Due to the complex geological conditions and many influencing factors in karst areas, this paper conducted theoretical, experimental research and calculation analysis on the design and construction of engineering piles of bridge engineering in karst cave areas. An algorithm for vertical capacity calculation of rock-socketed piles in karst area based on load transfer method was developed. The results using this new method were analyzed and compared with the results from the static load test of three engineering piles in karst area, and the differences are relatively small. Through static load tests of pile foundation in karst area and study of the side resistance of rock-socketed pile in karst area, the friction resistance of rock-socketed pile and the effect of pile-end resistance, the bearing capacity characteristics of rock-socketed pile in karst area were obtained, achieving the load-sharing effect of cave roof in a rather scientific way. In view of the failure mechanism of the karst cave roof under the pile tip and the large proportion of lateral resistance of the rock-socketed pile, a calculation model for the stability of the karst cave roof under the combined action of the side resistance of the rock-socketed pile and the pile tip resistance is proposed.
Purpose
High reliability and high power-to-weight ratio are the technical difficulties in the development of aviation piston heavy fuel engines. This paper aims to provide a design evaluation method of the aero piston engine block, which can help R&D personnel quickly evaluate the performance of engine block, including effective bearing capacity and fatigue deformation, save a lot of experimental time and shorten the R&D cycle.
Design/methodology/approach
In this paper, structural efficiency is used to evaluate the reliability and durability of the engine block. Structural efficiency is a new evaluation method that lists its corresponding connotation according to different objects. In this paper, the function of the engine block in the engine is explained in detail, and three quantifiable connotations of the structural efficiency of the engine block are put forward. In the subsequent calculation, the calculation is carried out according to the three indexes, and the calculation results are used as the indexes to evaluate the performance of the engine block.
Findings
The structural efficiency evaluation method proposed in this paper can quickly and effectively evaluate the performance of the block from many aspects. Under the same boundary conditions, the two design schemes are simulated and analyzed, and the durability test is carried out. The analysis and experimental results show that Scheme 2 has good performance, which verifies the feasibility of the evaluation method.
Originality/value
This paper provides a method for rapid evaluation of engine block performance.
High power using ratio in the process of pile driving of hydraulic static pile divers with quasi-constant-power is acquired. For being convenient for improving on the machine and quickening the course of pile driving , studying on the impact of the piston diameter of pile driving cylinder, the initial displacement of piston and the piston diameter of lift cylinder on the pile driving depth and force in the process of pile driving under adding force is need. For lucubrating the impact, the process of pile driving under adding force of hydraulic static pile divers with quasi-constant-power were analysed. The hydraulic system of pile driving under adding force was modelled in AMESim. The main parameters of the model of the hydraulic system were set; and then the dynamics simulation of the hydraulic system was achieved. The simulation results were analysed. The simulation results show that the pile driving force under adding force increases by inches when augmenting the initial displacement of piston of lift cylinder, or falling the piston diameter of lift cylinder, or both. Furthermore the pile driving depth and force of pile driving under adding force increases rapidly and the capacity of pile driving tones up when augmenting piston diameter of pile driving cylinder.Index Terms -Hydraulic static pile driver. Pile driving. AMESim. Hydraulic servo system. Simulation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.