ISPRS, Vol-34, Part 2W2, “Dynamic and Multi-Dimensional GIS", Bangkok, May 23-25, 2001 
325 
gen-8,-24 -56,24 8,24 56,-24 ¿=101,301 y=1,241 
gen 56,-24 8,24 64,24 64,-24 /=301,401 /=1,241. 
While, the boundary definition is as: 
fixx/=1; fixx^=401; fix y/=1; 
apply pres=17.4 /=241 prep cten=2.2e' 3 
£>u=2500 s£>=536. 
4.3 The file format of RFPA 
The 2D-RFPA applies squares for grid division and could input 
external *.Txt files. The geometry and mechanical information 
described in the data file includes: 
1) label information; 
2) total number of material zones; 
3) total number of points and coordinate pairs; 
4) calculation steps; 
5) Mechanical parameters: homogeneous degree of 
elastic module, even value of elastic module, 
homogeneous degree of strength, even value of 
strength, homogeneous degree of Poisson ratio, even 
value of Poisson ratio, homogeneous degree of 
self-weightiness, and even value of self-weightiness. 
5 CASE STUDIES 
This paper gives a practical example in coal mine. The data file 
of a geological section from LYNX is input as data source to 
RFPA for numerical calculation and mining subsidence analysis. 
Based on detailed borehole exploration data a fine geological 
model was established where a reversed fault with 
six-meter-drop distance is of serious importance for the coal 
mining under the west district of Pingdingshan City. 
The step-by-step numerical analysis for the mining influence is 
conducted by RFPA. A typical space image of the mining 
influence when the workface is 120m from the fault is shown in 
figure 6. Here, the black dots represent for the damaged area 
and the white dot represent for the concentration of compression 
stress. 
According to the systematical analysis on the dynamic 
stress-strain process of overburden and the action law of the 
fault, the safety width of the fault-protection coal pillar was 
decided as 80m, which had ever been dangerously design as 
50m. With 80m width the coal pillar could ensure the fault not to 
move during the whole mining process and guarantee that the 
building above the mining area not to be seriously damaged 
because of the move of the fault. 
REFERENCE 
-Houlding.S.W., (1994). 3D Geoscience Modeling: Computer 
Techniques for Geological Characterization. Springer-Verlag. 
-Hu Jinxing et al., 1999. Application study on volume 
visualization technique of 3D geoscience modeling. J China Coal 
Society. 24(4) :345-349. 
-Wu Lixin et al. (1999). A ID-coding method containing quadrant 
label for non-boundary 3DGIS. In Chen Jun edited: Proc. of 
D/WG/S.i05-108 
-Wu Lixin et al (2000), The mine of 21 st century: digital mine. J 
China Coal Society, 25(4): 337-342 
-Wu Lixin et al. (2001), A Brief Introduction to mine GIS 
(TT-MGIS 2000 ) and its key technology. Mine Surveying, (1): 5-8 
-Wu Lixin et al. (2001), A new method for mining influence based 
on fine geological structures. In Xie Heping edited: Computer 
Applications in The Minerals Industry, Balkema: 731-734