Since the Zheng father and son led the Shenwu army to retreat south, the two wings of Jishan fell into the enemy, but the wars and large-scale confrontations between the two wings of Jishan occurred in autumn and winter; after the flood season came into the spring, the scale of combat and confrontation quickly shrank, and even broke out from direct contact.

This is mainly caused by Funiu Mountain, Tongbai Mountain and Songshan Mountain Range, including Jishan Mountain. It has frequent rainstorms every year during the rainy season, causing heavy rain to occur, causing the waters of Wuli, Ru, Ying, Yi and Luo to become majestic and unrestrained after the flood season, often causing damage to roads, Jinliang, dams, rivers and canals, making it difficult for people and animals to move.

If the camp location is not well chosen and the mountain torrent is invaded and irrigated, the losses will be even more terrifying.

However, nothing is absolutely absolute.

The Chihu people gathered 300,000 troops at the middle road expenses last autumn and entered Ru and Cai from the wings of Jishan. At this time, not only did there be no sign of withdrawal, but they were even driving the civilians to further repair the roads and Jinqiao on the wings of Jishan, and select high and dangerous places to build strong villages, which are very stance to continue to confront each other with a long-term high intensity.

The many actions of the Chihu people are not bluffing.

????????????????????? The Military Information Department is not clear about how Chihu's senior management made the decision. At this time, the enemy troops gathered in front of Ru Cai are still mainly troops under the command of the Zhennanzong Prince's Mansion. There is no sign of more troops gathering and mobilization. However, the enemy's food, fodder and other materials consumed on the Ru Cai battlefield are no longer limited to Yunshuo, Hedong, Heluo, Jingxi and other places under the jurisdiction of Zhennanzong Prince's Mansion.

In addition to the switch, Yanji and other places, and even as far as the Bohai Sea, there are cattle, sheep, livestock, cloth, leather, iron and other materials, which are being continuously transported to Zhengxu and other places.

In the letters published by Chihu people, it has been mentioned many times recently that half of the fu were called by Taiyuan.

All these show that Jingxiang intends to pretend to be poor and cry for poverty, which does not play much role in the Chihu people. The military confrontation along Guangchengze and the Majian River may not end in a short time.

However, the terrain restrictions were not only targeted at the Chihu people, but also caused by the surge in the river water after the flood season.

Especially in the Ruzhou Basin, both sides of the Beijun River (Ru River) originate from Jishan. The tributary streams and rivers in Funiu Mountain are very strong and urgent after the flood season, and often destroy roads and bridges, cutting the interior of the Ruzhou Basin extremely severely.

For example, the Majian River in front of everyone may have shallow water in the dry season, which can be only three or four meters wide. You can directly wading through the river by riding a horse. There is no need for ferries or bridges. However, after the flood season, a heavy rain in the mountains brought down the mountain torrent. The river channel is more than tens of meters wide, and the water is like a galloping horse. At this time, people and animals want to travel between the left and right sides, which becomes extremely dangerous and difficult.

At this time, the enemy did not retreat. Instead, they took advantage of the inconvenience of reinforcements on the east coast and besieged Guangcheng and other villages. How should the Department respond?

Towards the east of Majian River, the roads and bridges belong to the hinterland of Ruzhou. The roads and bridges are washed away by floods. It is fast to repair roads and build floating bridges, but there is no need to worry too much.

Wang Ju went south for nearly a year. When he returned this time, he hurriedly searched for Xu Huai to discuss the resettlement of the Khitan remnants. He didn't know much about the many strategies formulated by the Department of the Bureau, but he wanted to know how the Department of the Bureau of the Bureau of the Taiwan Straits solved the traffic on both sides of the Taiwan Straits after the Majian River entered the flood season.

"These piers are still extremely structured and cannot be washed away by floods. Before the enemy seized the bridge, they could only set fire to the wooden beams and bridge boards on them, but they could not do anything about the piers," said Shi Zhen. "Yunyang had already started casting arch beams before the New Year and will be transported to Guangcheng to install iron bridges one after another. It can take two or three months to install. At that time, the east bank of Majian River will be the most fierce time to undertake the enemy's offensive. The envoy came to Guangcheng here mainly to see the preparations for the next stage of defensive operations..."

"Iron cast arch beam?" Wang Ju asked with some surprise, "Three groups of bridge piers, each with more than six meters wide between two spans, directly build cast iron arch beams instead of building iron cable bridges?"

The Tubo Dynasty had long mastered the relatively mature iron chain bridge technology. Three or four hundred years ago, the Tubo Dynasty built an iron chain bridge before the Lushui River. It was called the Shenchuan Iron Bridge, which connects the north and south sides of the Lushui River. At this time, a thirty-foot-long iron chain bridge was also built in the west of Zhaoling City, spanning the Ru River after the diversion, connecting the left and right sides.

However, to build iron cable bridges in flat and wide areas, it is more difficult to build strong and towering giant piers at both ends. Only in this way can we pull more than a dozen iron cables as huge as arms on the surface of the river.

In addition, the cable bridges are still very limited, and the most important thing is the limited load bearing scale.

If several heavy-loaded carriages were on the bridge deck at the same time, not only would the iron cables thirty or forty feet long swing deep, but it would also be a severe test for the sturdiness of the piers on both sides.

