Yangzhou pile foundation recruitment

(1) The required time is: t = SV = 36 km100 km/h = 0.36 h = 21.6 min;

(2) 1 the volume of the pile is V=Sh=6m2×5 1m=306m3,

1 pile mass: m = ρ v = 2.5×103kg/m3× 306m3 = 765000kg = 765t;

(3) liquid nitrogen is easy to vaporize and absorb heat, which lowers the surrounding temperature and freezes the soil; If the surrounding soil is very dry and has no moisture, it cannot be frozen; This method has the advantages of fast refrigeration, no pollution, low noise, economic safety, strong adaptability, simple process, and no influence on underground structures after frozen soil melts.

(4) Because water droplets and ice crystals in the air will reflect and refract light in foggy days and rainy days, it will affect photoelectric ranging.

(5) If you want to save electricity, you can turn on and off street lamps regularly and use energy-saving lamps.

(6) As shown in the figure, the left power supply, pressure sensor and electromagnet together form a control circuit; The power supply, light bulb and moving contact on the right constitute the working circuit.

So the answer is:

Question1:21.6;

Question 2: 765;

Question 3: Vaporization (evaporation) of liquid nitrogen absorbs heat; No; Rapid refrigeration;

Question 4: Water droplets and ice crystals in the air will reflect and refract light in foggy and rainy days;

Question 5: Control the number of street lamps in different time periods, or control the work of street lamps in different sections, or control the brightness of lights, or develop energy-saving lamps.

Question 6: As shown in the figure.