China No. 1: The Longest And Largest Section Rectangular Pipe Jacking In China.

At present, the longest rectangular pipe jacking project with the longest distance and the largest section in China is carried out smoothly in Suzhou City North Road. As a breakthrough in city underground pipe gallery construction bottleneck "diamond", the formation of R & D in the construction process of the "super long and large rectangular pipe jacking pipe gallery construction method and a series of new technology and new process of urbanization in our country in the implementation of a large area of underground pipe gallery project has demonstration significance.

Pipe jacking

Non excavation rectangular pipe jacking construction

Effect map of underground comprehensive tube Gallery

Suzhou as one of the first batch of the National Gallery of pilot city, as early as 2011 on the completion of the first underground comprehensive pipe gallery in Jiangsu Province - Suzhou Industrial Park North pipe gallery. According to the Suzhou City Road Comprehensive Pipe Gallery Project of 312 national highway reconstruction, a total length of 11.5 kilometers, Suzhou city is the largest building, underground pipe gallery pipeline will be built up, accommodating the planning area of tap water, sewage, gas, electricity, telecommunications, mobile, Unicom, cable television and other 9 categories pipeline.

The top 233.6 meters, the top of the length of the country the most

"Suzhou North Road Comprehensive Pipe Gallery" is the first batch of pipe jacking construction technology in China. The yuan and Tong pipe jacking project is the largest pipe jacking section and the longest jacking distance rectangular pipe jacking project, with a total length of 233.6 meters. Project Manager Yan Xiaodong introduced. Unlike pipe jacking construction and shield construction, jacking construction is like piling, and the more power is at the rear, the harder it will be. The extra long pipe jacking construction and the longer the jacking distance, the resistance will increase exponentially.

In order to push the "awesome", we must increase the thrust force in the jacking process, project chief engineer Ji Hongxin introduced engineering using 30 200 tons of Jack, provide 6000 tons of thrust force for pipe jacking machine; but for jacking length, jacking resistance, but also design and manufacture two jacking it is not only the relay, the normal pipe section, but also to achieve sub relay jacking. "This is an important measure to solve the shortage of our main force and long pipe jacking." Ji Hongxin said.

The key to the progressive construction is that the lower penetration of the yuan and the ponds is the key to the construction. The difficulty of the jacking is far above the long distance, and the pipe jacking machine can only go under the bed of the river like a snail. The width of the yuan and the pond is 40 meters, the water depth is 3 meters, and the top of the pipe is only 3.5 meters at the top of the pipe. During the process of jacking, the iron and Shanghai Engineering Bureau of the construction party strengthened the 1 meter thick reinforced concrete slab at the bottom of the river bed to ensure the safety of the construction of the lower river. It is understood that the overall penetration of the bottom and the top of the pond is 820 square meters.

It is 9.1 meters wide and 5.5 meters high.

The section size of 9.1 meters wide and 5.5 meters high is also the most widely used in the field of rectangular pipe jacking construction in the pipe Corridor project. The pipe jacking machine, which has been developed exclusively for this purpose, has two floors high and the weight of 266 tons.

To control this "super missile" for nearly a hundred days in the depths of 9 meters underground in Suzhou City, the precision of the jacking must be controlled in centimeter level. "We use three laser instruments to monitor the position of the pipe jacking machine in real time. The surveyors carry out manual retest with the total station every day, so as to ensure the accuracy of the measurement data, so as to accurately guide the jacking construction. Project Manager Yan Xiaodong said.

According to the geological survey data show that the pipe jacking machine for silt zone through multi clamp silt and silty sand layer. "Such a layer of soil is like a sponge filled with water, and it is very easy to sprout in the process of jacking." Ji Hongxin introduced it. In the face of technical difficulty hitherto unknown, they developed the earth pressure balance type rectangular pipe jacking machine combined cutter, and set 6 pressure sensors in the working face, real-time control of water pressure and adjust the jacking force, speed and volume of excavated earth, to ensure the safety of underground pipe jacking machine in walking.

Open the top of the ground and break through a number of difficult construction bottlenecks

As the first use of rectangular pipe jacking technology in underground pipe gallery construction project, although the construction of comprehensive pipe gallery domestic rectangular pipe jacking degree is high, but still faces on the theory of the construction of rectangular pipe jacking shortage, lack of key technical specification, problem of higher degree. Therefore, it is very necessary to systematically study the design theory, construction technology, construction specification and standard of long distance rectangular pipe jacking with large section.

Trenchless construction method of rectangular pipe used in this project, has the advantages of green, environmental protection and safety, "Chinese first top" of super long and large rectangular pipe jacking pipe section design and manufacture, design and manufacture, rectangle jacking force calculation, pipe jacking and receiving shaft construction, starting well upper soil disturbance law and rectangular pipe jacking super long and large rectangle jacking, drag reduction, monitoring a series of mechanical theory and technology research of as many as 21.

"Only unearthed this one, you need to face into the soil improver, the cutter after mixing evenly, by two sets of spiral unearthed will mould the improved soil transferred to the soil in the bucket, by car to transport unearthed in the starting shaft, and then hanging to the ground slag pool on the mound." Yan Xiaodong said, "hundreds of steps together, which is like a" snail shell to do Temple ", and every working procedure are not mature experience can learn."

It is reported that push before the project with China University of Geosciences (Wuhan) to carry out joint research, break through a number of difficult construction bottleneck, leaving a large number of first-hand information, summed up a series of construction technology standards, will provide valuable experience for the future of China's underground pipe jacking pipe gallery construction bigger and longer.

Ductile reading:

Pipe jacking is a kind of trenchless pipe laying technology similar to shield method for underground engineering. Pipe jacking machine is used to form holes, and the precast pipe is jacked into the working well to form a continuous lining structure pipe laying technology. The control system of the earth pressure balance for the working principle, through the broadsword plate and a profiling knife on the positive soil whole section cutting, by injecting slurry to strengthen the stability of the soil and soil improvement, change the rotational speed of screw conveyor and jacking speed to control the amount of dumping, the soil stability and control in the set pressure value range value the pressure of earth pressure in the cabin, so as to achieve the stability of soil excavation cutting surface.

Application conditions: water rich strata in silty and sandy soil, silty clay, clay layer, construction of complex geological conditions but also in general rock under.

　　Construction features: small construction area, without moving pipeline, has little effect on the city ground environment; low noise construction process, no dust emission; "green, environmental protection and safety; precast pipe jacking, short construction period, low cost; has good economic and social benefits.

（Source: Sina Net）