It has been thirteen days since the Chu army took Aocang, and it was transported day and night in thirteen days, and not much grain was transported, and the reason for this was that the expansion of the wharf in the early stage was delayed for seven days, and at the same time, there were too few boats to really transport grain.

The Aocang in the garden was not rebuilt, but the concrete continued to be poured, and the location was changed to the south of the Aocang, where a six-meter-high and twenty-mile-long wall was to be built. The construction of the city is the same as the construction of the granary, the difference is that the granary is horizontal, the city wall is vertical, the granary pouring area is 200,000 square meters, although the city wall is 20 miles long and six meters high, it is actually only 48,000 square meters, and the city head is intermittent, similar to the steep design at the top of the city wall of Chen Yingwang City, it is only 60,000 square meters.

The wall was built in order to save the strength of the defense and reduce the casualties of the Chu army. Unfortunately, the stock of cement is only more than 700 tons, which is only half of the total demand. This half of the wall will be poured at a rate of 1.5 miles a day, and the remaining half will take more than 40 days to repair because less than 20 tons of cement arrives every day.

"It's going to take four days to finish?" Under the scaffolding made of bamboo, Xiang Yan watched the craftsman pour buckets of concrete into the formwork, and asked so much, and Feng Ren corrected and accompanied him.

"Yes." After pouring the wharf in the north of the city of Daliang, it took a lot of time for the people to go to Aocang, and it took a lot of time to set up a posture and lay a good foundation, and today is the third day of pouring.

"When's going to happen?" Xiang Yan asked, the ten-mile Great Wall was built on the front of Aocang, and the two sides had not yet been built. "It is reported that the Qin army has left Luoyang, and there are still eight days to travel thirty miles a day, and if it travels a hundred miles a day, it will only be three days."

"Can the Qin army travel a hundred miles a day?!" Feng Renjie was a little surprised, such a fast marching speed was really rare.

"Yes. When Bai Qi led the Qin army to save Han, he traveled 100 miles a day and killed 130,000 Wei troops. Later, the Qin army defeated the Zhao army, sinking 20,000 Zhao and dying in the river. Xiang Yan mentioned the Battle of Huayang thirty-seven years ago, but he didn't say it completely.

It took the Qin army eight days to reach from Xianyang to Huayang, which lasted more than 1,200 li (520 km), and after arriving, they went into battle without any rest, defeated and killed 130,000 Wei troops, and then defeated the Zhao army, 'sinking 20,000 of them to the river'. With the style of Bai Qi, it is impossible to put the heads of 20,000 Zhao pawns, and would rather sink them in the Yellow River. This is actually a water battle, Qin Guozhou's division defeated Zhao's Zhou's division, so that '20,000 of its soldiers were sunk in the river', and the Qin army's march was so fast, it also relied on water transportation by boat.

"If that's the case," Feng Ren groaned. "Three-Day ......"

"It's not a few days to finish, it's a few days?" What Xiang Yan asked was not the same thing as what Feng Ren answered.

"It's poured when it's finished." Feng Renjiao's answer surprised Xiang Yan. "After pouring, it has been condensed in one night, and it has been condensed in one day and night."

"That's how it is!" This time it was Xiang Yan's turn to be surprised, and he naturally asked a question. "It looks like a city of fifty miles in Yingdu, four feet and eight feet high, can't it be built in more than 100 days?"

"Definitely." Feng Ren smiled, "If the craftsmen have enough materials and everything is properly arranged, the city can be built in forty days." ”

"Forty days?" Xiang Yan couldn't believe it, but it was not like a joke. He added, "How much does it cost? ”

"The city is four feet high and eight feet, and five thousand square meters need to be poured in one mile, and the materials are naturally different from this wall. The wall was no more than three inches thick, and the wall was twice as thick, at least seven inches. In this way, one side needs to consume 600 pounds of concrete, and 300 tons of cement is needed to build a mile; The tendons should also be doubled, each square of 60 catties of tendons, one mile needs 150 tons of tendons. These two items alone cost seventy-five gold. ”

Feng Renjie is very familiar with the cost of concrete, and more and more experiments have also allowed him to gradually understand the properties of concrete, thus correcting the previous estimate of 3,000 tons of cement in one city. "It's a lot of work. The labor required for the wooden mold requires four working days for every ten square meters, and 2,000 working days for 5,000 square meters; It takes one man-day for every 400 catties to break, bend and tie the tendons, and 1,500 man-days for 150 tons;

It takes four man-days to pour one cubic meter of concrete, one cubic meter of seven inches thick is six .3 square meters, and 3,200 man-days are required for five thousand square meters. In addition, it also requires labor for sand, stone excavation and transportation, and 1,200 tons require 600 man-days; It also needs the labor of the city foundation, and the city of one mile needs a thousand working days. In this way, it would take 8,300 man-days to build a city for one mile, or 10,000 man-days. Twenty dollars per working day will cost twenty gold. ”

"One mile costs ninety-five gold, and fifty miles is more than four thousand seven hundred gold?" Xiang Yan finally had a number in his heart. He wanted to pour Xiangcheng with concrete, but unfortunately the more than 4,700 gold was not taken out.

"Yes." Feng Renjiao nodded, he vaguely guessed that Xiang Yan wanted to build the city, so he said: "However, the bottom layer is poured concrete, and the top three zhang and eight feet are built with bricks and stones, and the cost can be reduced by at least half, and I am not afraid that the Qin people will flood the city with water." ”

"Really?" Xiang Yan's eyes lit up, and the cost was reduced by half to just over 2,300 gold, and Xiang County could still take out this money, but it was just a little more than a year's income.

