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

Abstract

It is difficult to build levees high enough to accommodate the predicted tsunami height due to budgetary constraints. Construction of high seawalls has not progressed because they would block views of the ocean. [Solution] By utilizing the existing levee and stacking a tsunami evacuation shelter that protrudes from the levee height on its backside, it is possible to increase the height slightly and achieve satisfactory strength. Furthermore, by providing an inclined surface on the protruding part, the direct force of the tsunami can be dispersed and mitigated by the upward force, making it possible to accommodate further height increases and making the structure stable. Since it saves the area and human lives, it is easy to gain the support of residents.

Description

[Technical Field]

[0001] This invention relates to a tsunami evacuation shelter that is integrated with the back of an existing levee in coastal areas prone to sudden tsunamis, avoiding direct hits from the wave force of the tsunami, maintaining the amount of survivable air inside even when underwater, and being close to houses, allowing for quick evacuation.The shelter has a protruding part above the height of the levee top and is equipped with a slope that cushions the direct hit of the tsunami wave force with an upward force. [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 overflows, and the shelters are simply cave-shaped structures within 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 three-building structure constructed in a piecemeal fashion would not fulfill the original function of a levee. Patent Document 4 is even larger, incorporating apartments, schools, hotels, and other structures within 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 shelters with high, sloping surfaces behind them to deflect direct wave force with upward force, which is inexpensive and takes advantage of the long length of the embankment to save many residents living along the embankment. [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, an explanation is needed as to why it is not raised any higher. Even in this case, it is easy to gain understanding that it is a good idea, as there is a basis that lives can be saved in tsunami evacuation shelters even if they are submerged. The challenge and mission is to save the estimated 320,000 deaths and 1 million casualties from the 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 tsunami-hit areas. This means 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 sturdy against typical wave forces. However, they are simply not tall enough to withstand the tsunami. It would be simplistic to dismiss them as useless simply because they are not tall enough. They are only short-sighted by the amount of height that exceeds the levees themselves. However, it would be unrealistic to build a 10-meter-tall high seawall. Therefore, we considered compensating for this lack of height with functionality. In other words, if the levee itself and the tsunami evacuation shelters were combined into a single structure, with a height that protrudes beyond the height of the levee, allowing air to be retained even when submerged, the crucial weakness of the levee, namely, the possibility of breaching, could be overcome. Furthermore, there are limits to simply raising the protruding height due to the magnitude of the direct wave force. Therefore, it is necessary to consider ways to mitigate the force of the direct waves. The levee, which was considered ineffective against a high tsunami in its current state and was instead considered a dangerous long structure that would collapse in an instant, could be revived, and a glimmer of hope could be seen that could save 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 this problem, the tsunami evacuation shelter of this invention, which is a dual-purpose structure integrated with the levee, is designed to be able to withstand tsunami heights that exceed the height of the existing levee by integrating the tsunami evacuation shelter, which protrudes higher than the height of the existing levee, onto the back of the existing levee, thereby achieving a tsunami height equivalent to that of the levee. Therefore, the tsunami evacuation shelter is designed to resist tipping over due to the tsunami wave force, and The shelter will create an upward force of wave power in the event of a direct hit from a tsunami by forming arcuate surfaces, inclined surfaces, or inclined surfaces on the extension of these surfaces, in parts or components that protrude above the top of the levee, or if the vertical wall of a precast product is exposed and there is space in front of it, wave-dissipating blocks will be placed to mitigate the direct hit of the tsunami. In addition, by using the embankment body below the top of the levee as a shield, the area directly hit by the tsunami can be reduced, and these measures will increase the resistance of the tsunami evacuation shelter to tipping over. This overlapping will prevent the existing embankment in front from tipping over, being damaged, or breached, and will thereby eliminate the difficulty of raising the height of the embankment alone. The tsunami evacuation shelter will also be able to expand its internal space by protruding above the height of the top of the levee, providing a ray of hope for coastal residents who are desperate as the number of evacuees increases. Even if the shelter is overflowed and submerged by a larger tsunami, when the interior is flooded, the water level will be at the height of the entrance and exit, and the airtight upper part will have the necessary air volume to survive underwater. It is a closed hollow structure, and is an unsealed structure with an entrance on the land side, so that there is no difference between the tsunami water pressure and the internal air pressure on the body wall, and so it is not subjected to a large bending moment, so the wall thickness can be made relatively thin, and even so, the weight of the concrete body and the pull-out resistance of the piles exceed the buoyancy acting on the body when submerged, so it will not float up, and a hollow structure is formed with end walls at any end in the length direction, and the embankment height required for the tsunami height is determined by the upward force due to the slope and extended slope, or by a straight wall to avoid a direct hit by the tsunami force. By using wave-dissipating blocks to mitigate tsunami force, resistance to tipping over can be increased, and the height of the tsunami evacuation shelter can be ensured, achieving the same height and effect as raising the embankment.The increased internal space allows for a larger evacuation capacity in the event of flooding, and the non-sealed structure means that lives can be saved even if a higher tsunami overflows.The mitigation of tsunami wave force and the synergistic effect of the embankment and the tsunami evacuation shelter overlapping at the front and back also 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 this invention, which is a dual-purpose structure integrated with the levee, has a large interior space when vehicular access is required for levee management. However, since both ends are closed, some ingenuity is required. The end walls can be made openable or multi-story, but in either case, people can enter through the land-side entrance, so wooden doors or half-open doors that can be easily broken down in an emergency are used to prevent danger.

