## 5 Conclusions  
To evaluate the rock-breaking effect of various fracturing methods on granite, this study employs a self-developed high-temperature and high-pressure model testing platform to conduct hydraulic fracturing and deflagration fracturing experiments on large-sized 40 \(\times\) 40 \(\times\) 40 cm\({}^{3}\) granite specimens under different conditions. Based on an analysis of the fracture morphology, fluid pressure, and other parameters, and supplemented by the numerical simulation results from the fracturing process, this paper draws the following conclusions.  
1. From the perspective of increasing the reservoir capacity, the rock-breaking effect of deflagration fracturing is significantly better than that of hydraulic fracturing. Moreover, the crack propagation in deflagration fracturing is almost unaffected by the geostress difference resulting from external loads. In contrast, the damage caused by hydraulic fracturing is mainly distributed along the direction of the maximum principal stress.
2. Temperature has a significant impact on the fracturing process of granite. Essentially, the microcracks generated within high-temperature rocks change their own mechanical properties, thereby influencing the fracturing process. During hydraulic fracturing, more localized damage zones will emerge in high-temperature rocks, and high temperatures tend to make the cracks produced by deflagration fracturing more regular.
3. Compared to a single wellbore, dual wellbores in hydraulic fracturing result in greater internal damage to the specimen. However, for deflagration fracturing, the configuration of dual wellbores exerts minimal influence on the overall rock-breaking effect, beyond enabling directional fracture propagation.
4. In summary, within EGS projects, the characteristics of both deflagration and hydraulic fracturing can be combined. Initially, deflagration fracturing can be utilized to create directional main fractures in the fractured section of the reservoir, addressing the issue of hydraulic fracturing, which tends to form main fractures along the direction of maximum principal stress. Subsequently, established and cost-effective hydraulic fracturing techniques can be employed to create more secondary fractures and fracture zones, thereby achieving the purpose of increasing the reservoir storage capacity.  
**Author Contributions:** Conceptualization, Y.Z. and B.B.; methodology, Y.Z.; software, H.Y.; formal analysis, H.Y.; investigation, Y.Z., H.C., T.Z., Z.Z. and H.L.; data curation, H.Y.; writing--original draft preparation, H.Y.; writing--review and editing, H.Y.; visualization, Y.Z.; project administration, B.B.; funding acquisition, B.B. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This paper received its funding from Projects supported by the National Key R&D Program of China (2022 YFE0128300), and the National Natural Science Foundation of China (41972316). The authors wish to acknowledge this support. The authors would like to thank [PERSON], [PERSON], and [PERSON] of the Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, for the helpful instructions on the conduction of the tests.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data used to support the findings of this study are available from the corresponding author upon request.  
**Conflicts of Interest:** On behalf of all the authors, the corresponding author states that there are no conflicts of interest.