"But it needs to be built slowly, and the city of fifty miles will be completed in a year." Feng Ren laughed. "If the general wants to build a city, the contemptible people should be preferential, and only five hundred gold will be charged, if it is the Zhao people and the Qi people, it should not be so."

"Ahh Under the rattan helmet, there is a smile that is tanned by the sun, and there is cunning in the flattery, like the contractor of later generations, Xiang Yan looked at him and felt very, very strange. "You actually want to help the Zhao people and the Qi people build a city?"

"Yes." Feng Renjiao is very calm about this. "From next year, the mountains and seas, ponds, customs duties and other taxes will no longer belong to the king, I am a vassal of the king, and I will share the worries of the king. If the cement production is sufficient, the Zhao and Qi people should build cities for them since they are enemies of the Qin state. Building a large city can earn thousands of gold, and a small city can also get hundreds of gold. ”

After the implementation of the Ao system, they were financially independent of each other, and every family had an account in their hearts. Everyone is thinking about how to make money and how to accumulate money in order to cope with the increasingly brutal war. The clans and counties divided up the income that originally belonged to the big mansion, and the big house could only find a way to make money by itself. A few days ago, Xiong Jing has been thinking about how to make money, this time I came to talk with Feng Ren, comparing the advantages and disadvantages of rammed earth and concrete construction, and suddenly found that doing engineering is also very profitable-

For a small city with a circumference of about 14 li, the walls are assumed to be 4 feet 8 feet high (the width of the base of the city should reach 20 meters, and the width of the head of the city should be at least 5 meters), then 1,740,000 cubic meters of earth would have to be excavated and 870,000 cubic meters of cooked soil should be rammed. It takes fifteen man-days to ram one cubic meter and 13.05 million man-days to ram the whole city.

It takes four or five years for 10,000 people to build a city, and it costs more than 20,000 gold to calculate 15 yuan per working day, and if you build a capital city with a circumference of 50 miles, it will cost more than 72,000 gold for labor alone, and the materials are not guaranteed. Even if the city was built with the slaves of the Qin State of eight yuan a day, it would cost more than 38,000 gold.

And pouring a capital city with a circumference of 50 miles with concrete is only 500,000 man-days, and the speed is also fast, and the contractor is less than 5,000 gold. Although the construction of the city in 40 days is somewhat exaggerated, regardless of the cost (the speed is too fast, the labor is not properly allocated, resulting in idleness, and the workers have to get money if they do not work, so the most economical way is to slow down the speed, extend the construction period, and complete the construction in one month in one year, so as to obtain new projects within the year and avoid layoffs), and it can definitely be built.

Of course, all countries built cities to levy common people. For example, Shouying, when Feng Huang rested in the twelve counties of Huaibei, he was asked to build the capital with the manpower and material resources of the twelve counties of Huaibei, so it took more than ten years to build the city wall of Shouying. But this does not mean that the project cannot be contracted, the government can requisition the common people, and the common people can also hire people to serve on their behalf, and use less than one-tenth of the money to hire Chu craftsmen to pour a stronger city that is not afraid of flooding, which is beneficial to the government and the common people.

After listening to Feng Ren's explanation of the reason for helping the Zhao people and the Qi people build the city, Xiang Yan suddenly felt a little emotional.

There are advantages and disadvantages to the Ao system, the advantage is that you can no longer see the corrupt officials, the money is your own money, it is meaningless to put it from the left pocket to the right pocket, and you have money to do whatever you want, and you should never prepare a heavy gift to go to Yingdu, please Ling Yin's son's servant's wife's younger brother's wife's sister's husband's uncle's uncle, in the hope that he will say a good word in Ling Yin's ear and get the appropriation;

Of course, there are also disadvantages, those poor counties that rely on Yingdu to help will weaken day by day, and may even disappear, which will lose the face of the Chu State, because the disappearance of the city is equivalent to the shrinkage of the territory; At the same time, it also lost the face of the royal court, and the incomparably respected king also had to deign to practice the art of lowly merchants, otherwise he would not be able to support the expenses of the royal court.

"Report to the General!" Xiang Chao was riding on a horse, and he saw his father standing under the scaffolding from a distance.

"What?" Xiang Yan smiled every time he saw his son, he had finally grown up, he had been crowned, and it was time to marry a wife.

"The Qin army marched very fast, and it will reach the Yan division in one day today." Xiang Chao said. With Aocang as the center, the cavalry of the Chu army walked to the west and south, continuing to suppress the reconnaissance of the Qin army's reconnaissance cavalry. It's just that there are too many cavalry of the Qin people, and after a few fights, the reconnaissance cavalry of the two sides gradually became a tacit balance of power, that is, they did not interfere with the enemy's reconnaissance, and the battlefield was transparent to both directions.

"How many Qin troops are there?" Xiang Yan estimated the mileage from Luoyang to Yanshi and nodded.

"About fifteen or sixty thousand, twice as many as our army." Xiang Chaodao. "The leader is still Yang Duanhe."

"The ears of the defeated generals!" Xiang Yan smiled. Among the generals of the Qin army that he valued, Meng Wu was the first, Li Xin was the second, and none of the others came to prominence. Perhaps, but he hasn't met it yet.

"Billing." Xiang Yan's smile flashed, and he turned around to return to the shogunate.

"General," Feng Ren called out to him. "The Qin army will arrive in ...... in a few days"

Feng Renjiao was worried that the Qin army was marching too fast, and the ten-mile Great Wall was not completed when the two armies faced each other. Xiang Yan didn't reply, and shouted: "Its speed is less than 100 miles, it's okay." ”