Datang: Li Shimin begged me to rebel

The trip to Chen Cang can be said to be very successful. It was only in the afternoon when the train started to turn around. According to this time, when the sun sets, everyone can return to Chang'an City.

This was unthinkable in the past. In just one day, Li Shimin could leave the palace and go to another city three hundred miles away to attend a meeting, and then return to Chang'an?

It can be said that on the way back, everyone was excited, including these ministers. They were all thinking about using the railway to do new things.

"Hey, that's not right." Li Shimin said suddenly.

"Father, what's the matter?" Since Li Shimin was not discussing a problem at this moment, the eldest grandson and the queen were naturally replaced here, and the ministers went to the other half of the carriage.

"The successful construction of this railway is not a good thing for me." Li Shimin said.

"Why is it not a good thing?" Li Ke was stunned, what was his father thinking of?

"Why is this not a good thing? Isn't this obvious? I can go to a city three hundred miles away to attend a completion ceremony in one day and then return to Chang'an. In the future, the speed of this railway will be faster and I will go to more places. Maybe the itinerary for the next month or even a few months has been arranged?"

"It is even possible to arrange a car for me to sleep and rest on this train. I rest at night and wake up in the day to continue working in another place? Where is it arranged every day? Anyway, the train will be fast at that time. There are so many places, is there still time?" Li Shimin asked with narrowed eyes.

Li Ke: "..."

He froze for a moment, because he suddenly thought of the leaders of later generations... Cough... If you want to do 70 in your 996s, you can't do it, you have to do 007's work... It seems that it is true?

"Cough, of course it's impossible. Dad, what are you thinking? It's so easy for you to travel, and the guards must follow." Li Ke coughed quickly and said.

"Really? This train has at least a dozen trains, and half of the carriages are enough to carry guards." Li Shimin looked at Li Ke and asked.

"Erlang, if you say this and let Zheng Guogong hear it, wouldn't you want to impeach you for not making progress?" Empress Changsun helped Li Ke out of the siege.

"Yes, that's right, besides, father, this is a good thing. Think about it, you have been diligent and thrifty in the palace. Although both the Taiji Palace and the Daming Palace are well built, any scenery can't be seen. It’s going to be like that over time.”

"However, if you work on the train, it will be different. Think about it, you will have different scenery to see when you wake up, and you can go to various places to see brand-new scenery in person. It is all work, and now you can still work every day. It's a good thing to see something different." Li Ke quickly began to argue.

"Is that so?" Li Shimin squinted at him.

"Of course, my son suddenly remembered some knowledge about bridges. I'm going to talk to Yan Shangshu and Duan Shangshu." Li Ke stood up.

"Wait, I see that you just want to trick me, do you think your father and I are not tired enough?" Li Shimin stared at him and said.

"No, Dad, you're thinking too much. I really had a flash of inspiration just now, and I suddenly had a new idea. I'll go talk to them." Li Ke said quickly.

"Come on, let's go together, I want to hear what you have to say, if you can't say anything new, just wait..." Li Shimin also stood up.

Li Ke: "..."

What else can we say now?Li Ke could only stand up silently and walked towards Duan Lun and Yan Lide, who happened to be communicating with each other.

After all, there must be many areas for cooperation between the Ministry of Industry and the Ministry of Construction in the future.

Seeing Li Shimin and Li Ke approaching, they naturally stood up and greeted Li Ke and the others, but the two were somewhat puzzled, wondering what His Highness and His Majesty were doing, didn't they just talk about everything that should be talked about?

"Well, Li Ke said that he has something to discuss with you about the bridge, and I am also very interested, so come and listen." Li Shimin nodded lightly.

Li Ke; "..."

Dad, aren't you forcing me?

"Your Highness, please tell me." Duan Lun and Yan Lide didn't take it seriously, but said seriously.

And as they came, the historian next to him naturally followed and sat beside him, listening silently.

"It's like this. I mainly have some ideas about the construction method of the bridge. You all record it. After you go back, you can find someone to make it out of wood and test it." Li Ke said quickly.

"The simplest and most common is the girder bridge, which is the bridge construction method we used on the Weihe Bridge. If the bridge with two piers and one section is made of steel, the single span can reach about 120 meters. This kind of continuous girder bridge is the main bridge construction method for a period of time, and it will also be the most used bridge method in the future." Li Ke said seriously.

Duan Lun and Yan Lide immediately took notes.

"But this kind of bridge has a fatal weakness, that is, its span is limited by structural problems, and the length cannot be too long. If we want to cross a large cliff and deep valley at one time in the future, such a structure is obviously not enough .”

"And according to the principles of mechanics, if the span is too long, only steel bridges can be used, but the cost of steel structures is too high. At present, the engineering department is studying a new structural method, prestressed concrete technology."

"It is to implant pre-stretched steel bars in the concrete, and use the steel's stretching desire to balance the external force on the bridge, so that its cost can be reduced to a lower level, and it can also bear higher loads."

"Prestressing? Your Highness really has a wonderful idea, and such a technique can also be thought of." Yan Lide's eyes lit up, and he couldn't help but praise.

As the original master craftsman of the Tang Dynasty, Yan Lide was naturally among the first batch to learn and come into contact with new physics and mathematics, because he had a foundation and had also learned Gewu before, but he just used brand new terms to carry out his previous knowledge. statistics.

So it is natural to learn quickly.

"Wait, that steel can be stretched?" Li Shimin couldn't help asking, because in his opinion, shouldn't steel be very hard?

"Yes, Your Majesty, in fact, everything in the world has a certain ability to deform. For example, dry wood will not bend within a certain length."

"But when the length of this piece of wood continues to elongate, it will show a slightly curved appearance. The same is true for steel. Although I have never seen it, I think that if the length of steel is 200 meters, it may look like noodles. It's just as soft." Yan Lide's emotional intelligence was average, and he immediately explained it to Li Shimin.

"Oh?" Li Shimin actually didn't understand, but he nodded seriously, motioning for Li Ke to continue.