## 5 Results and Discussion
### CSNS Site
In the _RCI_ and _RQD_ models of the fracture zone (Figure 4c,d), there is an anomalous area in the exposed section that is similar to the \"Sroline\" structure exhibited by the ZZZK94 and ZZZK94B boreholes. However, the _RQD_ values, which range from 0 to 40 for the completely weathered and strongly weathered granites, are not as well constrained as the _RCI_ results (Figure 4d). While the completely weathered granite has an _RQD_ value that is close to 0, other _RQD_ results for strongly weathered and moderately  
Figure 5: Geological modeling (using GOCAD software) of (**a**) weathering, (**b,c**) the _RCI_ values, and (**d**) the _RQD_ values. Note: for the RCI, The light blue layer represents a problematic geological body (e.g., fractured rocks or displaced soils). weathered granites range from 0 to 100. Because _RQD_ is defined using the cumulative borehole length (which is greater than 10 cm) and cores are discretized into smaller units, the _RQD_ may be affected by sudden changes at different rock layer interfaces. Unlike the _RQD_ value, the _RCI_ value can be calculated at multiple scales (1 cm, 3 cm, 10 cm, 30 cm, 50 cm, and 100 cm); thus, layer discontinuities are not an issue. At lower _RCI_ values, the _RCI_ value is more informative than the _RQD_; at high _RCI_ values, the correspondingly high _RQD_ values give us confidence in our _RCI_ analyses (Figure 4c,d). The _RCI_ values, in conjunction with the _RQD_ values, provide detailed information about the underground rock mass structure. While potential rock weaknesses induced by chemical alteration are minimal (affecting less than 1 m of some boreholes), the deep drilling boreholes revealed potential stability issues in the layers beneath the CSNS main equipment areas, such as broken or fractured rocks (boreholes ZZK99, ZZK94, and ZZK88), water table changes (boreholes ZZK104 and ZZK105), moderate weathering at deeper depths than expected (boreholes ZZK94 and ZZK94B), and water leakage greater than 5 L/min (boreholes ZZK99 and ZZK104). The water leakage signifies that the fractures created by extensional joints are highly developed and penetrate deeply into nearby rock units [52]. In borehole ZZK94 (at depths of 40-50 m), part of the core was filled with mud. In order to better understand the distribution of this mud unit, we drilled additional boreholes, such as borehole ZZK94B, in a grid around ZZK94 at intervals of 10 m. From these boreholes, we determined that the fractured zone is not a band but is concentrated in a nest-like formation. Because the rock both above and below the mud layer is pristine and unfratured, we eliminate weathering and faulting as potential causes for the infiltration of mud into these rocks and instead decided that the mud layer represents a compositional and stress-related transition zone. When determining the stability and suitability of an RI site, we often investigate problematic geological bodies more thoroughly so that we can quantify both the horizontal and vertical extent of the body, as well as the potential effects this body will have on the engineering and architectural design of the RI. Our results were particularly instructive during the construction of CSNS. Between the potentials for slope failure and the desire to avoid the intrusive contact zone between the gneiss and granite layers, the institute's orientation was shifted by 180\({}^{\circ}\). The linear accelerator is located in the sloped area, and the target station, which requires a safe and stable foundation, is located at the top of a hill composed of slightly weathered granite from which 40 m of the weathered cover was excavated. Based on this analysis, the layout of the SIA at CSNS, including the layout of the main instruments, was altered. The final position of the ring accelerator was moved \(\sim\)150m to the southwest. While the original target site was located on a steep slope, the adjusted target station was located at more stable granitic bedrock, a change that is conducive to the stable operation of the RIs equipment.