existing embankment and prevent it from collapsing, thereby preventing regional devastation.

[0012] Furthermore, the tsunami evacuation shelter of the present invention, which is a dual-purpose structure integrated with a levee, is characterized in that the area within the shelter near the open structure entrance is enclosed in a U-shape in plan view with a pool wall that is slightly higher than the height of the entrance, or by extending the enclosure to the end walls at both ends, thereby reducing the intrusion of floating debris and forming a temporary pool of tsunami water, which contributes to damping the direct hit of the tsunami wave, and in the event of a large tsunami, by raising the water surface to the height of the pool wall of the pool, the air from the floor height of the shelter is not allowed to escape as internal air, i.e., by using compressed air, the volume of survival air retained inside can be increased compared to the open structure without an enclosure.

[0013] Furthermore, the tsunami evacuation shelter of the present invention, which is a dual-purpose structure integrated with the levee, is characterized in that the top of the levee can be used as a road for levee management or for general vehicle and bicycle traffic.

[0014] Furthermore, the tsunami evacuation shelter of the present invention, which is a dual-purpose structure integrated with the levee, is designed to accommodate tsunami heights that are even slightly higher than the top height of the existing levee, which has a height limit.It is characterized by the fact that the overturning resistance can be increased by installing a small levee on the top, or by incorporating the top of the existing levee and raising it, or by extending the shelter to the rear, thereby allowing for the installation of an even higher small levee.

[0015] In addition, the tsunami evacuation shelter of the present invention, which is a dual-purpose structure integrated with the levee, is characterized by extending the shelter in the direction of private houses to facilitate faster evacuation, and by expanding or extending in a direction perpendicular to the levee. Levees are called various names such as quays, breakwaters, storm surge barriers, seawalls, and revetments, but here we will refer to them collectively as levees. Tsunami evacuation shelters can also be used to protect against tsunamis, floods, storm surges, typhoons, strong winds, tornadoes, and missile blasts. [Effects of the Invention]

[0016] By utilizing existing levees, we can avoid the enormous costs of traditional tsunami countermeasures, such as relocation to higher ground, high seawalls, and tsunami towers. Instead, we can save the lives of many coastal residents who fear a direct or sudden tsunami hit. Moreover, they can be saved from a tsunami that could strike at any time within 24 hours. It's a miracle from the depths of despair. Families are not torn apart, and what a blessing it is. By integrating existing low, old levees with tsunami evacuation shelters, we can simultaneously strengthen them. We can appreciate the hard work our predecessors put into building levees along this long coastline and make effective use of them. They can be brought back to life. Levee managers can also breathe a sigh of relief by promoting this initiative. Furthermore, by incorporating tsunami evacuation shelters into levees, levee managers can promote projects that strengthen the nation's resilience. Contributing to saving many lives is both rewarding and encouraging. It also avoids the unfortunate and unfortunate fate of being held accountable and sued. Tsunami evacuation shelters behind levees are particularly effective in coastal areas with narrow inlets where tsunamis strike like demons, and even more so in densely populated areas with limited garden space. They can also be applied to river sections where tsunamis simultaneously ascend, where the height of the levees is insufficient, and to sheet-pile revetments, if the ground conditions are resolved. The entrances and exits of levee evacuation shelters are designated seats for each resident, a gift from heaven, allowing them to jump right in. If measures are in place to save lives, cooperation can be united to achieve pre-disaster prevention. Total estimated damage is estimated at 170 trillion yen, and it is unclear how much of that will be human life, but these lives are precious. Pre-disaster prevention must begin with human life. The 320,000 lives that had been given up or even ignored—the 1 million victims—are seeing hope of survival. The individuals themselves are completely unaware that they are counted among them. They vaguely understand, but do not believe they will die. Seeing hope of survival makes people more positive. Various wisdom emerges. If evacuation were possible 24 hours a day, year-round, seamless response, people would be able to practice self-help. They would be able to respond instantly. Such efforts would allow people to live their daily lives with peace of mind. What a blessing! We can expect regional solidarity. If the Tohoku reconstruction budget is burdened with the enormous and noticeably slow progress of tsunami countermeasures, further increasing the burden in the event of a disaster, Japan will surely sink. Therefore, building crematoriums for 320,000 people and securing the necessary land would have a significant economic impact. The failure to respond despite predictions of damage 10 years in advance would be a true embarrassment to the world. It is clear that this will be the target of criticism. Who is responsible? The lack of a clear responsibility and lack of self-awareness beyond the levee managers is what is driving the slow progress. It's all our own doing, and self-help, mutual help, and public assistance are not progressing no matter how long we wait. But first, we need to make the decision to protect our own lives. The locations of family members going to school and work are predicted daily, allowing them to act together as a family, strengthening their sense of unity and bonds and preventing the family from drifting apart. A tsunami evacuation shelter on a nearby levee can be thought of as a safe zone that you can jump into immediately, a reserved seat that provides emotional support. This is how the national budget should be used. It is clear to everyone that if we prepare today for a tsunami that could happen tomorrow, we will be safe from tomorrow onwards. It becomes a social asset. It allows us to be grateful for the precious time we have now. No one would call this a waste of money.Saving lives would also save life insurance companies from bankruptcy. Tsunamis can strike at any time—maybe tomorrow—but investing national funds in shelter construction could save 320,000 lives. The estimated death toll of 320,000 people at home in the middle of winter at night is estimated at 320,000, likely due to being swept away with their homes and drowning. However, with this invention, even if homes are washed away, lives that escape to the levee will not be swept away. It's far too cheap compared to the preciousness of life. Japan, still stuck in pretend training for television for 10 years, is self-satisfied, adept at creating alibis, and is declining without doing anything. It's only ridiculed around the world. Let's make a difference. Precast concrete shelters can be manufactured in factories, are high-quality, and are suitable for transportation. Construction time is short. Hurry. [Brief explanation of the drawings]

