The extraction of landslide deformation using terrestrial laser scanning (TLS) has many important applications. The landslide deformation can be extracted based on a digital terrain model (DTM). However, such methods usually suffer from the ill-posed problem of a multiplicative error model as illustrated in previous studies. Moreover, the edge drift of commonly used spherical targets for point cloud registration (PCR) is ignored in the existing method, which will result in the unstable precision of the PCR. In response to these problems, we propose a method for extracting landslide deformations from TLS data. To archive the PCR of different period point clouds, a new triangular pyramid target is designed to eliminate the edge drift. If a fixed target is inconvenient, we also propose a PCR method based on total station orientation. Then, the use of the Tikhonov regularization method to derive the weighted least squares regularization solution is presented. Finally, the landslide deformation is extracted by DTM deference. The experiments are conducted on two datasets with more than 1.5 billion points. The first dataset takes Lashagou NO. 3 landslide in Gansu Province, China, as the research object; the point cloud data were collected on 26 February 2021 and 3 May 2021. The registration accuracy was 0.003 m based on the permanent triangular pyramid target and 0.005 m based on the total station orientation. The landslide deforms within 3 cm due to the ablation of the frozen soil. The second dataset is TLS data from the Lihua landslide in Chongqing, China, collected on 20 April 2021 and 1 May 2021. The overall deformation of the Lihua landslide is small, with a maximum value of 0.011 m. The result shows that the proposed method achieves a better performance than previous sphere-based registration and that the weighted least square regularization iterative solution can effectively reduce the ill-condition of the model.

To reduce the loss of life and property caused by the collision of a ship against a bridge pier, this study proposes a new type of anticollision facility. The facility uses corrugated steel plates and corrugated steel pipes (CSPs), or ordinary steel plates and corrugated steel pipes (OSPs), as structural elements to form a honeycomb structure, which can greatly improve the impact resistance of bridge piers and reduce any damage to ships. To evaluate the anticollision performance of the proposed anticollision facility, this work uses the CSPs and OSPs as study objects in the impact test research. A pendulum impact test system was utilized to compare and analyze the column with CSP and OSP specimens and the column without any anticollision facilities. Test results show that the CSP and OSP specimens have a relatively high energy dissipation effect. When the impact energy is small, the energy dissipation effect of the OSPs with the same plate thickness is stronger than that of the CSPs. When the impact energy is large, the energy dissipation effect of the CSPs with the same plate thickness is stronger than that of the OSPs. In addition, the extreme value analysis method is used to analyze the relationship curve between the peak value of the D1 lateral displacement and the specimen’s plate thickness, weight, and natural frequency; the optimal thickness, weight, and natural frequency values of the CSP and OSP specimens are also deduced. Taking the optimal value of the specimen’s natural frequency as a target, the structure of the CSP and OSP specimens is optimized. When the optimized plate thickness is 2.50 mm, the ratios of the optimal value of the specimen plate thickness, weight, and natural frequency to the optimal calculation value are all in the range of [0.80, 1.12]. OSP and CSP specimens are found to have the best energy dissipation effect. The peak value of the D1 lateral displacement of the top of the column equipped with the CSPs is at least 88.37% lower than that of the column without any anticollision facilities. For the top of the column equipped with the OSPs, the peak value of the D1 lateral displacement is at least 80.37% lower than that of the column without any anticollision facilities. Optimization results show that the extreme value analysis method is suitable for the optimal design of anticollision facilities for piers.

A new type of corrugated steel protection system (CSP) for the bridge pier is proposed to improve the impact resistance of the bridge pier and reduce the loss caused by the collision of the ship against the pier. A new bolt numerical simulation method and finite element model establishment method are proposed and verified by the impact test. The results show that the new method can effectively simulate the mechanical behavior of bolts and CSP. Parameters analysis was carried out subsequently by the verified finite element model which showed that the energy absorbing ability of CSP increases with corrugated steel pipe wall thickness and its weight decreases. It is concluded that CSP (2.0 mm) is the optimal structural type, and compared with the existing FRP Fender System. The results show that the energy absorbing ability of CSP (2.0 mm) is strong, and its final absorbed energy can reach 86.13% of the total energy of the model structural system (7.22 MJ).

To ensure the safety of ships and bridges at the same time during collisions, a new type of bridge pier protection system is proposed, in which one is composed of corrugated steel plates, bolts, and corrugated steel pipes (CSP), and the other is composed of ordinary steel plates, bolts, and corrugated steel pipes (OSP). To study their anticollision performance, a pendulum impact test and numerical simulation were carried out. Comparing the test results with the simulation results, it was shown that the simulation results are basically consistent with the test results. Then, the influence curves of the impact velocity, specimen thickness, weight, and frequency are analysed to evaluate the anticollision performance of CSP/OSP and optimize their structure. When the impact energy is low, the peak values of the lateral impact force and lateral displacement of the column equipped with OSP are all smaller than those of the column equipped with CSP. When the impact energy is high, the peak values of the lateral impact force and lateral displacement of the column equipped with OSP are larger than those of the column equipped with CSP. However, under the same impact energy, the total energy peak value of the CSP specimen is larger than that of the OSP specimen. Results can provide a certain numerical analysis basis for the structural design and research of new types of corrugated steel protection system for bridge pier.