In CO2 foam flooding progress, foams formed by CO2 and surfactant solution can reduce the fluidity of CO2, improve sweep efficiency and flow behavior of CO2 in heterogeneous oil reservoir, prevent fingering and channeling and improve recovery efficiency. However, the study on the CO2 foam flooding characteristics is still in the initial stage, this paper focused on experimental testing the CO2 foam fluid flooding characteristics. Factors affecting the foam flooding efficiency, such as surfactant concentration, foam quality, injection method and core permeability, were studied in more detail in the paper, and influencing laws of factors on flooding efficiency and recovery efficiency were analyzed, moreover, based on experiments, the optimum foam quality and injection method, which have a practical and theoretical significance to the engineering application, were obtained.

To meet the needs of sponge city construction, based on the design method of mix proportion of green porous sponge ecological concrete, the engineering performance of green porous sponge ecological concrete was studied with orthogonal experimental. The results show that the compressive strength of the specimens peaked at the 0.9% admixture of sponge; based on the optimal admixture of sponge, the compressive strength of the specimens peaked at the 12% admixture of mineral powder; compared with the ordinary concrete, the water-retaining property of green porous sponge ecological concrete is twice than ordinary, and green porous sponge ecological concrete has high permeability and low evaporation; under the same external temperature, the maximum temperature of concrete surface is lower than ordinary; and under three work conditions, the volumes of water going through the green porous sponge ecological concrete, respectively, are 1.78 kg/(s·m2), 1.47 kg/(s·m2), and 1.62 kg/(s·m2), and the value of second totally dry condition is minimum because of water blocking affection of the internal sponge. The research results will provide help for the infrastructure construction of sponge city and play an important guiding significance to promote the construction of resource-saving and environment-friendly cities.

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A numerical simulation method of the rock bolts non-destructive testing based on ANSYS is presented. ANSYS/ LS-DYNA which is a kind of software of rock bolts dynamic finite domain analysis is used to establish a three-dimension model, after sine curve excitation is loaded, the reflection curve of naked rock bolts, or rock bolts with different defects are got, and the relationship curve between elastic modulus and stress wave velocity are got correspondingly. Experiment result proved that the aboved method was satisfied to simulate the stress wave propagation and the reflection situation in the rock bolts.

Second harmonic generation (SHG) is one of the common techniques in the nonlinear ultrasonic test. The contact-type defects play an important role in material damage, which are hard to be detected. The traditional nonlinear parameter β used to evaluate the micro damage in material is derived from the classical stress-strain relation, which is more suitable for the anharmonicity of crystal rather than the contact-type defects. Recently, the theoretical model based on the bilinear stiffness law was derived, and the validity and applicability need to be further studied. For this purpose, by the numerical method, the contact interface in mortar is characterized based on the damage indicator γ. The relation between the excitation voltage and γ is obtained. Moreover, the effects of the crack length and orientation on the damage indicator γ are also obtained. The experimental method is also used to characterize the contact interface in mortar. Combining with the existing work, the results obtained in this article are discussed, and further conclusions can be drawn. The conclusions in this article provide potential of quantitative detection of the contact interface and quality evaluation of bonding layers in materials.