The method for pulling large diameter single crystals with the abovesaid difficulties avoided is developed.Here the free melt surface does not depend on the growing crystal diameter and remains minimal during the whol...The method for pulling large diameter single crystals with the abovesaid difficulties avoided is developed.Here the free melt surface does not depend on the growing crystal diameter and remains minimal during the whole growing process.The essence of this method is that at the stage of radial crystal growth the melt level in the crucible of a variable cross-section(for instance,in a conical crucible)is raised.展开更多
针对在越江海高水压水下超大直径盾构隧道联络通道施工过程中缺乏足够的工程技术标准和案例经验、设计与施工面临众多挑战问题,以广州海珠湾超大直径盾构隧道区间的6条联络通道工程为例,对工程地质补勘资料及现场施工情况进行分析,揭示...针对在越江海高水压水下超大直径盾构隧道联络通道施工过程中缺乏足够的工程技术标准和案例经验、设计与施工面临众多挑战问题,以广州海珠湾超大直径盾构隧道区间的6条联络通道工程为例,对工程地质补勘资料及现场施工情况进行分析,揭示原矿山法设计施工方案存在的不足,并基于此提出“矿山法结合地层冻结加固方案”和“机械顶管法施工方案”2种优化方案;随后在安全性、经济性、施工工期等方面对不同工法进行综合优选分析,同时引入碳排放指标进行绿色低碳评估。研究结果表明:1)机械顶管法在安全性和施工效率上优于其他方案,能够显著缩短施工周期;2)相比矿山法结合地层冻结加固方案,机械顶管法方案碳排放量减少了2 747.51 t CO_(2e)。展开更多
文摘The method for pulling large diameter single crystals with the abovesaid difficulties avoided is developed.Here the free melt surface does not depend on the growing crystal diameter and remains minimal during the whole growing process.The essence of this method is that at the stage of radial crystal growth the melt level in the crucible of a variable cross-section(for instance,in a conical crucible)is raised.
文摘针对在越江海高水压水下超大直径盾构隧道联络通道施工过程中缺乏足够的工程技术标准和案例经验、设计与施工面临众多挑战问题,以广州海珠湾超大直径盾构隧道区间的6条联络通道工程为例,对工程地质补勘资料及现场施工情况进行分析,揭示原矿山法设计施工方案存在的不足,并基于此提出“矿山法结合地层冻结加固方案”和“机械顶管法施工方案”2种优化方案;随后在安全性、经济性、施工工期等方面对不同工法进行综合优选分析,同时引入碳排放指标进行绿色低碳评估。研究结果表明:1)机械顶管法在安全性和施工效率上优于其他方案,能够显著缩短施工周期;2)相比矿山法结合地层冻结加固方案,机械顶管法方案碳排放量减少了2 747.51 t CO_(2e)。
