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Analysis on the Survey Techniques of Shield Tunnels in Sandy Pebble Stratum
(1 High Slope and Geological Hazard Research & Treatment Division of China Hydropower Technology Research and Development Center, Xi′an 710065; 2 PowerChina Northwest Engineering Corporation Limited, Xi′an 710065; Lanzhou Rail Transit Corporation Limited, Lanzhou 730030)
Abstract The investigation and evaluation of water-rich and sandy pebble stratum is directly related to the suc? cess and failure of shield tunnel construction, but it is difficult to meet the technical requirements of shield construction in the sandy pebble with conventional survey and evaluation methods. In order to solve the problems of ground settlement due to over-excavation, tunnel collapse, blockage caused by large-size and high-strength pebbles and over-wear of cutterhead and so on, it studied the effect of grain size compositions of sandy pebbles, quantities of boulders, saturated uniaxial compressive strengths and quartz contents of pebbles on selection, design and construction of shield machine, summarized the survey techniques and methods for obtaining relative parameters of sandy pebble stratum, proposed a way of boulder grouping based on evaluation of the shield construction of Lanzhou rail transit in water-rich sandy pebble stratum. As for the shield tunnel passing through sandy pebble stratum, in-situ full particle size analysis should be carried out along the alignment during survey, and statistical analysis should be conducted regarding the contents, sizes and occurrence probabilities of pebbles and boulders at different depths.
Abstract：
The investigation and evaluation of water-rich and sandy pebble stratum is directly related to the suc? cess and failure of shield tunnel construction, but it is difficult to meet the technical requirements of shield construction in the sandy pebble with conventional survey and evaluation methods. In order to solve the problems of ground settlement due to over-excavation, tunnel collapse, blockage caused by large-size and high-strength pebbles and over-wear of cutterhead and so on, it studied the effect of grain size compositions of sandy pebbles, quantities of boulders, saturated uniaxial compressive strengths and quartz contents of pebbles on selection, design and construction of shield machine, summarized the survey techniques and methods for obtaining relative parameters of sandy pebble stratum, proposed a way of boulder grouping based on evaluation of the shield construction of Lanzhou rail transit in water-rich sandy pebble stratum. As for the shield tunnel passing through sandy pebble stratum, in-situ full particle size analysis should be carried out along the alignment during survey, and statistical analysis should be conducted regarding the contents, sizes and occurrence probabilities of pebbles and boulders at different depths.
YAN Gengsheng1,
2 HE Xiaoliang1,
2 HAN Jinming3 ZHAO Shuang3 ZHAO Cheng1 etc
.Analysis on the Survey Techniques of Shield Tunnels in Sandy Pebble Stratum[J] MODERN TUNNELLING TECHNOLOGY, 2019,V56(5): 19-25
2019, Vol. 56 