Tunnel crown deformation generated by pipe jacking technology in a weak rock underground coal mine

An adit is one of the important parts of roadway access for underground mine construction. It is a horizontal or nearly horizontal access for mine working. This access is also usually used for draining of water, transportation of ore and waste, and ventilation. Conventional drill-blast methods as well as traditional road header operations are common methods for adit construction. However, those methods face some problems pertaining to environmental, safety issues and tunnel heading advance rate. The drill-blast method in shallow strata may generate ground vibration problems. Moreover, drill-blast in soft ground relies on the fact that the excavated ground stands up with no support for a period of time, and this situation may generate surface subsidence. On the other hand, using the traditional road header method takes a longer time for tunnel advance. Nowadays, considering higher safety due to less vibration, remaining strength of surrounding rock condition due to drilling and blasting, faster tunnel advance rate and working environment is better for laborers compared to drill and blast, mine contractors are looking to change traditional mining industry and tunnel lining methodologies by using trenchless technology for a mine access. This paper presents the use of pipe jacking technology for construction of a sloped main roadway in a weak rock underground coal mine. The study was conducted by means of numerical simulation based on real field data. This simulation is useful for predicting the behavior of the tunnel crown deformation.