Pearl Tower

The Pearl Tower is also called Baoguang tower. It is located in Zhongfeng, Tianma mountain, Songjiang District, Shanghai. Because the tower is inclined, it is also called inclined tower. Tianma mountain is the eighth peak of "nine peaks among clouds", which is the largest of the nine peaks. Yuanzhijiao temple is one of the largest Buddhist temples in the nine peaks. It was built in the 13th year of Tang Dynasty (859 AD). Originally in the southwest of Huating County, daoshui collapsed during the Tianfu period of Jin Dynasty (936-942 A.D.) and moved to the mountain. It was expanded in Song Dynasty. There is a pearl protection tower behind the temple, which was built by Xu Daquan of Gongyun mountain in 1079. Chunyou five years (AD 1245) rebuilt.

The tower is of brick and wood structure, octagonal in plane, seven stories, 18.82 meters high, pavilion style. Each floor has waist eaves, flat seats and railings, which used to be an exquisite pagoda. According to historical records, during the reign of Emperor Qianlong of the Qing Dynasty, a fire broke out at the top of the mountain due to Buddhist activities and firecrackers. The veranda and the heart of the pagoda were all destroyed, and only the body of the pagoda was left. After that, the local people believed that there were relic pearls in the bricks of the pagoda, so they dug out the treasure wantonly. One third of the two parts of the pagoda foundation were excavated, which resulted in the obvious inclination of the ancient pagoda. In addition, the soil around the pagoda was different, resulting in uneven subsidence of the pagoda.

The Pearl protection tower was built in 1097 A.D. at the end of the Yuan Dynasty in the Northern Song Dynasty. It is of brick and wood structure, with eight sides and seven floors, and is 18.81 meters high. It was rebuilt in 1245. In 1788, a fire broke out in the 53rd year of the reign of Emperor Qianlong of the Qing Dynasty, leaving only the brick tower. The inclination of the tower is up to 30. Its top vertical line is 2.27 meters away from the bottom tower center, and its slope has exceeded that of the famous Leaning Tower of Pisa in Italy. Therefore, it is known as "Leaning Tower of Pisa in Shanghai" and has become a great spectacle in Shanghai. In order to protect the Pearl Tower, the body of the tower was reinforced at the end of 1987 to protect its majestic posture.

Pearl Tower

The Pearl protection tower, also known as the jewel protection tower, was built in 1079, the second year of Yuanfeng in the Northern Song Dynasty. It is a seven story octagonal stone structure and 18.82 meters high. It is located in Tianma mountain scenic spot, Sheshan Town, Songjiang District, Shanghai. It is a cultural relic protection unit in Shanghai.

For thousands of years, due to the change of foundation, the tower body gradually inclines to the southeast. As of 2015, the Pearl protection tower deviates 2.28 meters to the East, with an inclination of 7.10 degrees. As its slope has exceeded the famous Leaning Tower of Pisa in Italy, it is known as "Leaning Tower of Pisa in Shanghai" and has become a wonder in Shanghai.

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Historical evolution

The pagoda is of brick and wood structure, octagonal in plane, seven stories, 18.82 meters high, pavilion style. Each floor has waist eaves, flat seats and railings. It used to be an exquisite pagoda. It is said that there are Sari beads hidden in the pagoda, which shine at night, so it is called "protecting jewelry pagoda".

It was built in the 27th year of Shaoxing in the Southern Song Dynasty, and was built by Zhou Wenda, general of Yinjia in the Southern Song Dynasty.

According to the records in volume 10 of Gan Shan Zhi, "Baoguang pagoda is half of Gan Shan, with a height of seven levels. Visitors can enjoy the view of the river and the sea."

According to Gan Shan magazine, "Ding Chou in Shaoxing of Song Dynasty, the Minister of appeasement, Zhou Wenda, presented the five color Buddhist relics given by Emperor Gaozong, and showed his precious light when he hid them in the middle, so it was named."

It was rebuilt in 1245. In 1788, a fire broke out in the 53rd year of the reign of Emperor Qianlong of the Qing Dynasty, leaving only the brick tower.

The tower has been left unattended for many years, causing serious damage.

According to the records of Ming Zhai Xiao Zhi written by various couplets of the Qing Dynasty, in 1788, the temple performed a performance to offer sacrifices to the gods and set off firecrackers. As a result, a fire broke out and destroyed the wood in the center of the tower, the escalator and the floor. The ladder, the eaves and the flat seat were also destroyed, leaving only the brick tower.

Later, some people found Yuanfeng coins of Song Dynasty in the cracks of the bricks, so they demolished the bricks to look for treasure. The brick body in the northwest corner of the ground floor was gradually demolished, forming a large hole about 2 meters in diameter, which was filled with rubble. Therefore, the tower body was inclined more and more seriously.

In 1982, it was found that the body of the tower tilted 6 ° 51 ′ 52 "to the southeast.

Because the tower is seriously inclined, it is commonly known as inclined tower.

Then, the Shanghai Municipal Commission of Cultural Administration organized a "research and repair team of song pearl protection tower in Tianma mountain" and determined the repair plan of "strengthening according to the current situation, keeping the slope but not falling".

