QUARTZ CONTENT VARIETY AND ITS INFLUENCE ON TBM CONSTRUCTION IN WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

Quartz is a general mineral in various rocks. The size and content of quartz grains not only control the strength, hardness and abrastivity of rock, but also influence the TBM driving efficiency directly. The identification of rock thin-sections is carried out with 124 pieces of rock samples from the West Route of South-to-North Water Transfer Project in China. The distribution law of quartz contents in the rocks from different zones is obtained, based on grain-size analysis of rocks. The influence of distribution characters of quartz contentd on the classification of surrounding rock mass cut by TBM and the driving efficiency in west route of South-to-North Water Transfer Project is analyzed according to the statistic results of quartz contents in different rocks, based on the characters of TBM construction. The research results show that there are obvious differences in the quartz contents of sandstone and greywacke, siltstone and slate. The quartz contents of sandstone and greywacke, siltstone are relatively higher, 74.21% and 80.41% respectively. While the quartz content of slate is relatively lower, 9.36%.The quartz contents of sandstone and greywacke, siltstone are commonly more than 60%.Their influence on the classification of surrounding rock mass cut by TBM belongs to the serious grade. The quartz content of slate is mostly less than 30%.Its influence on the classification of surrounding rock mass cut by TBM is from the slight to the obvious grade. The higher the quartz content is,the bigger the hardness and abrastivity are,the bigger the cutter consumption is,the slower the Penetration Rate and Advance Rate of TBM are.The research results can provide references for optimizing type selection of TBM,classification of surrounding rock mass cut by TBM and prediction of construction progress in the West Route of South-to-North Water Transfer Project.