The shape of the failure locus of a material is significant for its strength predictions. Even when constitutive models include the same critical stress surface, different critical stress ratios can be predicted for an identical applied isochoric strain path. In this article, we investigate critical stress predictions of different constitutive models, which include the surface according to Matsuoka-Nakai (MN). We perform analytical investigations, true triaxial test simulations with hypoplasticity and barodesy, and discrete element modelling (DEM) simulations to investigate the friction dependency of the stress Lode angle. Our results demonstrate that in hypoplasticity, the direction of the deviatoric stress state at critical state depends solely on the direction of the applied deviatoric strain path. In contrast, in barodesy, the predictions are also dependent on the friction angle of the material. In addition, we compare these results with those obtained with a standard elastoplastic MN model. To validate this friction dependency on the stress Lode angle, we conduct DEM simulations. The DEM results qualitatively support the predictions of barodesy and suggest that a higher friction results in a higher Lode angle at critical stress state.

In view of the problem that the alignment of internal and external detection data mainly relies on manual verification and excavation verification, and can not make full use of mining detection information, feature information and mileage information are extracted from internal and external detection data as input and output variables, and the mapping relationship between them is established by using limit gradient lift (XGBoost) algorithm. Predict the outer detection mileage of the internal detection point, take the internal detection information as the benchmark, and use step by step translation to realize the alignment of the internal and external detection data, and conduct a comprehensive analysis according to the alignment results. The results show that the mileage error of all stations and valve chambers after data alignment is within 5m, the latitude and longitude distribution changes in the same height, and the alignment result points meet the accuracy requirements. In the example analysis, the degree of AC and DC interference of the pipeline is small, and the cathodic protection of the pipeline is normal. Although the soil corrosion is strong, there is metal loss and no obvious corrosion pits and corrosion products are found at the damage of the corrosion layer, indicating that the pipeline is in good running condition. The research results can provide theoretical basis for improving the level of pipeline integrity management.

Piles are deep foundation elements that play a crucial role in supporting substantial structural loads, particularly in the construction of heavily loaded port structures and bridges. Pile driving involves the installation of piles into the shoreline and/or seabed. These piles can be composed of different materials, including wood, concrete, steel, or a combination thereof. This article aims to provide an overview of pile driving fundamentals, highlight the common issues faced during the pile driving process, and potential solutions to address these challenges. The typical problems encountered in the advancement of displacement piles on large-scale marine projects are considered to include overrunning of piles, driving piles out of alignment, failing to account for obstructions, unexpected soil conditions, pile damage, lateral movement in adjacent piles, pile handling, and pile driving analysis issues. During pile installation, it is not uncommon to observe substantial differences between the field measurements obtained using a pile dynamic analyzer (PDA) and the axial capacity predicted by a GRLWEAP analysis. These discrepancies often arise when incorrect parameters are employed in the analysis. It is crucial to meticulously evaluate factors such as pile type, axial capacity, and site conditions during the design phase. Additionally, this article underscores the utmost significance of conducting a thorough soil investigation, including an understanding of the site's geology and development history. If necessary, conducting an indicative test pile program also helps to ensure the success of pile foundation design and construction.