When adopting a construction scheme consisting of
excavation followed by laying of tracks prior to tunnel breakthrough, there is
a technical problem with accurate docking of ballastless tracks through parallel
adit without an azimuthalclosure check condition.
Consequently, a method ensuring the directional accuracy of the CPⅡ traverse by measuring the azimuth with a highprecision gyroscope is proposed. By discussing the accuracy matching
and poor tolerance standards of the two azimuthal coordinates as well as
confirming the matching of tunneltracklaying construction clearance, checking the closure error of the
highprecision gyroscope, and optimizing the matching
between the lateral deviation and the construction clearance, the following
constraints for using a CPⅡ gyroscope in an extralong tunnel are obtained.(1) First, the accuracy of the CPⅡ traversecoordinate azimuth and gyroscopecoordinate azimuth is almost the same; (2) the closure error of the
coordinate azimuth and relativeclosure errors of the
extremelength traverse meet secondclass tolerance requirements for the tunnel; (3) matching of
gyroscope with the tunnelconstruction clearance should
be optimized; and (4) the lateral deviation of the constructioncontrol traverse points in CPⅡ should be
within 5 m of the tunnelconstructionclearance distance. According to the constraints for application of
gyroscope azimuth side, a method for the calculation of constrained gyroscope
azimuth is determined for CPⅡ traverse in the tunnel.
The results of this method show that every indicator complies with the
requirements of the inspection standards of construction. This indicates the
feasibility of the CPⅡ traversebased method for the constrained gyroscope azimuth in the tunnel.
WANG Guangke
,
WANG Zhengbang
,
CHEN Guangjin
,
FU Hongping
. Discussion on Application of a Gyroscopic Coordinate
Azimuthal Constraint in CPⅡ Traverse Adjustment Prior to Longtunnel Breakthrough[J]. Tunnel Construction, 2021
, 41(1)
: 60
-66
.
DOI: 10.3973/j.issn.2096-4498.2021.01.007