[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 surge upstream, such as levees and 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 and unity can lead to proactive 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. We must first consider proactive disaster prevention for 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 don't believe they will die. Seeing hope of survival makes people more positive. Various wisdom emerges. If continuous 24-hour evacuation becomes possible all year round, people will be able to practice self-help. They will be able to respond to evacuation instantly. With this effort, people will be able to live their daily lives with peace of mind. What a blessing it will be. We can look forward to solidarity in the community. If the Tohoku reconstruction budget is increased further by the huge amount of tsunami countermeasures that are progressing so slowly that no one can see, the sinking of Japan will be imminent. It appears that this is the case. If that's the case, then building a crematorium for 320,000 people and securing the necessary land would have a significant economic impact. The failure to respond despite predictions of damage dating back 10 years would be a true embarrassment to the world. It's clear that we will be the target of criticism. Who is responsible? The first step is to clarify who is responsible. Progress is slow due to the lack of self-awareness and the lack of specific responsibilities beyond those responsible for the levee. This is a self-inflicted disaster, and no progress will be made no matter how long we wait for self-help, mutual aid, or public assistance. However, we must first resolve to protect our own lives. By planning the locations of family members going to school and work every day, we can act together as a family, strengthening our sense of unity and bonds and preventing the family from drifting apart. Tsunami evacuation shelters on nearby levees can be considered a safe zone where we can quickly jump in, a designated seat for emotional support. This is where the national budget should be spent. It's clear to everyone that preparing today for a tsunami that could happen tomorrow will ensure safety from tomorrow onward. This will be a social asset. It will allow us to be grateful for the precious time we have. No one would call this a waste. Saving lives would prevent life insurance companies from going bankrupt. Tsunamis can strike at any time, even 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. With this invention, even if homes are washed away, those who escape to the levee will be protected. 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. [Figure 23] Cross-section of a tsunami evacuation shelter with a sloped top protruding from the levee height to increase the tsunami levee height by capturing the upward force of the tsunami. [Figure 24] Cross-section of a tsunami evacuation shelter with an arc-shaped top that protrudes above the levee height, allowing for the upward force of the tsunami to be absorbed and the levee height to be increased. [Figure 25] Cross-section of a tsunami evacuation shelter with a higher levee made by extending the slope on the top part of the levee. [Figure 26] Cross-section of a tsunami evacuation shelter that has a slope or extended slope in front of the vertical wall of a precast product that protrudes above the height of the levee, obtaining upward force and mitigating the direct impact of wave force. [Figure 27] Cross-section of a tsunami evacuation shelter that uses wave-dissipating blocks in the space in front of the vertical wall of a precast product that protrudes above the height of the embankment to mitigate the force of direct waves. [Figure 28] Cross-section of a tsunami evacuation shelter with a higher levee, created by installing a slope or extended slope in front of and on top of the part that protrudes higher than the levee height. [Figure 29] If a dike maintenance road is required, the internal space must be enlarged. 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 naturally has 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] For tsunami heights exceeding the height of the existing levee, a tsunami evacuation shelter that protrudes higher than the height of the existing levee is installed integrally on the back of the existing levee to realize a levee equivalent to the tsunami height, and the tsunami evacuation shelter is designed to resist tipping over due to the force of the tsunami, and the tsunami evacuation shelter creates an upward component of the wave force in the event of a direct hit by the tsunami by forming an arc surface, an inclined surface, or an inclined surface on an extension thereof, in the parts and components that protrude higher than the top of the levee, or in the case of a precast product where the vertical wall is exposed and there is space in front of it, wave-dissipating blocks are arranged. By placing the shelter above the levee, the force of the direct hit of the tsunami can be mitigated, and by using the levee body below the top of the levee as a shield, the area directly hit by the tsunami can be reduced, which increases the resistance of the tsunami evacuation shelter against tipping over. This overlapping prevents the existing levee in front from tipping over, being damaged, or breaching, which eliminates the difficulty of raising the levee alone. The tsunami evacuation shelter can also be made to protrude above the height of the levee top, which can expand the internal space, providing a ray of hope for the coastal residents who were in a desperate situation as the number of evacuees increased. Even if the dike is overflowed by a larger tsunami and submerged, the water level will be at the height of the entrance and exit when the interior is flooded, and the airtight, top-closed