科研之友
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摘要
Formulas for tunnel crown settlement and horizontal displacement measurement are presented in this paper according to the theory of tunnel displacement as measured by a total station with three-dimensional (3D) coordinate measurement and with remote distance measurement (RDM). Comparison tests using 3D coordinate measurement, RDM, and traditional measurement (i.e.,precision levels and tape extensometers) were conducted at a tunnel construction site. Tests showed that measurement of displacement by a total station is more convenient than that by traditional methods. Measurement of crown settlement by a total station with 3D coordinate measurement produces an error, which accounts for a 13% difference in total crown settlement. The accuracy of horizontal displacement measurement by a total station with 3D coordinate measurement is weak compared with RDM and traditional methods. Three-dimensional coordinate measurement is therefore not suitable for tunnel horizontal displacement. Tunnel displacement measurement by a total station with RDM obeys the law of curve and so meets the demand of construction monitoring attained by traditional methods. Use of a total station with RDM is the best method for measuring tunnel displacement, especially in tunnels with weak surrounding rock.