In 1984, construction and repair began. Traditional construction techniques were adopted. First, bamboo and wood frames were used to support the tower, and then iron hoops were built on the eaves of each floor. Then, eight steel bars were used to run down from the top of the tower. After arriving at the base of the tower, they stretched out in all directions like crab claws, directly connecting with the underground rocks, so as to support the tower and maintain the strange posture of slanting but not toppling.

According to the test, the Pearl Tower after repair can resist the earthquake with magnitude less than 6 and the wind with magnitude less than 10. The whole project was completed in 1987.

As its slope has exceeded the famous Leaning Tower of Pisa in Italy, it is known as "Leaning Tower of Pisa in Shanghai" and has become a wonder in Shanghai.

In order to protect the Pearl Tower, the body of the tower was reinforced at the end of 1987 to protect its majestic posture.

The mystery of not falling

Folklore

Legend 1: 20 meters to the east of the tower, there is an ancient ginkgo tree. According to legend, it was planted by Zhou wenda. The ancient trees were like dragon claws and rushed westward to hold the tower. The local old man said that the ginkgo tree is the hand of the mountain god, supporting the Pearl Tower, so it has been inclined for hundreds of years.

Legend 2: one dark night a hundred years ago, several mysterious people came to the foot of the Pearl protection tower. They planed at the bottom of the tower with pickaxes. After a while of busy, they seemed to find something.

So as long as at night, treasure diggers will often appear at the foot of the pagoda; finally one day, a big hole will be dug out at the bottom of the pagoda.

So a kind of horror began to spread, the Pearl Tower of the town tower treasure was dug away, the Pearl Tower will collapse.

According to this legend, Lin Xiaoming believes that the treasure of the pagoda that was dug up in the legend is likely to be a relic.

But was the relic really stolen at the bottom of the tower? According to the structure of Jiangnan ancient pagoda, the five color relic beads should be hidden at the top of the fork. The brick structure of the pagoda has a heavenly palace, in which a silver box is hidden, and then it is sealed when the top is covered.

After searching for information, Lin Xiaoming seems to find the answer: "in the 53rd year of Qianlong reign, the Pearl protection tower experienced a fire, the top of the tower was completely burned, and the wooden structure disappeared." According to legend, the reason why the fire happened in the Pearl protection tower was also related to the relics hidden in the tower.

It is said that after the relics were buried in the pagoda, people came to make pilgrimage, so the incense was very popular for a long time. During the reign of Emperor Qianlong in the Qing Dynasty, fireworks fell in the heart of the pagoda during the pilgrimage, causing a fire.

According to the statement, it seems that the reason for the tilt of the Pearl Tower is due to treasure digging.

Expert answers

1. Through observation, Professor Gong Chengtong of Mathematics Department of East China University of science and technology got two reasons for negation

(1) It is true that the bottom of Tianma mountain pagoda is missing a large angle, but from the observation of the mathematical shape, it is found that the tilt direction does not correspond to the missing angle. According to the position of the center of gravity, it is considered that the hollowing out of the pagoda is not the reason for the tilt of the pagoda.

(2) The wood structure in the tower has a certain supporting effect on the tower body, but the wood structure should be symmetrically distributed. The fire makes the wood structure disappear. The support deep into the tower body will be affected to a certain extent, but it will not cause the tower body to skew in a certain direction.

Gong Chengtong concluded that the tilt of the tower should be due to "great changes in foundation conditions compared with the year when the tower was built"

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In the later expert argumentation and repair operation, Gong Chengtong's conclusion was confirmed: the excavated soil layer shows that the tower body of Tianma mountain inclined tower is located on two kinds of foundations, that is, half on the mountain bedrock and half on the ballast, which leads to the inclination of the tower body, which is caused by the great change of the foundation condition, and has nothing to do with the lack of angle

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2. Yang Jiayou, a famous ancient architecture expert in China, said that the tower is built on a hillside. In terms of soil layer, if the southeast soil is deeper and the northwest soil is shallower, then its foundation is hard on one side and soft on the other. This is the main reason for the tilt of the tower. In addition, the fire during the Qianlong period caused serious damage to the tower and further aggravated the tilt of the tower.

3. Building experts suggest that the tilt of the tower has a lot to do with the building materials used in the tower. The material of the Pearl protection tower is concrete structure. In ancient buildings, thick rice was used to make porridge and paste, which was mixed with lime and sand. This material is very strong and close to modern reinforced concrete. In addition to the building materials, the construction structure of the Pearl protection tower is also very special. The body of the Pearl protection tower is an octagonal structure, and the design of the tower door is to open a door every other side. Moreover, the doors of each floor are not opened on the wall in the same direction, so that the wall that does not open is like four legs supporting the tower body of each floor. Each layer of wall is connected and does not bear the pressure of one layer, so that the force on the tower body is very uniform. At the same time, because of the use of very strong materials such as lime and glutinous rice, even in the event of strong typhoon, earthquake and other external forces, some walls will break, and the tower will not collapse easily. Although the Pearl protection tower tilts due to stratum reasons, it can still keep an oblique posture.

Repair and protection

monitor

Four cameras, wind speed and direction meters, and sensors in the middle of the tower are installed on and around the tower. The physical condition of Tianma mountain inclined tower will be monitored in real time, and the termite, deformation, settlement, wind speed, wind direction, moisture content, salinity, humidity, temperature, precipitation, crack, leakage and location will be mastered through big data

Chinese PinYin : Hu Zhu Ta