Leaning Tower of Pisa
In fact, many experts have been arguing about the reasons for the tilt. At first, some scholars thought that architects deliberately built the leaning tower of Pisa to show their superb architectural skills.
In the 20th century, with the deepening of the research on the leaning tower of Pisa, combined with some previous understandings, the truth gradually surfaced: the original design of the leaning tower of Pisa was supposed to be a vertical building, but it began to deviate from the correct position at the early stage of construction.
Its inclination is undoubtedly related to the soil quality. Because in the19th century, the famous architect Radska took samples in the foundation of the leaning tower, which confirmed that the soil condition was the cause of the tower's inclination. There are several layers of soil under the leaning tower of Pisa, which are made of different materials. Sediments in each soil layer are alternately formed with soft clay, while the groundwater layer is about 1 m deep. This conclusion is obtained after observing the composition of foundation soil. The latest excavation sampling shows that the bell tower was built on the edge of the ancient coast, so the soil has been desertified and sunk during construction.
However, some experts found that Pisano, the first architect, knew that the tower was built on the alluvial land of a river valley, just like Pisa, so he was not completely ignorant of the geological structure of the foundation. Moreover, after he found the inclination on the third floor, he immediately stopped working and waited for the foundation to stabilize, which has solved some problems. When the second architect continued to build, he noticed that the tilt height was adjusted and took some measures to reduce the weight of the tower. The third architect was built between the seventh and eighth floors, but the bell tower has changed, and the eighth floor leans to the north. Moreover, when the bell tower was built, it had some characteristics of mosque minarets, and there was no roof to reduce the weight and balance of the tower. These practices of architects are similar to those of other places in Pisa.
Leaning tower of Pisa at sunset
Florence, another famous Italian city, was built in 1420. The Cathedral of Santa Maria del fiore is located in a swamp, with soft soil and great danger of sinking, but it has been hundreds of years now and has not tilted at all. Therefore, some experts and scholars speculate that the inclination of the leaning tower of Pisa is expected by architects and related to designers and builders for hundreds of years.
At this time, many people may have questions. The leaning tower of Pisa can't tilt so much at once. What is the tilting process?
The leaning tower of Pisa was laid on 1 173, and was built by the famous architect Bonano Bisano. The original design height of the tower was about 100 m, but after five or six years of construction, the tower began to tilt on the third floor. The architect then ordered the suspension of work and wanted to wait for the foundation to stabilize before returning to work. However, in his lifetime, he failed to realize his desire to continue construction.
By 1275, the tower has been tilted by more than 90 cm. In the same year, architect Di Simon resumed the construction of the tower, and in view of the tilt problem, some measures were taken in the construction, not only thinning the tower wall, using lightweight materials, but also leaving a cavity of 30 to 80 cm between the inner wall and the outer wall. By 1284, the tower was built to the sixth floor, and the tilt continued. That year, Disimone died and stopped working.
Since then, the famous architect tommaso Pisana continued to build the seventh and eighth floors, and finally 1350 was completed. The tower is 56 meters high and has a total weight of 1.45 million tons. Except for a few granite pillars, the external materials are all white and black marble.
Construction process of leaning tower of Pisa
However, after the completion of the leaning tower, the inclination continued. According to relevant statistics, during the period of 1829- 19 10, the annual average dip angle was 3.8 mm, and the dip speed has slowed down since the beginning of the 20th century. During the period of 19 18- 1958, the annual average dip angle is 1. 1 mm, and during the period of 1959- 1969, the annual average dip angle is/kloc-. The annual average inclination is 1.26 mm. After that, the annual average inclination is 1. 19 mm. So far, the tower deviates from the vertical (that is, the top of the tower deviates from the vertical) by more than 5 meters.
In fact, speaking of the Leaning Tower of Pisa, do you know why it is so famous?
Let's go back to 1590. Galileo, a 25-year-old professor at the University of Pisa, is conducting a great scientific experiment. Students, teachers and passers-by are watching. At Galileo's command, an iron ball weighing 10 pound and an iron ball weighing 10 pound fell from the top of the tower at the same time. Soon, two balls landed at the same time. Then repeat the experiment again and the result is still the same.
Illustrations of the leaning tower of Pisa in textbooks
This experiment proves that Aristotle's statement that "the speed at which an object falls is proportional to its weight" is wrong. At the same time, the law of free fall is proved-regardless of the size of the object, if the influence of air resistance is removed, its acceleration is exactly the same. Galileo's experiment not only corrected a long-standing fallacy in physics, but also made the Leaning Tower of Pisa famous all over the world.
The leaning tower of Pisa is world famous. In fact, experts and ordinary people are very concerned, and they are worried about whether it will fall.
According to the tilt speed of the leaning tower of Pisa in recent years, expert Professor Gary thinks that if the flowers calculated according to this tilt speed suddenly collapse without other reasons, then the leaning tower will collapse after 250 years because the center of gravity of the tower exceeds the outer edge of the tower foundation.
However, the relevant personnel of the Leaning Tower of Pisa Service Bureau believe that it is obviously unreliable to calculate by mathematical methods, and the Leaning Tower of Pisa is a comprehensive problem. Some researchers have also found such a problem. The leaning tower of Pisa once tilted to the east and then turned to the south. It is believed that this tower has been tilted for hundreds of years and will not fall down. If we only use mathematical methods to calculate whether it will drop after 250 years, I am afraid it is not that simple.
Miracco Li plaza
After all, Pisa people are most concerned about the leaning tower. They have a saying that the leaning tower of Pisa is as strong as Pisa people and will never fall down.
But then again, whenever experts take some measures to strengthen the foundation of the leaning tower, its tilting speed will be accelerated. For example, 1838 reinforced, 1934 sprayed 90 tons of cement into the foundation and made waterproof works, which made the tower more unstable and even walked and tilted faster. However, during the period from 1973 to 1975, the private wells within 3km of Fiona Fang of the leaning tower were closed, and the groundwater level became stable and the inclination speed slowed down.
1990 65438+1On October 7th, a famous TV presenter in Italy announced that the leaning tower of Pisa was temporarily closed. The municipal government decided to temporarily close the leaning tower for maintenance, which is the first time that the leaning tower of Pisa has been officially closed to the public since its completion.
The Italian government spent 25 million pounds to start the restoration project, including strengthening the foundation and pumping groundwater, and supporting the tower with steel wires and cables. The restoration project was completed at 200 1, and immediately straightened about 38 cm. According to the latest survey, from 200 1 to 20 13, the inclination of the leaning tower of Pisa decreased by 2.5 cm.
See here, do you have a deeper understanding of the Leaning Tower of Pisa? It is not only one of the famous landmarks in Italy, but also the pride of Italians. It is also a masterpiece of human creative spirit and has also been included in the World Heritage List. Great buildings may really need some coincidences. If the architects at that time knew that geology was not suitable for building towers, they might not see this great building, but we can see the hard work of every geological engineer from it.