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This paper investigates the development of wall-climbing robots (WCRs) with sliding suction cups (SSCs) based on the authors' recent research work. The merits and the challenges of the SSCs are analyzed in detail aiming at wheeled WCRs(WWCRs). The dynamic model of WWCRs is presented. It should be noted that the suction force derived from SSCs has great influence on the motion characteristics of WCRs. To utilize the merits, get over the weaknesses of SSCs and increase the service abilities of wall-cleaning robots, a series of tether supported wall sliding robots (WSRs) with large SSCs are designed. The control strategies of suction force are investigated to improve the adaptability to complex wall surfaces.

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In this paper, firstly, based on the fractal theory, Hertz contact theory and fractal network, the prediction model of the ECR for rough interface is established in consideration of the modified hypothesis, 3-D interface topography and elastic-plastic deformation. Secondly, using the engineering data of material, the influences of fractal dimension D, fractal roughness G , dimensionless loading force F* and friction coefficient μ on the ECR are analyzed by numerical simulation. Finally, compared with the classical models, the tendency of established model is same as that of other models. During the design stage of electrical equipment, the present model of the ECR can provide a theoretical reference for the accurate ECR prediction of rough interface.

Compared with the construction method of a tunnel with a middle drift, the construction method of a tunnel without a middle drift is a more advanced, novel, efficient, and energy efficient. Moreover, the blasting excavation of late-excavated tunnel parts exerts a vibration impact on the lining structure of early excavated tunnel parts. To analyze and predict the influence of late-excavated tunnel blasting on an early excavated tunnel and surrounding rocks in a triangular area, this study uses the Ansys LS-DYNA software to build a three-dimensional tunnel model simulating multihole blasting and the fluid–solid interaction method to assess the interaction of different materials. In addition, the different working conditions of surrounding rock levels and explosive equivalents are simulated. The distribution law of peak particle vibration velocity and maximum principal stress peak value of surrounding rocks and the lining along the transverse and longitudinal directions of the early excavated tunnel are generalized based on the numerical simulation results. The influence of the blasting of a late-excavated tunnel on the initial lining, secondary lining, and the middle triangular area of a double-arch tunnel is analyzed. The relationship between the surrounding rock level, explosive equivalent, and vibration velocity peak value is concluded. The field experiment-measured vibration velocities from the double-arch tunnel without a middle drift in the Chenjiachong tunnel of the Chuyao expressway in Yunnan Province, China, are in satisfactory agreement with the numerical simulation results. The results of this study are verified by the field blasting vibration data of the Chenjiachong and Changba tunnels and can provide reference and guidance for the blasting engineering practices of late-excavated double-arch tunnels without a middle drift.