We cover a variety of geotechnical works which are related with tunnelling and blasting works.
Rock Bolting is used for securing the rock mass from collapsing or for improving the rock stability of the excavated face. It is an additional support form and it is usually followed by shotcreting. Soil nailing has the same philosophy but is used to maintain slope stability. Both are followed by shotcreting works and have a variety of bolts and nails depending on the geology. Applications can be found at road construction, tunnel construction, deep excavations, shafts, slopes, etc. Asia Tunnelling & Construction P/L have the adequate machinery, experienced personnel and staff to successfully manage these works at the top quality.
Shotcrete spraying has a variety of applications and plays a major role in temporary support. Wet or dry method is used together with wiremesh or steel fibers to form the temporary support for geotechnical works and is commonly used in tunnel construction. Depending on the nature of works, different equipment, technics and setting up is required for the smooth and successful completion of the project. Asia Tunnelling & Construction P/L have the adequate machinery, experienced nozzlemen and staff to successfully manage shotcreting works at the top quality.
Before constructing a Cross Passage or a Pump Sump, a steel bracing has to be installed to support the bored tunnel at the location where the segment will be removed. A ring beam has the diameter of the bored tunnel but can vary in thickness and span. Usually rings beams consist of five rings that are erected at the same time and jointed together by cross beams. An opening is available at the CP or PS location for removing the segment and accessing in to the proposed structure. Erecting a ring beam requires experienced personnel as working at height and lifting of heavy beams in a confined space can cause accidents.
Once the formation level is reached in a station box, the location where the TBM will start the journey will be marked. However, the ERSS structure is still in the way and has to be demolished to facilitate the launch. A tunnel eye is a demolition job that usually requires to demolish a 1.2m thick heavily reinforced wall and assess the ground conditions behind it before the TBM launch or retrieval. Demolition works can be done mechanical or even manually depending on site conditions.
Grouting is the procedure when a cement mix is pumped into a ground to improve its geotechnical characteristics and minimize the water ingress.Grouting is also used to fill up voids, gaps or pockets. Ground improvement is common in tunneling works before starting the excavation and to minimize the water ingress. Different types of grout mixes are available, depending on the geology faced at each project.