Numerical Simulation And Field Monitoring Of Tunnel Supporting Structure Stability Analysis

In our country, highway tunnel is required setting inverted arch under the conditionsof different section faces and different surrounding rock grade. It has different regulationsin the Code for Design of Road Tunnel and Guidelines for Design of Highway Tunnel.The inverted arch construction has complexity and cost big of the characteristics. Atpresent a large number of completed and under construction tunnel engineering mostlyuses the empirical method to cancel the construction of inverted arch, study of numericalsimulation and field test about this aspect is little. So the study about canceling invertedarch on the tunnel design and construction has the important theory significance andpractical value.In this paper, two lane tunnels on inverted arch of setting requirements is the startingpoint. According to Ⅳ grade surrounding rock requires setting up inverted arch in theCode, but Ⅳ1grade surrounding rock recommendatory cancels inverted arch in theGuidelines. The article does depth study about can or not can cancel inverted arch fromfield monitoring and numerical simulation of two aspects to Ⅳ1grade surrounding rock.Based on the actual under construction tunnel, Ⅳ1grade surrounding rock withoutinverted arch section is determined as the field monitoring measurement object. Sitemonitoring measurement has mainly four aspects including the first lining and the contactpressure of surrounding rock, the second lining stress, strain of steel arch, axial force ofbolt. To arrangement and analysis of monitoring date, surrounding rock and deformationstress of supporting structure are analyzed, as basis to judge the stability of surrounding.The two lane tunnel model is established using the combination of ANSYS software andFLAC3D software, including flat tunnel model1and inverted arch tunnel model2.Using FLAC3D does static calculation of the above two models under Ⅳ1gradesurrounding rock, comparative analysis the two kinds of model surrounding rock stabilityand deformation stress of supporting structure in tunnel excavation process. Aimed at themodel1, parting of section face is monitored including stress change of the surroundingrock and the two lining with simulation calculations, compared analysis with the fieldmonitoring results.In summary, the main conclusions of this paper are as follows: 1. According to Ⅳ1grade surrounding rock tunnel, including date analysis of fieldsome monitoring section face and comparing analysis of numerical simulation the twokinds of model, one point of view is put forward about the two lane Ⅳ1gradesurrounding rock tunnel can use flat instead of inverted arch to design and construction.2. According to the axial force of bolt of field monitoring date analysis, oneconclusion is put forward about optimization design of first lining bolt supporting.