The shield machine is not the whole of the ground wire      

The first shield machine in Ji'nan is a surprise to the public. It is true that the shield machine is a good tool for the construction of rail traffic, but the whole construction can not be completed by the shield machine alone. Because of a rail line, there are underground lines, there are stations, and even some light rail, different sections of the construction are different. I take the R1 line in Ji'nan as an example to give you a brief introduction of how the rail transit line is built.

The shield also followed a group of odd jobs

The so-called shield machine construction method, the image of the use of the shield machine through the subway route through a tunnel. This method can not affect the ground traffic, it is an ideal way of construction. But not all lines are able to use a shield machine. In general, the buried depth of 10 meters below the line, can the shield machine can be used. When the buried depth is too shallow, it is necessary to excavate the construction.

Of course, the shield machine battle, is not like a walk like pangolin burrows, there must also be a set of auxiliary equipment. Such as large gantry crane put it into the tunnel operation, hoist transport muck and quantity, in particular, the power consumption of the shield machine is particularly large, it requires a separate line.

No shield machine, there are two kinds of construction technology

In the construction of the R1 line, in the transition section from the ground to the ground, the way of clear digging and backfilling is adopted. The so-called open cut method is to use the pre built envelope structure to dig down from the ground to the place where the structure is to be done, and then pour the finished frame structure and fill it back to the original ground. In short, the method of digging is to see the construction method of others on the ground.

In addition to the open cut method, there is a subsurface excavation method, that is, it is directly excavated directly inside the soil and does not need to be excavated from the ground, but the shaft and working well need to be dug. Compared with the hidden excavation method, the open cut method is generally cheaper, the construction is reliable and the safety is high, which can guarantee the quality of the main structure, but the construction has great influence on the surrounding traffic. While the excavation method has relatively high cost and large construction risk, but the construction has no impact on the road traffic on the ground, especially for the city center and some deep buried structures.

A rotary drill can also be used in a light rail piling machine

Take the Ji'nan city iron R1 line as an example, the R1 line is both vacant and into the ground, and the vacant part mainly refers to the subway running on the elevated level. The construction of viaducts is basically the same as the construction of viaducts. They all need to build pile foundations, pier columns and caps. The difference is that the viaduct is on the top, while the subway is elevated with orbit above.

Generally speaking, there are two main construction tools for the construction of pile foundation: piling machine and rotary drill. According to the relevant person in charge of the Municipal Department of Ji'nan, the piling machine mainly includes three parts of pile hammer, pile frame and power device. The first place in the choice of pile dug a pit, and then use the hammer blow constantly and continuously to the pit excavation, poured into the mud, through the pile hammer broken rock into the mud, and mud is constantly being used in the pipeline out, mud gravel with machines were screened out, the filtered mud is injected in the pit, so repeatedly, until the pit was hit in the standard position, and then poured into the concrete, making pile, pile on the pier and pile cap construction started. This is the way the construction of the R1 line test section is being developed.

The rotary drill is suitable for dry (short spiral) or wet (rotary bucket) and rock formation (core drill). It is a simple rotary drill bucket type rotary drill through the bottom valve with broken rock and soil, and directly in the drill bit, and then by the drilling machine lifting device and a telescopic rod will be made drill hole dumping, such cycles, constantly borrow dump, until the drilling depth to the design, then began to form on the pile foundation pile foundation concrete injection, started the construction of pier column and pile cap.