[0017] [Figure 1] Image of cross section of existing levee subjected to storm surge wave force [Figure 2] Image of cross section of existing levee subjected to tsunami wave force [Figure 3] Image of a cross section of a levee and the inverted trapezoidal box-shaped tsunami evacuation shelter behind it, absorbing wave force. [Figure 4] Cross-section of a parallelogram and box-shaped tsunami evacuation shelter along a levee and slope [Figure 5] Cross-section of a tsunami evacuation shelter consisting of a dike, rectangular precast concrete structures behind it, and a culvert box [Figure 6] Schematic cross-sectional diagram for calculating the required wall thickness based on the relationship between the shelter's weight and buoyancy [Figure 7] Type A, cross-section of shelter for vulnerable evacuees [Figure 8] Type B, cross-section of a shelter for able-bodied people [Figure 9] Plan of the A, A, B, B series of shelter arrangements [Figure 10] Alternating shelter arrangement plan of A, B, A, B [Figure 11] An explanatory plan showing the pool wall attached to the boundary wall and a through hole at the bottom of the boundary wall. [Figure 12]A diagram showing the upper surface of the shelter open to the administrative road, general road, and bicycle path. [Figure 13] Cross section of the shelter with a small embankment on the top surface [Figure 14] Cross section of the existing levee, with the top raised to make the entire structure even higher [Figure 15] Cross-section of the embankment after extending it into the hinterland and raising it to increase its resistance to overturning [Figure 16] An explanatory plan showing the extension of the linked shelters perpendicular to the levee towards the local community and elementary school. [Figure 17] A cross-section of a rectangular box structure of a tsunami evacuation shelter that protrudes above the height of the levee, with the base longer than the height. [Figure 18] Cross-section of a tsunami evacuation shelter that protrudes above the height of the levee and has a box-type pile foundation structure [Figure 19] A cross-section of a tsunami evacuation shelter that protrudes from the height of the levee, with a heavy box structure with a thicker bottom. [Figure 20] A cross-section of a tsunami evacuation shelter that protrudes above the height of the levee, with components extending above the top of the levee. [Figure 21] Cross-section of a tsunami evacuation shelter that protrudes from the height of the levee, with components covering the top of the levee. [Figure 22] A cross-sectional view of a tsunami evacuation shelter that protrudes from the height of the levee, with additional members added to the top of the tsunami evacuation shelter or to the top members of the levee to further increase the height of the levee. DETAILED DESCRIPTION OF THE INVENTION

[0018] Common reference numbers are used throughout the drawings and detailed description to refer to the same elements.

