Rod structure has been widely used in aerospace engineering and civil engineering. Nondestructive testing is a very important method applied to detect unseen flaws in structures, ultrasonic wave nondestructive testing has been used in many areas. Finite Element Method is one of the most widely used numerical methods but would have a high cost when doing simulation on ultrasonic wave due to the requirement of small time interval and element size. Wavelet based finite element method could improve the spatial resolution with fewer elements needed but still needs very small time interval. Laplace transform could easily convert the time domain into frequency and then inverse to time domain. This paper presents an innovative method combining Laplace transform and B-spline wavelet on interval (BSWI) finite element method, which could not only decrease the element number but also increase the time integration interval. Moreover, this innovative method is applied to simulate the ultrasonic wave propagation in 1D rod structure as well as used for nondestructive testing of damages in rod structures.

Gravity caissons are widely used in the construction of coastal ports owing to their simplicity, high capacity, and easy construction. The verification of resistance to seismic liquefaction and earthquakes is necessary and important in the design and construction of coastal ports. In this study, a numerical program was developed based on elasto-plastic theory and a coupled finite element–finite difference method. The seismic resistance of a caisson wharf was assessed using the proposed program. Furthermore, gravel piles were designed to resist liquefaction-induced disaster. It was found that the lateral spreading of liquefied soil would cause large sliding and rotational deformation in the gravity caisson. Adding gravel piles, it can decrease the deformation of the caisson foundation, and improve the stability of the caisson wharf.

Earth pressure is the most important type of load acting on the supporting structure of a foundation pit, and it is also a key factor in the design of foundation pit supporting. However, in engineering practice, the calculated value differs greatly from the actual value, which puzzles many engineers. This paper analyzes the field measured data of the earth pressure of the foundation pit in Minghucheng (Jinan city), and compares the calculated values of the Rankine active earth pressure and the passive earth pressure theory. The analysis finds that: (1) The measured value is between the active earth pressure and the passive earth pressure, and as the excavation of the foundation pit and the inward displacement of the supporting structure, the measured earth pressure value becomes smaller and approaches the active earth pressure. (2) When the pre-stressed anchors is applied, due to the fastening effect of the anchors, the earth pressure behind the supporting pile has a tendency to increase. (3) The theoretical value of Rankine’s active earth pressure in the soil-rock combination is obviously lower than the measured values.

The technology of recoverable anchors / cable greatly avoids the disadvantage of traditional anchors / cable, such as non-recyclable, waste of resources and occupy underground space. However, there are many problems existed in the development, design and application processes. Taking a foundation pit project in the city of Jinan as an example, the numerical analysis of the whole construction processes was conducted to study the mechanical behaviour of supporting systems. It is found that the supporting pile has major deformation during the excavation and anchors recycle. For the process of anchor recycle, the bending form of supporting pile transformed from outward to inward. Moreover, the horizontal displacement of pile top increased by 21.4%. The axial force of upper anchor increased during the recycle of lower anchor, for example, the axial force of uppermost anchor increased by 21.3% comparing to the state that no anchor was recycled. Therefore, for the real project of anchor recycling, the internal force redistribution and deformation property of supporting system should be fully considered, to avoid the influence to the surrounding buildings and the foundation pit itself.

With the rapid development of the method of shield tunnel in our country, the shield in the tunnel and the internal structure exist a lot of prefabricated and assembled internal structure can be roughly divided into full cast-in-place, full precast, and precast and cast-in-place structure. However, it has the disadvantages of more internal structural joints, poor waterproof performance, and complex structural stress. Therefore, combined with the actual engineering case, the construction process is simulated by using the finite element analysis software, and the influence of the segmental and internal structure cooperative deformation and joint mechanical performance is considered to further analyze the deformation characteristics of shield tunnel assembly internal structure, which can provide a reference for the construction and design of similar projects.