Today, Liu Feng and the people from the Quality Supervision Department of the Road Bureau participated, mainly to play a supervisory role, and they were to make sure that the cement mixing pile of Chujianghe's mechanical construction could meet the requirements.

Therefore, in the face of each of them's questions, Chu Jianghe could not be sloppy.

Chu Jianghe smiled slightly and said, "That's a good question." ”

Not only him, but even Liu Feng, Qiao Tianhong and others are also very curious about this question, because this machine is to strengthen the foundation, so what is the way to prove that the foundation has been reinforced?

Railway construction, is not a sentence that can be solved, Chu Jianghe needs to come up with sufficient evidence, the reason given before, is that under ideal circumstances, the pile foundation of the construction can meet the requirements.

But what the actual situation is, how to ensure and detect, is very important.

"Everybody come over here first. Chu Jianghe did not answer him immediately, but led everyone to the front of the foundation pit that was being dug.

At this time, a small excavator is digging the foundation pit, and has dug several flat foundation pits, with a depth of less than two meters.

"This foundation pit is put cement slurry, when we design the cement mixing pile, there is a standard for the amount of cement, for example, for example, the cement mixing pile with a diameter of 50 cm per linear meter, we use 50kg of cement, theoretically speaking, it can meet the role of foundation reinforcement. Chu Jianghe explained in detail, saying: "Then when we mix the cement slurry, we first add ten bags of cement to this big iron bucket, and then add how many people, this proportion is fixed, and how much is the water level, we can mark it in this big iron bucket." ”

The meaning of Chu Jianghe is very simple, first put cement and water according to the design, in a certain container, put a certain amount of water and cement every time, and the cement slurry produced will not be very different.

"We made the cement slurry in a large iron drum, then introduced it into the pit, pressed it into the duct with a pressure pump, and finally into the drilling rig. Chu Jianghe continued to explain: "In this way, we can control the amount of cement slurry according to a certain speed and sinking rising speed, and the amount of slurry sprayed can meet the design requirements." ”

After adjusting the concentration of the cement slurry, and then controlling the speed of drilling descent and lifting, as well as the amount of cement slurry sprayed at the nozzle, the amount of cement slurry sprayed per linear meter can be calculated, so as to strictly control the quality of the pile.

"Boss Chu, what are the standards for making cement slurry?" asked another member of the Quality Supervision Department of the Road Bureau.

"Yes, this is very simple, we can use the instrument to measure the specific gravity of the slurry, as long as the specific gravity is controlled within a range, it is qualified and easy to control. Chu Jianghe replied.

Because there is no easy way to measure the concentration of cement slurry, Chu Jianghe has to use the method of detecting mud from bridge pile foundation to control the quality of cement slurry.

"What if the amount of cement per linear meter of 50kg is insufficient?" Liu Feng also asked.

"This one is very simple, before starting construction, we do some test piles. Chu Jianghe explained: "For example, we do nine test piles, three of which use 50kg of cement per linear meter, the other three use 55kg of cement per linear meter, and the last three use 60kg of cement per linear meter. ”

The reason why the test pile is used is because in the design process, the amount of cement required per linear meter is only a design value, and this design value is not very accurate.

During specific construction, the cement content per linear meter needs to be determined by test piles.

"After the pile is completed, what can we do to test it?" asked the first member of the Quality Supervision Department of the Road Bureau, surnamed Chen.

"For testing, our design institute has also designed a machine, which is still in production, and it can be manufactured in half a month at most, but before that, I will give you a brief explanation. "The Chu River channel.

When designing the cement mixing pile machinery, Chu Jianghe took into account the detection of cement mixing piles.

Only construction, if the construction quality is qualified, the later inspection is very important.

Just like the pile foundation of the bridge, after the construction is completed, a third-party instrument is also needed to test, and the next step of the process construction can only be carried out after the test is qualified.

"What tests are there?" This time, even Qiao Tianhong was interested.

"For cement mixing piles, we use them to strengthen the foundation so that the foundation does not sink, so I think the first item that needs to be tested is static pressure. Chu Jianghe said lightly.

Regarding the detection method, Chu Jianghe didn't even say anything about Qiao Tianhong, Qiao Tianhong also mentioned this matter before, but Chu Jianghe didn't have time to answer because he was busy.

"The so-called static pressure, is the use of a certain quality of the problem, according to a certain stacking method, the cement mixing pile has been completed, the static pressure of heavy objects, we measure the settlement of the static pressure process, to determine the qualified or unqualified, for example, in a specific time, the static pressure of heavy sinking does not exceed two centimeters, it is qualified. Of course, the amount of sinking needs to be calculated, and when the time comes, determine how much can meet the requirements. Chu Jianghe explained.

With this explanation, everyone understood.