[0019] Many residents live in coastal areas along the levees. Furthermore, in narrow cove areas, many homes are densely packed close to the shoreline. In the coves, the tsunami waves will be amplified in height, and as the force of the waves increases, houses will be wiped out, sweeping away. It is easy to imagine the scenes of people being swallowed up and tossed about by the waves. Measures must be taken urgently. The shelter will be supported behind the levees, making it possible to utilize the rigidity, weight, and long length of the existing levees. By integrating with the existing levees, the bearing capacity will be improved, and many lives in coastal areas will be saved. These combined effects make the tsunami evacuation shelter a dual-use structure that has a mutually beneficial effect on the levees. There are two types of shelters. Type A has no wall at the entrance and is for those with weaker evacuations, such as wheelchair users, the elderly, and pregnant women. Type B has a standing wall at the back of the entrance that is about 80 cm higher than the entrance, as well as a pool wall to prevent floating objects from entering, increase the evacuation space, and increase the amount of air held underwater. It is for able-bodied people, as they will need to climb over it. If possible, it is advisable to attach a handle.

[0020] Figure 1 shows a cross-section of typical wave forces on existing levees throughout Japan under conditions of high waves. Figure 2 illustrates the wave forces experienced by a 10-meter tsunami. Wave forces are said to be three times the hydrostatic pressure. This is subject to severe overflow. Figure 3 illustrates a typical tsunami evacuation shelter, designed to match the slope of the back of the levee, and its seaward sidewall and trapezoidal box structure combine to resist the wave forces of a large tsunami. Figure 4 shows a parallelogram with a slope that matches the slope of the levee, while Figure 5 shows an example of a box culvert, a rectangular precast product. The space between the levee and the back is filled with concrete to form a single unit. To mitigate the effects of overflow, the height of the shelter's top is generally set to be equal to or lower than the height of the existing levee's top. Partition walls are installed at regular intervals along the length of the levee, taking into account the spacing of the existing levee's joints and gaps, creating hollow rooms. The shelter should be approximately 10 meters long, divided into blocks, with intermediate walls added for reinforcement if necessary. A lightweight, hollow air-retaining shelter will float. To prevent a tsunami evacuation shelter from floating, the weight of the hollow concrete structure must be greater than the buoyancy acting on the structure. Figure 6 shows a simplified rectangular diagram for calculating the required wall thickness for reinforced concrete with a specific gravity of 2.5. The entrance and exit are located at the bottom of the landward side wall or end wall. The structure is not airtight, but rather non-sealed. Since the air and water pressures inside and outside the shelter are equal according to Pascal's principle, no bending moment is applied to the walls, and structural wall thickness is not required. In extreme cases, a wall as thick as a single sheet of paper would suffice. However, a box-like wall thickness is necessary to support and support the strong wave forces acting on the dike behind it. The necessary cover and wall thickness are also necessary to protect against salt damage. The structure also needs to have adequate rigidity and resistance to twisting and deformation. A box-shaped shelter that extends to the back and rear is naturally endowed with a resistance moment against overflow and tipping due to its box-shaped characteristics. For simplicity, an example of a rectangular wall thickness calculation is shown below. The weight of the structure must be greater than the buoyancy. Assuming a roughly 2m high embankment, with a 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 specific gravity of reinforced concrete of 2.5, 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 is a thin 0.2m thick plastic cast product, 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 won't float, but the thinness means there's less room for weight. For Type B, which has a pool wall, the weight of the pool wall is added. With a 0.3m wall thickness, the weight increases by 0.3 * 0.8 * 2.5 = 0.6 tons. A wall thickness of 0.2m would add 4 tons. Assuming a distance of 1m to the entrance / exit, buoyancy = 2*3 - 0.8*1 = 5.2 tons, so 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, so if a precast product is used, the wall thickness should be 0.25m or more. However, if we consider this as per 10m of extension, the remaining landward wall of the entrance / exit is 7m, the end wall is 2*3*0.2m to 0.3m, and there are also intermediate walls and corner reinforcing haunches, so mathematically it should be fine, but some leeway is still needed.

