Research on the detection technology of structure intensity parameters of Rigid Optional Site

Abstract

The feasibility analysis which selects the spreading cement site of service area of expressway as unsupported random launching site is studied in this paper. The structure stress in cement slab is calculated based on load characteristic of launch vehicle, and the key influence factors of bearing capacity of rigid pavement is discussed. Analysis result shows, to flexural-tensile stress of pavement bottom, the thickness of rigid pavement has significant influence comparing with other factors, and the flexural-tensile stress of pavement bottom will increase with the increment of pavement modular, while decrease with the increment of equivalent modular of top surface of soil base. To verify the accuracy of the built influence regularity of stress change in rigid cement slab, a 3D finite element model of optional site is created, which used to certify the vary regularity achieved by theoretical analysis. Simulation and comparison result shows the influence regularity to load stress of the thickness of rigid pavement, and pavement modular generated by theoretical analysis coincides with 3D finite element model. Introduction To enlarge the optional range of launching site, the scheme is presented that the broad rigid pavement of expressway service area is chosen as optional site of missile random launching. But, as a kind of brittle material, the selected cement concrete site of expressway service area shows lower capability of adapting to inhomogeneous deformation of roadbed. When bearing the load to ground, it has much higher requirement of non-deformability of roadbed. In current design method of cement concrete pavement, the non-deformability of roadbed is mainly attributed by static modulus of resilience . Under the influence of small diameter of plate-bearing, big differential between applied load and effective bearing load of roadbed, the test result has much difference relative to reality . When analyzing the stress of cement concrete pavement, the pavement structure is often simplified to elastic anchor plate system or elastic multi-layer system. Directed toward the evaluation problem of bearing capacity of service area of expressway, the loaded concrete slab stress model which generated by external load is established while the load stress computing theory of Westergaard is applied based on the mechanical property of optional site constructed materials, which can offer technical support for selecting and expending missile unsupported launching site. Theoretical analyzing of launching site load stress Different to common cement concrete pavement, when computing structure stress, to the broad site of expressway service area, the given method of design specification can not be applied for the less load action frequency. And the method which applying equivalent fatigue damage principle which converting the action order number of different axle type and load level to standard axle load can not adopted. Thus, the load stress computation theory which established by Westergaard is adopted to compute the structure stress although the applied theory will underrating the bearing capacity of foundation, and the influence degree is much finite to judge the variation regularity of parameter sensitivity of ultimate bearing capacity. International Conference on Advances in Mechanical Engineering and Industrial Informatics (AMEII 2015) © 2015. The authors Published by Atlantis Press 460 When the external load acts on the middle of concrete slab, the stress in concrete slab can be expressed as: 2 3(1 ) (ln 0.6159) 2 c P r h l μ σ π + = + (1) Where P ——the load to ground; h ——thickness of concrete slab; r ——radius of relative rigidity; μ ——Poisson ratio; l——a constant related to contact ground radius of external load. While exists