## 3 Dynamic Response Analysis of Ground Buildings Under Blasting
### Analysis of the Influence of Buildings Under Residual Footage Blasting  
The established numerical model is used to simulate the blasting of 170 kg of explosive at the remaining 400 m of the working face, and data are obtained from each monitoring  
Figure 4: The relationship between the maximum safe charge of one blast and the advancing distance of the working face. point. The representative data of the monitoring points are selected for comparison with the field monitoring data to verify the accuracy of the model, as shown in Table 4.  
From the table, the maximum error between the field monitoring data and the numerical simulation data of selected monitoring points is 13.9%. The heterogeneity of rock and soil mass, the geological structure, and the influence of the top mined area cannot be considered in a numerical calculation process. Therefore, the error of the numerical simulation data is within an acceptable range for engineering. In summary, the numerical calculation model and parameters are accurate and can be used to analyze and evaluate the impact of blasting on the vibrations of ground buildings in the final mining stage of the working face. According to Figure 4, when the remaining footage of the working face is 200 m, the maximum charge of one blast is 130 kg. Figures 5-7 are the cloud maps of the vibration velocity of different buildings under this situation. From the figure, the maximum vibration velocities in the X, Y, and Z directions in the science and technology building are 0.521 cm/s, 0.462 cm/s, and 0.623 cm/s, respectively, and are all located on the bottom story. The Z-direction velocity is the largest of the three directions. The maximum combined velocity is 0.75 cm/s, which is located at the bottom of the frame column. The maximum vibration velocities in the X and Y directions in the district office are 0.487 cm/s and 0.448 cm/s, respectively, and are located at the contact position between the bottom story of the frame column and the ground. The horizontal vibration velocity decreases as the story rises. The Z-direction vibration velocity of the roof and the bottom of the frame column are large, and the maximum velocity is 0.589 cm/s near the roof. The maximum combined velocity is 0.741 cm/s at the contact position between the roof and the frame column. The maximum vibration velocities in the X, Y, and Z directions, respectively, and the maximum combined velocities in the chimney are 0.44 cm/s, 0.426 cm/s, 0.624 cm/s, and 0.727 cm/s, which are all located on the roof. This is because the roof of the chimney is weakly constrained by the ground, and the roof has a significant amplification effect. Combined with the cloud maps of the vibration velocity in all directions, the vibration velocity in the Z-direction is higher than in the X and Y directions. Therefore, the buildings are dominated by vertical vibration. The maximum vibration velocity of the ground in the three directions is within the range of 0.8, which is required by the 'Blasting Safety Regulations'. The buildings are therefore all in a safe state. Figure 8 shows the cloud map of the maximum effective stress of the buildings under blasting load. The maximum effective stresses of the science and technology building, the district office, and the chimney are 0.462 MPa, 0.309 MPa, and 0.356 MPa, respectively, and are located at the bottom. The effective stress is the largest for the science and technology building, the second-largest for the chimney, and the smallest for the district office. This is because the science and technology building is close to the blasting site, and the chimney is a masonry structure, which is significantly affected by seismic waves. Combined with the vibration velocity, stress response, and building structure of the ground, the blasting effect has the greatest influence on the chimney compared with the other buildings.