## 4 Analysis of Test Results
### Spatial Distribution Characteristics of Goaf Pressure
#### 4.2.2 Goal Pressure Inversion Analysis
The high correlation between DOFS and DIC measurements validates the reliability of this dual monitoring approach, establishing a robust framework for future mining operation safety assessments and deformation control strategies. Overburden subsidence in the goat region induces horizontal tensile fractures within the key strata, resulting in articulated structures that generate tensile stress on the fiber optic sensors. The sensing elements within fractured zones exhibit substantial strain amplification until reaching peak deformation. Strain gradients are detected in the intact fiber segments adjacent to fracture boundaries, indicating variable tensional effects from the articulated formation within specific ranges. The superior key stratum in the unmined coal face demonstrates minimal mining disturbance, facilitating enhanced sensor-formation coupling. Consequently, the strain profile amplitude within the intact rock mass proximate to the cantilever region is notably reduced compared to the measurements from the sensors embedded in the goat-overlying strata. Beyond the gravitational loading, the sensors in the goat zone are subjected to additional residual stresses. The temporal lag between face advancement and peak strain manifestation persists in the rightward monitoring section. As model advancement progresses, compaction occurs in the goat zone proximate to the excavation boundary. While the left-side peak pressure location in the compacted region maintains stability, the compaction-affected zone expands progressively. The right-side maximum pressure exhibits continuous lateral displacement concurrent with face progression. By incorporating fiber optic settlement measurements into Equation (16), the inverted goat pressure distribution is derived, as depicted in Figure 12. The comparative analysis at 124 cm advancement reveals relative deviations of 2.5% in the right-side peak pressure position and 8.88% in the compaction zone extent. At 164 cm, these variations measure 6.97% and 2.56%, respectively. Further advancement to 192 cm yields deviations of 5.41% and 0%, while at 232 cm, the discrepancies are 4.36% and 7.45%, respectively. When the working face is advanced to 124 cm, 164 cm, 192 cm, and 232 cm, respectively, the corresponding Root Mean Square Error (RMSE) values for the fiber optic monitoring method are 0.98, 1.20, 1.03, and 1.07, and the corresponding Coefficient of Determination (R2) values are 0.82, 0.72, 0.79, and 0.85. The pressure profile inverted from the optical sensing data demonstrates a substantial correlation with the BPPS measurements, validating the methodology's efficacy. The pressure evolution within the goat region is predominantly governed by the primary and cyclic fracturing mechanisms of the key strata. The stress field distribution exhibits a strong correlation with the overburden displacement patterns, demonstrating progressive intensification corresponding to key stratum failure development. Analysis of pressure monitoring data across four different advancement distances reveals a remarkable consistency in the pressure distribution characteristics of the gob  
Figure 12: Comparison between the goat pressure inverted by optical fiber data and the goat pressure detected by BPPS. (**a**) Advance to 124 cm, (**b**) Advance to 164 cm, (**c**) Advance to 192 cm, (**d**) Advance to 232 cm. area, as measured by both the BPPS sensor and the optical fiber monitoring system. Both monitoring methods exhibit a typical, approximately \"U-shaped\" pressure distribution pattern: higher pressure values are observed at the two ends of the gob area (within the 0-40 cm and 140-260 cm regions), while the middle region (40-140 cm) maintains a relatively stable low-pressure state. Although the BPPS data demonstrate some degree of dispersion, their distribution trend aligns closely with the pressure inversion curves obtained from the optical fiber system, particularly in regions where pressure changes are dramatic.