hollow structure will have the necessary air volume to survive underwater, and the entrance and exit will be located on the land side, making it an unsealed structure.As a result, there is no difference between the tsunami water pressure and the internal air pressure on the body wall, so it will not be subjected to a large bending moment, and the wall thickness can be made relatively thin.However, the weight of the concrete body and the pull-out resistance of the piles will exceed the buoyancy acting on the body when submerged, so it will not float up.A hollow structure will be formed with end walls at any two ends in the length direction, and the dike height required for the tsunami height will be set as above. By mitigating tsunami force with the upward force of inclined or extended inclined surfaces, or by using wave-dissipating blocks that avoid a direct hit from the tsunami force in straight walls, the resistance to tipping over can be increased, and the height of the tsunami evacuation shelter can be ensured, achieving the same height and effect as raising the embankment, and the increased internal space can ensure a greater evacuation capacity in the event of flooding, so that lives can be saved even if a higher tsunami overflows.This non-sealed structure, which mitigates tsunami wave force and has a synergistic effect of the embankment and the tsunami evacuation shelter overlapping at the front and back, also reinforces the existing embankment, prevents it from collapsing, and prevents regional devastation. Levees are built to be strong against the wave force and lateral force of high waves. Therefore, the seaward side wall of a box-shaped shelter is basically made integral with the back of the levee, tightly attached to it. This has a mutual effect, in that it absorbs part of the wave reaction force and also hides to avoid a direct hit from the wave force. On the other hand, levees are vulnerable to overflows that exceed their crest, so the top of the shelter is generally made lower than the crest height of the levee, but it would be better to make the levee as high as possible. To do this, it is necessary to make it structurally strong, or to mitigate wave force. Here, a slope is used, which has the same effect as increasing the levee height by mitigating wave force. Naturally, a higher slope has the same effect as increasing the levee height. It can also reduce the overturning moment, so it is advantageous from a structural standpoint. The shelter's frame is made of concrete, with a non-sealed, hollow structure that provides the necessary air volume for survival of 1 m3 per person. The entrance / exit should be approximately 0.7 m high and 2–5 m wide. It should be located at the bottom of the landward-facing side and end walls. The shelter's ends are enclosed by vertical walls and end walls. The concrete frame must be heavy enough to overcome buoyancy and remain stable even when submerged. Therefore, the concrete frame wall thickness must be at least 30 cm for standard reinforced concrete. 25 cm or thicker is preferable for precast products. Assuming end walls are installed at 10-m intervals, Type A in Figure 7 accommodates 0.7 x 2.4 x 10 = 16.8 people based on the internal air volume. It is recommended to install a slope or ramp toward the back of the entrance / exit. Type A, intended for those with limited ability to evacuate quickly, such as the elderly, pregnant women, and wheelchair users, requires handrails. Therefore, lowering the base slab by 0.3 m ensures an entrance height of 0.7 m above ground level. The gap between the back of the levee and the new tsunami shelter can be filled with concrete mortar or integrated with the new shelter. Alternatively, the impact of the old and new concrete can be mitigated by using waterproof sheets, fiber sheets, plywood, elastite, or other joint materials or thin materials. However, because the new and old levees differ in the amount of expansion and contraction caused by temperature changes and drying shrinkage over time, appropriate joint materials must be used to prevent cracking and avoid mutual interference. Since the existing levees have joints at regular intervals, the spacing of the end walls of the new concrete shelter must be adjusted to avoid these effects. The height of the entrance / exit shelter should be approximately 0.7 m to prevent people from concentrating at the same time, but the width should be 2 m to 5 m, considering the possibility of two people or two-wheeled vehicles jumping in at the same time. See Figures 1 to 8. [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 mitigate the wave force of the tsunami and also increases the amount of air required for survival. 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 walls extending to the vertical walls and end walls at both ends. Care must be taken with the latter, as the remaining air volume is less than with the former. It is recommended that the height be about 10cm 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 shelter will make it more comfortable. See Figures 8, 9, 10 and 11. [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, evacuees 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 room 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. See Figures 9, 10, and 11. [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 the shelters will 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 put the entrance and exit directly in front, making evacuation quicker. 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 16. [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 in the event of a tsunami, 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 in case of an emergency. In any case, regular awareness-raising, education, and training are necessary for tsunami countermeasures. [Example]

