"Second uncle, let's do it, Brother Xu and I will walk in front first, and you will follow the heels to make sure that everyone can get the oil lamp tube."

Yue Guanchao and Xu Xiake went down to the bottom of the steps, and their feet were paddled towards the stone bridge a few times, making sure that the stone bridge was still stable, and then they walked forward on the railing.

Just now, just standing on the edge of the cliff could make a gap in the gray fog of the insect swarm, and the power of human oil added more than a star and a half after the two of them walked onto the copper bridge:

At this moment, the two of them walked all the way along the bridge deck, and the swarm changed from a calm state to a panicked roar, as if something had disturbed the phalanx.

Wherever the lamp tube went, the gray mist immediately dispersed and dodged outward, and when the human oil torches walked over, a straight crack was opened directly along the gray mist, as if there was an invisible force covering the bridge, completely dividing the insect swarm, so that they would never be able to break through the barrier and close the crack.

This magical scene surprised everyone!

Song Siyuan was surprised, but also understood that this was not a miracle, but the flue produced after the combustion of human oil, and when the flue completely dissipated, the gray fog would definitely cover the bridge deck again.

"Song Qianjin, you can come here, everyone stand out and don't squeeze together, you have to keep the flue tight, you can't let them disperse."

Yue Guanchao's voice did not fall, Song Siyuan and they walked on the copper bridge with a lamp tube in pairs, the smoke produced by the three lamp tubes was even thicker, and after they walked to the bridge deck, the flue was constantly stretched and widened, so that the entire bridge deck was released from the gray fog, and finally the chaos was completely dissipated and became clearly visible.

Just now, everything was not real, and at this moment, the gray fog completely withdrew from the bridge deck, and Song Siyuan saw the bridge clearly.

According to the distance of the field of vision, the bridge is at least 800 meters long, such a long distance, if there is no thick and steady pier, let alone a thousand years, it is estimated that more than a hundred years are Xuan, most of the solid bridges, even if the bridge deck collapses, it can still be seen that the bridge piers stand firmly, which is the truth that the ancients said to build a bridge and hit the pier first.

It can be said that only the bridge piers are stable and strong, a bridge can stand in the river bank canyon, otherwise, let the bridge be bells and whistles, the flood and landslide are enough to destroy even the slag, the copper bridge in front of them is the same, not to mention the bridge deck as thick as rough wood, just say that the bridge pier skeleton, is already a miracle of ancient civil engineering.

Yue Qingshan looked at the pier under the bronze bridge, and praised in his mouth: "Tut-tut, this keel beam pier, the technology of the Tang Dynasty, is indeed superior to any dynasty!" ”

"Second Uncle Yue, do you know this kind of bridge pier?"

Song Siyuan just looked at the bridge pier and was familiar, and didn't know what it was, and when she heard that Yue Qingshan could call out the name of the bridge pier, her eyes became curious.

"Daughter, this kind of Tang bridge has been lost, the old man can know, or because I saw it when I went down to the Tang tomb!"

Yue Qingshan knew that Song Siyuan liked to collect this kind of ancient cultural materials, so he cleared his throat and continued: "When I was young, I followed the old lady to the Tang Tomb of the princes in Shaanxi, and I also saw this kind of tomb bridge made of keel beams in the tomb river, but it was only 100 meters long, not as wide as we saw!" ”

The so-called keel beam pier is a bridge pier technique used by the ancients to build giant bridges.

This kind of bridge pier technique was founded in Luban, and then carried forward by the Qin and Han dynasties, and finally became a mature skill in the Tang Dynasty, and produced a corresponding variant system, which was used to build verandahs, flying pavilions, bridges and plank roads and other buildings!

Since this kind of pier is the highest skill, the things used will not be ordinary things, and bintie, giant wood, and boulders are indispensable.

Bin iron is a cast iron that has been forged by thousands of hammers, which is ten million times stronger than a general cast iron, and if it is properly maintained, it can even be achieved without rust and erosion for thousands of years, which can be said to be the hardest metal in the records of the ancients.

In the Tang Dynasty, the price of Bin Iron was higher than that of gold and silver, and the common people could not hide it privately, and only allowed the government to manufacture utensils.

As for the giant wood, it is a thousand-year-old tree that grows in the deep mountains and old forests, and this thousand-year-old wood is fine, hard as iron, and more durable than steel.

In addition to the above two things, the boulder only exists as an adjunct, and it is much easier to obtain.

After the things are ready, these boulders will be cut into cylinders, and the huge hole in the middle of the cylinder mouth will be temporarily set aside, dozens of cylinders will be stacked on top of each other to form a high bridge pier, and then the bin iron can be melted and poured into the cylindrical giant hole, and so on the bin iron condensed, the gap between these boulders will be completely filled by the bin iron, forming a solid bridge pier of stone clad iron.

Numerous piers are arranged at a distance of ten meters from front to back, forming a dragon-shaped row of piers just above the water, and then the giant trees can come in handy.

The part of these piers exposed to the water surface will be reserved for three to four meters of grooves, due to the ruggedness of the river, the piers are often high and low, once these giant trees fall into the groove, they will also be unable to form a plane because of the height difference, the craftsman will trim the giant trees, and use the giant trees to repair the situation of high and low staggered, and directly level the bridge.

When the giant timber and the pier form a neat plane, and the most difficult part of the pier has been completed, the craftsman will continue to cut the giant timber and build a keel beam frame on the pier, so that the piers are connected to each other and easy to fasten the copper plate of the bridge deck.

The form of this keel beam is like a human joint spine, interspersed with mortise and tenon techniques, and the fangs on both sides are like bird's wings to spread their arms, and the middle position is just used to display the copper plate on the bridge deck.

At this point, the entire keel beam pier can be considered completely completed.

"Second Uncle Yue, since you can tell the steps and practices, it can be seen that the practices have been handed down, what do you mean by being lost?"