[0021] Utilizing natural theorems can also be useful. According to Archimedes' theorem, air, which has a lighter specific gravity than water, rises underwater. The rising air is concentrated in an upward-convex space. According to Archimedes' theorem, a shelter is subjected to a buoyant force equivalent to the volume of water displaced by the object. Although it is a hollow shelter containing air and is light, the weight of the structure must exceed the buoyancy. Furthermore, when a 10m tsunami hits, Boyle's law causes the internal volume to compress to half, simultaneously halving the buoyancy. According to Pascal's principle, the pressure inside and outside the shelter is equal. For this reason, the walls surrounding a shelter with an entrance at the bottom of the side wall will not be subjected to a pressure difference between the inside and outside, as would be the case with an airtight structure. Walls the thickness of a single sheet of paper would be sufficient. According to Boyle's law, the horizontal water surface near the bottom and at the height of the shelter's entrance creates an enclosed space. At a tsunami height of 10 meters, the water pressure is 2 atmospheres. The air inside the shelter is compressed by half at the top, by one-third at 20 meters, and by one-quarter at 30 meters. The water level and surface also rise accordingly, so don't panic. Because the interior is a confined space, the water level rises slowly at 1 / 20 the normal rate, with the internal water level of 0.5 meters and the external water level of 10 meters linked. Air always remains in the ceiling above. The air intake is naturally positioned at the top, sucking in air that has been compressed and risen near the ceiling of the top panel. Buoyancy is equivalent to the volume of air in the shelter underwater, so as the water level of the shelter rises, buoyancy also gradually increases. However, if the water level rises above the height of the shelter's entrance, the internal air is compressed, reducing its volume and decreasing buoyancy. When determining shelter capacity, it's important to consider the elderly, children, and the elderly, who have limited lung capacity, as they consume half the amount of oxygen. This allows for a margin of error, allowing for overcapacity. In 2013, news of a rescue from a shipwreck 30 meters deep off the coast of Nigeria, 62 hours after the water pressure caused by a maximum tsunami of 34 meters, was reported. Once the first wave subsides, the water level will recede and fresh air will be replaced. Designed for a flow rate of 1 cubic meter per hour, there's no need to worry too much. The first priority is to build shelters without further ado. If we hesitate and fail to act, we'll be submerged in the tsunami without any protection, and even a brief moment of air loss will kill us. The Odawara Council was a waste of time, full of discussion and research, without achieving its goal of saving lives. The time lost over the past 10 years will never be regained. We can't expect anything in the next 10 years.There is no one in charge who needs to produce results. However, I believe that if we move forward with courage, we can regain a time of success in the next 10 years.

[0022] No matter how high a tsunami is, six waves will occur over a six-hour period, creating a wave trough for natural air circulation. This allows for the design of air volume based on the tsunami period, or one hour. If an elementary school is nearby, consider extending the tsunami evacuation shelter nearby. In extreme cold, installing a connecting passageway with a covered wind tunnel, like an airplane ramp, can prevent sudden deaths from hypothermia. Such measures offer a glimmer of hope for the estimated one million casualties, a figure that represents each individual, immaterial mass of life. While transportation dimensions are limited, factory-fabricated precast concrete promises higher quality and shorter construction times. Consider using rectangular box culverts. Pouring concrete between the levee slope and the culvert creates a unified structure. Additionally, in case of lack of air and shortness of breath, it is advisable to place a life ring with a 10-meter rope. This will be useful for surfacing, breathing, and returning to the surface after the tide goes out. The rope anchor should be attached to the inside of the shelter wall, and the life ring should be attached to the outside of the shelter. The total volume of air in the inflatable ring must not be lost. However, you will need to find a way to roll up the rope so that only the ring floats up. [Example]

