The Study Of The Sichuan-tibet Highway102Tunnel Complex Geological Environment Surrounding Rock’s Advanced Forecast And Excavation Method

With the rapid development of China’s national economy and social，nationalinfrastructure constructions continue to enlarge，also the tunnel and underground workscontinue to emerge. Moreover as the key project of transportation，the tunnel projecthas been paid more and more attention. Because of the strong secluded in the tunneland underground work excavated，also being difficult to control within the mountaingeological situation，the tunnel construction and operation can constantly emergevarious geological disaster，especially in the construction section. As those， theslightest mistake will can cause significant accidents，causing heavy losses to the state.Therefore，the paper sets about studying the advanced geological forecast and theexcavation method which aims at Sichuan-Tibet Highway102tunnel. To supplementthe insufficient which the initial exploration data can’t meet the requirements of tunnelconstruction，based on collecting this tunnel regional project geological data andreading the project’s design documents，and by analyzing the project geologicalcharacteristics and experience of the similar projects in this region，it guides us tochoose the suitable advanced geological forecast. In addition，in order to optimize theconstruction scheme to the weak surrounding rock where the tunnel passes through，and provide reference and guidance for the construction site，it processes the numericalsimulation analysis of construction stage for the project used the excavation method.In this paper is relied on the project of the Sichuan-Tibet Highway102tunnelwhich is located102large landslide groups，complex geological condition，and thetunnel passes through multiple fault fracture zone. In order to ensure the safety andspeediness of construction，this paper mainly carries out the following work:①Based on investigating the regional geological conditions，collecting102tunnelregional project geological data，detailedly reading the project design documents，andthen combined with the experience of the analogous projects in this area and theadvantages，disadvantages of the advanced geological forecast，it guide us choose itwhich fits for the project.②The paper detailedly discuss the basic principle，advantages and disadvantagesof the geological radar，and analyze the choosing of geological parameters with thearrangement of the measuring line which is related to the geological radar of theforecasting process. Also by the application of geological radar advanced forecast in the102tunnel，the paper summarizes the congruent relationship between geologicalradar images with the bad geological，that is to say the reflection potter character.③Using the finite element software， the paper analysis the deformationcharacteristics of surrounding rock which tunnel passes through the different classes ofsurrounding rock. And also by analyzing the vault displacement changing rule wherethe excavation face with the surrounding rock interface is in different distance，itshows that using monitoring data to process advanced geological forecast is feasible.④Combined the Sichuan-Tibet Highway102tunnel’s excavation method with theproject geological environment，the paper takes on optimization studying to two-stepmethod for the construction of102tunnel used，and determines the reasonable spacingbetween the reasonable excavation height on the steps with the up and down stepswhere tunnel is in the construction process of IV/V grade surrounding rock. Bythose， it provides guidance for the speediness construction.