Mountain Tunnel Surrounding Rock Deformation Characteristics And Its Control Technology Research

In order to make a research about characteristics and control technology ofsurrounding rock deformation in entrance of mountain tunnel, field monitoring anddata processing, data analysis and numerical simulation about a couple of GuizhouProvince mountain tunnel engineering were performed. The time and space effectcame up. The effect of the front slope rate, surrounding rock grade, constructionmethod and other factors taken as variables to tunnel surrounding rock deformationand stability are analyzed. The change of the balance of surrounding rock tunnelexcavation stress field is caused by the deformation of surrounding rock. Anddeformation leads to the tunnel surrounding rock stress distribution. This complexevolution affects the stability of tunnel structure, especially to the entrance inmountain tunnel of shallow rock. As the stress of surrounding rock is affected bytopography, and that tunnel surrounding rock stress state is very complex, thestability of tunnel to environmental changes is very sensitive. Based on thedeformation characteristic of the mountain tunnel surrounding rock, the authorpredicted the deformation of surrounding rock with relevant theory. That’s theresearch results of this paper.Based on the mountain tunnels in Guizhou Province, the deformationcharacteristics of the mountain tunnel surrounding rock and control technology wasstudied by means of monitoring, theoretical analysis and numerical calculation. Themain results can be illustrated as follows.(1) The deformation monitoring technology of the mountain tunnelsurrounding rock and factors which may be influence the result are summed. Thedeformation characteristic of the mountain tunnel surrounding rock was studied bymonitoring and theoretical analysis. The time effect and space effect will be furtherexplained. The deformation of large surrounding rock was monitored and analyzed.And the deformation characteristics of the mountain tunnel surrounding rock wereobtained.(2) The tunnel construction process was simulated with FLAC3D numericalsimulation software. The surrounding rocks grade, the front slope height, the frontslope rate and construction method are considered as the factors to influence thecharacteristics of surrounding rock deformation in entrance of mountain tunnel. The simulation result showed that the surrounding rock grade is related to thedestruction area; the displacement of surrounding rock is determined by the heightand rate of front slope; the reasonable construction method can effectively changethe stress state of surrounding rock and the range of disturbance. Thethree-dimensional numerical calculation results of climb tunnel indicated that thedeformation occurred in the surrounding rock behind the excavation face in thedistance of9meters; the deformation is stable below the excavation face in thedistance of24meters. The result of analysis about surrounding rock and supportingstructure displacement showed that the deformation of large surrounding rock inclimb tunnel results from the failure of the front slope.(3)Based on the discussion about the supporting mechanism of supportstructure, the supporting measures to large deformation were brought up. Tunnelrock deformation prediction with BP neural network was carried out. And then, aset of deformation control technology of the mountain tunnel surrounding rock wassummed up. The accident causes and treatment measures in climb tunnelengineering were further discussed and analyzed.