At seven o'clock in the evening, the conference room of the third project branch of the fifth standard of the Tianlu route, the leadership team and department heads, as well as the persons in charge of the construction of the two tunnels Zhao Ritian and Qiao Ganglie, all gathered here. Pen, fun, pavilion www. biquge。 info

During the excavation of the Fengmingshan Tunnel in the afternoon, the mechanical excavation could not be excavated and the heat melted was analyzed.

"Today is the first day of construction of the Fengmingshan Tunnel, after a long day, and was forced to stop the construction, the main reason is that the situation is very different from the content prepared in our construction plan. Shu Cheng spoke first.

It can be said that the Fengmingshan Permafrost Tunnel is not only the first permafrost tunnel to be constructed on the Tianlu Route, but also the first construction of the Fengmingshan Permafrost Tunnel for the entire country.

When there is a hot thaw phenomenon, how to deal with it and what to do next, there is no leading reference, so Shu Cheng and others can only explore step by step and summarize a set of processes and methods suitable for plateau permafrost tunnels.

Once this construction method is affirmed and adopted by the superiors, the project department of Shucheng can apply for a national patent in this regard!

This kind of national patent is not comparable to ordinary patents, such as the highest award in the national construction industry, the Luban Award and the Zhan Tianyou Award, all need this information in order to be shortlisted, otherwise, it is simply in vain.

These two awards are not something you can buy with a lot of money, you need to have real engineering performance in them.

"Boss Zhao and Boss Qiao have rich experience in tunnel construction, let's talk about it first, how to prevent heat melting, and how to construct it next?" Shu Cheng first looked at Zhao Ritian and Qiao Ganglie.

In the entire project department, Shu Cheng, Lin Xiaoyong, Wu Batian, Yan Yuyang and Chang Kai have no experience in tunnel construction.

Some construction teams may not have as much professional knowledge as the project department personnel, but the construction experience is richer than many project department members.

Zhao Ritian and Qiao Ganglie glanced at each other, and finally Zhao Ritian spoke: "In fact, it is not the first time we have encountered the phenomenon of hot thaw, when we were in the three northeastern provinces, we also dried some frozen soil bridges, although they are not tunnels, nor are they plateau frozen soil, I am here to put forward some of my own opinions." ”

For the number of construction teams and projects owned by Zhao Ritian, Shucheng has not been clear before, and only through understanding during this period of time did he know that Zhao Ritian has 167 construction sites all over the country, with a contract value of more than 1.5 billion.

If the profit is calculated at 10 percent, there will be 150 million after these projects are done!

What's more, the jobs that Zhao Ritian got were all good jobs, and the profits were far more than that, which can also understand why the Li family has been in the 31st Bureau of the railway.

With such a large amount of money behind the back, as well as Li Aiguo's operation in the head office, the Li family will only become stronger and stronger.

"First of all, I think the simplest way is to use the simplest method, the frozen soil is melted because of heat, we can completely block the sun, build an awning, this method is also the simplest, it can be said that it is also the most practical!" Zhao Ritian said.

For this method, it should be said that everyone sitting here can think of it, isn't the frozen ground melted when it is heated? Then we cover the sunlight and keep the frozen soil warm, and even if the heat melts more slowly.

"After the establishment of the awning, we will cover the slope after excavation, which is to protect the temperature in the frozen soil, and will not be too affected by the atmospheric temperature, after all, during the day, the temperature is still high, with this double heat preservation, I think the hot melt phenomenon should not be too serious." Zhao Ritian said this, and continued: "And at night, we can put away the awning, and also put away the materials covering and insulation, so that the frozen soil is exposed." ”

Regarding the meaning of Zhao Ritian's words, Shu Cheng understood.

During the day, when the sun is direct, first use an awning to block the sun, and then cover the frozen soil with materials to isolate the air and keep it warm, and the heat thaw phenomenon will definitely be alleviated.

And at night, why put away the awning and mulching materials?

That's because at night in the highlands, the temperature is very low, and the awnings and mulching materials are removed, allowing the frozen soil to come into direct contact with the atmosphere.

Since the temperature of the atmosphere is lower than that of the frozen soil, the frozen soil will absorb heat dissipation, resulting in the temperature of the frozen soil being even lower and re-compacting.

In this way, the temperature decreases and becomes more stable than the permafrost at night, which absorbs cold air at night.

Once the day is covered with insulation and awnings again, it is even more difficult for the permafrost to melt because it absorbs the cold air at night.

What's more, in the plateau area, there are more times of the day when the temperature is low than the time when the temperature is high, which means that there will be more and more cold air stored in the frozen soil, and the phenomenon of hot melting is not easy to appear at all.