[0023] Tsunami evacuation shelters that are integrated with embankments and are dual-purpose structures are designed to be integrated with the back of the embankment, protruding higher than the height of the embankment, to achieve a tsunami height equivalent to that of the embankment, in case of tsunami heights that exceed the height of the embankment.The tsunami evacuation shelters are designed to be highly stable rectangular box structures with a base dimension that is larger than the height dimension, pile foundation box structures with a reduced base dimension, or heavy box structures with a thick base, to resist tipping over due to tsunami wave force, and the tsunami evacuation shelters are designed to be able to withstand direct hits from wave force at parts that protrude higher than the top of the embankment. By using the embankment body below the top of the embankment as a shield against the tsunami, the area directly hit by the tsunami can be reduced, which increases the resistance of the tsunami evacuation shelter to collapse. This overlapping prevents the existing embankment in front from collapsing, being damaged, or breaking, which eliminates the difficulty of raising the embankment alone. The tsunami evacuation shelter is designed to protrude from the top of the embankment, expanding the interior space. This brings hope to the coastal residents who are desperate and are facing an increased number of evacuation requests, and the long extension of the embankment can be used to extend the shelter. It is possible to extend the structure in the longitudinal direction, and even if it is overflowed and submerged by a larger tsunami, the water level will be at the height of the entrance and exit when the interior is flooded, and it will be an airtight, top-closed hollow structure with the necessary air volume to survive underwater, and the entrance and exit will be located on the land side, making it an unsealed structure.This means that the body wall will not be subjected to a large bending moment, so the wall thickness can be made relatively thin, and even then, the weight of the concrete body and the resistance of the piles will exceed the buoyancy acting on the body when submerged, so it will not float up.End walls can be provided at any end of the length to form a hollow box, and the embankment will be able to be constructed to the height required for the tsunami height. By ensuring the height of the tsunami evacuation shelter, the same effect as raising the levee can be achieved, ensuring a larger evacuation capacity in the event of flooding. Furthermore, if a pool wall is installed inside, the amount of air that can be held can be increased. Alternatively, by installing a small levee on the top of the tsunami evacuation shelter or on the components on the top of the levee, it is possible to contribute to even higher tsunami heights. The synergistic effect of the tsunami wave force and the levee overlapping the front and back of the tsunami evacuation shelter will reinforce the existing levee and prevent it from collapsing, thereby preventing regional devastation. Embankments are strong against the wave force and lateral force of high waves. Therefore, the seaward side wall of the box-shaped shelter is basically made integral with the back of the embankment, tightly adhering to the back of the embankment. This has a mutual effect, which can be said to bear part of the reaction force of the waves, or to hide and avoid a direct hit from the waves. On the other hand, embankments are vulnerable to overflow that exceeds the top. Therefore, the top of the shelter is basically made lower than the height of the top of the embankment to avoid the impact of overflow. The shelter's body is made of concrete, and is a non-sealed hollow structure with a space that can secure the amount of air necessary for survival of 1m3 per person, with an entrance and exit about 0.7m high and 2m wide. A maximum height of 5m is possible. They are installed at the bottom of the landward side and end walls. Vertical walls and end walls enclose the space at both ends of the shelter. The concrete structure must be heavy enough to overcome buoyancy and remain stable even when submerged. This means that the concrete structure's wall thickness must be at least 30cm for standard reinforced concrete. 25cm or more is preferable for precast products. Assuming end walls are installed at 10m intervals, Type A in Figure 7 accommodates 0.7*2.4*10=16.8 people based on the internal air volume. It is advisable to install a slope or ramp toward the back of the entrance / exit. Handrails are required for Type A, which is intended for those with limited ability to evacuate quickly, such as the elderly, pregnant women, and wheelchair users. Therefore, lowering the base slab by about 0.3m ensures an entrance / exit height of 0.7m above ground level. The gap between the back of the levee and the new tsunami shelter can be filled with concrete mortar or integrated, or the impact of the old and new concrete can be mitigated by using waterproof sheets, fiber sheets, plywood, elastite, or other joint materials and thin materials. However, since the new and old levees differ in the amount of expansion and contraction due to temperature changes and drying shrinkage over time, appropriate joint materials must be used to prevent cracking and prevent mutual interference. The existing levees have joints at regular intervals, so the spacing of the end walls of the new concrete shelter must be adjusted to avoid this impact. The shelter height should be approximately 0.7m to prevent people from concentrating at the same time at the entrance and exit, but the width should be 2m to 5m, taking into account the possibility of two people or two-wheeled vehicles jumping in at the same time. [Example]