[0030] This is a tsunami evacuation shelter that is installed at the back of the embankment and protrudes above 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 will get in the way so they are not installed. This is an example of a rectangular box structure with a base dimension that is larger than the height dimension, making it highly stable and easy to resist tipping moments. See Figure 17. [Example]

[0031] A tsunami evacuation shelter built on the back of a levee, protruding above the height of the levee's top, will not be hit directly by floating debris if it is below the height of the existing levee. For able-bodied people, a pool wall can be installed inside, which increases the air retention volume. For weak people, walls are not installed as they get in the way. An example of a pile foundation structure with reduced base dimensions that resists the overturning moment. See Figure 18. [Example]

[0032] This is a tsunami evacuation shelter that is installed at the back of the embankment and protrudes above 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 will get in the way and will not be installed. An example of a structure in which the thickness of the base is increased to increase weight and therefore resist the tipping moment. See Figure 19. [Example]

[0033] This is an example of a tsunami evacuation shelter that is installed behind a levee and protrudes above the height of the levee's top, with part of the shelter's structure built on top of the existing levee's top. The thick members are able to withstand the direct force of tsunami debris. See Figures 20 and 21. [Example]

[0034] This is an example of a tsunami evacuation shelter that is installed at the rear of a levee and protrudes above the height of the levee's top, with the shelter body covering the front of the existing levee's top. By covering the levee's top, it can further withstand direct hits from tsunami debris. See Figure 22. [Example]

[0035] This is an example of a tsunami evacuation shelter that is built behind a levee and protrudes above the levee crest height, with a small levee built on top of the shelter crest or on a member on the top of the existing levee, making it possible to withstand even higher tsunami heights. See Figures 13, 14, and 22. [Example]

[0036] This is a tsunami evacuation shelter that is installed at the rear of the levee and protrudes from the height of the levee's top, and if it is lower than the height of the existing levee, it will not be hit directly by floating debris. An example of increasing the height of the tsunami levee by providing a slope in front of the protruding part to raise the height and diverting the direct hit of the tsunami with an upward component of the force, thereby mitigating the wave force. See Figure 23. [Example]

[0037] This is an example of increasing the height of a tsunami levee by making the protruding part of the raised wall an arc surface, which can reduce the wave force by deflecting the direct hit of the tsunami with an upward force component. See Figure 24. [Example]

[0038] This is an example of how the height of the tsunami levee can be further increased by extending the slope of the protruding surface to further deflect the direct hit of the tsunami with an upward force, thereby mitigating the wave force. See Figure 25. [Example]

[0039] When using concrete culverts or precast products as tsunami evacuation shelters with fixed shapes, the protruding vertical walls will be hit directly by the tsunami, so by providing a sloped front surface and an extended sloped surface, the wave force can be mitigated by deflecting the direct hit of the tsunami with an upward component of the force, and this is an example of increasing the height of the tsunami levee. See Figure 26. [Example]

[0040] In the case of concrete culverts and precast products, which have fixed shapes, direct hits are received on the protruding vertical walls, so wave-dissipating blocks can be placed in the extra space in front to mitigate the direct hit. See Figure 27. [Example]

[0041] This is a tsunami evacuation shelter that is installed at the rear of the embankment and has a height that protrudes entirely from the height of the embankment's top, so if it is below the height of the existing embankment, it will not be hit directly by drifting debris. In the protruding part, an inclined surface and an extended inclined surface are installed from the top of the existing embankment, which generates an upward force and can mitigate direct hits and wave force, thereby achieving even greater height. See Figure 28. [Example]

[0042] If levee management requires vehicle passage, the interior space should be large. However, since both ends are closed, some ingenuity is required. The end walls may be openable or multi-story, but in either case, since there is a possibility of intrusion from the land-side entrance 5, wooden doors or half-open doors that can be easily broken down in an emergency should be used to prevent danger. See Figure 29. [Explanation of symbols]