In addition, during the construction process, with the excavation progressing, the top rock layer will quickly carry out anchoring and grouting, and then also carry out hanging net spraying, as long as the arch skeleton support is all done, there is no need to worry about the collapse of the tunnel.

"According to what you said, Boss Zhao, do we still have to put away the awning every day?" Yan Yuyang asked.

"There is no need, the awning can be completely made of steel quilting structure, the supports on both sides are wheeled, and two steel rails or I-beams are laid on the ground, and they can be slid directly on it." Zhao Ritian said.

"Among them, I think that if the construction is done in winter, the phenomenon of hot melting should not occur." At this time, Lin Xiaoyong came up with a sentence.

"Indeed, theoretically speaking, the temperature is very low during the day and night in winter, and there should be no hot melting, but during the construction process, due to mechanical vibration, or blasting and other reasons, it is also possible that there will be local hot melting." Shucheng Road.

After all, construction machinery operations and blasting will generate heat, and the frozen soil will melt when heated, which is an unavoidable problem.

"The question now is how to prevent the occurrence of heat melting in the summer construction, after all, we wait until the winter to build, and in December, the construction site can not work at all, the weather is too cold, whether the construction machinery can be started, is still a problem." Shucheng Road.

"Yes, now we have to take measures according to the actual situation." Wu Batian also said.

"Manager Shu, I think we can do the test first, the excavation of small parts, and the protection of these two methods, if the effect is good, it can be promoted, after all, it is now the experimental stage." Qiao Ganglie also spoke.

"Well, is there anything else the others can do?" Shu Cheng asked.

"In fact, from today's construction, it is found that the place where the hot thaw phenomenon occurs, is the place where the vegetation is cleaned up, can we carry out advance support at the entrance of the cave, that is, the frozen soil near the entrance, carry out bolt grouting, first stabilize the hole, and then carry out the construction inside." Zhao Ritian said again.

In fact, in terms of design, there is a requirement to implement R32 self-propelled advanced bolt pre-injection ultra-early strength cementitious base as an advanced support.

But as soon as the excavation was excavated today, there was a hot melt phenomenon, which broke everyone's thinking.

"Okay, this is to prepare the awning and insulation materials in advance, and then carry out advanced support to see how the site is doing, of course, this is also a small area of construction." Shu Cheng said: "In addition, for the excavator can not be excavated, in addition to the microshock loose blasting method, is there any other good way?" ”

The current construction is carried out by exploration, otherwise, there is no need to engage in such a test section, and if there is a small area of construction, it is easy to solve any situation.

"Will it work with a breaker?" Chang Kai asked.

"This is definitely not good, not that the breaker can crush the frozen soil, but the construction efficiency of the breaker is too low, once the excavation is carried out, it is necessary to quickly carry out the bolting rod hanging net spraying support, and the workers of the next process can not wait." Shucheng Road.

The so-called crushing hammer is the excavator's bucket, which is replaced by a crushing hammer to crush the harder things.

"By the way, Lao Zhao, has the drill hole trolley over there entered the site?" Shu Cheng asked.

"It's already in, and the one from Old Joe's side has also entered." Zhao Ritian said.

Because the efficiency of artificial anchoring is too low, and it is a plateau area, the physical strength is far from keeping up, and the work of two people can only be done by four people.

Although the power of the construction machinery is affected, it is still much faster than manual drilling.

"Lao Zhao and Lao Qiao, there is one thing, I want to say it, now the workers are working, and their physical strength can't keep up at all. In addition, tunnel construction, such as shotcrete and grouting, requires manual labor. Once physical labor is carried out, it is very likely that there will be hypoxia, altitude sickness and other situations, I suggest that each of your squads, the daily construction time, not set at eight hours, at most four hours, and then change shifts, divided into several teams every day, take turns to work. "Shucheng Road.

For a long time, from the state to the owners, to the construction headquarters and units at all levels, they have put the safety of life in the first place and strictly put an end to deaths.

In highland areas, if you work for too long, you are likely to become unwell.

And due to the lack of oxygen and other conditions, altitude sickness will be more intense, although the construction site medical staff are fully equipped, but I am afraid of any accidents.

"Okay, I'll go back and arrange this." Zhao Ritian said.

When it comes to safety, Zhao Ritian never relaxes.

Subsequently, everyone discussed some details in the construction and asked the construction team to pay attention.

In fact, most of this meeting was discussed by the person in charge of the construction team and the leadership team, like Xu Jin and others, who couldn't interject at all, after all, they didn't have any experience in this area, so they could only listen to the discussion of the audience.

After the meeting, Shu Cheng called Zhao Ritian, Qiao Ganglie and the leadership team to his office, ready to discuss with them the news he had just received. (To be continued.) )