Why doesn t the bedrock on the rails collapse, and the rails don t sink in?

The rails are erected on the dirt, because the contact area between the rails and the train wheels is small, but the train is very heavy, so the pressure on the rails is quite large (pressure weight contact area), therefore, sleepers and stones must be laid under the rails to distribute the weight of the train and prevent the rails from sinking into the soil due to too much pressure. And why is there a stone under the railroad tracks? This is because the rails and sleepers have to bear the weight of the train for a long time, and one of the tasks of the broken stone is to act as a buffer to prevent the rails from sinking.

In addition, the train passes through the tracks at high speed, which generates noise and high heat, and the other two important jobs of stone crushing are to absorb noise and absorb heat. If you pay attention, you will find that the stones paved between the railroad tracks are chiseled, and the shape is very irregular, so that the stones are easy to break, so that the high heat generated by the passing of the train can be absorbed because of the fragmentation of the stones; If you pave a round and smooth stone, it will not be easy to break, and the effect of heat absorption will not be good.

Because the speed of high-speed rail is very fast, it is very dangerous if a stone suddenly appears on the track, in order to solve this problem, in the design of high-speed rail track, the concrete structure is used instead of the sleeper gravel track structure.

Improving the service life of the train track, avoiding some problems, can better reduce the pressure, can effectively prevent deformation.

The main reason is that the high-speed rail is particularly fast, which is not suitable for running on ballasted tracks.

The train puts a lot of pressure on the roadbed, according to p f

S knows, in order to reduce the pressure of the train to the foundation, the stress area must be increased, and the rail is laid on the sleeper, the stress area of the train and the roadbed can be increased, so as to reduce the pressure of the train to the roadbed, prevent the pressure of the roadbed from being pressed, and the train can run safely when passing

The train travels from the tracks, the pressure on the roadbed is certain, and the wide and heavy roadbed should be laid before the rails are laid on the railway, which increases the stress area of the roadbed and reduces the pressure, so as to achieve the purpose of protecting the roadbed

Therefore, choose B

The train puts a lot of pressure on the roadbed, according to <>

It is known that in order to reduce the pressure of the train to the foundation, the stress area must be increased, and the rail is spread on the sleeper, the stress area of the train and the roadbed can be increased, so as to reduce the pressure of the train to the roadbed, prevent the collapse of the roadbed, and the train can run safely when passing.