However, Chushan has long tried to build a real iron bridge, which is to use cast iron parts to replace wood to cast straight bridges. Straight bridges or rib arch beams, but due to the casting process and iron production, the span of the iron bridges built are usually extremely limited. In Tongbai Mountain, in addition to the narrow spans, dangerous streams and rifts, it is also often built multiple solid piers in rivers with gentle water flow under the weirs and ponds, and built short-span iron bridges.

Even so, the amount of material used for each iron bridge is as high as tens of thousands or even tens of thousands of kilograms. Only after Chushan smelting and forging technology of large components was made so luxurious. At the same time, it was mainly because a large number of hydraulic equipment in Chushan had to be built on both sides of the stream with steep terrain, and a large number of bridges were needed to open the passage between the hydraulic workshop and the outside world.

To build an iron bridge with a total length of up to 12 or 3 meters on the Majian River, it may take millions of kilograms of iron materials. It is no longer rare for Jingxiang at this time. However, the problem is that except for the piers built at both ends next to the embankment, there is only one group of piers in the river channel in a torrential flow, which means that the single span length of the iron bridge will reach more than six meters.

Wang Ju usually doesn't care much about the technical details in the engineering industry. At this time, he really doesn't know how the Construction Institute can cast such a long span of iron bridge?

"At first, I was considering building a double-span bridge, but the group of stone piers in the river still had the risk of being washed away. I asked for the construction of a single-span iron bridge in the courtyard!" Shi Zhen said.

The piers at both ends are close to the river embankment, which is very convenient to reinforce later. Even simply laying some wooden stakes on both sides can greatly reduce the impact of the water flow. However, the piers directly built in the river channel not only have to withstand extremely severe tests during the flood season, but the foundation is also easily emptied by the water flow a little bit.

Even when a mountain torrent breaks out, small groups of enemy troops sneak into the upstream mountains to cut down huge trees and put them into the turbulence, which will pose a great threat to the bridge piers.

】

Giving up the piers in the river and directly building a single-span bridge across the river can avoid many disadvantages, but the iron bridge with a span of 12 or 3 feet is really beyond Wang Ju's imagination.

Wang Ju could only shruggle at Shi Zhen, Xu Wuli and the others at this moment, and then talk about it when the construction institute built the bridge.

In the afternoon, Xu Huai returned to the camp on the east bank of Majian River from Songxian. He and everyone listened to Wang Ju, Sun Yanguan, Xu Yan and Xiao Chunyu in the tent. He told the details about the situation where the aiding troops went north along the Lu River through Shanju County, Dali Kingdom, and the remnants of the Khitans went south along the Lu River from Nangqian, and finally the two sides met at the foot of the Shenwang Mountain.

In addition to successfully receiving the Khitan advance troops and severely damaging the biggest obstacle for the main forces of the Khitan remnants to move south, Wang Ju also roughly understood the terrain and customs of the Dogansi area.

Based on the experience of the remnants of the Khitan tribe, they also roughly drew the orientation and topographic maps of the old roads of the Tang and Tibet, Lushui and Tea and Horse Road, which basically confirmed that Shenyu Mountain and Semogang were located in a certain area west of Sichuan and Shu.

???????????????????????? It’s just that there is the Qionglai Mountains in the middle, but no one can know the relative direction.

Seeing Xu Huai heard Wang Ju and others telling the journey, he didn't say a word, staring at the mountains west of Sichuan and Shu on the map, Han Gui asked, "The envoy thought there should be a road here that could connect to the Tubo highlands west..."

Although there are fewer and fewer flashing memory scenes now, Xu Huai knows that there should be a road leading to the Tubo Highlands, which is the famous Sichuan-Tibet Line in later generations.

Xu Huai nodded and pondered:

"Although the two main channels connecting the Tubo highlands in the world, the Tang-Tibet Road and the Tea-Horse Road, were formed three or four hundred years ago when the Tubo Dynasty rose, and were well-known to the world, since the Qin and Han Dynasties, Yazhou and Lizhou in southwest of Sichuan and Shu, as the place where the Qing Qiang tribes lived for generations, there were many records of contact with the Dongnu, Ling-Tibet Country, and Bailang Country that lived in Duogansisemogang and other places at that time. It is unlikely that the Qing Qiang people will come into contact with the Dongnu, Bailang and other barbarians through the Tang-Tibet Road or the Tea-Horse Road? I think there should be some wild mountain roads in the Qionglai Mountains, which are familiar to the local Qiang-Tibet Barbarians, but they are not recorded in history books!"

"Do you send a messenger to Shenyu Mountain immediately, and Xiao Shuai sent someone to search the terrain from Shenyu Mountain to the east to find a way to Sichuan and Shu?" Han Gui asked with a cheerful look.

"In addition to Master Xiao, we should also send people directly to Yazhou and Lizhou to explore the road. We will work in a two-pronged way, and perhaps we can find the corresponding channel faster," Shi Zhen said. "Otherwise, Xiao Shuai led the remnants of the Khitan to go south, but eventually asked the Chihu people to discover the road that was directly into Sichuan and Sichuan first, which would still be a big problem!"

Whether the remnants of the Khitans stayed near the foot of Shenyu Mountain or continued to migrate south, there were still many difficulties in the future. If Jingxiang continued to send people to reinforce through the tea and horse road on the southern line, the journey would be extremely long and the cost would be extremely high.
Chapter completed!