Traditionally, what does national security mainly include?

National security is the basic interest of a country, and it is an objective state in which there is no danger, that is, there is no external threat and infringement, and there is no internal chaos and disease.

The concept of national security is the cognition, evaluation and expectation of the history, present situation, development, law and essence of national security and related issues, including fact cognition, value evaluation and subjective expectation.

Said the main control end bearing pile penetration, with pile end elevation as the reference index; The elevation control of friction pile tip is given priority to, with penetration as the reference index.

If you understand it, you must first make clear the concept of penetration: penetration generally refers to the depth mm that a hammered pile enters every 10 blow, which is expressed by (mm/ 10 blow). It is not a literal permeability, but an indicator of soil hardness.

Therefore, it is easy to understand that end-bearing piles have to hit hard rock strata, so it is judged by penetration. Friction pile depends on the friction between the pile body and the surrounding, so it is judged by elevation (buried length).