Precise leveling of the very long Qinling mountain tunnel

The Qinling tunnel with length of 18. 488km is located on the railway line from Xi’an (Shanxi Province) to Ankan (Sichuan Province) in the middle of Qinling mountain. It is the longest double track railway tunnel in China and takes the third place in the world. According to the design, the break-through error in vertical direction caused by the altimetric control surveying is limited to 18mm for the case of one piercing face. Because the leveling route reaches over 120km in length and must go over two mountains in 2 800m height, the first-order precise leveling and precise gravity measurement should be carried out in the construction stage. In this paper the field leveling approach, the application of new technology, some experience as well as the office calculation with final results analysis are introduced. By meticulous planning, organization and observation, the final accuracy of vertical difference between two tunnel end points is only 8mm, and it provides reliable surveying guarantee for this great tunnel engineering. Finally it is pointed out that this vertical difference distinguishes obviously from the primary measurement result as high as 114mm. It means that the primary result is not accurate enough.     

利用非金属矿物原料研制半渗透陶瓷隔板

利用五种非金属矿物原料,按照科学的制造工艺,研制成功了高压半渗透隔板仪的核心部件——半渗透陶瓷隔板,广泛用于油气勘探和开发中测定流体分布和孔隙大小。其主要技术指标为:突破压力(过气)1—2兆帕(MPa),过水压力0.001—0.05兆帕,抗拉强度141kg/cm~2,抗压强度1310kg/cm~2,产品合格率达75％以上,其中达到国际先进水平的占32％。     

黑色岩系——安康矿业突破发展的突破口

安康黑色岩系中数条成矿带已初具大型矿床规模,如铅锌矿、金矿、铜多金属矿、重晶石矿、瓦板岩矿等,对此,应进一步加大勘查力度,使安康矿业有一个突破性发展。     

沉管隧道加测陀螺边的地下导线贯通误差预计模拟法研究

针对传统加测陀螺边的地下导线贯通误差预计的解析法没有考虑随机误差的相互抵偿性,使预计结果偏于保守的问题,基于蒙特卡洛模拟方法,顾及陀螺定向测量的观测方式和误差分布规律,提出一种利用模拟观测值代替陀螺观测值进行贯通误差预计的方法,并以港珠澳大桥沉管隧道1∶1实景模拟试验验证该方法的可行性与可靠性。结果显示,该模拟方法能够有效预计贯通误差,对加测陀螺边的地下导线网型有良好的应用效果,可以为优化地下导线控制网提供参考。     

Precise leveling of the very long Qinling mountain tunnel

1 lntroductionl. l G6neraI sitUation of tbe projectThe tunnel proect consists Of the rnaor twcrlanetunnel and paraIIel hollows. The height of its en-trance is 869 m and that of its exit is l 022 m,sothe height difference between entrance and exitreaches l53 m. The height of the mountain ridgeexceeds 2 800 m and the relative height differencewithin the survey area is about 2 000 rn.l. 2 Presentation of problemsThe original vertical controI surveying is complet-ed with the second-order leveli…