The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B5. Beijing 2008 
580 
The outbreak quantity and the underbreak quantity at intervals 
of 1 .Om determined like that are used to calculate total outbreak 
quantity and underbreak quantity at the up line and down line 
sections by total both cross section average method and are as 
per the Table 6. 
Figure 26. Graphic of excavation cross section 
Space 
Overbreak(m 3 ) 
Underbreak(m 3 ) 
An up line 
1,566.99 
1,703.58 
A down line 
1,481.22 
2,041.71 
Table 6. Total underbreak and overbreak in the object tunnel 
5. CONCLUSION 
As the results that more precise tunnel internal cross section is 
determined as using the data obtained by ground laser scanning 
scheme in the tunnel and the cross section management system 
in the tunnel which is useful in the practical works is developed, 
the following conclusions are obtained. 
Figure 24. Flowchart of estimation for excavation 
Figure 25. Result of excavation cross section 
(STA. 17+805 □ STA. 17+807) 
First, as using ground laser scanner, 3 dimensional data with the 
high accuracy could be promptly and exactly obtained and the 
random cross section at intervals of 0.1m, 0.5m and 1.0m could 
be promptly determined as passing through the step of data 
treatment. And as utilizing laser scanning scheme, not only 
outbreak quantity and underbreak quantity of each cross section 
but also outbreak quantity and underbreak quantity occurred at 
total tunnel length could be promptly and exactly calculated. 
Second, as the results of analyzing the accuracy of dimensions 
by the number of measuring point for determining internal cross 
section, the laser scanning scheme appeared about 2.9% 
difference from the standard cross section dimensions, which 
meaned about 2.2% improvement of dimensional accuracy as 
compared with cross section dimensions determined by 15 
measuring points. This, although there is the minute difference 
in a cross section, means that there is very big difference from 
the pre-existing quantity in considering the length of whole 
tunnel. Accordingly, it shows that the utilization of laser 
scanning scheme makes it possible to calculate more precise 
outbreak quantity and underbreak quantity as compared with 
the existing measuring methods. 
Third, the cross section management system in the tunnel 
making it possible to calculate more precise outbreak quantity 
and underbreak quantity at the step of tunnel excavation and 
monitor them was developed. The developed GUI program 
makes more efficient and economical tunnel excavation 
management and monitoring possible and is judged to 
contribute to providing and utilizing the important foundation 
data for the maintenance and the management of tunnel as 
abstracting the data of random cross section in future.