Research Of The Stability Of Surrounding Rock During High Geostress Tunnel Construction

Based on the theory of the stability of surrounding rock, the paper had analyzeddetailedly the factors of influencing high ground stress surrounding rock’s stabilityand then had a quantitative analysis in allusion to Several larger factors of influencinghigh ground stress surrounding rock’s stability and took reasonable dischargingpressure support measures according to the problems of high ground stressconcentration and large deformation in surrounding rock tunnel construction, thatprovided certain theoretical basis for high geostress tunnel construction. This paperstudies the main work was as follows:1. From the high geostress definition, types, grid partition, unit boundary conditions,wall rock failure mode, model parameter and teaching,a high geostress highwaytunnel numerical model was established , the numerical model was validated, and itput forward the calculation procedure in this paper.2.According to the stability of surrounding rock of theory and through numericalsimulation method ,it set up a large amount of numerical model to analyze affect ofsurrounding rock stress and deformation in the process of tunnel excavation and itcontrasted that the influence weights of various factors on account of parameters ofsurrounding rock, tunnel buried depth, tunnel hole diameter and the lateral pressurecoefficient, tunnel profile form as well as depth-span ratio six factors change in theprocess of the surrounding rock tunnel construction to lead to the deformation andstress of the surrounding rock were different forms. It draw that the strength of surrounding rock, buried depth, span were the main factor on high ground stresssurrounding rock stress and deformation and lateral pressure coefficient, high crossthan also had a certain effect for high geostress surrounding rock stress anddeformation, the form changes of the section of surrounding rock was smallinfluence on stress and deformation.3.Through numerical simulation, it quantitatively analysis the main factors of theinfluence on the stability of surrounding rock In the high geostress highway tunnelconstruction process.It obtained quantitative formula and the influence law of thesurrounding rock stress and deformation, and numerical simulation results of thequantized formulas for comparison and analysis could be applied to high geostresstunnel construction surrounding rock stress and deformation of the largest estimate.4. For tunnel construction surrounding rock stress concentration and deformation aftertoo large, took discharging pressure trough method, borehole discharge pressure,lining selection, such as anchor arrangement discharging pressure supportmeasures.through numerical simulation, the effect was obvious, it provide thescientific theory for actual high geostress tunnel engineering design and construction.