Write an explanatory article about Tunxi ancient bridge.

Tunxi ancient bridge is called Zhenhai Bridge. Founded in Jiajing 15 (156 3) in Ming Dynasty, it has a history of 470 years and is one of the rare large-scale ancient stone arch bridges in our province. The old bridge is located in the Sanjiangkou of Tunxi, that is, the intersection of Xin 'anjiang, Lushui and Hengjiang, crossing the estuary of Hengjiang and running through Laojie and Liyang from east to west. In the old days, it was used to enter and leave Tunxi. The bridge is a six-pier seven-hole stone arch bridge, with a length of133m, an approach bridge at both ends of15m, a width of 6m and a height of10m. The arch span ranges from13m to15m. The upper part is a solid-bellied stone arch with equal cross section, and the lower part is a mortar masonry gravity pier. The pier is isosceles triangle, and the toe of the upper head is inclined and arched. Zhenhai Bridge was originally named Tunpu. Huashanjiao and Bajiazhan in the east of the bridge are the birthplace of Tunxi market, as well as the bustling water inlets of weeping willows and several towers. "Xiheng Inventory" has a poem "Tunpu Return to Sail": "Clear water is the most upstream, and weeping willows berth and return to the ship. Fishing songs are far and near with the wind, and sails are high and low with the autumn moon. Flying tired to play with trees and birds, long leisure will eventually envy beach gulls. Village smoke rises from the balcony, full of waves and autumn. Zhenhai Bridge was built in the 15th year of Jiajing in Ming Dynasty (1536). According to legend, Dai Shiliang, a rich man in Long Fu, built it specially for his daughter. In the early years of Qing Emperor Kangxi, Cheng donated 6.7 million yuan, which took two years to build. Tongxing was damaged by water on 17. Cheng Ziqian said, "It's my fault that the bridge is not strong. "So the sole proprietorship rebuilt, and the bridge died without success. His son, Cheng Yue, was Yuan Wailang, a senior official of the Guangxi Department at that time. In order to inherit his father's wishes, he finally built the bridge. Zhenhai Bridge was originally named Tunpu. Huashanjiao and Bajiazhan in the east of the bridge are the birthplace of Tunxi market, and also the bustling waterspouts of weeping willows and several towers on the river bank. There is always a poem "Tunpu Return to Sail": "The clear water is the most upstream, and the weeping willows are moored to the boat. Fishing songs spread far and near with the wind, and sails rise and fall with the autumn moon. Flying tired to play with trees and birds, long leisure will eventually envy beach gulls. Village smoke rises from the balcony, and it is another wave of autumn. "1In May, 934, the famous writer Yu Dafu idled away to Tunxi and spent the night by the Xin 'an River. Although Tunxi was burned by bandit Zhu Laowu at that time, the wall fell down and the house was destroyed, the poet praised her warmly. He "reclined on the pillow, combined with the rain rhyme on the awning, in a hazy dream" and wrote a famous article "Sleeping at night and Tunxi". He left a well-known quatrain: "Xin 'an River is full of water, people on both sides of the river are scattered like boats, dreaming for a few nights under Tunxi Bridge, and heartbroken spring scenery is like Yangzhou. "