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Trenchless Technologies

Trenchless Technologies is a general term used for a group of technologies for new pipelines construction or rehabilitation of existing pipelines with minimum or without any excavations. These technologies provide possibilities for cheaper and faster installation or rehabilitation of gas and water lines, sewer lines etc. without limiting of the traffic, with minimum risks for the existing infrastructure in the area, with minimum environmental impact, practically in any soils and under various obstacles, like roads, railways, buildings, rivers, canals, at large depths etc.

Advantages of trenchless technologies over open cut excavation methods

The application of trenchless technologies is connected with series of social, technical, economic and other advantages compared to open cut techniques for installation or rehabilitation of underground infrastructure:


- Possibility to be applied in the presence of obstacles and at places with complicated underground infrastructure
- Extending the lifetime by more than 50 years
- Significantly shorter implementation time compared to the conventional method


Lower price in comparison with the open cut excavation methods: Less consumption of resources, due to the lack of large scale excavations typical for the open cut techniques; Lower indirect costs and higher cost-effectiveness


-Less mechanization: much less energy is used for execution of the construction works which considerably reduces the emissions of greenhouse gases and 2  
- Considerably lower levels of exposure to  Resipirable Suspended Particulate Matter (RSPM) at the jobsite compared to the conventional excavation methods 
-Minumum impact on the flora and fauna and water sources closely located, due to the minimum excavations or the lack of such 


- minimum impediments to the people living and working in the job site area
- no intensive traffic of construction machinery and blocking of roads and entrances
- low noise and pollution levels
- no delays in daily traffic 
- higher safety levels for the personnel at the job site and the society, due to the lack of large scale excavations


Stroitelna Mehanizatsia AD uses state-of-the-art trenchless technologies for solving complicated problems of underground infrastructure in a cost-effective manner with care to the environment and public life. 

2004 Stroitelna Mehanizatsia AD implemented the first drilling under the bed of a big river in Bulgaria – installation of a water-main under Maritsa river by using Horizontal Directional Drilling technology. The company has been gaining extensive experience in such projects and up to now pipes with total length of over 1,5km have been installed under Maritsa river only.  

2006 The company uses the Microtunnelling technology for the first time in the country. As a member of the Consortium “Microtunnelling Bulgaria” the company uses the above technology and installs sewer pipes during the construction of Metrostation No.8 near Sofia University. In 2010 the company was the main contractor of a project implemented by using the same technology. By using its own microtunnelling machine Stroitelna Mehanizatsia AD constructed a culvert with diameter 2400mm, running under Plovdiv ring-road and also under Sofia-Bourgas double railway.  

2008 The first drilling in a solid rock in the country became a fact. Stroitelna Mehanizatsia AD implemented a drilling near the town of Dzebel by using a horizontal directional drilling machine bought specially for this purpose.

2009 The company introduced “Cured-in-place Pipe”/CIPP/ trenchless technology for rehabilitation of aged pipelines in Bulgaria. The start was made with the implementation of the rehabilitation of a water-main in Lovech with total length of the pipes of 800m and diameters 400mm to 600mm. 

2010 Stroitelna Mehanizatsia AD becomes a preferential partner for Bulgaria and some countries in the region of the world “giant” Sekisui – manufacturer of equipment and materials for CIPP and SPR technologies. With the strong support of its partner, Stroitelna Mehanizatsia AD realized one of the most complex rehabilitation projects by CIPP technology of a water-main with the impressive parameters of 1220mm and total length of 360m in Sofia. The project was completed in the beginning of 2011 and was honored with the most prestigious award given by the International Society for Trenchless Technologies, No-Dig Award for a project implemented in 2011.

2011 The company introduced the “Spirally wound in-place pipe”/SPR/ technology on the Bulgarian market, which is used for rehabilitation of aged and structurally damaged gravity pipelines. The first project implemented in Bulgaria by using the above technology was completed in Plovdiv where an aged sewer collector in a very bad condition with the existing danger of a road collapse was renovated. Immediately after, another project by using SPR technology started in Aurubis copper refinery in Pirdop, where Stroitelna Mehanizatsia AD rehabilitated more than one kilometer of sewer pipelines.    


Stroitelna Mehanizatsia AD is a preferred partner also outside Bulgaria.  

2008 The company implemented series of complicated drillings for the Iran-Italy gas line construction in the region of the city of Komotini, Greece. Stroitelna Mehanizatsia AD installed steel casing pipes with diameter of 1600mm under busy roads and railways and Via Egnatia highway, by using Horizontal Directional Drilling Technology.  

2010 Stroitelna MEhanizatsia AD implemented horizontal directional drilling with total length of almost one kilometer under rivers and canals for installation of the gas line connecting the Serbian gas-holder facility Banatski Dvor with the gas transmission network of Serbia.