After all, the purpose of the construction of cement mixing pile is to prevent the foundation of the road base from sinking, and the static pressure test really needs to be done.

"Is there a second test?" Liu Feng asked curiously.

With Chu Jianghe's explanation, Liu Feng found that Chu Jianghe knew a lot of things.

"Yes, static pressure is only one of the tests, how to say that the cement mixing pile is also a pile, but this kind of pile is not the same as the bridge pile foundation, it is certainly not suitable to use a small chip to detect, my idea is that a batch of cement mixing piles, two thousandths of the core is pumped out of the core, this core is random, if the core is extracted, the strength does not meet certain requirements, then the cement mixing pile is not qualified. "The Chu River channel.

Chu Jianghe is very clear, static pressure fraud is very simple, but the core pulling is different.

If it is only a static pressure test, the quality of the cement mixing pile cannot be detected or guaranteed.

However, with the detection of core pulling, it is easy to find out what the quality of the pile is, and the core pulling can also know whether the strength of the cement mixing pile can meet the requirements.

Because in the design, after the cement slurry and the soil are fused and combined, its strength must meet certain requirements, and this strength cannot be reached, and it cannot be qualified.

The core-pull test just meets this requirement.

However, because there are too many cement mixing piles, such as the cement mixing piles designed by Chu Jianghe in the Shentan Railway, the diameter is 50 centimeters, and the spacing is 1.2 meters.

One kilometer down, thousands of cement mixing piles, if each one is core-pulled, it takes too much time, then it is much easier to select a few as representatives.

"In other words, after the cement mixing pile is formed, after a certain number of days, two tests are required, one is a static pressure test and the other is core pulling," Liu Feng concluded.

"Yes, Ju Liu, that's what it means. Chu Jianghe nodded.

"Then who will do the testing?" Liu Feng frowned.

Cement mixing pile detection is definitely a big cake, because there is no cement mixing pile in China, once it is carried out on a large scale in the future, there will be a lot of work to detect the unit of cement mixing pile, which is a money-making project.

"This can be a third-party agency that inspects the pile foundation of the bridge, or you can come forward by the road bureau itself. Chu Jianghe thought for a while.

In fact, Chu Jianghe wanted to take it over by himself and set up a testing company by himself, but it was quite difficult to get this certificate, not to mention whether the road bureau would let it go, it was not certain.

After thinking about it, Chu Jianghe decided to give up this piece, as long as he controls the manufacturing of cement mixing pile machinery and testing machinery, it is also a huge wealth.

"Well, I'll go back to the Road Bureau to discuss this matter and see what Zhao Bureau thinks. Liu Feng paused.

"Boss, the machine is installed, and you can start experimenting. At this moment, the technician of the manufacturing plant stepped forward to the Chu River River.

"Let's get started. "The Chu River channel.

"Good. After the technician finished speaking, he instructed the workers to take their places, and under an order, the machinery that stirred the cement slurry was first driven by the diesel engine.

Because there was no electricity in this place, Chu Jianghe had to bring in a large generator to generate electricity.

With a roar, the workers began to work.

"Put ten bags of cement first!" The technician commanded.

According to the previous explanation, the workers poured cement while releasing water.

In less than ten minutes, the cement slurry was mixed evenly, the pressure pump was also turned on, and at the same time, the cement mixing pile machinery was also started.

"When it's down, it's not sprayed, but when it's up. The technician said.

I saw the cement mixing pile machine, slowly drilling the soil surface, and began to drill down.

"Bureau Liu, you see, the number of meters is marked on the machine, and we can see how many meters have been drilled into the drill pipe by looking at how many meters have been drilled. Chu Jianghe pointed to the mechanical road.

"The design is quite thoughtful. Liu Feng said with a smile.

Obviously, Liu Feng is still very satisfied with Chu Jianghe's machine.

At the beginning, the workers were not familiar with it, but fortunately, the technicians were more experienced and knew the operation, and although the speed was slow, the process was very smooth.

"We sprayed the slurry once on site, and then sank it for the second time, and when the drill pipe was lifted down, the second slurry was sprayed. The technician said.

"By the way, there is one more thing I forgot to mention, we can use the method of spraying multiple times to ensure that the cement slurry penetrates into the soil. "The Chu River channel.

"In other words, if one spraying is not enough, can you still spray it a second time?" Liu Feng said.

"That's right, that's what it means. "The Chu River channel.

In fact, ordinary railways, in Chu Jianghe's view, two sprays and four stirring are enough, and more is a waste.

The so-called two sprays and four stirring, that is, spraying the slurry twice, all when lifting the rod, but stirring the soil layer, it takes four times.

Because whether the drill pipe is sinking or lifting, it is cutting the soil layer and stirring!