[0024] Type B in Figure 8 is for able-bodied people, and requires them to climb over a wall. Providing a pool or gathering area at the entrance to the shelter acts as a damper to reduce the wave force of a tsunami and also increases the amount of air needed to survive. Type B can accommodate 0.6*2.4+0.8*1.4=25.2 people. Figures 9 and 10 show floor plans where the pool walls and vertical walls are U-shaped, or Figure 11 shows plans where the vertical walls at both ends and the walls extend to the end walls. Note that the latter has less remaining air volume than the former. It is recommended that the height should be about 10 cm higher than the entrance height. It is a good idea to provide handles on the top of the entrance wall and on the pool wall. Providing a bench inside the room will make it more comfortable. [Example]

[0025] By using the lower parts of the intermediate walls and retaining walls of shelters as passage holes between adjacent rooms, multiple shelters can be installed in a row along the long axis, like a row of houses. Figure 9 shows an example of a continuous arrangement: A, A, B, B. By installing a passage hole at the bottom of B, shelters can escape to the next room even if one room is damaged and flooded up to the ceiling. Figure 10 shows an example of an alternating arrangement: A, B, A, B. It is recommended that evacuees decide in advance which shelter they will escape to. However, caution is required, as drilling a hole between adjacent rooms A and B may result in a loss of air volume in B. Having residents decide which shelter to escape to during advance training will ensure a straight and quick evacuation. However, as shown in Figure 11, extending the Type B pool wall to the boundary wall and installing a passage hole at the bottom of the boundary wall at the height of the pool wall or the entrance / exit height allows continuous passage between A and B and continuous movement along the entire length of the shelter. [Example]

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

[0027] If the top of the existing levee could be made a little higher against a tsunami height, say L1, and more homes and residents could be saved, then we could consider constructing a small embankment on top of the shelter, as long as it could withstand the shelter's collapse and be strong enough to withstand the shelter's collapse. Furthermore, if it were possible to raise the height of the existing embankment, including its top, in conjunction with the embankment, the overall height of the small embankment could be further increased. Furthermore, if the tsunami evacuation shelter could be extended to the land behind it, it would be more resistant to collapse and the small embankment could also be made taller. See Figures 13, 14, and 15. [Example]

[0028] It is expected that the combination of levees and shelters will be able to better resist the force of tsunami waves. However, people who are some distance from shelters will still be unsure whether to flee to an evacuation agreement building, the mountain, or higher ground. Therefore, the shelters will be extended and expanded toward the town, i.e., perpendicular to the levees. This can be considered a way of extending a helping hand. In particular, extending and expanding them toward the elementary school will bring the entrance and exit closer, allowing for quicker evacuation. The lives of elementary school students, who hold the future, must not be taken. Protecting them is the greatest responsibility of adults. In areas with declining population, cooperation from residents, such as by providing vacant land, can be expected. See Figure 15. [Example]

