Pre-splitting blasting has been widely employed in river channel slope excavation to effectively mitigate damage to the retained rock mass, reduce blast-induced vibrations, and optimize blasting parameters for water-saturated slopes. Investigation of reasonable parameters for pre-splitting blasting in such conditions is important for river channel excavation projects. Based on geometric, physical, and dynamic similarity principles, an experimental model for pre-splitting blasting water-saturated slopes was designed, utilizing concrete as a substitute for red sandstone and detonators instead of emulsified explosives. The quality of pre-split crack formation, slope face shaping, and retained rock mass damage were evaluated under various conditions. The results showed that the pre-split crack formation quality and slope shaping quality significantly improved. The damage to the retained rock mass was reduced by 24.86% when the hole diameter increased from 0.8 cm to 1.2 cm. Field test results indicated that the optimal blasting effect can be achieved with a pre-split hole diameter of 115 mm and a hole spacing of 80 cm in a practical application of pre-splitting blasting for water-saturated slopes when the geological conditions involve medium-hard rocks.

Reinforced concrete structures are usually subjected to explosion impact load, resulting in severe damage. Different protective materials are typically laid on reinforced concrete slabs to improve the explosion resistance. The experimental study on the explosion resistance of reinforced concrete slabs with different protective materials was conducted using the drop hammer test, and an accelerometer tested the impact of reinforced concrete. An embedded piezoelectric intelligent aggregate is used to monitor the internal damage signal of a reinforced concrete slab under the drop hammer impact load. The test results show that both carbon fiber reinforced matrix composites(CFRP) and polyurea can effectively protect the specimens in the single-layer reinforced structure, with an average decrease of 78.20% and 79.05% relative to reinforced concrete acceleration and 40.98% and 65.79% peak impact stress, respectively. Additionally, the average acceleration reduction of polyurea-concrete-CFRP(IPC), polyurea-CFRP-concrete(ICP), and CFRP-concrete-polyurea(CIP) compared with reinforced concrete slabs are 70.29%, 77.46% and 79.85% in the composite protective structure, respectively. The average peak impact stress reduction is 32.73%, 56.32%, and 51.07%, respectively, which can effectively protect the specimens and improve the impact resistance of concrete slabs. It can provide a reference for related engineering applications.

In response to the poor excavation effect of traditional blasting in complex lithology tunnels, a method called advanced cutting control blasting is proposed based on the research of traditional smooth blasting and pre-splitting blasting. This method involves conducting the blasting around weak surrounding rock areas after tunnel contouring hole blasting. A quasi-three-dimensional model was established, and numerical simulations were conducted using the fluid-structure interaction(ALE) algorithm and ANSYS/LS-DYNA finite element analysis software to compare the advanced cutting control blasting method with traditional pre-splitting and smooth blasting methods. The results show that compared to smooth blasting and pre-splitting, advanced cutting control blasting reduced the depth of damage around the tunnel contour by 6.85% and 10.08%, respectively. Based on simulation results, field blast test plans were designed, and comparative tests between smooth surface blasting and advanced cutting control blasting methods were carried out. The blast results demonstrated that after adopting the advanced cutting control method, the tunnel contour had good shaping effects without block falling or collapse in weak surrounding rock areas, while over-excavation was effectively controlled. Three-dimensional cross-sectional scanning data and statistical results of post-blast sections indicated that compared to well-performing smooth surface blasting, maximum over-excavation decreased by 35.98%, average over-excavation decreased by 25.60%, concrete consumption decreased by 26.3%, and flatness standard deviation increased by 24.29%. This method has been verified through field practice as it reduces over-excavation while mitigating blast damage in complex lithology areas, thereby improving tunnel retaining rock flatness.