以云南云县至临沧高速公路中某一隧道为例,探究软弱围岩隧道的适宜开挖方式,运用MIDAS GTS NX软件建立有限元模型,模拟接近实际条件的CD开挖法、环形开挖法和台阶开挖法对隧道稳定性的影响,将模型导入FLAC 3D 5.0中利用强度折减法计算...以云南云县至临沧高速公路中某一隧道为例,探究软弱围岩隧道的适宜开挖方式,运用MIDAS GTS NX软件建立有限元模型,模拟接近实际条件的CD开挖法、环形开挖法和台阶开挖法对隧道稳定性的影响,将模型导入FLAC 3D 5.0中利用强度折减法计算不同开挖方法开挖后隧道的安全系数。结果表明,环形法开挖的隧道其拱顶沉降和拱腰横向位移最小,围岩应力最小,且产生塑性应变的位置与其他方法开挖不同;利用强度折减法计算得出环形法的安全系数最大。可见,开挖软弱围岩隧道时,环形法相比于其他的方法结果更加理想。展开更多
The Yinchanggou-Qiluogou Pb-Zn deposit,located in the western Yangtze Block,southwest China,is hosted by the Upper Sinian Dengying Formation dolostone.Ore bodies occur in the Qiluogou anticline and the NS-and NNW-tren...The Yinchanggou-Qiluogou Pb-Zn deposit,located in the western Yangtze Block,southwest China,is hosted by the Upper Sinian Dengying Formation dolostone.Ore bodies occur in the Qiluogou anticline and the NS-and NNW-trending faults.Sulfide ores mainly consist of sphalerite,pyrite,galena and calcite,with subordinate dolomite and quartz.Seventeen ore bodies have been discovered to date and they have a combined 1.0 million tons of sulfide ores with average grades of 2.27wt%Zn and 6.89wt%Pb.The δD（H2O-SMOW） and δ18O（H2O-SMOW） values of fluid inclusions in quartz and calcite samples range from-68.9‰ to-48.7‰ and 7.3‰ to 15.9‰,respectively,suggesting that H2O in the hydrothermal fluids sourced from metamorphic water.Calcite samples have δ13C（PDB） values ranging from-6.2‰ to-4.1‰ and δ18O（SMOW） values ranging from 15.1‰ to 17.4‰,indicating C and O in the hydrothermal fluids likely derived from a mixed source of metamorphic fluids and the host carbonates.The δ34S（CDT） values of sulfide minerals range from 5.5‰ to 20.3‰,suggesting that thermal chemical reduction of sulfate minerals in evaporates were the most probable source of S in the hydrothermal fluids.The 206Pb/204Pb,207Pb/204Pb and 208Pb/204Pb ratios of sulfide minerals fall in the range of 18.11 to 18.40,15.66 to 15.76 and 38.25 to 38.88,respectively.The Pb isotopic data of the studied deposit plot near the upper crust Pb evolution curve and overlap with the age-corrected Proterozoic basement rocks and the Upper Sinian Dengying Formation hosting dolostone.This indicates that the Pb originated from a mixed source of the basement metamorphic rocks and the ore-hosting carbonate rocks.The ore geology and C-H-O-S-Pb isotopic data suggest that the YinchanggouQiluogou deposit is an unusual carbonate-hosted,strata-bound and epigenetic deposit that derived ore-forming materials from a mixed source of the underlying Porterozoic basements and the Sinian hosting carbonates.展开更多
文摘以云南云县至临沧高速公路中某一隧道为例,探究软弱围岩隧道的适宜开挖方式,运用MIDAS GTS NX软件建立有限元模型,模拟接近实际条件的CD开挖法、环形开挖法和台阶开挖法对隧道稳定性的影响,将模型导入FLAC 3D 5.0中利用强度折减法计算不同开挖方法开挖后隧道的安全系数。结果表明,环形法开挖的隧道其拱顶沉降和拱腰横向位移最小,围岩应力最小,且产生塑性应变的位置与其他方法开挖不同;利用强度折减法计算得出环形法的安全系数最大。可见,开挖软弱围岩隧道时,环形法相比于其他的方法结果更加理想。
基金financially supported by the National Basic Research Program of China(973 Program,No. 2014CB440905)the Key Program of National Natural Science Foundation(No.41430315)the National Natural Science Foundation of China(Nos.41272111 and 41163001)
文摘The Yinchanggou-Qiluogou Pb-Zn deposit,located in the western Yangtze Block,southwest China,is hosted by the Upper Sinian Dengying Formation dolostone.Ore bodies occur in the Qiluogou anticline and the NS-and NNW-trending faults.Sulfide ores mainly consist of sphalerite,pyrite,galena and calcite,with subordinate dolomite and quartz.Seventeen ore bodies have been discovered to date and they have a combined 1.0 million tons of sulfide ores with average grades of 2.27wt%Zn and 6.89wt%Pb.The δD（H2O-SMOW） and δ18O（H2O-SMOW） values of fluid inclusions in quartz and calcite samples range from-68.9‰ to-48.7‰ and 7.3‰ to 15.9‰,respectively,suggesting that H2O in the hydrothermal fluids sourced from metamorphic water.Calcite samples have δ13C（PDB） values ranging from-6.2‰ to-4.1‰ and δ18O（SMOW） values ranging from 15.1‰ to 17.4‰,indicating C and O in the hydrothermal fluids likely derived from a mixed source of metamorphic fluids and the host carbonates.The δ34S（CDT） values of sulfide minerals range from 5.5‰ to 20.3‰,suggesting that thermal chemical reduction of sulfate minerals in evaporates were the most probable source of S in the hydrothermal fluids.The 206Pb/204Pb,207Pb/204Pb and 208Pb/204Pb ratios of sulfide minerals fall in the range of 18.11 to 18.40,15.66 to 15.76 and 38.25 to 38.88,respectively.The Pb isotopic data of the studied deposit plot near the upper crust Pb evolution curve and overlap with the age-corrected Proterozoic basement rocks and the Upper Sinian Dengying Formation hosting dolostone.This indicates that the Pb originated from a mixed source of the basement metamorphic rocks and the ore-hosting carbonate rocks.The ore geology and C-H-O-S-Pb isotopic data suggest that the YinchanggouQiluogou deposit is an unusual carbonate-hosted,strata-bound and epigenetic deposit that derived ore-forming materials from a mixed source of the underlying Porterozoic basements and the Sinian hosting carbonates.