[0029] Although the shelter is hollow, cracks can cause air to leak underwater. Air leakage can be fatal. Possible causes include drying shrinkage of concrete over time, distortion and cracks in the structure caused by a major earthquake preceding the tsunami, and cracks due to differences in age with the existing levee, the location of joints, and surface contact. Countermeasures are necessary. Placing convex plastic bags or airtight sheet bags upside down along the interior walls provides double the safety and prevents air leakage in the event of an emergency. Personally, I find garbage bags to be effective. While the required air volume is typically 1.0 m3 / person-hour, children and the elderly have lower lung capacity, so applying half the characteristic value can provide additional air in cases of overcrowding. A life jacket, a water-permeable framework to prevent floating debris from entering, a small air tank, a small oxygen tank, a floating debris protection plate, a flashlight, a smartphone, a radio, a hand warmer, bread, water, a portable toilet, a blanket, warm clothing, a disaster preparedness backpack containing garbage bags, a waterproof sheet, a shovel for removing mud that has accumulated outside, and even a life jacket with a 10-meter rope attached in case you get short of breath. You can surface and return to your original location when the tide goes out. Placing a water-permeable gabion near the entrance / exit will prevent floating debris from entering, and pulling it inside will serve as a seat. A long bench can be used as a bench. It can easily withstand a six-hour evacuation. A wooden raft is also acceptable. It's best to place the life jacket outside the shelter and anchor it inside. A raft large enough for about 10 people is acceptable. It's also a good idea to install protective devices and cushioning devices such as tires on the land-facing sidewall to mitigate the force of impacts from floating debris. To prevent people from getting wet from a tsunami flooding the interior, it is a good idea to prepare platform seats, rubber boats, vinyl floating floors, air mattresses, and boards inside. It is also a good idea to consider installing holes through adjacent rooms to prepare for any eventuality. In any case, regular awareness-raising, education, and training are necessary for tsunami countermeasures. [Example]

[0030] A tsunami evacuation shelter that is installed at the back of the embankment and protrudes from the height of the embankment's top, and if it is below the height of the existing embankment it will not be hit directly by floating debris. For able-bodied people, if a pool wall is installed inside, the air retention volume will be large. For weak people, walls are not installed as they get in the way. An example of a rectangular box structure with a base dimension larger than the height dimension, which is highly stable and can easily withstand tipping moments. [Example]

[0031] A tsunami evacuation shelter that is installed at the back of the levee and protrudes from the height of the levee top, and if it is below the height of the existing levee it will not be hit directly by floating debris. For able-bodied people, if a pool wall is installed inside, the air retention volume will be large. For weak people, walls will get in the way so they are not installed. An example of a pile foundation structure with reduced base dimensions that resists the tipping moment. [Example]

[0032] A tsunami evacuation shelter that is installed at the back of the embankment and protrudes from the height of the embankment top, and if it is below the height of the existing embankment it will not be hit directly by floating debris. For able-bodied people, if a pool wall is installed inside, the air retention volume will be large. For weak people, walls are not installed as they get in the way. An example of a structure where the thickness of the base is increased to increase the weight and resist the tipping moment. [Example]

[0033] This is an example of a tsunami evacuation shelter that is installed at the back of a levee and protrudes above the height of the levee's top, with part of the shelter body being installed on top of the existing levee's top.The thick components can withstand the direct force of tsunami debris. [Example]

[0034] This is an example of a tsunami evacuation shelter that is installed at the back of a levee and protrudes above the height of the levee's top, with the shelter body covering the front and above the top of the existing levee.By covering the top of the levee, it can further withstand direct hits from tsunami debris. [Example]

[0035] This is an example of a tsunami evacuation shelter that is installed behind the embankment and protrudes above the height of the embankment top, with a small embankment installed on top of the shelter or on components on the top of the existing embankment, making it possible to withstand even higher tsunami heights. [Explanation of symbols]

