Study On Static And Dynamic Mechanical Properties Of Water-saturated Concrete

Concrete structures such as dams,offshore platforms,piers and ports,which have been in service for a long time in the water environment,are filled with pore water and reach the state of water saturation.Their mechanical properties will change significantly compared with those of dry concrete.Therefore,different from dry concrete,the research on the static and dynamic mechanical properties and anti explosion properties of water saturation and concrete is carried out to get the results under different loads It is of great academic significance and engineering value to provide the necessary mechanical material parameters for the design of the above structures.Firstly,the MTS static compression test and cyclic loading and unloading test are carried out for water saturated concrete and dry concrete,and the basic mechanical parameters and stress-strain curve are obtained.Combined with the failure mode of the specimen,the compressive performance and damage mechanism of water saturated concrete and dry concrete are compared and discussed.Through the static splitting tensile test of water saturated concrete and dry concrete,the change of tensile strength of water saturated concrete is analyzed.Secondly,the SHPB test data of different types of concrete are summarized and analyzed,and the method of characterizing the strain rate of this loading by 1.38 times of the average strain rate of the whole section corresponding to the SHPB test data of concrete materials is proposed,so as to standardize the value of strain rate.The SHPB dynamic compression test of water saturated concrete and dry concrete is carried out,and the dynamic mechanical response of water saturated concrete is discussed.From the analysis of test data,it is found that water saturated concrete has obvious strain rate effect,but its sensitivity is lower than dry concrete.The anti explosion test of water saturated concrete slab and dry concrete slab was carried out,the results show that the front and back of the water saturated concrete slab are larger than the dry concrete slab,and the anti explosion performance of the water saturated concrete is poor.Then,based on the analysis of the static and dynamic mechanical test data,the parameters of HJC constitutive model are determined,and the strength parameters,state equation parameters,rate effect parameters and damage parameters suitable for water saturated concrete are obtained.Finally,based on the HJC constitutive model parameters determined in this paper,LS DYNA software is used to simulate the anti explosion process of the water saturated concrete slab,and the failure process of the concrete slab is repeated.From the point of view of stress wave,the mechanism of stress propagation,front and back failure and failure modes at different positions in the process of explosion are discussed.Combined with the comparative analysis of test data,the correctness of HJC constitutive model parameters determined in this paper is verified.The above work has an important guiding significance for the structural design and mechanical characteristics analysis of the concrete fortification which has been serving in the water environment for a long time.