Research On Supporting Technology Of Inclined Shaft Crossing Over Soft Rock In Bayin Coal Mine

The deformation mechanism of soft rocks is different, and its failure mechanism is verycomplicated. Soft rock roadway supporting has become one of the technical problems ofstrata control. The soft rock supporting is based on surrounding rock type, rock deformationand instability condition, requiring different supporting principles and supporting programs.Because of “Weak–Broken” complex soft rock, the roadway supporting is posing a challengefor Bayin coal mine. Site surveys, numerical calculations and theoretical analysis methods arecombined to research supporting problems and the conclusions are as following:(1) The characteristics of rock mechanics of the project area are identified according togeological survey and measurement of the rock mechanical parameters. It draws theconclusion that the roof of the surrounding rock is “Weak–Broken” complex soft rock andreveal that the rapid rock deformation, the quick pressure and the prone to caving are the mainreasons for the serious damage and difficulties in supporting to the shaft.(2) By in-site observation, the characteristics of the wellbore surrounding rockdeformation and failure are mastered：①When the coal seam is at the top of the wellbore, thesurrounding rock deformation is rapid and destruction of boring appears after caving, andeven "caving" phenomenon;②The top rock of the wellbore cave off when the coal seam isin the rib or bottom of wellbore, causing the rate of convergence of the around rock largely.According to the deformation characteristics of the wellbore， the reasons of failurecharacteristics of the wellbore deformation and failure are analyzed, putting forward theprinciple:“Rock stability, High strength and support, the Overall control", which are the waysto control the surrounding rock deformation.(3) Three-dimensional finite element numerical simulation software MIDAS/GTS isused to analyze the deformation of the wellbore with no supporting, gaining the results of stress distribution and rock deformation when the wellbore has different cross-section.(4) According to the theory of "extreme homeostasis arch support", the concept of"reducing the development of self-stabilizing balance of the arch and controlling the stabilityof homeostatic balance of rock mass in the arch "is put forward. Combining the rockmechanics and the conditions of wellbore deformation, two different supporting programs areproposed separately, and numerical simulation is used to analyze and optimize the supportingprograms.The supporting practice and measurement of Bayin proves that the proposed scheme caneffectively control the deformation of the soft rock shaft.