[0036] 1 Embankment 2 Tsunami evacuation shelter 3 Shelter wall 4. Air space inside the shelter 5. Entrance / exit 6 Embankment top 7 Back of existing levee, slope 8 High wave force 9 ground 10 sea level 11 Tsunami wave force 12 Overflow tsunami wave force 13 Inverted trapezoid box shelter 14 Parallelogram Box Shelter 15 Rectangular shelter, culvert box shelter 16 Concrete filling 17 Pool wall 18 Wheelchair 19 Handrail 20 Water-permeable floating debris intrusion prevention fence set 21 Chaise lounge 22 Swimming ring 23 Handle, anchor 24 Rope 25 Horizontal water surface formed at the height of the entrance / exit when a tsunami approaches 26 Horizontal water surface formed at the height of the pool wall when a tsunami approaches 27 Shelter floor that retains air until flooding reaches the height of the pool wall 28 Vehicle 29 Bicycles 30 Guardrail 31 Small embankment 32 Haunch 33 Partition walls, dividing walls, boundary walls, stop walls, and end walls separating adjacent structures 34 Connecting door and passageway to adjacent rooms at the bottom of the bulkhead 35 Buttress 36 Front wall 37 Existing embankment top end raised concrete section 38 Intermediate wall, reinforced wall 39 Resistance to tsunami wave force 40 Housing 41 Land side wall 42 A tsunami evacuation shelter that protrudes from the top of a levee and has a base that is longer than its height. 43 Tsunami evacuation shelters that protrude from the top of a levee and have pile foundations 44 Tsunami evacuation shelter that protrudes from the top of the levee and has a thickened base. 45 Shelter element extended above the top of the levee 46 Shelter material intended to cover the top of the levee 47 Small embankments installed on the top of tsunami evacuation shelters or on shelter components extended above the top of embankments

Claims

1. In the event of a tsunami height exceeding the height of the existing levee, a tsunami evacuation shelter that protrudes higher than the height of the existing levee is installed integrally with the rear of the existing levee, thereby achieving a levee equivalent to the tsunami height; the tsunami evacuation shelter is a highly stable rectangular box structure with a base dimension larger than its height, a pile-foundation box structure with the base dimension reduced, or a heavy box structure with a thick base, which resists tipping over due to tsunami wave force; the tsunami evacuation shelter will be directly hit by wave force at the protruding height above the top of the levee, but the levee body below the top of the levee can be used as a shield to reduce the area directly hit by the tsunami, thereby increasing the resistance of the tsunami evacuation shelter to tipping over; this overlapping arrangement prevents the existing levee in front from tipping over, being damaged, or breaching, thereby eliminating the difficulty of raising the levee alone; the tsunami evacuation shelter has an increased internal space due to its height protruding from the height of the top of the levee; This brought hope to coastal residents who were in a desperate situation as the number of evacuees increased, and even if the shelter is overflowed and submerged by a larger tsunami, it is an airtight, top-closed, hollow structure with the water level at the entrance and exit height when the interior is flooded, and has the air volume necessary to survive underwater, and the entrance and exit are located on the land side, making it an unsealed structure. This means that the wall thickness can be made relatively thin because the body wall is not subjected to a large bending moment, but even so, the weight of the concrete body and the resistance of the piles exceed the buoyancy acting on the body when submerged, so it does not float up. End walls are provided at either end of the length to form a hollow box, and by ensuring the height of the levee required for the tsunami height with the height of the tsunami evacuation shelter, it has the same effect as raising the levee and can secure a larger evacuation capacity in the event of flooding. This tsunami evacuation shelter is a dual-purpose structure that is integrated with the levee and is characterized by the synergistic effect of the tsunami wave force and the overlapping of the front and back of the levee and the tsunami evacuation shelter, which reinforces the existing levee and prevents it from collapsing, thereby preventing regional devastation.

2. A tsunami evacuation shelter that is a dual-purpose structure integrated with the embankment described in claim 1, characterized in that it is extended in the extension direction by utilizing the long extension of the embankment.

3. A tsunami evacuation shelter that is a dual-purpose structure integrated with the levee described in claim 1, characterized by having a pool wall inside to increase air retention capacity.

4. A tsunami evacuation shelter that is a dual-purpose structure integrated with the embankment described in claim 1, characterized in that a small embankment is provided on the top of the tsunami evacuation shelter or on a component on the top of the embankment, thereby contributing to the prevention of even higher tsunami heights.

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