大地四边形在隧道洞口投点控制测量中的应用

研究目的：施工测量是隧道施工中的基础工作，在隧道施工中如何做好控制测量是一个必须重视的问题，包括现场布设控制点位、外业测量、内业整理等工作都需要根据工程实际情况选择正确、合适的方法。 研究方法：本文从洞口的投点布设要求、大地四边形的特点及适用性、大地四边形的内业计算方法、工程实例等几方面进行介绍，通过比较、分析，阐述了大地四边形在隧道控制测量中应用的理论和方法。 研究结果：提出大地四边形控制网是用于洞口控制测量的一种比较方便、精确度高的方法。本文中的计算方法和实例运用对类似隧道施工中的投点位置选择、洞口控制网布设、内业数据处理等工作有一定的参考作用。 研究结论：施工控制网的布设有很多种形式。具体采用何种形式应根据控制测量的要求，并结合工程的特点进行选择，既要保证控制测量的精度，又要方便施工。

APPLICATION OF GEODETIC QUADRANGLE METHOD IN THE CONTROL SURVEY OF TUNNEL PORTAL PLUMBING

Research purpose: Construction survey is the fundamental work for tunnel construction. We must pay sufficient attention to how to control survey well during construction. We must select correct and exact methods on the base of actual situation of project for setting positions of control points, survey outside and file inside. Research mtehod: The paper introduced the requirements for setting plumb points on tunnel portal, characteristics of geodetic quadrangle survey method, its application and calculation methods for inside work, and gave some concrete project examples. Research result: The paper also expatiated the theories and methods applied to geodetic quadrangle survey method for tunnel control survey and raised out the geodetic quadrangle control net, is a quite convenient method with high precision for control survey on tunnel portals. Calculating method and application to concrete examples can be a kind of reference to selection of plumb points position, set of tunnel survey control net and treatment of data from inside work for similar tunnel construction. Research conclusion: There are many forms for set of tunnel survey control net. We must choose the proper form according to the requirement of control survey and construction characteristics, to ensure the precision of control survey and be convenient to the construction.