[0043] 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 48 slope 49 arc surfaces 50 Extended Inclined Surface 51 Reinforced walls and reinforcement members 52 Wave-dissipating blocks 53 Upward component of wave power

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 will be installed integrally at the back of the existing levee to create a levee equivalent to the tsunami height. The tsunami evacuation shelter will resist tipping over due to the force of the tsunami, and the tsunami evacuation shelter will create an upward component of the wave force in the event of a direct hit by the tsunami by forming an arc surface, an inclined surface, or an inclined surface on an extension thereof, in the parts and components that protrude higher than the top of the levee. At the same time, the levee body below the top of the levee will act as a shield, thereby increasing the area directly hit by the tsunami. It is said that these measures can increase the resistance of the tsunami evacuation shelter to tipping over, and that this overlapping can prevent the existing levee in front from tipping over, being damaged, or breaking, which can eliminate the difficulty of raising the levee alone.The tsunami evacuation shelter can also expand its internal space by being made to protrude from the top of the levee, so that even if the number of evacuees increases and it is overflowed and submerged by a larger tsunami, when the interior is flooded, the water level will be at the height of the entrance and exit, and it will have the necessary air volume to survive underwater. The dike is an airtight hollow structure with an upper closed section, and the entrance and exit are located on the land side, making it an unsealed structure. This means that there is no difference between the tsunami water pressure and the internal air pressure on the wall of the structure, so it is not subjected to a large bending moment, and the wall thickness can be made relatively thin. However, the weight of the concrete structure and the pull-out resistance of the piles exceed the buoyancy acting on the structure when submerged, so it will not float up. A hollow structure is formed with end walls at any end in the length direction, and the height of the dike required for the tsunami height is determined by the upward force due to the slope and extended slope, or by wave-dissipating blocks that prevent a direct hit by the tsunami force in the case of a straight wall. By mitigating wave force, the shelter's resistance to tipping over is increased, allowing the height of the tsunami evacuation shelter to be secured, achieving the same height and effect as raising the embankment, and the increased internal space allows for a larger evacuation capacity in the event of flooding, saving lives even if a higher tsunami overflows or floods.This is a non-sealed structure, and the tsunami evacuation shelter is a dual-purpose structure that is integrated with the embankment, characterized by the mitigation of tsunami wave force and the synergistic effect of the embankment and the tsunami evacuation shelter overlapping at the front and back, reinforcing the existing embankment and preventing it from collapsing, thereby preventing regional devastation.

2. In the event of a tsunami height exceeding the height of the existing levee, a tsunami evacuation shelter that protrudes higher than the existing levee height will be installed integrally behind the existing levee, thereby realizing a levee equivalent to the tsunami height. The tsunami evacuation shelter will resist tipping over due to the force of the tsunami, and if the precast product has exposed vertical walls and there is space in front of it, wave-dissipating blocks will be placed to mitigate the direct impact force of the tsunami. In addition, the levee body below the top of the levee will be used as a shield to reduce the area directly hit by the tsunami. It is said that the resistance of the shelter to tipping over can be increased, and that this overlapping can prevent the existing levee in front from tipping over, being damaged, or breaking, which can eliminate the difficulty of raising the levee alone.The tsunami evacuation shelter can also expand its internal space by being made to protrude from the top of the levee, so that even if the number of evacuees increases and it is overflowed and submerged by a larger tsunami, when the interior is flooded, the water level will be at the height of the entrance and exit, and it will be an airtight upper closed shelter with the necessary air volume to survive underwater. It is a hollow structure with an entrance and exit on the land side, and as there is no difference between the tsunami water pressure and the internal air pressure on the wall of the structure, it is not subjected to a large bending moment, so the wall thickness can be made relatively thin, and even so, the weight of the concrete structure and the pull-out resistance of the piles exceed the buoyancy acting on the structure when submerged, so it will not float up, and a hollow structure is formed with end walls at any end in the length direction, and the embankment height required for the tsunami height is mitigated by the upward force due to the slope and extended slope, or by wave-dissipating blocks that avoid a direct hit from the tsunami force in the case of straight walls. This increases the resistance to tipping over, allowing the height of the tsunami evacuation shelter to be secured, achieving the same height and effect as raising the embankment, and the increased internal space allows for a larger evacuation capacity in the event of flooding, so lives will be saved even if a higher tsunami overflows or floods.The non-sealed structure also reduces tsunami wave force, and the synergistic effect of the embankment and the tsunami evacuation shelter overlapping at the front and back reinforces the existing embankment, prevents it from collapsing, and prevents regional devastation.

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