Thirty-one years ago today, on June 26, 1994 (May 18, 1994 in the lunar calendar), the main trunk canal of "Introducing Da into Qin" was completed. At 11:58 midnight on June 26, 1994, after the last row of guns of the 18th Engineering Bureau of the Ministry of Railways sounded, the 86.95-kilometer-long trunk canal of "Introducing Da into Qin" was connected by 33 tunnels. In order to penetrate this trunk canal, tens of thousands of construction engineers and technicians from China, Japan, Italy and other countries have endured 18 spring and autumn, enduring untold hardships and overcoming many difficulties, and finally got their wish. The "Introduction to Qin" project is to transfer the water from the Datong River at the junction of Gansu and Qinghai provinces from the Paradise Temple in Tianguang Tibetan Autonomous County, Gansu Province, across mountains and mountains, across two watersheds, and transfer water to the Qinwangchuan, 60 kilometers east of Lanzhou City. The Qinwangchuan has a flat terrain and fertile soil. It covers an area of more than 1,000 square kilometers. The annual precipitation is only 200 mm, and the evaporation is large. Due to the lack of drought and rain, the vegetation here is sparse and the traces are rare. After the completion of the "Introduction to Qin" project, 440 million cubic meters of clear river water can be drawn from the Datong River every year to irrigate 860,000 acres of wasteland. The Qinwangchuan is expected to become another grain production base in Gansu after the "Hexi Corridor". The annual production of grain is 144 million kilograms, and the annual output value of agriculture, forestry and animal husbandry exceeds 380 million yuan. " The "Import Big into Qin" project is a key project in our country's "Eighth Five-Year Plan" with an investment of 1.57 billion yuan, of which the World Bank lent 123 million yuan, which is the largest investment in the water diversion project under construction in our country. This project is managed by the internationally common "Fidique" terms, which has brought the management level of water conservancy construction in our country to a new level. The "Import Big into Qin" project is the most difficult water diversion project in our country, with a total length of 86.95 kilometers. The tunnel equivalent to the railway single-track tunnel accounts for 75 kilometers, which can be called the "long underground river". This project also encounters many world construction problems such as super-large buried depth, super-large water head, super-long tunnel ventilation, and extremely soft rock.