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The framework security of a bridge is essential as a critical component of traffic engineering. Even though the bridge structure is damaged to various degrees due to various reasons, the bridge will be wrecked when the damage reaches a particular level, suggesting a negative influence on people’s lives. Based on the current situation and existing problems of structural damage identification of bridges, a structural damage identification technology of continuous beam bridges based on deflection influence lines is proposed in this paper in order to keep track of and always detect broken bridge elements, thereby extending the bridge’s service life and reducing the risk of catastrophic accidents. The line function expression of deflection impact on a multi-span continuous beam bridge was first obtained using Graphic Multiplication theory. From the theoretical level, the influence line function of the continuous beam bridge without extensive damage was computed, and a graph was generated. The photographs of the DIL as well as the first and second derivatives, the deflection influence line distinction and its first and second derivatives, and the DIL distinction and its first and second derivatives of a continuous beam bridge in a single position and multi-position destruction were fitted in this paper. Finally, after comparing multiple work conditions and multiple measuring points, it was found that the first derivative of deflection influence line difference had the best damage identification effect. The design was completed and tested, which had verified the feasibility of this theory.

The stress and deflection effects of the line changes before and after the bridge damage are used as indicators to evaluate the bridge damage and the initial damage site. Then a method of combining information is proposed to improve the accuracy of the damage site. Three-span continuous reinforced concrete was used in the analysis. According to the test, the effectiveness of damage identification based on the damage change of the influence line and the feasibility of the damage location method based on multi-sensory information fusion are confirmed.

Hydraulic fracturing is commonly applied in the shale gas exploitation industry. However, the mechanical mechanism of permeability under fracturing has so far been unclear. In this study, an analysis of laboratory experiments on hydraulic fracture propagation and bedding plane reactivation in shale is presented. To investigate microcrack occurrence under fracturing, several small slices were collected from the fracture surface and scanned with a scanning electron microscope (SEM). It was found that observed microscopic microcracks could not be produced by fluid pressure as the latter generated compressive stresses at the site of microcracks. Rather, the microcracks were produced by tensile stress concentration in front of the propagating fracture. This implies that bedding plane reactivation was caused by fracture propagation along the plane. An analysis of microcrack lengths showed that shale exhibited anisotropy in fracture toughness with resistance to fracture propagation parallel to bedding planes being twice as small compared to resistance to fracture propagation in the direction normal to bedding planes.