| In this paper, the arching mechanism, evolution characteristics and regulatorymechanism of the pressure-arch in highway tunnels were analyzed using the combinationmethods of theoretical analysis and numerical calculation, based on the characteristic ofhighway tunnel in China, regarding a practical engineering as the background and resultsobtained as follows:The definition of pressure-arch of highway tunnel was given, and the boundaryparameters of the pressure-arch were initially determined. Considering the size of thehighway tunnel excavation, the strength variation of the surrounding rock and the stressstate of the highway tunnel, the geometry shapes of the pressure-arch and its mechanicsevolution characteristics were revealed. Then, the engineering mechanics models werebuilt through fitting the equations of the pressure-arch curve, and the mechanics stabilityof the arch structure and the instability failure modes were analyzed. The results willprovide a theoretical basis for the construction and reinforcing design of highway tunnels.Secondly, according to the elastic-plastic theory of surrounding rock stress,pressure-arch change trend and morphological characteristics were studied, under thedifferent stress state of surrounding rock for highway tunnel, to uncover the effectivestress state of surrounding rock environments for the pressure-arch. Then, it can beextended to the three-dimensional analysis of surrounding rock pressure-arch that itsdevelopment characteristics can be revealed from its shell morphology changes, and thestrength characteristics of surrounding rock can be depicted from the aspect of stress.Finally, with full column anchoring bolts, the systematic anchorage model wasestablished that the pressure-arch change characteristics could be studied from theperspective of planar and three-dimensional analysis under the regulatory mechanism, andsurrounding rock stability was estimated on the basis of the third strength theory. |
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