Microtunneling

Microtunneling is becoming increasingly used as a method of constructing trenchless sewers in large cities.

 

Microtunneling has been the main method of construction of reservoirs in Europe, America, and Japan for several decades.

 

An important feature of microtunneling technology is the high accuracy of penetration and constant monitoring of its trajectory. Micro-tunneling allows you to perform tasks for laying communications in the most difficult conditions, where previously there was nothing to do without special methods (water reduction, freezing, etc.).

 

From the ground surface, mines are built: starting and receiving, the distance between them can reach from 50 to 5000 meters, and the depth is about 8 to 100 meters. In terms of the mine can be round or square with the dimensions of the sides of about 5 meters.

 

From the starting shaft, the working body of the AVN micro-tunnel complex (microboard) carries out sinking at excessive water pressure in the bottom hole. Water supply to the cutting working body AVN and suction of the formed pulp are carried out by pumps installed on the ground surface next to the starting shaft. Individual links of steel or reinforced concrete lining pipes are also fed into the starting shaft, which are pressed into the ground by jacks, which allows horizontal sinking of the collector.

 

Correct the accuracy of the penetration with the help of a ground control station on the laser beam. All technological and control functions in microtunneling are computerized. The spent pulp is pumped into the sump, the water from which is reused in the sinking, and the solid sediment is taken to the landfill as it accumulates.

 

Microtunneling by the AVN complex is carried out in automatic mode, under the control of operators located in the control unit.

 

A special tunneling machine uses a microboard that makes a hole in the ground of the required diameter and at the required depth. The shield is driven by a powerful jack station, which is located in the mine; the mine is pre-constructed without fail at a depth equal to the metric of the object being laid. The first shaft, the starting one, is necessary for plunging jacks into it. It is the jacks that ensure the penetration of the shield to the length corresponding to the length of the pipes that push through the soil. The earth remaining after work is mixed with water supplied by the feed pump of the cutting wheel. The resulting mixture is sent to the sump, where the soil settles and is subsequently removed from the mine. The maximum accuracy of the work is achieved by the laser navigation device.