What is the best way to prevent the cement manhole cover from opening?

Well, mainly used for the construction of groundwater. It can be vertical, inclined and combined in different directions, but it is generally vertical and can be used for drinking water, irrigation, hiding or storing things.

Well is of great significance to the development of human civilization. Before the emergence of wells, human beings lived by water and could only live in places with surface water or springs. The invention of water wells expanded the scope of human activities. China is one of the earliest countries in the world to develop and utilize groundwater. The earliest well discovered in China is the well of Hemudu ancient cultural site in Yuyao, Zhejiang, about 5700 years ago. This is a very delicate square wooden well with a depth of 1.35 m and a side length of 2 m. It can be inferred that the original well appeared much earlier.

According to the buried distribution of groundwater and the lithologic structure of aquifer, human beings have created a variety of well types. People in China have been using barrel wells for a long time. Most of them have a diameter of 1 ~ 2 meters and a depth of several meters to 20 ~ 30 meters. During construction, people can directly enter the shaft to dig earthwork. This kind of well is only suitable for exploiting shallow groundwater.

In order to exploit deep groundwater, tube wells with small diameter (several centimeters to tens of centimeters) and considerable depth (several tens to hundreds of meters) have been developed. Pipeline drilling requires special drilling machinery and complex technology. As early as 250 BC, in China's present Sichuan Province, a large number of wells tens of meters or even 100 meters deep were dug in hard rocks to exploit underground brine to cook salt. After drilling exposes the confined aquifer containing salt water. Groundwater often flows out by itself from wells, which are artesian wells.

China Sichuan Ziliujing (now Zigong City) got its name from this. In modern countries, tube wells are mainly used to mine groundwater, power rigs are used to drill wells, and various pumps are used as water lifting tools. Before China 1949, only a few cities had several tube wells, and few wells pumped water by electricity. By 1980, there were 2.2 million motor wells in China, which were widely used for water supply in industrial and mining towns and agricultural irrigation.